PDBsum entry 1l0x

Immune system

PDB id: 1l0x

Contents

Protein chains

236 a.a. *

221 a.a. *

Ligands

GOL ×3

Waters ×181

* Residue conservation analysis

References listed in PDB file

Key reference

• Title: Structures of two streptococcal superantigens bound to tcr beta chains reveal diversity in the architecture of t cell signaling complexes.
• Authors: E.J.Sundberg, H.Li, A.S.Llera, J.K.Mccormick, J.Tormo, P.M.Schlievert, K.Karjalainen, R.A.Mariuzza.
• Ref.: Structure, 2002, 10, 687-699. [DOI no: 10.1016/S0969-2126(02)00759-1]
• PubMed id: 12015151

Abstract

Superantigens (SAGs) crosslink MHC class II and TCR molecules, resulting in an overstimulation of T cells associated with human disease. SAGs interact with several different surfaces on MHC molecules, necessitating the formation of multiple distinct MHC-SAG-TCR ternary signaling complexes. Variability in SAG-TCR binding modes could also contribute to the structural heterogeneity of SAG-dependent signaling complexes. We report crystal structures of the streptococcal SAGs SpeA and SpeC in complex with their corresponding TCR beta chain ligands that reveal distinct TCR binding modes. The SpeC-TCR beta chain complex structure, coupled with the recently determined SpeC-HLA-DR2a complex structure, provides a model for a novel T cell signaling complex that precludes direct TCR-MHC interactions. Thus, highly efficient T cell activation may be achieved through structurally diverse strategies of TCR ligation.

Figure 3.
Figure 3. Diverse TCR b Chain Molecular Surface Burial by Bacterial SuperantigensMolecular surface of (A) hVb2.1 buried by SpeC, (B) mVb8.2 buried by SpeA, and (C) mVb8.2 buried by SEB. Colors are as follows: CDR1 buried molecular surface, red; CDR2 and associated FR buried molecular surface, green; HV4 and associated FR buried molecular surface, yellow; CDR3 buried molecular surface, blue.

The above figure is reprinted by permission from Cell Press: Structure (2002, 10, 687-699) copyright 2002.