Figure 6 - A germline-encoded surface is required for recognition of CD1d-glycolipid complexes.

(a) Predicted surface CDR map of V14i-DO TCR (far left; CDR loop colors, key). Because the CDR3 loop of the human V24i-NKT15 TCR that has been crystallized is longer than that of DO-11.10, the TCR chain from the V24i-V11 TCR iNKT (Protein Data Bank accession code, 2CDE), which has the same CDR3 length as that of DO, was modeled onto the V24i-NKT15 TCR from the TCR–CD1d–-GalCer crystal structure. Individual DO-11.10 CDR3 residues were then replaced in the V24i-2CDE model for the surface map. In the TCR surfaces identified by mutational analysis (right), residues required for the recognition of glycolipids -GalCer, GSL-1' and iGb3 retain their CDR loop colors from the structure at left; residues with no affect on recognition when substituted with alanine are dark gray; and residues not substituted are light gray. (b) Surface map of the human V24i-NKT15 TCR (left) predicted from the TCR–CD1d–-GalCer crystal structure. In the TCR surface identified by crystallographic analysis (right), residues that make direct contact with CD1d–-GalCer retain their CDR loop color as in the structure at left; residues that do not make contact with CD1d–-GalCer are dark gray; and residues not in the CDR loops are light gray.