1ac6
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(New page: 200px<br /><applet load="1ac6" size="450" color="white" frame="true" align="right" spinBox="true" caption="1ac6, resolution 2.3Å" /> '''CRYSTAL STRUCTURE OF ...)
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Revision as of 08:37, 20 November 2007
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CRYSTAL STRUCTURE OF A VARIABLE DOMAIN MUTANT OF A T-CELL RECEPTOR ALPHA CHAIN
Overview
The crystal structure of a mutant T cell receptor (TCR) V alpha domain, containing a grafted third complementarity-determining region (CDR3) from, a different V alpha was determined at 2.3 A resolution by molecular, replacement using the wild-type V alpha structure as a search model. Like, the wild-type V alpha domain, the mutant crystallized as a homodimer very, similar to TCR V alpha V beta and antibody V(L)V(H) heterodimers, with the, CDR loops disposed to form part of the antigen-binding site. However, the, relative orientation of the two chains in the mutant V alpha homodimer, differs from that in the wild-type by a rotation of 14 degrees such that, the buried surface area in the dimer interface of the mutant is 140 A2, less than in the wild-type. While the residues forming the interface are, essentially the same in the two structures, there are only four pairs of, interface hydrogen bonds in the case of the mutant compared with eight for, the wild-type. These results suggest that multiple relative orientations, of the V alpha and V beta domains of TCRs may be possible, providing a, significant contribution to TCR combining site diversity.
About this Structure
1AC6 is a Single protein structure of sequence from Mus musculus. Full crystallographic information is available from OCA.
Reference
Dual conformations of a T cell receptor V alpha homodimer: implications for variability in V alpha V beta domain association., Li H, Lebedeva MI, Ward ES, Mariuzza RA, J Mol Biol. 1997 Jun 13;269(3):385-94. PMID:9199407
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