Extended Data Fig. 4: Crosslinking mass spectrometry outlines the conformations of BiP and GRP94.
From: Conformational plasticity of a BiP–GRP94 chaperone complex
(a) Intra-GRP94 crosslinks mapped onto the open (PDB ID: 2O1V) or semi-closed (homology model based on PDB ID: 7KW7) GRP94 dimer. For simplicity, only MD and NTD are shown. Crosslinks from the MD region in protomer B - K455 (B), K458 (B), K447 (B) to the NTD region within the same protomer and to protomer A are shown - K114 (A/B), K161 (A/B), K95 (A/B), K97 (A/B). Crosslinks shown in purple support the open conformation, crosslinks shown in orange support the semi-closed conformation. (b) Intra-BiPSBD crosslinks between the SBDα and SBDβ (identified in the BiP-GRP94 FL XL-MS dataset, Supplementary Table 1) mapped onto the closed (left panel, PDB ID: 5E85) and open (right panel, PDB ID: 5E84) BiPSBD structure. The BiPSBD domains are aligned based on the SBDβ. Crosslinks between the beta-sheet-rich subdomain, SBDβ (residues K446, K447, K521, K523) and the alpha-helical lid, SBDα (residues K573, K579, K581, K585) outline their close proximity and therefore indicate that the BiPSBD is in the closed conformation.
