6fe4 | pdb_00006fe4

Crystal structure of the complex between Shiga toxin Stx2 B subunit and neutralising Nb113

spinqualitylabelsall models 6fe4, resolution 3.00Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 6fe4 is a 10 chain structure with sequence from Alpaca and Bp933. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Gene: stxB2, stx2B, L0104 (BP933) Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function [STXB_BP933] The B subunit is responsible for the binding of the holotoxin to specific receptors on the target cell surface, such as globotriaosylceramide (Gb3) in human intestinal microvilli. Publication Abstract from PubMed BACKGROUND: Shiga toxin-producing Escherichia coli (STEC) are a subset of pathogens leading to illnesses such as diarrhea, hemolytic uremic syndrome and even death. The Shiga toxins are the main virulence factors and divided in two groups: Stx1 and Stx2, of which the latter is more frequently associated with severe pathologies in humans. RESULTS: An immune library of nanobodies (Nbs) was constructed after immunizing an alpaca with recombinant Shiga toxin-2a B subunit (rStx2aB), to retrieve multiple rStx2aB-specific Nbs. The specificity of five Nbs towards rStx2aB was confirmed in ELISA and Western blot. Nb113 had the highest affinity (9.6 nM) and its bivalent construct exhibited a 100-fold higher functional affinity. The structure of the Nb113 in complex with rStx2aB was determined via X-ray crystallography. The crystal structure of the Nb113-rStx2aB complex revealed that five copies of Nb113 bind to the rStx2aB pentamer and that the Nb113 epitope overlaps with the Gb3 binding site, thereby providing a structural basis for the neutralization of Stx2a by Nb113 that was observed on Vero cells. Finally, the tandem-repeated, bivalent Nb113(2) exhibits a higher toxin neutralization capacity compared to monovalent Nb113. CONCLUSIONS: The Nb of highest affinity for rStx2aB is also the best Stx2a and Stx2c toxin neutralizing Nb, especially in a bivalent format. This lead Nb neutralizes Stx2a by competing for the Gb3 receptor. The fusion of the bivalent Nb113(2) with a serum albumin specific Nb is expected to combine high toxin neutralization potential with prolonged blood circulation. Structural Basis for the Specific Neutralization of Stx2a with a Camelid Single Domain Antibody Fragment.,Bernedo-Navarro RA, Romao E, Yano T, Pinto J, De Greve H, Sterckx YG, Muyldermans S Toxins (Basel). 2018 Mar 1;10(3). pii: toxins10030108. doi:, 10.3390/toxins10030108. PMID:29494518 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.

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