1t0m
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(New page: 200px<br /><applet load="1t0m" size="450" color="white" frame="true" align="right" spinBox="true" caption="1t0m, resolution 2.0Å" /> '''Conformational switch...)
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Revision as of 00:46, 21 November 2007
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Conformational switch in polymorphic H-2K molecules containing an HSV peptide
Overview
Polymorphism within the MHC not only affects peptide specificity but also, has a critical influence on the T cell repertoire; for example, the CD8 T, cell response toward an immunodominant HSV glycoprotein B peptide is more, diverse and of higher avidity in H-2(bm8) compared with H-2(b) mice. We, have examined the basis for the selection of these distinct antiviral T, cell repertoires by comparing the high-resolution structures of K(b) and, K(bm8), in complex with cognate peptide Ag. Although K(b) and K(bm8), differ by four residues within the Ag-binding cleft, the most striking, difference in the two structures was the disparate conformation adopted by, the shared residue, Arg(62). The altered dynamics of Arg(62), coupled with, a small rigid-body movement in the alpha(1) helix encompassing this, residue, correlated with biased Valpha usage in the B6 mice. Moreover, an, analysis of all known TCR/MHC complexes reveals that Arg(62) invariably, interacts with the TCR CDR1alpha loop. Accordingly, Arg(62) appears to, function as a conformational switch that may govern T cell selection and, protective immunity.
About this Structure
1T0M is a Protein complex structure of sequences from Mus musculus. Full crystallographic information is available from OCA.
Reference
The structure of H-2K(b) and K(bm8) complexed to a herpes simplex virus determinant: evidence for a conformational switch that governs T cell repertoire selection and viral resistance., Webb AI, Borg NA, Dunstone MA, Kjer-Nielsen L, Beddoe T, McCluskey J, Carbone FR, Bottomley SP, Aguilar MI, Purcell AW, Rossjohn J, J Immunol. 2004 Jul 1;173(1):402-9. PMID:15210799
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