2h3h
Crystal structure of the liganded form of Thermotoga maritima glucose binding protein
Structural highlights
FunctionEvolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedWe report the design and engineering of a robust, reagentless fluorescent glucose biosensor based on the periplasmic glucose-binding protein obtained from Thermotoga maritima (tmGBP). The gene for this protein was cloned from genomic DNA and overexpressed in Escherichia coli, the identity of its cognate sugar was confirmed, ligand binding was studied, and the structure of its glucose complex was solved to 1.7 Angstrom resolution by X-ray crystallography. TmGBP is specific for glucose and exhibits high thermostability (midpoint of thermal denaturation is 119 +/- 1 degrees C and 144 +/- 2 degrees C in the absence and presence of 1 mM glucose, respectively). A series of fluorescent conjugates was constructed by coupling single, environmentally sensitive fluorophores to unique cysteines introduced by site-specific mutagenesis at positions predicted to be responsive to ligand-induced conformational changes based on the structure. These conjugates were screened to identify engineered tmGBPs that function as reagentless fluorescent glucose biosensors. The Y13C*Cy5 conjugate is bright, gives a large response to glucose over concentration ranges appropriate for in vivo monitoring of blood glucose levels (1-30 mM), and can be immobilized in an orientation-specific manner in microtiter plates to give a reversible response to glucose. The immobilized protein retains its response after long-term storage at room temperature. Structure-based design of robust glucose biosensors using a Thermotoga maritima periplasmic glucose-binding protein.,Tian Y, Cuneo MJ, Changela A, Hocker B, Beese LS, Hellinga HW Protein Sci. 2007 Oct;16(10):2240-50. Epub 2007 Aug 31. PMID:17766373[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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