A structure–activity relationship study elucidating the mechanism of sequence-specific collagen recognition by the chaperone HSP47 Original Research Article

Heat-shock protein 47 (HSP47) is a chaperone that facilitates the proper folding of procollagen. Our previous studies showed that the high-affinity HSP47-binding motif in the collagen triple helix is Xaa-(Thr/Pro)-Gly-Xaa-Arg-Gly. In this study, we further investigated structural requirements for the HSP47-binding motif, using synthetic triple-helical collagen-model peptides with systematic amino acid substitutions at either the Thr/Pro (=Yaa−3) or the Arg (=Yaa0) position. Results obtained from in vitro binding assays indicated that HSP47 detects the side-chain structure of Arg at the Yaa0-position, while the Yaa−3 amino acid serves as the secondary recognition site that affects affinity to HSP47.