2bc3 is a 2 chain structure with sequence from Streptomyces avidinii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf.
Publication Abstract from PubMed
The structure of a full-length streptavidin has been determined at 1.7 A resolution and shows that the 20 residue extension at the C terminus forms a well-ordered polypeptide loop on the surface of the tetramer. Residues 150-153 of the extension are bound to the ligand-binding site, possibly competing with exogenous ligands. The binding mode of these residues is compared with that of biotin and peptidic ligands. The observed structure helps to rationalize the observations that full-length mature streptavidin binds biotinylated macromolecules with reduced affinity.
Crystallographic analysis of a full-length streptavidin with its C-terminal polypeptide bound in the biotin binding site.,Le Trong I, Humbert N, Ward TR, Stenkamp RE J Mol Biol. 2006 Feb 24;356(3):738-45. Epub 2005 Dec 15. PMID:16384581[1]
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.
↑ Le Trong I, Humbert N, Ward TR, Stenkamp RE. Crystallographic analysis of a full-length streptavidin with its C-terminal polypeptide bound in the biotin binding site. J Mol Biol. 2006 Feb 24;356(3):738-45. Epub 2005 Dec 15. PMID:16384581 doi:10.1016/j.jmb.2005.11.086
