Download MendeleyCrystal structure of a superantigen bound to the high-affinity, zinc-dependent site on MHC class II.
Li, Y., Li, H., Dimasi, N., McCormick, J.K., Martin, R., Schuck, P., Schlievert, P.M., Mariuzza, R.A.(2001) Immunity 14: 93-104
- PubMed: 11163233
- DOI: https://doi.org/10.1016/s1074-7613(01)00092-9
- Primary Citation of Related Structures:
1HQR - PubMed Abstract:
MHC class II molecules possess two binding sites for bacterial superantigens (SAGs): a low-affinity site on the alpha chain and a high-affinity, zinc-dependent site on the beta chain. Only the former has been defined crystallographically. We report the structure of streptococcal pyrogenic exotoxin C (SPE-C) complexed with HLA-DR2a (DRA*0101, DRB5*0101) bearing a self-peptide from myelin basic protein (MBP). SPE-C binds the beta chain through a zinc bridge that links the SAG and class II molecules. Surprisingly, SPE-C also makes extensive contacts with the MBP peptide, such that peptide accounts for one third of the surface area of the MHC molecule buried in the complex, similar to TCR-peptide/MHC complexes. Thus, SPE-C may optimize T cell responses by mimicking the peptide dependence of conventional antigen presentation and recognition.
Organizational Affiliation:
Center for Advanced Research in Biotechnology, University of Maryland Biotechnology Institute, Rockville, MD 20850, USA.
