3q5t

Publication Abstract from PubMed

The alphabeta T cell receptor (TCR) is a multimeric complex whose beta chain plays a crucial role in thymocyte development as well as antigen recognition by mature T lymphocytes. We report here crystal structures of individual beta subunits, termed N15beta (Vbeta5.2Dbeta2Jbeta2.6Cbeta2) and N30beta (Vbeta13Dbeta1Jbeta1.1Cbeta2), derived from two alphabeta TCRs specific for the immunodominant vesicular stomatitis virus octapeptide (VSV-8) bound to the murine H-2K(b) MHC class I molecule. The crystal packing of the N15beta structure reveals a homodimer formed through two Vbeta domains. The Vbeta/Vbeta module is topologically very similar to the Valpha/Vbeta module in the N15alphabeta heterodimer. By contrast, in the N30beta structure, the Vbeta domain's external hydrophobic CFG face is covered by the neighboring molecule's Cbeta domain. In conjunction with systematic investigation of previously published TCR single-subunit structures, we identified several conserved residues forming a concave hydrophobic patch at the center of the CFG outer face of the Vbeta and other V-type Ig-like domains. This hydrophobic patch is shielded from solvent exposure in the crystal packing, implying that it is unlikely to be thermodynamically stable if exposed on the thymocyte surface. Accordingly, we propose a dimeric pre-TCR model distinct from those suggested previously by others and discuss its functional and structural implications.

A conserved hydrophobic patch on Vbeta domains revealed by TCRbeta chain crystal structures: Implications for pre-TCR dimerization.,Zhou B, Chen Q, Mallis RJ, Zhang H, Liu JH, Reinherz EL, Wang JH Front Immunol. 2011;2:5. doi: 10.3389/fimmu.2011.00005. Epub 2011 Mar 1. PMID:22566796^[1]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine.