seeded-synthesis-of-cdsecds-rod-and-tetrapod-nanocrystals

Seeded Synthesis of CdSe/CdS Rod and Tetrapod Nanocrystals

We demonstrate a method for the synthesis of multicomponent nanostructures consisting of CdS and CdSe with rod and tetrapod morphologies. A seeded ...

UC Berkeley

Lawrence Berkeley National Laboratory

Gaussia luciferase (GLuc) from the copepod Gaussia princeps is both the smallest and brightest known luciferase. GLuc catalyzes the oxidation of coelenterazine to produce an intense blue light but with a very short emission half-life. We report mutated GLucs with much longer luminescence half-lives that retain the same initial intensity as the wild-type enzyme. The GLuc variants were produced using cell-free protein synthesis to provide high yields and rapid production of fully active product as well as simple non-natural amino acid substitution. By incorporating homopropargylglycine and attaching PEG using azide-alkyne click reactions, we also show that the four methionines in GLuc are surface accessible. The mutants provide a significantly improved reporter protein for both in vivo and in vitro studies, and the successful non-natural amino acid incorporation and PEG attachment indicate the feasibility of producing useful bioconjugates using click attachment reactions.

Multiply mutated Gaussia luciferases provide prolonged and intense bioluminescence.

The Hsp70 family of molecular chaperones is an essential class of chaperones that is present in many different cell types and cellular compartments. We have compared the bioactivities of the prokaryotic cytosolic Hsp70, DnaK, to that of the eukaryotic Hsp70, BiP, located in the endoplasmic reticulum (ER). Both chaperones helped to prevent protein aggregation. However, only DnaK provided enhanced refolding of denatured proteins. We also tested chaperone folding assistance during translation in the context of cell-free protein synthesis reactions for several protein targets and show that both DnaK and BiP can provide folding assistance under these conditions. Our results support previous reports suggesting that DnaK provides both post-translational and co-translational folding assistance while BiP predominantly provides folding assistance that is contemporaneous with translation.

Comparing the functional properties of the Hsp70 chaperones, DnaK and BiP.

Transition-metal oxide nanocrystals are interesting candidates for localized surface plasmon resonance hosts because they exhibit fascinating properties arising from the unique character of their outer-d valence electrons. WO(3-δ) nanoparticles are known to have intense visible and near-IR absorption, but the origin of the optical absorption has remained unclear. Here we demonstrate that metallic phases of WO(3-δ) nanoparticles exhibit a strong and tunable localized surface plasmon resonance, which opens up the possibility of rationally designing plasmonic tungsten oxide nanoparticles for light harvesting, bioimaging, and sensing.

Tunable localized surface plasmon resonances in tungsten oxide nanocrystals.

A (nano)crystal-clear view: With doped semiconductor nanocrystals, local chemical events can be probed through their perturbation of the carrier density of the nanocrystal. Examples demonstrate that redox processes and ligand chemistry can induce changes in the vacancy density within copper(I) sulfide nanorods, allowing such events to be detected by strong shifts in localized surface plasmon resonance.

Article	Year
Multiply mutated Gaussia luciferases provide prolonged and intense bioluminescence. Biochemical and biophysical research communications\| PubMed ID: 19825431	2009
Comparing the functional properties of the Hsp70 chaperones, DnaK and BiP. Biophysical chemistry\| PubMed ID: 20435400	2010
Tunable localized surface plasmon resonances in tungsten oxide nanocrystals. Journal of the American Chemical Society\| PubMed ID: 22332881	2012
Doped Nanocrystals as Plasmonic Probes of Redox Chemistry. Angewandte Chemie (International ed. in English)\| PubMed ID: 24155083	2013

Karthish Manthiram

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