Adolescent Health in Myanmar
Support Burnet’s Adolescent Health Programs in Myanmar today.
Support Burnet’s Adolescent Health Programs in Myanmar today.
Support Burnet’s Adolescent Health Programs in Myanmar today.
Support Burnet’s Adolescent Health Programs in Myanmar today.
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.