Download MendeleyStructural and Functional Role of Threonine 112 in a Superantigen Staphylococcus Aureus Enterotoxin B.
Baker, M.D., Papageorgiou, A.C., Titball, R., Miller, J., White, S., Lingard, B., Lee, J., Cavanagh, D., Kehoe, M., Robinson, J., Acharya, K.R.(2002) J Biol Chem 277: 2756
- PubMed: 11704673
- DOI: https://doi.org/10.1074/jbc.M109369200
- Primary Citation of Related Structures:
1GOZ - PubMed Abstract:
Bacterial superantigens are potent T-cell stimulatory protein molecules produced by Staphylococcus aureus and Streptococcus pyogenes. Their superantigenic activity can be attributed to their ability to cross-link major histocompatibility complex class II molecules with T-cell receptors (TCRs) to form a tri-molecular complex. Each superantigen is known to interact with a specific V(beta) element of TCR. Staphylococcal enterotoxin B (SEB, a superantigen), a primary cause of food poisoning, is also responsible for a significant percentage of non-menstrual associated toxic shock syndrome in patients with a variety of staphylococcal infections. Structural studies have elucidated a binding cavity on the toxin molecule essential for TCR binding. To understand the crucial residues involved in binding, mutagenesis analysis was performed. Our analysis suggest that mutation of a conserved residue Thr(112) to Ser (T112S) in the binding cavity induces a selective reduction in the affinity for binding one TCR V(beta) family and can be attributed to the structural differences in the native and mutant toxins. We present a detailed comparison of the mutant structure determined at 2.0 A with the previously reported native SEB and SEB-TCR V(beta) complex structures.
Organizational Affiliation:
Department of Biology and Biochemistry, University of Bath, Claverton Down, Bath BA2 7AY, United Kingdom.
