2RDH

Crystal structure of Staphylococcal Superantigen-Like protein 11

Summary for 2RDH

• Entry DOI: 10.2210/pdb2rdh/pdb
• Related: 2RDG
• Descriptor: Superantigen-like protein 11, PHOSPHATE ION, SODIUM ION, ... (4 entities in total)
• Functional Keywords: ob fold, beta grasp, toxin
• Biological source: Staphylococcus aureus
• Total number of polymer chains: 4
• Total formula weight: 91151.92

Authors

Chung, M.C.,Wines, B.D.,Baker, H.,Langley, R.J.,Baker, E.N.,Fraser, J.D. (deposition date: 2007-09-24, release date: 2007-12-18, Last modification date: 2023-10-25)

Primary citation

Chung, M.C.,Wines, B.D.,Baker, H.,Langley, R.J.,Baker, E.N.,Fraser, J.D.
The crystal structure of staphylococcal superantigen-like protein 11 in complex with sialyl Lewis X reveals the mechanism for cell binding and immune inhibition
Mol.Microbiol., 66:1342-1355, 2007

PubMed Abstract: Staphylococcus 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.

PubMed: 18045383
DOI: 10.1111/j.1365-2958.2007.05989.x

Experimental method

X-RAY DIFFRACTION (1.7 Å)