Name: Automated Protocols for Macromolecular Crystallization at the MRC Laboratory of Molecular Biology (Video) | JoVE Journal
Uploaded: 2018-01-24T13:00:00.000+00:00
Duration: 11 min 20 s
Description: Learn automated protocols for macromolecular crystallization using nanoliter vapor diffusion experiments. This method produces high-quality crystals for structural studies of proteins, DNA, RNA, and their complexes.

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5 minutes

The MRC-LMB crystallization facility is kindly supported by the Medical Research Council (UK). We thank members of the LMB for their support: Olga Perisic (PNAC), Tony Warne, Fusinita Van den Ent and Pat Edwards (Structural Studies), Steve Scotcher and the other members of the Mechanical Workshop, Neil Grant and Jo Westmoreland (Visual Aids), Paul Hart and Tom Pratt (IT). We also would like to thank to Steve Elliot (Tecan, UK), Mitchell Stuart and Heather Ringrose (Hamilton Robotics, UK), Paul Thaw, Robert Lewis and Joby Jenkins (TTP Labtech, UK), Paul Reardon (Swissci AG, Switzerland), George Stephens and Donald Ogg (Alphabiotech, UK), Neil Williams (Markem Imaje, UK) and Graham Harris (The Cleveland Agency) for technical help.

