3e2h
From Proteopedia
Structure of the m67 high-affinity mutant of the 2C TCR in complex with Ld/QL9
Structural highlights
FunctionHA1L_MOUSE Involved in the presentation of foreign antigens to the immune system. Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedT cells are known to cross-react with diverse peptide MHC Ags through their alphabeta TCR. To explore the basis of such cross-reactivity, we examined the 2C TCR that recognizes two structurally distinct ligands, SIY-K(b) and alloantigen QL9-L(d). In this study we characterized the cross-reactivity of several high-affinity 2C TCR variants that contained mutations only in the CDR3alpha loop. Two of the TCR lost their ability to cross-react with the reciprocal ligand (SIY-K(b)), whereas another TCR (m67) maintained reactivity with both ligands. Crystal structures of four of the TCRs in complex with QL9-L(d) showed that CDR1, CDR2, and CDR3beta conformations and docking orientations were remarkably similar. Although the CDR3alpha loop of TCR m67 conferred a 2000-fold higher affinity for SIY-K(b), the TCR maintained the same docking angle on QL9-L(d) as the 2C TCR. Thus, CDR3alpha dictated the affinity and level of cross-reactivity, yet it did so without affecting the conserved docking orientation. Distinct CDR3 conformations in TCRs determine the level of cross-reactivity for diverse antigens, but not the docking orientation.,Jones LL, Colf LA, Stone JD, Garcia KC, Kranz DM J Immunol. 2008 Nov 1;181(9):6255-64. PMID:18941216[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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