5xpw

Structure of amphioxus IgVJ-C2 molecule

spinqualitylabelsall models 5xpw, resolution 2.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 5xpw is a 1 chain structure with sequence from Branchiostoma floridae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.003Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function C3ZN36_BRAFL Publication Abstract from PubMed The emergence of adaptive immunity in jawed vertebrates depended on the appearance of variable immune receptors, BCRs and TCRs, which exhibit variable-J-constant (VJ-C)-type Ig superfamily folds. Hitherto, however, the structures of IgV-J-IgC-type molecules had never been characterized in invertebrates, leaving the origin of BCR/TCR-type molecules unknown. Using x-ray crystallography, the structure of a VJ-C2 molecule, named AmpIgVJ-C2, was determined in amphioxus (Branchiostoma floridae). The first domain shows typical V folding, including the hydrophobic core, CDR analogs, and eight conserved residues. The second domain is a C2-type Ig superfamily domain, as defined by its short length and the absence of beta-strand D- and C1-typical motifs. AmpIgVJ-C2 molecules form homodimers, using "three-layer packing dimerization," as described for TCRs and BCRs. The AmpIgVJ-C2 V domain harbors a diglycine motif in beta-strand G and forms a beta-bulge structure participating in V-V intermolecular interaction. By immunohistochemistry, AmpIgVJ-C2 molecules were primarily found in mucosal tissues, whereas PCR and sequence analysis indicated considerable genetic variation at the single-gene level; these findings would be consistent with an immune function and a basic ability to adapt to binding different immune targets. Our results show a BCR/TCR-ancestral like molecule in amphioxus and help us to understand the evolution of the adaptive immune system. Discovery and Analysis of Invertebrate IgVJ-C2 Structure from Amphioxus Provides Insight into the Evolution of the Ig Superfamily.,Chen R, Zhang L, Qi J, Zhang N, Zhang L, Yao S, Wu Y, Jiang B, Wang Z, Yuan H, Zhang Q, Xia C J Immunol. 2018 Apr 15;200(8):2869-2881. doi: 10.4049/jimmunol.1700906. Epub 2018, Mar 7. PMID:29514951 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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