1. The two fully automated systems (initial screening)
<ol>
	<li>System 1: preparation of 72 96-well crystallization plates filled with screening kits (LMB plates)
	<ol>
		<li>Prior to performing the procedure, ensure that the system&#39;s robots are initialized and their controlling software is open. Turn on the chiller of the tube-cooling carrier about 30 minutes before the main program will be started.</li>
		<li>Place a test plate on the motorized SBS carrier of the plate sealer. Run the plate sealer and check that the film is properly applied. Repeat this test twice more to verify that the plate sealer is ready.</li>
		<li>Then, add 20 L of deionized water to the main container of the liquid handler. Disconnect the coupling inserts from the small container (20% ethanol rinsing solution) and connect the inserts to the main container.</li>
		<li>Enter the appropriate screen name (Table 1) on the inkjet printer touchscreen. Then, open and close the carousel door to trigger the carousel rotation. Open the door when the first stack presents itself.</li>
		<li>Fully load the first stack with 22 crystallization plates, each with column 1 facing out. Fully load the next two stacks in the same way.</li>
		<li>Load the remaining 6 plates in the highest positions of the fourth stack. Then, close the carousel door.</li>
		<li>Verify that the chiller display indicates 14 &#176;C. Gently and repeatedly invert the selected screening kits for 1 minute. Then, open the front panel of the liquid handler.</li>
		<li>Open the tubes and place them in the cooling carrier according to the standard 96-well layout (A1, A2, etc.). Upon placing each tube in the carrier, place its lid on a tray in the same 96-well layout.</li>
		<li>Cross-check the tube positions and ensure that all tubes are level and settled in the carrier. Then, close the front panel.</li>
		<li>In the &#39;Startup&#39; window of the liquid handler software, select &#39;Run maintenance&#39; and open the flushing program. Run the program to flush the 20% ethanol from the system and to wash the outsides of the liquid-dispensing tips.</li>
		<li>When flushing is complete, click &#39;Cancel&#39; to return to &#39;Startup&#39;. Select &#39;Run an existing process&#39; and click &#39;Start your selection&#39;. Open the &#39;MRC kit dispensing&#39; program. Fill in &#39;18&#39; for &#39;Instances&#39; in the configuration screen and run the program.</li>
		<li>Monitor the system as the first four plates are labeled, filled, and sealed.</li>
		<li>Once all 72 plates have been prepared and placed back in the carousel, switch the coupling inserts from the main container to the small container. Run the &#39;Start up flush&#39; program (see step 1.1.10).</li>
		<li>Turn off the chiller and discard the empty screening kit tubes. Carefully remove the 72 prepared plates from the carousel. Discard incorrectly-filled or poorly-sealed plates. Store the ready-to-use plates at 10 &#176;C.</li>
	</ol>
	</li>
	<li>System 2: setting up crystallization droplets (100 nL protein + 100 nL condition) from a single sample in 20 LMB plates
	<ol>
		<li>First, ensure that the system&#39;s robots are on, the nanoliter dispenser is initialized with its software open, and the liquid handler&#39;s method manager is open. Turn on the microtube-cooling carrier about 15 minutes before the main program will be started.</li>
		<li>Place a test plate on the motorized SBS carrier of the plate sealer. Run the plate sealer and verify that the plate is properly sealed. Test the plate sealer three times.</li>
		<li>Then, run the nanoliter dispenser to set 100-nL droplets of test solution in a test plate. Check under a microscope that the droplets are set correctly. Close the nanoliter dispenser software and remove the strip-holder block from the deck.</li>
		<li>Next, insert in the custom-designed plate holder (see Representative Results: Crystallization Devices Developed at the LMB) the LMB plate with the highest relative quantity of volatile reagents in its conditions (Table 1). Remove the adhesive film from the plate.</li>
		<li>Open the liquid handler front panel and place the unsealed plate on the deck, at the back of the first sliding carrier (Sliding carriers may be pulled out for ease of access).</li>
		<li>Cover the plate with an SBS aluminum lid. Settle the lid towards the rear left corner of the carrier by applying gentle pressure to the opposite corner of the lid.</li>
		<li>Unseal, load into the sliding carriers, and cover the remaining 19 plates in the same way, working from most to least volatile conditions. Once the microtube-cooling carrier is at 4 &#176;C, as indicated by a green light, remove its cover.</li>
		<li>Cut off the lid of a microtube containing (at least) 440 &#181;L of protein sample (Table 2). Ensure that the sample has no foam above the meniscus, as this will interfere with the liquid detection system. Place the tube in Position 1 of the microtube-cooling carrier.</li>
		<li>Place a PCR plate on the liquid handler deck in front of the plate-moving adapter carrier. Then, close the front panel.</li>
		<li>After loading the deck, ensure that the nanoliter dispenser deck is clear of the strip-holder block and that the carriers at the back of the 50-&#181;L tip stacks are clear of the aluminum SBS lids.</li>
		<li>In the liquid handler &#39;Method Management&#39; interface, select &#39;Setup plates&#39;. Monitor the initialization of both systems and fill in the run parameters. Follow the guidelines of the Method Management interface (prompts, figures and a tip-management system help with preparation).</li>
		<li>Double-check that all required components are ready, and then start the process.</li>
		<li>Monitor the system as the nanoliter dispenser sets the drops in the first plate and the plate sealer subsequently seals the plate.</li>
		<li>Once all 20 plates have been prepared with crystallization droplets and automatically returned to the sliding carriers, open the front panel and gently remove the plates. Check that the plates are correctly sealed before storing them for crystallization.</li>
		<li>Clean the SBS lids with a 20% ethanol solution before stacking them on the left-hand side of the liquid handler for storage. Discard the PCR plate and the microtube.</li>
		<li>Turn off the microtube-cooling carrier and wipe away the condensation. Leave a paper towel on top of the cooler surface to absorb further condensation. Then, replace the carrier cover and close the front panel.</li>
	</ol>
	</li>
</ol>
2. Optimization of the conditions
<ol>
	<li>Syringe-based liquid handler: producing two linear gradients of concentrations into the reservoirs of a crystallization plate (the 4-corner method).
	<ol>
		<li>First, ensure that the liquid handler is on and initialized with its software open.</li>
		<li>On the &#39;GRADIENT&#39; tab: Open the required program, select the crystallization plate type and the final volume in the reservoirs (Table 3). The advanced setting for &#39;max shot vol&#39; should be lowered from 6,000 to 3,000 when using solutions containing [isopropanol] &#62; 10% v/v and [MPD] &#62; 20% v/v.</li>
		<li>Prepare the syringes. Place a piston in each syringe (pointed ends down) and insert the back of the syringes into the designated grooves underneath the robot head. Twist a syringe clockwise to lock it in position (The program will start only with all the required syringes attached correctly).</li>
		<li>Prepare the troughs. Remove the stainless-steel frame and insert the troughs. The 4 positions on the left correspond to the 4 corners A, B, C, D. Switch to &#39;SET UP&#39; tab which displays the volumes of solutions required in each syringe (on Table 3, 0.5 mL dead volume was added to the volumes displayed). Pour the corner solutions into their respective troughs and place the frame back on the deck (the frame holds in position with 2 small magnets located at the front of the deck). An alternative way to proceed with this step is to pour the solutions into the troughs when they are already placed on the deck.</li>
		<li>Place the crystallization plate on the motorized SBS carrier.</li>
		<li>Click &#39;ASPIRATE&#39; and wait for this step to be completed (when pistons stopped on their way up).</li>
		<li>Switch to the &#39;RUN&#39; tab and run program.</li>
		<li>Upon completion of the program, go back to the SET UP tab and click &#39;REMOVE&#39;: the system purges the syringes from leftover solutions, and then lifts the pistons all the way up. &#39;PURGE&#39; may be requested instead of &#39;REMOVE&#39;; this will leave the pistons at the bottom position, ready to aspirate more solutions with the same syringes.</li>
		<li>Remove the syringes by twisting them anticlockwise.</li>
		<li>Discard syringes and troughs in the appropriate bin (or rinse them with deionized water and then 20% v/v ethanol solution for reuse).</li>
		<li>Seal the plate and place it onto the microplate mixer for 3 min at 1,000 rpm, or 10 min when highly viscous solutions are being mixed. The plate is ready for setting up crystallization droplets on the nanoliter dispenser.</li>
	</ol>
	</li>
	<li>Additive screening protocol 1 (setting up crystallization droplets in a 96-well crystallization plate pre-filled with additive screen)
	<ol>
		<li>First, prepare the condition with initial concentrations of reagents increased by 10% (min. vol. 15 mL when transferring the condition from a container onto the additive screen with the liquid handler).</li>
		<li>Ensure that the liquid handler is ready to operate. Open the program &#39;Add screen to additives&#39; for a single plate (enter volume in reservoirs: &#39;72 &#181;L&#39;). Prompts, figures and a tip-management system (12 x 1,000 &#181;L tips required) help with making sure the robot is ready to operate according to the selections.</li>
		<li>Retrieve the additive screen from the -20 &#176;C incubator and remove its aluminum seal immediately (use the plate holder), then place the plate on the deck of the liquid handler. The program operates according to a portrait layout (the plate is placed with the A1-corner located in the front-left of the carrier). Also place also the container filled with the condition. Run the program.</li>
		<li>Once the reservoirs of the plate have been filled, place it onto the microplate shaker and run the program. Rinse the container of condition with deionized water and 20 % ethanol for reuse.</li>
		<li>Set up the droplets on the nanoliter dispenser. First, unseal the crystallization plate (use the plate holder). Then, place the plate and the 8-well protein strip in the first position of the strip-holder block. The &#39;Setup&#39; tab on the controlling software displays the actual positions of each component on the deck. Load each well of the strip with protein sample according to the drop size required (Table 4). Run the program to prepare droplets.</li>
		<li>Upon completion of the program, remove the plate from the deck and seal it immediately (use the plate sealer, 3-inch wide adhesive tape). Discard the strip in the appropriate bin.</li>
		<li>Assess the size, shape, and centering of the droplets under the microscope before storage.</li>
	</ol>
	</li>
	<li>Additive screening protocol 2 (setting up crystallization droplets in a 96-well crystallization plate with a re-usable additive screen)
	<ol>
		<li>First, prepare the additive screen: leave the corresponding frozen 96-well cell culture plate to thaw at room temperature for 40 min. Then, centrifuge the additive screen at 1,000 x g for 2 min.</li>
		<li>Prepare the condition (min. vol. 15 mL when transferring the condition from a container onto the additive screen with the liquid handler).</li>
		<li>Fill the reservoirs of a 96-well crystallization plate with the condition. On the liquid-handler, proceed the same way as protocol 1, step 2.2.2, but enter &#39;80 &#181;L&#39; for the volume in reservoirs.</li>
		<li>Set up the droplets on the nanoliter dispenser with 3 components on the deck (the plate containing the additive screen, along with the crystallization plate and the 8-well protein strip in the first position of the strip-holder block, Table 4).</li>
		<li>Seal the cell culture plate containing the screen with an aluminum sheet and place it back in the -20 &#176;C incubator.</li>
		<li>Assess the size, shape, and centering of the droplets under the microscope before storage.</li>
	</ol>
	</li>
</ol>

