2wd6 | pdb_00002wd6

Crystal structure of the Variable Domain of the Streptococcus gordonii Surface Protein SspB

spinqualitylabelsall models 2wd6, resolution 2.30Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2wd6 is a 2 chain structure with sequence from Streptococcus gordonii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.3Å Ligands: CA, GOL, K Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function SSPB_STRGN May bind sialic acid residues of salivary agglutinin (SAG) in a calcium-dependent reaction. The interaction of SAG with its receptor in various oral streptococci modulate bacterial colonization of oral tissue and is associated with reduced levels of dental caries. Evolutionary Conservation 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 Antigen I/II (AgI/II) family of proteins are cell wall anchored adhesins expressed on the surface of oral streptococci. The AgI/II proteins interact with molecules on other bacteria, on the surface of host cells, and with salivary proteins. Streptococcus gordonii is a commensal bacterium, and one of the primary colonizers that initiate the formation of the oral biofilm. S. gordonii expresses two AgI/II proteins, SspA and SspB that are closely related. One of the domains of SspB, called the variable (V-) domain, is significantly different from corresponding domains in SspA and all other AgI/II proteins. As a first step to elucidate the differences among these proteins, we have determined the crystal structure of the V-domain from S. gordonii SspB at 2.3 A resolution. The domain comprises a betabeta-supersandwich with a putative binding cleft stabilized by a metal ion. The overall structure of the SspB V-domain is similar to the previously reported V-domain of the Streptococcus mutans protein SpaP, despite their low sequence similarity. In spite of the conserved architecture of the binding cleft, the cavity is significantly smaller in SspB which may provide clues about the difference in ligand specificity. We also verified that the metal in the binding cleft is a calcium ion, in concurrence with previous biological data. It was previously suggested that AgI/II V-domains are carbohydrate binding. However, we tested that hypothesis by screening the SspB V-domain for binding to over 400 glycoconjucates and found that the domain does not interact with any of the carbohydrates. Crystal structure of the variable domain of the Streptococcus gordonii surface protein SspB.,Forsgren N, Lamont RJ, Persson K Protein Sci. 2009 Jul 16. PMID:19609934 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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