Structural Basis for Abrogated Binding between Staphylococcal Enterotoxin a Superantigen Vaccine and Mhc-II?
Krupka, H.I., Segelke, B.W., Ulrich, R., Ringhofer, S., Knapp, M., Rupp, B.(2002) Protein Sci 11: 642
- PubMed: 11847286 
- DOI: https://doi.org/10.1110/ps.39702
- Primary Citation of Related Structures:  
1DYQ - PubMed Abstract: 
Staphylococcal enterotoxins (SEs) are superantigenic protein toxins responsible for a number of life-threatening diseases. The X-ray structure of a staphylococcal enterotoxin A (SEA) triple-mutant (L48R, D70R, and Y92A) vaccine reveals a cascade of structural rearrangements located in three loop regions essential for binding the alpha subunit of major histocompatibility complex class II (MHC-II) molecules. A comparison of hypothetical model complexes between SEA and the SEA triple mutant with MHC-II HLA-DR1 clearly shows disruption of key ionic and hydrophobic interactions necessary for forming the complex. Extensive dislocation of the disulfide loop in particular interferes with MHC-IIalpha binding. The triple-mutant structure provides new insights into the loss of superantigenicity and toxicity of an engineered superantigen and provides a basis for further design of enterotoxin vaccines.
Organizational Affiliation: 
Lawrence Livermore National Laboratory, Macromolecular Crystallography, Biology and Biotechnology Research Program, University of California, Livermore, California 94551, USA.