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<li>Reis, N. M., Chirgadze, D. Y., Blundell, T. L., Mackley, M. R. <a target="_blank" href="https://www.ncbi.nlm.nih.gov/pubmed/19923710">The effect of protein-precipitant interfaces and applied shear on the nucleation and growth of lysozyme crystal.</a> Acta Crystallogr D Biol Crystallogr. 65, 1127-1139 (2009).</li>
<li>McPherson, A., Koszelak., S., Axelrod, H., Day, J., Robinson, L., McGrath, M., Williams, R., Cascio, D. <a target="_blank" href="https://www.sciencedirect.com/science/article/pii/0022024886901715">The effects of neutral detergents on the crystallization of soluble proteins.</a> J. Crystal Growth. 76 (3), 547-553 (1986).</li>
<li>Sauter, C., Ng, J. D., Lorber, B., Keith, G., Brion, P., Hosseini, M. W., Lehn, J. -M., Giegé, R. <a target="_blank" href="http://www.sciencedirect.com/science/article/pii/S0022024898008525">Additives for the crystallization of proteins and nucleic acids.</a> J. Crystal Growth. 196, 365-376 (1999).</li>
<li>McPherson, A., Cudney, B. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Searching+for+silver+bullets%3A+an+alternative+strategy+for+crystallizing+macromolecules%5BTitle%5D)+AND+%22J.+Struct.+Biol%22%5BJournal%5D)">Searching for silver bullets: an alternative strategy for crystallizing macromolecules.</a> J. Struct. Biol. 156, 387-406 (2006).</li>
<li>Gorrec, F. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Protein+crystallization+screens+developed+at+the+MRC+Laboratory+of+Molecular+Biology%5BTitle%5D)+AND+%22Drug+Discov.+Today%22%5BJournal%5D)">Protein crystallization screens developed at the MRC Laboratory of Molecular Biology.</a> Drug Discov. Today. 21, 819-825 (2016).</li>
<li>Ericsson, U. B., Hallberg, B. M., DeTitta, G. T., Dekker, N., Nordlund, P. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Thermofluor-based+high-throughput+stability+optimization+of+proteins+for+structural+studies%5BTitle%5D)+AND+%22Anal.+Biochem%22%5BJournal%5D)">Thermofluor-based high-throughput stability optimization of proteins for structural studies.</a> Anal. Biochem. 357, 289-298 (2006).</li>
<li>Chari, A., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((ProteoPlex%3A+stability+optimization+of+macromolecular+complexes+by+sparse-matrix+screening+of+chemical+space%5BTitle%5D)+AND+%22Nat.+Methods%22%5BJournal%5D)">ProteoPlex: stability optimization of macromolecular complexes by sparse-matrix screening of chemical space.</a> Nat. Methods. 12, 859-865 (2015).</li>
<li>Newman, J., Egan, D., Walter, T. S., Meged, R., Berry, I., Ben Jelloul, M., Sussman, J. L., Stuart, D. I., Perrakis, A. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Towards+rationalization+of+crystallization+screening+for+small-+to+medium-sized+academic+laboratories%3A+the+PACT%2FJCSG%2B+strategy%5BTitle%5D)+AND+%22Acta+Crystallogr+D+Biol+Crystallogr%22%5BJournal%5D)">Towards rationalization of crystallization screening for small- to medium-sized academic laboratories: the PACT/JCSG+ strategy.</a> Acta Crystallogr D Biol Crystallogr. 61, 1426-1431 (2005).</li>
<li>Wilson, J. <a target="_blank" href="http://www.tandfonline.com/doi/abs/10.1080/08893110410001664837">Automated Evaluation of Crystallisation Experiments.</a> Cryst. Rev. 10, 73-84 (2004).</li>
<li>Snell, E. H., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Establishing+a+training+set+through+the+visual+analysis+of+crystallization+trials.+Part+I%3A+%E2%88%BC150+000+images%5BTitle%5D)+AND+%22Acta+Crystallogr+D+Biol+Crystallogr%22%5BJournal%5D)">Establishing a training set through the visual analysis of crystallization trials. Part I: ∼150 000 images.</a> Acta Crystallogr D Biol Crystallogr. 64, 1123-1130 (2008).</li>
<li>Haupert, L. M., Simpson, G. J. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/pubmed?term=((Screening+of+protein+crystallization+trials+by+second+order+nonlinear+optical+imaging+of+chiral+crystals+%28SONICC%29%5BTitle%5D)+AND+%22Methods%22%5BJournal%5D)">Screening of protein crystallization trials by second order nonlinear optical imaging of chiral crystals (SONICC).</a> Methods. 55, 379-386 (2011).</li>
<li>Newman, J., Fazio, V., Lawson, B., Peat, T. <a target="_blank" href="http://pubs.acs.org/doi/abs/10.1021/cg1004209">The C6 Web Tool: A Resource for the Rational Selection of Crystallization Conditions.</a> Cryst. Growth & Des. 13, 12219-12223 (2010).</li>
</ol>

We hereby state a conflicting commercial interest since LifeArc commercializes the following items: the 96- and 48-well MRC plates, the MRC hanging drop seal, the MORPHEUS, Pi, ANGSTROM and LMB crystallization screens.

