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

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.

HSP47 binds to triple-helical collagen, recognizing Yaa0 and Yaa−3 side-chains in the Xaa-Yaa−3-Gly-Xaa-Yaa0-Gly sequence. Structural preferences for Yaa0 and Yaa−3 were determined using synthetic collagen-mimetic peptides.Figure optionsDownload as PowerPoint slide