Fig. 6. S-S bonding between TCR and pMHC proteins in solution.

a Persistent binding of PA4C/H2-D^b to 6218αC TCR. SPR sensorgrams of immobilized 6218 TCR (black) or 6218αC TCR (red) exposed to PA4C/H2-D^b sequentially injected at increasing concentrations. b Abrogation of persistent binding by reducing agent (DTT). PA4C/H2-D^b monomers were incubated in 2 mM DTT overnight before SPR analysis as in a. c Short half-life of short-lived 6218αC TCR-PA4C/H2-D^b complexes. SPR data for a 12-s interval spanning the transition from pMHC monomer injection to buffer injection. Some data points between −0.5 s and 0 s are outside the limits of the y-axis. Sensorgrams are aligned so that the onset of measurable dissociation occurs at time = 0.1 s. Error bars show the range of 2 experiments for 6218 TCR-PA/H2-D^b, 3 experiments for 6218 TCR-PA4C/H2-D^b (2 without DTT and 1 with DTT) and 1 experiment for 6218αC TCR-PA4C/H2-D^b (with DTT). d Progressive S-S bond formation over a timescale of minutes. SPR sensorgrams for immobilised 6218αC TCR exposed to 100 μM PA4C/H2-D^b for 1 min (dotted line), 5 min (dashed line) or 20 min (solid line) followed by injection of buffer only. Source data are provided as a Source Data file.