1AC6

CRYSTAL STRUCTURE OF A VARIABLE DOMAIN MUTANT OF A T-CELL RECEPTOR ALPHA CHAIN

Summary for 1AC6

• Entry DOI: 10.2210/pdb1ac6/pdb
• Descriptor: T-CELL RECEPTOR ALPHA (2 entities in total)
• Functional Keywords: receptor, v alpha domain, site-directed mutagenesis, three-dimensional structure, glycoprotein
• Biological source: Mus musculus (house mouse)
• Total number of polymer chains: 2
• Total formula weight: 24208.55

Authors

Li, H.-M.,Mariuzza, R.A. (deposition date: 1997-02-13, release date: 1998-02-25, Last modification date: 2024-10-30)

Primary citation

Li, H.,Lebedeva, M.I.,Ward, E.S.,Mariuzza, R.A.
Dual conformations of a T cell receptor V alpha homodimer: implications for variability in V alpha V beta domain association.
J.Mol.Biol., 269:385-394, 1997

PubMed Abstract: 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.

PubMed: 9199407
DOI: 10.1006/jmbi.1997.1047

Experimental method

X-RAY DIFFRACTION (2.3 Å)