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Crystal Structure of Staphylococcal Enterotoxin G (SEG) in Complex with a Mouse T-cell Receptor Beta Chain

Journal Article · · Journal of Biological Chemistry
Superantigens (SAgs) are bacterial or viral toxins that bind MHC class II (MHC-II) molecules and T-cell receptor (TCR) in a nonconventional manner, inducing T-cell activation that leads to inflammatory cytokine production, which may result in acute toxic shock. In addition, the emerging threat of purpura fulminans and community-associated meticillin-resistant Staphylococcus aureus emphasizes the importance of a better characterization of SAg binding to their natural ligands that may allow the development of reagents to neutralize their action. The three-dimensional structure of the complex between a mouse TCR {beta} chain (mV{beta}8.2) and staphylococcal enterotoxin G (SEG) at 2.0 {angstrom} resolution revealed a binding site that does not conserve the 'hot spots' present in mV{beta}8.2-SEC2, mV{beta}8.2-SEC3, mV{beta}8.2-SEB, and mV{beta}8.2-SPEA complexes. Analysis of the mV{beta}8.2-SEG interface allowed us to explain the higher affinity of this complex compared with the others, which may account for the early activation of T-cells bearing mV{beta}8.2 by SEG. This mode of interaction between SEG and mV{beta}8.2 could be an adaptive advantage to bestow on the pathogen a faster rate of colonization of the host.
Research Organization:
BROOKHAVEN NATIONAL LABORATORY (BNL)
Sponsoring Organization:
DOE - OFFICE OF SCIENCE
DOE Contract Number:
AC02-98CH10886
OSTI ID:
1018669
Report Number(s):
BNL--95085-2011-JA; KP1605010
Journal Information:
Journal of Biological Chemistry, Journal Name: Journal of Biological Chemistry Journal Issue: 2 Vol. 286; ISSN JBCHA3; ISSN 0021-9258
Country of Publication:
United States
Language:
English