1- Preparation and use of initial screens stored in plates
Screening kits should be mixed before being dispensed into plates because light precipitation or phase separation occurs in some tubes during storage. When a screen is composed of two kits (2 x 48 tubes), the first tube of the second kit is placed in in location E1 of the cooling carrier. When a screen is composed of 4 kits (4 x 24 tubes), the first tube of the second kit is placed in in location C1, the first tube of the third kit is placed in location E1 and the first tube of the fourth kit is placed in location G1. While inserting the tubes in their cooling carrier, lids are placed on a tray following the standard 96-well landscape layout. Since well numbers are indicated on top of the lids by the manufacturers, this enables cross-checking if all tubes have been placed in the right order. This also helps to replace the correct lids on the tubes when filling a reduced number of plates.
We store the pre-filled plates at 10 &#176;C, a compromise to avoid freezing and storage at 4 &#176;C that may cause deterioration of conditions and issues with sealing. Plates are stored for up to several months with normally no noticeable condensation on the inner face of the seal. This is less true for LMB05, LMB06, LMB09 and LMB10 plates as these contain conditions with relatively high concentrations of volatile reagents (Table 1). Small amount of condensation on the inner side of the seal reduces sealing efficiency and can cause cross-contamination between wells while unsealing the plates. To help with preventing condensation during initial cooling, plates can be first transferred from the carousel into an insulated picnic cooler which is stored in a 4 &#176;C cold room overnight. The very slow cooling minimizes the development of temperature gradients within the sealed wells and hence reduces condensation overall15. In addition, once the plates are stored in the 10 &#176;C incubator, an in-house custom SBS polystyrene lid is placed on the plate at the top of each stack (not shown).
The entire set of our pre-filled plates can be used as a large initial screen against a novel, water-soluble, protein sample. Alternatively, fewer plates may be selected to match specific requirements. For example, LMB15 and LMB19 are screens formulated specifically for membrane protein samples26,27, or LMB20 is a screen formulated with heavy-atoms to facilitate the experimental phasing of diffraction data28 (see also: <a href="https://www.youtube.com/watch?v=Gpb4SypWnQY&amp;t=11s">Formulation of the MORPHEUS protein crystallization screens</a>).
2. Setting up crystallization droplets
When using the system 2, screening kits with significant amounts of volatile reagents should be processed first. This avoids condensation forming on the rubber of the SBS lids, which could affect lid handling and plate sealing. An SBS lid has a bit of clearance when on the top of a plate, which is why they need to be aligned initially (see Protocol, step 1.2.6). The protein dead volumes in the wells of the PCR plate are relatively generous (0.8 &#181;L, see legend of Table 2). Note that equally generous dead volumes are employed when using the nanoliter dispenser individually with protein in 8-well strips (Table 4). Smaller dead volumes may work, however some samples adhere to the tips, calibration of a robot may become slightly inaccurate, the room may be warmer than usual, etc. All lead to sample losses covered by the generous dead volumes in order to consolidate the approach.
Recent developments enabled further miniaturization of experiments and hence the volume of sample required for screening crystallization conditions can be significantly reduced by integrating the corresponding technology29,30. However, some aspects of further miniaturization need careful consideration, such as the evaporation of droplets31 and the manipulation of microcrystals32.
Finally, centrifugation of the plate (2,000 rpm, 1 min) could be integrated as a routine final step when setting up crystallization droplets (in spherical upper-wells). A more consistent size and shape of droplets resulting from centrifugation may reduce reproducibility issues33,34. Surely, centered drops will ease the later assessment of experiments using a microscope as the required focal length will be similar across the entire plate.
3. Advantages of the 4-corner method
The most significant advantage of the 4-corner method is its simplicity, which minimizes errors and facilitates straightforward automated protocols. For example, the 4 corner solutions will always be placed on the deck of a liquid handler following the same layout. Also, all programs are based on fixed ratios between the solutions (Figure 3C). 
Manual preparation of the 4 corner solutions is preferred to automated handling of solutions at high concentrations which can be highly viscous. Relatively fast and accurate aspiration/dispensing is then possible on most types of liquid handlers with minimum requirements for optimization of liquid classes. Nevertheless, some corner solutions may still be too viscous for a robot operating with a liquid-system to operate efficiently. This is why we opted for a liquid handler operating with positive displacement (Figure 3B).
In addition to the 2 linear gradients of concentrations, a third component (i.e., a set of buffers/additives) can be tested at a constant concentration in a convenient way. For this, a relatively large volume of a core set of corner solutions at a suitably higher concentration, excluding the component to be varied, is prepared first. Then, stock solutions including this component is added to adjust the final concentrations. For example, 50 mL of a set of 4 corner solutions are prepared at 10 % higher concentrations than initially. This core set is then split into 5 smaller subsets of 4. Finally, 10% in volume of different buffer-pH solutions is added to each subset.
4. Formats and types of additive screens
The screens are normally stored at -20 &#176;C (Figure 4) since they are not used regularly and contain volatile/unstable compounds. The use of a frozen additive screen stored in a deep well block (1 mL in wells) must be planned early because it will take 12-24 hr for all the additive solutions to thaw completely at room temperature. Also, a multitude of users share the same additive screen, potentially causing problems with cross-contamination. Finally, the height of deep well blocks makes them unsuitable for most nanoliter dispensers. As a convenient solution to circumvent these issues, the screen should be transferred from the deep well block to low-profile plates (Figure 4).
Historically, additive screens which include a broad variety of single reagents (with single concentrations) have been very popular35,36. However, other types of additive screens have been developed that integrate mixes of additives37 or a reduced number of single additives found at different concentrations38. Finally, a complementary approach is to investigate the effect of additives on the samples prior to crystallization39,40.
5. More considerations
Good practice: Most screens contain harmful or even toxic substances and hence adequate personal protection must be employed during the protocols. Equally, moving parts of the robots may lead to injuries, especially when trying to manually interfere while a program is running (although most of the robots have emergency stop button/system). Because of the technical complexities involved, regular checking of robots, screens and programs with previously characterized test samples are important for sustained high levels of reproducibility.
Throughput: As an indication, between 4,000 to 8,000 LMB plates are produced yearly with the system 1 (and subsequently employed by users for initial screening). It is not adapted to stock a large amount of pre-filled plates at 10 &#176;C when the expected turnover is much lower, as after 4-5 months, some conditions will start to deteriorate and evaporate. Different approaches to automation protocols have been implemented for small- to medium-size laboratories41.
Storing and assessing experiments: After preparing the droplets, plates are stored on low-vibration shelves in a room at 4 or 18 &#176;C with tightly controlled temperature (+/- 0.5 &#176;C maximum deviation). Experiments are assessed using cold light source microscopes. Various automated imaging systems are commercially available, however one should carefully consider all aspects: Will the speed required to scan a plate be sufficient for high throughput? Will objects other than crystals interfere with autofocus? Will the resulting quality of images be sufficient to spot very small crystals (especially around the edge of the droplets)?42,43,44
Comparison of crystallization conditions: After careful investigations about the nature of the initially-obtained crystals, one can analyze trends and similarities across conditions using the <a href="https://search.mrc-lmb.cam.ac.uk/screens2/search.html">LMB screen database</a> or the C6 <a href="http://c6.csiro.au/">Web Tool</a>45.

X-ray crystallography is extensively applied to further advance our understanding of biological and disease mechanisms at the atomic level and to subsequently assist rational approaches to drug discovery1. For this, purified and concentrated (2-50 mg/mL) macromolecular samples of protein, DNA, RNA, other ligands, and their complexes are trialed for their propensity to form ordered three-dimensional lattices through crystallization2,3,4. When high quality crystals are obtained that diffract X-rays, the crystal structure may be solved at near atomic resolution5,6. Crucially, the conditions to crystallize a novel sample cannot be predicted and the yield of high quality crystals is usually very low. An underlying reason is that many samples of interest have challenging biochemical properties, which make them unstable on the corresponding timescale for crystallization (typically a few days). Finally, the process is compounded by the time required to produce samples and sample variants, and to optimize their purification and crystallization7,8.
A crystallization condition is a solution with a precipitant that reduces sample solubility, and conditions often also contain buffers and additives. Hundreds of such reagents are well suited to alter the parameters of the crystallization experiments as they have low propensity to interfere with sample integrity (such as protein or nucleic acid unfolding). While testing millions of combinations of crystallization reagents is not feasible, testing several to many screening kits - formulated with various strategies9,10 - is possible with miniaturized trials and automated protocols. In this perspective, the most amenable technique is probably vapor diffusion with 100-200 nL droplets sitting on a small well above a reservoir containing the crystallization condition (25-250 &#181;L), implemented in specialized crystallization plates11,12. The protein sample and condition are often combined in a 1:1 ratio for a total volume of 200 nL when setting up the droplets in the upper-wells. Robotic nanoliter protein crystallization can be implemented with alternative techniques and plates such as the under-oil batch13 and the Lipidic Cubic Phase14 (the latest one being applied specifically to trans-membrane proteins that are very poorly soluble in water).
<a href="http://www2.mrc-lmb.cam.ac.uk/groups/JYL/WWWrobots/robot.html">The crystallization facility at the MRC-LMB</a> was started in the early 2000s and an early summary of our automated protocols was presented in 200515. A historical introduction to protein crystallization was presented and also an outline of the advantages of robotic nanoliter approach (then a novel approach to routine experimentation). Since macromolecular crystallization is essentially a stochastic process with very little or no useful prior information, employing a broad variety of (suitable) initial conditions increase the yield of quality diffraction crystals16. Besides, an often-overlooked advantage of a large initial screen is to significantly reduce the need for optimization of samples and crystals in many cases. Of course, one may still need to proceed with optimization of some initial conditions later. Typically, the concentration of reagents and the pH are then systematically investigated. More reagents can also be introduced into the optimized condition(s) to further alter parameters of crystallization. Certainly, one should attempt crystallization with a sample freshly prepared, hence the corresponding protocols must be straightforward and available any time.
Here, two fully automated systems designed at the MRC-LMB (systems 1 and 2) and the corresponding protocols are fully described. The main application of these two systems is initial screening by vapor diffusion in sitting drop crystallization plates. System 1 integrates a liquid handler, an automated carousel to stock plates, an inkjet printer for plate labeling and an adhesive plate sealer. On the system 1, 72 96-well plates are filled with commercially available screening kits (80 &#181;L of condition transferred to reservoir from a starting volume of 10 mL in test tubes), labeled and sealed. The plates are then stored in a 10 &#176;C incubator where they are available to users anytime (as initial screens called &#39;LMB plates&#39;).
System 2 integrates a liquid handler, a nanoliter dispenser, and an adhesive plate sealer. On the system 2, sitting droplets (100-1,000 nL) for vapor diffusion experiments are produced by combining conditions and the sample in the upper-wells of 20 48- or 96-well plates pre-filled with conditions. This means 1,920 initial screening conditions are trialed when using 20 LMB plates on the system 2.
Robots are also used individually for the optimization of selected conditions, and the corresponding semi-automated protocols are also described. The 4-corner method17 is employed routinely to produce optimization screens. The corresponding protocol first requires the manual preparation of 4 solutions (&#39;A, B, C, and D&#39;). Two linear gradients of concentrations (for two main crystallization agents) are then automatically generated directly into the reservoirs of a crystallization plate. For this, a syringe-based liquid handler dispenses the 4 corner solutions at different ratios.
To further optimize a condition, one can employ additive screens that potentially enhance the properties of resulting crystals18. Two approaches are available for additive screening: a protocol starting with additives dispensed into the reservoirs of crystallization plates before setting up the droplets (protocol 1) and another protocol where the additive screen is dispensed directly onto the droplets (protocol 2).
Other useful developments that were initiated at the MRC-LMB to facilitate automated macromolecular crystallization, are also presented. Essentially, crystallization plates and associated devices such as a stackable Society of Biomolecular Screening (SBS) lid that minimizes evaporation of conditions when using the system 2.
For brevity, it is assumed that users are familiar with the basic functions and maintenance of the nanoliter dispenser, the inkjet printer, and the adhesive plate sealer. Unless stated otherwise, plates on the deck of the robots are positioned such that the well A1 (&#39;A1-corner&#39;) is towards the back-left corner of a plate carrier.

