Figure 3.

Conformational changes in open B∗37:01/β₂m induced by interaction with chTapasin.A, 2D ¹H-¹³C SOFAST HMQC spectra of U-[¹⁵N, ²H], ¹³CH_3-labeled alanine, isoleucine, leucine, and valine residues of human β₂m (H31C) in the B∗37:01 (G120C)-FEDLRVJSF bound state (in red). The sample was subsequently incubated with chicken Tapasin and UV irradiated for 40 min prior to collecting additional ¹H-¹³C SOFAST HMQC spectra (in cyan). Both spectra were collected at 600 MHz ¹H magnetic field, at 25 °C. Due to lack of stereospecific assignments, the CD1 and CD2 methyl groups of Leu54 are not indicated. B–D, Zoomed regions of the ¹H-¹³C SOFAST HMQC spectra with arrows highlighting methyl probes experiencing minor chemical shift changes upon chTapasin binding, indicated by a slow-exchanging minor state peak. E, Methyl probes that show a detectable slow-exchanging minor peak upon chTapasin binding are shown as red spheres on the predicted B∗37:01/β₂m/chTapasin model by BAKER-ROBETTA (29).