An alternative conformation of the T-cell receptor alpha constant region

J Mol Biol. 2010 Jul 23;400(4):828-37. doi: 10.1016/j.jmb.2010.05.053. Epub 2010 May 31.

Abstract

Alphabeta T-cell receptors (TcRs) play a central role in cellular immune response. They are members of the Ig superfamily, with extracellular regions of the alpha and beta chains each comprising a V-type domain and a C-type domain. We have determined the ectodomain structure of an alphabeta TcR, which recognizes the autoantigen myelin basic protein. The 2.0-A-resolution structure reveals canonical main-chain conformations for the V(alpha), V(beta), and C(beta) domains, but the C(alpha) domain exhibits a main-chain conformation remarkably different from those previously reported for TcR crystal structures. The global IgC-like fold is maintained, but a piston-like rearrangement between BC and DE beta-turns results in beta-strand slippage. This substantial conformational change may represent a signaling intermediate. Our structure is the first example for the Ig fold of the increasingly recognized concept of "metamorphic proteins."

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Crystallography, X-Ray
  • Mice
  • Models, Molecular
  • Molecular Sequence Data
  • Protein Conformation
  • Protein Structure, Quaternary
  • Receptors, Antigen, T-Cell, alpha-beta / chemistry*

Substances

  • Receptors, Antigen, T-Cell, alpha-beta

Associated data

  • PDB/3MFF