<table><tbody><tr><td>&lt;strong&gt;Robots&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Freedom EVO&amp;reg;</td><td>Tecan</td><td>n/a</td><td>Liquid handler (System 1). Aspiration/Dispense based on system liquid. Integrates an automated carousel. EVOware plus controlling software v.2.4.12.0.&amp;nbsp;</td></tr><tr><td>Microlab&amp;reg; STAR&amp;trade;</td><td>Hamilton</td><td>n/a</td><td>Liquid handler (System 2). Aspiration/Dispense based on positive displacement (CO-RE&amp;trade; technology). Hamilton STAR controlling software v.4.3.5.4785 with method management interface.</td></tr><tr><td>Mosquito&amp;reg;</td><td>TTP Labtech</td><td>n/a</td><td>Microsyringe-based nanoliter dispenser used to set up droplets (System 2 and stand-alone), 3-position deck. Controlling software v.3.11.0.1422.&amp;nbsp;</td></tr><tr><td>Dragonfly&amp;reg;</td><td>TTP Labtech</td><td>n/a</td><td>Syringe-based liquid handler used to produce optimization screens (4-corner method). Controlling software v.1.2.1.10196.&amp;nbsp;</td></tr><tr><td>Adhesive plate sealer</td><td>Brandel</td><td>n/a</td><td>Integrated to Systems 1 and 2 (also used as stand-alone robot).</td></tr><tr><td>Inkjet printer 9232</td><td>Markem-Imaje</td><td>n/a</td><td>Integrated to System 1. Touchscreen interface.</td></tr><tr><td>&lt;strong&gt;Crystallization screens&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>Crystal Screen&amp;trade; 1</td><td>Hampton Research</td><td>HR2-110</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB01</td></tr><tr><td>Crystal Screen 2&amp;trade;</td><td>Hampton Research</td><td>HR2-112</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB01</td></tr><tr><td>Wizard&amp;trade; Classic 1</td><td>Rigaku</td><td>1009530</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB02</td></tr><tr><td>Wizard&amp;trade; Classic 2</td><td>Rigaku</td><td>1009531</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB02</td></tr><tr><td>Grid Screen&amp;trade; Ammonium Sulfate</td><td>Hampton Research</td><td>HR2-211</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB03</td></tr><tr><td>Grid Screen&amp;trade; PEG/LiCl</td><td>Hampton Research</td><td>HR2-217</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB03</td></tr><tr><td>Quick Screen&amp;trade;</td><td>Hampton Research</td><td>HR2-221</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB03</td></tr><tr><td>Grid Screen&amp;trade; Sodium Chloride</td><td>Hampton Research</td><td>HR2-219</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB03</td></tr><tr><td>Grid Screen&amp;trade; PEG 6000</td><td>Hampton Research</td><td>HR2-213</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB04</td></tr><tr><td>Grid Screen&amp;trade; MPD</td><td>Hampton Research</td><td>HR2-215</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB04</td></tr><tr><td>MemFac&amp;trade;</td><td>Hampton Research</td><td>HR2-114</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB04</td></tr><tr><td>PEG/Ion&amp;trade;</td><td>Hampton Research</td><td>HR2-126</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB05</td></tr><tr><td>Natrix&amp;trade;</td><td>Hampton Research</td><td>HR2-116</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB05</td></tr><tr><td>Crystal Screen Lite&amp;trade;</td><td>Hampton Research</td><td>HR2-128</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB06</td></tr><tr><td>Custom Lite screen</td><td>Molecular Dimensions Ltd</td><td>n/a</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB06</td></tr><tr><td>Wizard&amp;trade; Cryo 1</td><td>Rigaku</td><td>1009536</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB07</td></tr><tr><td>Wizard&amp;trade; Cryo 2</td><td>Rigaku</td><td>1009537</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB07</td></tr><tr><td>JBS1</td><td>JenaBioScience</td><td>CS-101L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB08</td></tr><tr><td>JBS2</td><td>JenaBioScience</td><td>CS-102L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB08</td></tr><tr><td>JBS3</td><td>JenaBioScience</td><td>CS-103L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB08</td></tr><tr><td>JBS4</td><td>JenaBioScience</td><td>CS-104L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB08</td></tr><tr><td>JBS5</td><td>JenaBioScience</td><td>CS-105L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB09</td></tr><tr><td>JBS6</td><td>JenaBioScience</td><td>CS-106L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB09</td></tr><tr><td>JBS7</td><td>JenaBioScience</td><td>CS-107L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB09</td></tr><tr><td>JBS8</td><td>JenaBioScience</td><td>CS-108L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB09</td></tr><tr><td>JBS9</td><td>JenaBioScience</td><td>CS-109L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB10</td></tr><tr><td>JBS10</td><td>JenaBioScience</td><td>CS-110L</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB10</td></tr><tr><td>Clear Strategy&amp;trade; Screen 1 pH 4.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB10</td></tr><tr><td>Clear Strategy&amp;trade; Screen 1 pH 5.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB10</td></tr><tr><td>Clear Strategy&amp;trade; Screen 1 pH 6.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB11</td></tr><tr><td>Clear Strategy&amp;trade; Screen 1 pH 7.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB11</td></tr><tr><td>Clear Strategy&amp;trade; Screen 1 pH 8.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB11</td></tr><tr><td>Clear Strategy&amp;trade; Screen 2 pH 4.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB11</td></tr><tr><td>Clear Strategy&amp;trade; Screen 2 pH 5.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB12</td></tr><tr><td>Clear Strategy&amp;trade; Screen 2 pH 6.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB12</td></tr><tr><td>Clear Strategy&amp;trade; Screen 2 pH 7.