Fig. 3. Contacts between TIL1383I and the HLA-A2 α1 helix, α2 helix, and the Tyr370D peptide.
a Gln72 and Arg75 on the HLA-A2 α1 helix participate in a complex network of electrostatic interactions involving Glu101 in the TIL1383I CDR3β loop, as shown in the left panel. An unusual salt bridge is also formed between Arg34 in CDR1β and Glu19 at the edge of the HLA-A2 β-sheet platform. The right image illustrates the contacts between the HLA-A2 α1 helix and the TCR. Linewidths are proportional to the number of contacts, enumerated above each line. b TCR contacts to the HLA-A2 α2 helix are shifted towards the helix short arm and the connecting linker region. Images are as in panel a, with the left emphasizing the reliance on electrostatic interactions and the right showing contacts made by the CDR loops to helix. c TCR contacts to the peptide are distributed from pTyr1 to pGln8, with pMet6 inserted into a deep pocket formed by CDR3α and CDR3β.