FIG. 3.

Crystal structure illustration of the A6 TCR HLA-A2–Tax11-19. One corner of the apex of the Vβ CDR3 loop (GLAG) inserts into a hydrophobic pocket formed by the alpha-1 helix of HLA-A2 and the side chain of the Tyr residue at position 8 in the Tax 11-19 peptide. The hydrophobic Leu residue at position 98 on the TCR Vβ loop makes several strong interactions with both the Tax peptide and HLA-A2. Leu is strongly favored (34 of 38 clones) at this position in the Vβ13.1-containing clonally expanded CD8⁺ T cells that bind the HLA-A2–Tax11-19 tetramer. The illustration was created by using MolScript (6) and Raster3D (18).