2rdh
Crystal structure of Staphylococcal Superantigen-Like protein 11
Structural highlights
FunctionSLL11_STAAU Secreted protein that plays a role in the inhibition of host immune system. Targets myeloid cells such as monocytes or granulocytes through binding with sialyllactosamine-containing glycoproteins (PubMed:18045383). Prevents initial rolling of neutrophils toward the site of infection by interacting with host SELPLG (PubMed:18045383). Disrupts neutrophil motility by induction of cell adhesion via interacting with glycans but independently of SELPLG (PubMed:30862940).[1] [2] 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 PubMedStaphylococcus aureus is a major pathogen that produces a family of 14 staphylococcal superantigen-like (SSL) proteins, which are structurally similar to superantigens but do not stimulate T cells. SSL11 is one member of the family that is found in all staphylococcal strains. Recombinant SSL11 bound to granulocytes and monocytes through a sialic acid-dependent mechanism and was rapidly internalized. SSL11 also bound to sialic acid-containing glycoproteins, such as the Fc receptor for IgA (FcalphaRI) and P-selectin glycoprotein ligand-1 (PSGL-1), and inhibited neutrophil attachment to a P-selectin-coated surface. Biosensor analysis of two SSL11 alleles binding to sialyl Lewis X [sLe(x)- Neu5Acalpha2-3Galbeta1-4(Fuc1-3)GlcNAc] coupled to bovine serum albumin gave dissociation constants of 0.7 and 7 mum respectively. Binding of SSL11 to a glycan array revealed specificity for glycans containing the trisaccharide sialyllactosamine (sLacNac - Neu5Acalpha2-3Galbeta1-4GlcNAc). A 1.6 A resolution crystal structure of SSL11 complexed with sLe(x) revealed a discrete binding site in the C-terminal beta-grasp domain, with predominant interactions with the sialic acid and galactose residues. A single amino acid mutation in the carbohydrate binding site abolished all SSL11 binding. Thus, SSL11 is a staphylococcal protein that targets myeloid cells by binding sialyllactosamine-containing glycoproteins. The crystal structure of staphylococcal superantigen-like protein 11 in complex with sialyl Lewis X reveals the mechanism for cell binding and immune inhibition.,Chung MC, Wines BD, Baker H, Langley RJ, Baker EN, Fraser JD Mol Microbiol. 2007 Dec;66(6):1342-55. PMID:18045383[3] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References
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