Quantitative Analysis of the Association Angle between T-cell Receptor Vα/Vβ Domains Reveals Important Features for Epitope Recognition
Fig 2
Differences in the TCR chain association geometries.
(A) Differences between the bound and unbound geometries. Shown are seven different receptor types in their unbound state as well as their bound state. Notably, for the 1G4 receptor the two unbound states are derived from different crystal structures, but are very similar. For some receptors, such as the 2C receptor, crystal structures including different ligands are available. In case of the 2C TCR, wild type (wt), 2C T7 and 2C T7 mutants are shown. In case of the E8 TCR, the two unbound states are derived from the same crystal structure. (B) Different conformations of the bound 2C TCR structures and their variants. The magnifications show the different CDR1/3 conformations observed in the m67 variant structure 2e2h (green), with respect to the 2C T7 variants (right, blue, 2oi9, 3e3q, and 2e7l) and the 2C wt structures (left, blue, 1g6r, 1mwa, and 2ckb). In the lower figures both variable domains are shown together with the placed cuboids for the structures 2e2h (m67, green, left+right) in comparison to 2e7l (T7 m6, blue/red, right) and 1mwa (2C wt, blue/red, left). The αCDR3 loops of the T7 variants differ in sequence and thus in their backbone conformations, whereas the CDR1 loop conformation is the same for the T7-wt, m6, and m13, but differs for m67 (upper left magnification). In the case of the m67 variant the CDR3 and CDR1 loop conformations are consistent with the 2C wt conformations (upper right magnification).