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB12</td></tr><tr><td>Clear Strategy&amp;trade; Screen 2 pH 8.5</td><td>Molecular Dimensions Ltd</td><td>MD1-16LMB</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB12</td></tr><tr><td>Index&amp;trade;</td><td>Hampton Research</td><td>HR2-144</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB13</td></tr><tr><td>SaltRX&amp;trade; 1</td><td>Hampton Research</td><td>HR2-107</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB14</td></tr><tr><td>SaltRX&amp;trade; 2</td><td>Hampton Research</td><td>HR2-109</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB14</td></tr><tr><td>MemStar&amp;trade;</td><td>Molecular Dimensions Ltd</td><td>MD1-21</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB15</td></tr><tr><td>MemSys&amp;trade;</td><td>Molecular Dimensions Ltd</td><td>MD1-25</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB15</td></tr><tr><td>JCSG-plus&amp;trade; Suite</td><td>Qiagen</td><td>130720</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB16</td></tr><tr><td>MORPHEUS&amp;reg; screen</td><td>Molecular Dimensions Ltd</td><td>MD1-46</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB17</td></tr><tr><td>Pi minimal screen</td><td>JenaBioScience</td><td>CS-127</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB18</td></tr><tr><td>Pi-PEG screen</td><td>JenaBioScience</td><td>CS-128</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB19</td></tr><tr><td>MORPHEUS&amp;reg; II screen</td><td>Molecular Dimensions Ltd</td><td>MD1-91</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB20</td></tr><tr><td>LMB crystallization screen&amp;trade;</td><td>Molecular Dimensions Ltd</td><td>MD1-98</td><td>Crystallization kit (test tubes, 10mL per condition) used in LMB21</td></tr><tr><td>&lt;strong&gt;Additive screens&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>HT additive screen</td><td>Hampton Research</td><td>HR2-138</td><td>Frozen in 96-well deepwell block (1 mL per well).</td></tr><tr><td>MORPHEUS&amp;reg; additive screen</td><td>Molecular Dimensions Ltd</td><td>MD1-93-500</td><td>Frozen in 96-well deepwell block (500 &amp;micro;L per well).</td></tr><tr><td>ANGSTROM additive screen&amp;trade;&amp;nbsp;</td><td>Molecular Dimensions Ltd</td><td>MD1-100</td><td>Frozen in 96-well deepwell block (1 mL per well).</td></tr><tr><td>MORPHEUS&amp;reg; additive screen</td><td>Molecular Dimensions Ltd</td><td>MD1-93</td><td>Frozen in 96-well cell culture Costar&amp;reg; plate with V-shaped wells (100 &amp;micro;L per well).</td></tr><tr><td>ANGSTROM additive screen&amp;trade;&amp;nbsp;</td><td>Molecular Dimensions Ltd</td><td>MD1-100-FX</td><td>Frozen in 96-well cell culture Costar&amp;reg; plate with V-shaped well (100 &amp;micro;L per well).</td></tr><tr><td>HIPPOCRATES additive screen</td><td>Molecular Dimensions Ltd</td><td>n/a</td><td>48 single additives (drug compounds found in MORPHEUS&amp;reg; III).</td></tr><tr><td>&lt;strong&gt;Other consumables&lt;/strong&gt;</td><td></td><td></td><td></td></tr><tr><td>96-well MRC 2-drop plate</td><td>Swissci</td><td>MRC 96T-UVP</td><td>Sitting-drop, vapor diffusion plate. Reservoir recommended volume: 80&amp;nbsp; &amp;micro;L. Range of useful droplet volumes: 10-1000 nL. UV transmissible.</td></tr><tr><td>48-well MRC 1-drop plate&amp;nbsp; (&#039;MAXI plate&#039;)</td><td>Swissci</td><td>MMX01-UVP&amp;nbsp;</td><td>Sitting-drop, vapor diffusion plate for scale-up/optimization. Reservoir recommended volume: 200&amp;nbsp; &amp;micro;L. Range of useful droplet volumes: 0.1-10 &amp;micro;L. UV transmissible.</td></tr><tr><td>MRC hanging drop seal</td><td>Swissci</td><td>n/a</td><td>Hanging-drop, compatible with both MRC vapor diffusion plates (MRC 96T-UVP and MMX01-UVP ). UV and X-ray transmissible.</td></tr><tr><td>Adhesive sealing tape</td><td>Hampton Research</td><td>HR4-50</td><td>3-inch wide Duck&amp;reg; HD Clear&amp;trade; for sealer and manual sealing.</td></tr><tr><td>Adhesive aluminium sheet</td><td>Beckman Coulter</td><td>538619</td><td>Used to reseal additive screens.</td></tr><tr><td>Ink cartridge</td><td>Markem-Imaje</td><td>9651</td><td>System 1 (inkjet printer).</td></tr><tr><td>Solvent cartridge</td><td>Markem-Imaje</td><td>8652</td><td>System 1 (inkjet printer).</td></tr><tr><td>50 &amp;micro;L tips&amp;nbsp;</td><td>Hamilton</td><td>235947</td><td>System 2 (STAR&amp;trade; liquid handler). Box of 6 sets with 1920 x CO-RE&amp;trade; tips in disposable stacks.</td></tr><tr><td>Reagent container</td><td>Hamilton</td><td>194052</td><td>Used to dispense a condition into plate(s) during additive screening protocols.&amp;nbsp;</td></tr><tr><td>PCR plate</td><td>Thermo Scientific&amp;trade;</td><td>AB-2150</td><td>System 2 (contains protein to be transfer to the Mosquito&amp;reg;). Abgene Diamond ultra, 384 V-shaped wells.</td></tr><tr><td>microsyringes</td><td>TTP Labtech</td><td>4150-03020</td><td>Spool of 26,000 microsyringes for the Mosquito&amp;reg; nanoliter dispenser (9mm spacing).</td></tr><tr><td>strip-holder block</td><td>TTP Labtech</td><td>3019-05013</td><td>SSB device for the Mosquito&amp;reg; strips, aka &#039;4-way Reagent Holder&#039;.</td></tr><tr><td>2 &amp;micro;L 8-well strip</td><td>TTP Labtech</td><td>4150-03110</td><td>Contains protein on the deck of the Mosquito&amp;reg;. Box of 40 strips, max. vol. in well is 3.2 &amp;micro;L.</td></tr><tr><td>5 &amp;micro;L 8-well strip</td><td>TTP Labtech</td><td>4150-03100</td><td>Contains protein on the deck of the Mosquito&amp;reg;. Box of 40 strips, max. vol. in well is 7.5 &amp;micro;L.</td></tr><tr><td>5 mL syringes</td><td>TTP Labtech</td><td>4150-07100</td><td>Syringe body and piston for the Dragonfly&amp;reg; liquid handler. Pack of 100.</td></tr><tr><td>Troughs/Reservoirs</td><td>TTP Labtech</td><td>4150-07103</td><td>Contains stock solutions on the deck of the Dragonfly&amp;reg;. Pack of 50.</td></tr><tr><td>Orbital microplate shaker</td><td>CamLab Limited</td><td>n/a</td><td>Variomag&amp;reg; for mixing conditions in a single plate (0-2000 rpm).</td></tr><tr><td>Microplate mixer</td><td>TTP Labtech</td><td>3121-01015</td><td>MxOne. Mixing condition in a single plate with 96 vibrating pins.</td></tr></tbody></table>

