4rgm

Structure of Staphylococcal Enterotoxin B bound to the neutralizing antibody 20B1

spinqualitylabelsall models 4rgm, resolution 2.69Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image   Print3D Structural highlights 4rgm is a 6 chain structure with sequence from Mus musculus and Staphylococcus aureus. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.689Å Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function ETXB_STAAU Staphylococcal enterotoxins cause the intoxication staphylococcal food poisoning syndrome. The illness characterized by high fever, hypotension, diarrhea, shock, and in some cases death. Publication Abstract from PubMed Staphylococcal enterotoxin B (SEB) is a superantigen that cross-links the major histocompatibility complex class-II (MHC- II) and specific V-beta chains of the T-cell receptor (TCR) thus forming a ternary complex. Developing neutralizing monoclonal antibodies (mAb) to disrupt the ternary complex and abrogate the resulting toxicity is a major therapeutic challenge because SEB is effective at very low concentrations. We show that combining two SEB-specific mAbs enhances their efficacy even though one of the two mAbs by itself has no effect on neutralization. Crystallography was employed for fine- mapping of conformational epitopes in binary and ternary complexes between SEB and Fab fragments. NMR spectroscopy was used to validate and identify subtle allosteric changes induced by mAbs-binding to SEB. The mapping of epitopes established that combination of different mAbs can enhance efficacy of mAb-mediated protection from SEB induced lethal shock by two different mechanisms: one mAb cocktail promoted clearance of the toxin both in vitro and in vivo by FcR mediated crosslinking and clearance; whereas the other mAb cocktail induced subtle allosteric conformational changes in SEB that perturbed formation of the SEB:TCR:MHC-II trimer. Finally structural information accurately predicted mAb binding to other superantigens that share conformational epitopes with SEB. Fine mapping of conformational epitopes is a powerful tool to establish the mechanism and optimize the action of synergistic mAb combinations. Mechanisms mediating enhanced neutralization efficacy of staphyloccoccal enterotoxin B by combinations of monoclonal antibodies.,Dutta K, Varshney AK, Franklin MC, Goger M, Wang X, Fries BC J Biol Chem. 2015 Jan 8. pii: jbc.M114.630715. PMID:25572397 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also Monoclonal Antibodies 3D structures

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