Fig. 5. Model for chaperone function of tapasin towards peptide-receptive MHC I.
Schematic of molecular motions leading to stabilized peptide-receptive clients (MHC I hc, teal; β2m, green) upon association with tapasin (orange; left, side view; right, top view). Conformational changes are indicated by black arrows. The dotted line indicates a polar interaction between tapasin (Glu72) and chaperoned MHC I (Tyr84 of the heavy chain, hc). For reasons of clarity, ERp57 (red) is not shown in the right panel.