User:Mariel Feliciano

Glucose/galactose-binding protein (GGBP) from ''[http://en.wikipedia.org/wiki/E._coli E. coli]'' is found in the [http://en.wikipedia.org/wiki/Periplasm periplasm] of the [http://en.wikipedia.org/wiki/Bacteria bacterium]. This protein is involved in the transport of [http://en.wikipedia.org/wiki/Glucose glucose]as well as the [http://en.wikipedia.org/wiki/Chemotaxis chemotaxis] toward it. It is composed of two [http://en.wikipedia.org/wiki/Rossman_fold Rossman folds] separated by three short segments of [http://en.wikipedia.org/wiki/Amino_acids amino acids] termed the <scene name='User:Mariel_Feliciano/Hinges_red/1'>"hinges"</scene> because on their role in the opening/closing mechanism of the protein. The protein exists in two conformations: glucose-bound (closed) and unbound (open). Upon ligand binding, changes in the torsional angles of the amino acids that compose the hinges produce a conformational change between the two domains that stabilize the closed conformation. Analysis of the structure with [http://consurf.tau.ac.il/ consurf] shows that amino acids that line the <scene name='User:Mariel_Feliciano/Binding_site_conserved_residue/1'>binding site</scene> and amino acids that compose the hinges are the most conserved. Despite its homology with other sugar-binding proteins like ribose-binding protein (RBP), the changes in torsional angles of the amino acids that compose the hinges and trigger the conformational changes between domains differ in both proteins. One of the structures reported in this article (PDB ID 2FW0) is the first crystal structure of the protein in its open conformation. The other structure reported in this article (PDB ID 2FVY) is an ultra-high resolution (0.95Å) crystal structure of the glucose-bound protein.