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Investigators at University of Oxford Report New Data on Bacterial Proteins

March 4, 2014



By a News Reporter-Staff News Editor at Life Science Weekly -- Current study results on Proteins have been published. According to news reporting originating from Oxford, United Kingdom, by NewsRx correspondents, research stated, "Streptavidin is one of the most important hubs for molecular biology, either multimerizing biomolecules, bridging one molecule to another, or anchoring to a biotinylated surface/nanoparticle. Streptavidin has the advantage of rapid ultra-stable binding to biotin."

Our news editors obtained a quote from the research from the University of Oxford, "However, the ability of streptavidin to bind four biotinylated molecules in a heterogeneous manner is often limiting. Here, we present an efficient approach to isolate streptavidin tetramers with two biotin-binding sites in a precise arrangement, cis or trans. We genetically modified specific subunits with negatively charged tags, refolded a mixture of monomers, and used ion-exchange chromatography to resolve tetramers according to the number and orientation of tags. We solved the crystal structures of cis-divalent streptavidin to 1.4A resolution and trans-divalent streptavidin to 1.6A resolution, validating the isolation strategy and explaining the behavior of the Dead streptavidin variant. cis-and trans-divalent streptavidins retained tetravalent streptavidin's high thermostability and low off-rate. These defined divalent streptavidins enabled us to uncover how streptavidin binding depends on the nature of the biotin ligand. Biotinylated DNA showed strong negative cooperativity of binding to cis-divalent but not trans-divalent streptavidin. A small biotinylated protein bound readily to cis and trans binding sites. We also solved the structure of trans-divalent streptavidin bound to biotin-4-fluorescein, showing how one ligand obstructs binding to an adjacent biotin-binding site. Using a hexaglutamate tag proved a more powerful way to isolate monovalent streptavidin, for ultra-stable labeling without undesired clustering."

According to the news editors, the research concluded: "These forms of streptavidin allow this key hub to be used with a new level of precision, for homogeneous molecular assembly."

For more information on this research see: Plug-and-play pairing via defined divalent streptavidins. Jmb Online, 2014;426(1):199-214 (see also Proteins).

The news editors report that additional information may be obtained by contacting M. Fairhead, Dept. of Biochemistry, University of Oxford, South Parks Road, Oxford OX1 3QU, UK. Additional authors for this research include D. Krndija, E.D. Lowe and M. Howarth.

Keywords for this news article include: Oxford, Europe, Streptavidin, United Kingdom, Bacterial Proteins.

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Source: Life Science Weekly


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