3chb

CHOLERA TOXIN B-PENTAMER COMPLEXED WITH GM1 PENTASACCHARIDE

spinqualitylabelsall models 3chb, resolution 1.25Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 3chb is a 5 chain structure with sequence from Vibrio cholerae. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 1.25Å Ligands: BGC, GAL, GLC, MES, NGA, SIA, UNX Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function CHTB_VIBCH The B subunit pentameric ring directs the A subunit to its target by binding to the GM1 gangliosides present on the surface of the intestinal epithelial cells. It can bind five GM1 gangliosides. It has no toxic activity by itself. Publication Abstract from PubMed Crystals of the 61 kDa complex of the cholera toxin B-pentamer with the ganglioside GM1 receptor pentasaccharide diffract to near-atomic resolution. We have refined the crystallographic model for this complex using anisotropic displacement parameters for all atoms to a conventional crystallographic residual R=0.129 for all observed Bragg reflections in the resolution range 22 A to 1.25 A. Remarkably few residues show evidence of discrete conformational disorder. A notable exception is a minority conformation found for the Cys9 side-chain, which implies that the Cys9-Cys86 disulfide linkage is incompletely formed. In all five crystallographically independent instances, the peptide backbone in the region of the receptor-binding site shows evidence of strain, including unusual bond lengths and angles, and a highly non-planar (omega=153.7(7) degrees) peptide group between residues Gln49 and Val50. The location of well-ordered water molecules at the protein surface is notable reproduced among the five crystallographically independent copies of the peptide chain, both at the receptor-binding site and elsewhere. The 5-fold non-crystallographic symmetry of this complex allows an evaluation of the accuracy, reproducibility, and derived error estimates from refinement of large structures at near-atomic resolution. We find that blocked-matrix treatment of parameter covariance underestimates the uncertainty of atomic positions in the final model by approximately 10% relative to estimates based either on full-matrix inversion or on the 5-fold non-crystallographic symmetry. The 1.25 A resolution refinement of the cholera toxin B-pentamer: evidence of peptide backbone strain at the receptor-binding site.,Merritt EA, Kuhn P, Sarfaty S, Erbe JL, Holmes RK, Hol WG J Mol Biol. 1998 Oct 9;282(5):1043-59. PMID:9753553 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Cholera toxin 3D structures User:David Solfiell/sandbox 1

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