Escherichia coli -Based Complementation Assay to Study the Chaperone Function of Heat Shock Protein 70

I start the role of heat shock proteins in comparing retro static protection to antigens that cause human infections such as malaria and tuberculosis. My research essentially focuses on the structure function features of the heat shock protein machinery of these pathogens that cause human infections. Heat shock proteins are generally highly concept, however, they display some level of functional specialization.

In addition, they are implicated in drug resistance. As such, there are ongoing efforts to target them towards reversing drug resistance in various disease models. They include biochemical, biophysical, bioinformatics, and cell biologic techniques.

In other words, various areas of techniques are used to study the roles of these proteins. In our case, the study of proteins the main agent of malaria, is that they are difficult to produce, and this limits the capability to start these proteins. For example, it is difficult to generate sufficient levels to crystallize and image the proteins.

We have established some of the bio-functional metrics of these proteins in the malaria person. We have also established assays to start the compounds targeting these proteins in agents causing malaria and TD.The current protocol is used to explore the chaperone or protein folding raw and in-cytoprotective function of HSP 70, using equal as a model. The protocol could also be adopted for screening small molecule inhibitors, targeting each protein 70.

To begin, label two milliliter micro centrifuge tubes. Pipette 50 microliter aliquots of E coli, DnaK 756 cultures into the tubes. Place the tubes on ice.

Add 10 to 50 nanograms of plasmid DNA into each separate tube with the E coli aliquots. Keep the tubes on ice for 30 minutes. Next, place the cells at 42 degrees Celsius for 60 seconds to heat shock the cells.

Pipette 950 microliters of fresh, two times yeast tryptone broth into the tubes. Then incubate the tubes in a shaker at 37 degrees Celsius. Pipette 100 microliters of the transformed cell culture and spread them onto agar plates with two times yeast tryptone containing antibiotics.

Centrifuge the rest of the cells for one minute at 5, 000 G at four degrees Celsius. Decant about 800 microliters of the broth. Re-suspend the pelleted cells in the remaining media.

Plate the recovered cells onto a two times yeast tryptone agar plate. Then incubate both agar plates at 37 degrees Celsius overnight. To plate the cells, use a sterile loop to pick up a single colony from the transformants.

Inoculate it into 10 milliliters of two times yeast tryptone broth supplemented with antibiotics. Now prepare serial dilution of the cells from 100 to 10 to the negative fifth in two milliliter, micro centrifuge tubes. Before spotting the cells, place agar plates supplemented with antibiotics and IPTG in an oven at 40 degrees Celsius with their lids partially open.

Once the plates are dry enough, spot two microliters of the serially diluted cells onto the agar plates. Spot each sample onto two separate plates. Incubate one plate at the permissive growth temperature of 37 degrees Celsius, and the other at the non-permissive growth temperature of 43.5 degrees Celsius.

To confirm the expression of recombinant proteins, use a sterile loop to pick up part of the remaining cells from the same colony of transformants. Inoculate the cells into 10 milliliters of antibiotic supplemented yeast tryptone broth. Incubate the cultures on a shaker overnight at 37 degrees Celsius.

All the E coli DnaK 756 cells grew at the permissive growth temperature of 37 degrees Celsius. However, only heterologous cells expressing DnaK, and KPf grew at the non-permissive growth temperature. Mutant cells expressing KPfV 436F only grew at 37 degrees Celsius, but failed to grow at 43.5 degrees Celsius.

To begin, pipette 80 microliters of transformed E coli cells into a vial. Pipette 20 microliters of four times, lamely SDS loading buffer into the vial. Boil the suspension at 100 degrees Celsius for 10 minutes in a heating block.

Then load 10 microliters of the sample onto a precast SDS gel. Electrophorese the gel at room temperature for one hour at 120 volts in SDS running buffer. Once electrophoresis is complete, stain the gel in Coomassie stain for one hour.

De-stain the gel in a detaining buffer, containing 50%methanol and 10%acetic acid in distilled water for two hours. Place the gel in a gel imaging system to visualize the protein bands. Next, transfer the proteins of the SDS gel to a nitrocellulose membrane.

Wash the nitrocellulose membrane three times in wash buffer. Transfer the membrane to 5%non-fat milk containing antibodies diluted to a ratio of one to 2, 000. Incubate the membrane with the antibodies at four degrees Celsius, while shaking at 60 RPM for one hour.

Next, wash the nitrocellulose membrane in TBS tween buffer, three times for 15 minutes each to remove any non-specifically bound antibody. Now transfer the membrane to a dish with the secondary antibody. Incubate the membrane at four degrees Celsius while shaking at 60 RPM for one hour.

After washing the membrane, as before, use an enhanced chemiluminescence detection reagent to resolve the bands. Visualize the bands, using a gel imager.