automated protocols for macromolecular crystallization at the mrc laboratory of molecular biology

Automated Protocols for Macromolecular Crystallization at the MRC Laboratory of Molecular Biology

When high quality crystals are obtained that diffract X-rays, the crystal structure may be solved at near atomic resolution. The conditions to crystallize proteins, DNAs, RNAs, and their complexes can however not be predicted. Employing a broad variety of conditions is a way to increase the yield of quality diffraction crystals. Two fully automated systems have been developed at the MRC Laboratory of Molecular Biology (Cambridge, England, MRC-LMB) that facilitate crystallization screening against 1,920 initial conditions by vapor diffusion in nanoliter droplets. Semi-automated protocols have also been developed to optimize conditions by changing the concentrations of reagents, the pH, or by introducing additives that potentially enhance properties of the resulting crystals. All the corresponding protocols will be described in detail and briefly discussed. Taken together, they enable convenient and highly efficient macromolecular crystallization in a multi-user facility, while giving the users control over key parameters of their experiments.

Automated systems and protocols for the routine preparation of a large number of screens and nanoliter crystallization droplets for vapor diffusion experiments are described and discussed.

When high quality crystals are obtained that diffract X-rays, the crystal structure may be solved at near atomic resolution. The conditions to crystallize ...

The overall goal of this procedure is to produce high-quality crystals from initial crystallization screening conditions. The crystals can be used to study the structures of proteins, DNA, RNA, and their complexes. Something about macromolecular structures has become increasingly challenging.And providing a broad variety of initial conditions increases the yield of useful crystals, while reducing the need for sample and crystal optimization. The two fully automated systems, the the LMB, facilitate the preparation of up to 1, 920 vapor diffusion experiments in nanoliter droplets. For brevity, it is assumed that users are already familiar with the basic functions and maintenance of the nanoliter dispenser, the inkjet printer, and the adhesive plate sealer.Prior to performing the procedure, ensure that the system's robots are initialized and their controlling software is open. Turn on the chiller of the tube cooling carrier, about 30 minutes before the main program will be started. Place a test plate on the motorized SBS carrier of the plate sealer.Run the plate sealer and check that the film is properly applied. Repeat this test twice more to verify that the plate sealer is ready. Then add 20 liters of deionized water to the main container of the liquid handler.Disconnect the coupling inserts form the smaller container of 20%ethanol rinsing solution, and connect the inserts to the main container. Enter the appropriate screen name on the inkjet printer touchscreen. Then open and close the carousel door to trigger the carousel rotation.Open the door when the first stack presents itself. Fully load the first stack with 22 crystallization plates, each with column one facing out. Fully load the next two stacks in the same way.Load the remaining six plates in the highest positions of the fourth stack, then close the carousel door. Verify that the chiller display indicates 14 degrees Celsius. Gently and repeatedly invert the selected screening kits for one minute.Then, open the front panel of the liquid handler. Open the tubes and place them in the cooling carrier in the standard 96-well layout. Upon placing each tube in the carrier, place its lid on the tray in the same 96-well layout.When using System 1, the label leads are placed on the tray in the 96-well layout to enable cross-checking that the tubes are arranged correctly. Cross-check the tube positions and then ensure that all tubes are level and settled in the carrier. Then close the front panel.In the Startup window of the liquid handler software, select Run Maintenance and open the Flushing program. Run the program to flush the 20%ethanol from the system and to wash the outsides of the liquid dispensing tips. When flushing is complete, click Cancel to return to Startup.Select Run An Existing Process and click Start Your Selection. Open the MRC Kit dispensing program. Fill in 18"for Instances in the Configuration screen and run the program, Monitor the system as the first four plates are labeled, filled, and sealed.Do not leave the system unattended until the preparation of the first four plates is complete. Once all 72 plates have been prepared and placed back in the carousel, switch the coupling inserts from the deionized water container to the 20%ethanol container. Run the startup flush program using the same process as before.Turn off the chiller and discard the empty screening kit tubes. Carefully remove the 72 prepared plates from the carousel. Discard incorrectly filled or poorly sealed plates.Store the ready-to-use plates at 10 degrees Celsius. First ensure that the system's robots are on, the nanoliter dispenser is initialized with its software open, and the liquid handler's method manager is open. Turn on the microtube cooling carrier about 15 minutes before the main program will be started.Place a test plate on the motorized SBS carrier of the plate sealer. Run the plate sealer and verify that the plate is properly sealed. Test the plate sealer three times.Then run the nanoliter dispenser to set 100 nanoliter droplets of test solution in a test plate. Shown here is a light micrograph of a 100 nanoliter droplet, produced by the nanoliter dispenser, with the test solution made with red dye. Close the nanoliter dispenser software and remove the strip holder block from the deck.Next, set in a custom-designed plate holder, a pre-filled 96-well crystallization plate with the highest relative quantity of volatile reagents in its conditions. Remove the adhesive film from the plate. Open the liquid handler front panel, and place the unsealed plate on the deck at the back of the first sliding carrier.Cover the plate with an SBS aluminum lid. Settle the lid towards the rear left corner of the carrier by applying gentle pressure to the opposite corner of the lid. When using System 2, screening kits with significant amounts of volatile reagents should be processed first.This avoids condensation forming on the SBS leads, which could effect automated handing of the leads or plate sealing. Unseal, load into the sliding carriers, and cover the remaining 19 plates in the same way, working from most to least volatile conditions. Once the microtube cooling carrier is at 4 degrees Celsius, as indicated by a green light, remove its cover.Cut off the lid of a microtube containing at least 440 microliters of a protein sample. Ensure that the sample has no foam above the meniscus, as this will interfere with the liquid detection system. Place the tube in Position 1 of the microtube cooling carrier.Place a PCR plate on the liquid handler deck in front of the plate moving adapter carrier. Then close the front panel. In the liquid handler method management interface, select Setup Plates.Monitor the initialization of both systems and fill in the run parameters, including the plate type and the number of drops for each condition, the drop size, the position of the first plate to be processed, and the number of plates. Click No when asked if you would like help loading the deck. Once you've checked that there are no empty tip racks, click OK.Once you've checked that there are enough tips for the run, click OK.When necessary, update the tip management system and click OK.Ensure that the nanoliter dispenser deck is clear of the strip holder block, and that the carrier is at the back of the 50 microliter tip stacks, are clear of the aluminum SBS lids.Double-check that all the other required components are ready and then start the process. Monitor the system as the nanoliter dispenser sets the drops in the first plate, and the plate sealer subsequently seals the plate. Do not leave the system unattended until the preparation of the first plate is complete.Once all 20 plates have been prepared with crystallization droplets and automatically return to the sliding carriers, open the front panel and gently remove the plates. Check that the plates are correctly sealed before storing them for crystallization. Clean the SBS lids with the 20%ethanol solution before stacking them on the left-hand side of the liquid handler for storage.Discard the PCR plate and the microtube. Turn off the microtube cooling carrier and wipe away the condensation. Leave a paper towel on top of the cooler surface to absorb further condensation.Then replace the carrier cover and close the front panel. OmpF and MreB were initially screened using these fully automated protocols. OmpF crystals of sufficient quality for X-ray diffraction were found in well A4 of the LMB 7 plate.Diffraction quality crystals of MreB were found in well D12 of the LMB 20 plate. Storing pre-fuel plates at 10 degrees Celsius is a compromise to avoid freezing and storage at 4 degrees, which may cause deterioration of crystallization conditions and condensation-related issues. When stored this way, plates may be used within four to five months.Between 4 and 8, 000 LMB plates are produced yearly with System 1 and are later used for initial screening. The protocols should be optimized differently when the expected turnover is much lower. Our entire set of pre-fuel plates is normally used as a large initial screen for a novel sample.However, fewer plates may be selected to much specific sample requirements. After preparing the droplets, plates are stored on low-vibration shelves with the temperature tightly controlled at 4 or 18 degrees Celsius. Experiments are assessed with scroll light source microscopes.After carefully investigating the nature of the crystals, traits and similarities across conditions can be analyzed with web-based tools such as the LMB or C6 Screen databases. Subsequent optimization of crystallization conditions may still be necessary. Additional automated protocols, with the 4-corner methods and additive screening are described in our manuscript.

