2ol3
From Proteopedia
crystal structure of BM3.3 ScFV TCR in complex with PBM8-H-2KBM8 MHC class I molecule
Overview
Binding degeneracy is thought to constitute a fundamental property of the T-cell antigen receptor (TCR), yet its structural basis is poorly understood. We determined the crystal structure of a complex involving the BM3.3 TCR and a peptide (pBM8) bound to the H-2K(bm8) major histocompatibility complex (MHC) molecule, and compared it with the structures of the BM3.3 TCR bound to H-2K(b) molecules loaded with two peptides that had a minimal level of primary sequence identity with pBM8. Our findings provide a refined structural view of the basis of BM3.3 TCR cross-reactivity and a structural explanation for the long-standing paradox that a TCR antigen-binding site can be both specific and degenerate. We also measured the thermodynamic features and biological penalties that incurred during cross-recognition. Our data illustrate the difficulty for a given TCR in adapting to distinct peptide-MHC surfaces while still maintaining affinities that result in functional in vivo responses. Therefore, when induction of protective effector T cells is used as the ultimate criteria for adaptive immunity, TCRs are probably much less degenerate than initially assumed.
About this Structure
2OL3 is a Protein complex structure of sequences from Mus musculus. Full crystallographic information is available from OCA.
Reference
How much can a T-cell antigen receptor adapt to structurally distinct antigenic peptides?, Mazza C, Auphan-Anezin N, Gregoire C, Guimezanes A, Kellenberger C, Roussel A, Kearney A, van der Merwe PA, Schmitt-Verhulst AM, Malissen B, EMBO J. 2007 Apr 4;26(7):1972-83. Epub 2007 Mar 15. PMID:17363906 Page seeded by OCA on Sun May 4 11:08:24 2008
