Fig. 2. Conformational changes upon client-chaperone engagement.

a Top view of superpositing peptide-receptive MHC I in the chaperone complex (MHC I hc, teal; tapasin, orange) with peptide-bound H2-D^b (gray, PDB ID 2F74) in cartoon representation. hc heavy chain; β1, β2, β strands of editing loop of tapasin. b Side view of the superposition shown in a β5, β6, β7, β strands of MHC I hc; β9, β10, β hairpin of tapasin. c View onto the concave interface of tapasin in superposition of MHC I-bound tapasin from the chaperone complex (tapasin, orange; MHC I hc, teal; β₂m, green) with client-free tapasin (gray, PDB ID 3F8U). d Superposition as in c but viewed onto the C-terminal domain of tapasin. IgC domain immunoglobulin constant domain, β₂m β₂-microglobulin.