2coq

Structure of new antigen receptor variable domain from sharks

spinqualitylabelsall models 2coq, resolution 2.10Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 2coq is a 1 chain structure with sequence from Orectolobus maculatus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Related: 1ver, 1ves Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT 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 new antigen receptor (IgNAR) antibodies from sharks are disulphide bonded dimers of two protein chains, each containing one variable and five constant domains. Three types of IgNAR variable domains have been discovered, with Type 3 appearing early in shark development and being overtaken by the antigen-driven affinity-matured Type 1 and 2 response. Here, we have determined the first structure of a naturally occurring Type 2 IgNAR variable domain, and identified the disulphide bond that links and stabilizes the CDR1 and CDR3 loops. This disulphide bridge locks the CDR3 loop in an "upright" conformation in contrast to other shark antibody structures, where a more lateral configuration is observed. Further, we sought to model the Type 3 isotype based on the crystallographic structure reported here. This modeling indicates (1) that internal Type 3-specific residues combine to pack into a compact immunoglobulin core that supports the CDR loop regions, and (2) that despite apparent low-sequence variability, there is sufficient plasticity in the CDR3 loop to form a conformationally diverse antigen-binding surface. Structure of a shark IgNAR antibody variable domain and modeling of an early-developmental isotype.,Streltsov VA, Carmichael JA, Nuttall SD Protein Sci. 2005 Nov;14(11):2901-9. Epub 2005 Sep 30. PMID:16199666 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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