automated-protocols-for-macromolecular-crystallization-at-mrc

Research

JoVE Journal

Biochemistry

The 3-D structure of a molecule provides a unique understanding of how the molecule functions. The principal method for structure determination at near-atomic resolution is X-ray crystallography. Here, we demonstrate the current methods for obtaining three-dimensional crystals of any given macromolecule that are suitable for structure determination by X-ray crystallography.

Protein Crystallization for X-ray Crystallography

Herein is described a robotic approach to high-throughput crystallization of membrane proteins in lipidic mesophases for use in structure determination using macromolecular X-ray crystallography.  Three robots capable of handling the viscous and sticky protein-laden mesophase integral to the method are introduced.

Use of a Robot for High-throughput Crystallization of Membrane Proteins in Lipidic Mesophases

Here we describe a general method for random microseed matrix screening. This technique is shown to significantly increase the success rate of protein crystallization screening experiments, reduce the need for optimization, and provide a reliable supply of crystals for data collection and ligand-soaking experiments.

Improving the Success Rate of Protein Crystallization by Random Microseed Matrix Screening

Here, we describe how to use the automated screening and data collection options available at some synchrotron beamlines. Scientists send cryocooled samples to the synchrotron, and the diffraction properties are screened, the data sets are collected and processed and, where possible, a structure solution is carried out—all without human intervention.

Fully Autonomous Characterization and Data Collection from Crystals of Biological Macromolecules

A novel sample holder for macromolecular X-ray crystallography along with a suitable handling protocol is presented. The system allows crystal growth, crystal soaking and in situ diffraction data collection at both, ambient and cryogenic temperature without the need of any crystal manipulation or mounting.

An All-in-one Sample Holder for Macromolecular X-ray Crystallography with Minimal Background Scattering

Structural studies of biomacromolecules by crystallography require high-quality crystals. Here we demonstrate a protocol that can be used by OptiCrys (a fully automated instrument developed in our lab) and/or microdialysis buttons for growing large high-quality crystals based on knowledge of the crystallization phase diagram.

Optimization of Crystal Growth for Neutron Macromolecular Crystallography

The signal-to-noise ratio of data is one of the most important considerations in performing X-ray diffraction measurements from microcrystals. The VMXm beamline provides a low-noise environment and microbeam for such experiments. Here, we describe sample preparation methods for mounting and cooling microcrystals for VMXm and other microfocus macromolecular crystallography beamlines.

A Sample Preparation Pipeline for Microcrystals at the VMXm Beamline

Here, we describe how to use the automated macromolecular crystallography pipelines for protein-to-structure, rapid ligand-protein complex analysis and large-scale fragment screening based on the CrystalDirect technology at the HTX Laboratory in EMBL Grenoble.

The Automated Crystallography Pipelines at the EMBL HTX Facility in Grenoble

This protocol details high-throughput crystallization screening, ranging from the 1,536 microassay plate preparation to the end of a 6 week experimental time window. Details are included about the sample setup, the imaging obtained, and how users can perform analyses using an artificial intelligence-enabled graphical user interface to quickly and efficiently identify macromolecular crystallization conditions.

High-Throughput Screening to Obtain Crystal Hits for Protein Crystallography

We present a protocol for the crystallization of proteins using the crystallization facility in the Research Complex at Harwell and subsequent in situ X-ray crystallographic data collection from crystals within the plates at Diamond's Versatile Macromolecular Crystallography in situ (VMXi) beamline. We describe sample requirements, crystallization protocols, and data collection guidelines.

Crystallization and In Situ Room Temperature Data Collection Using the Crystallization Facility at Harwell and Beamline VMXi, Diamond Light Source

Learn automated protocols for macromolecular crystallization using nanoliter vapor diffusion experiments. This method produces high-quality crystals for structural studies of proteins, DNA, RNA, and their complexes.

Automated Protocols for Macromolecular Crystallization at the MRC Laboratory of Molecular Biology

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