A SYNTHETIC MODEL OF COLLAGEN STRUCTURE TAKEN FROM BOVINE MACROPHAGE SCAVENGER RECEPTOR

A putative collagen structure from macrophage scavenger receptors binds to a wide range of ligands. In order to elucidate the ligand's binding mode, this collagen structure was constructed using short peptides. This was accomplished by the reaction of a tri-bromoacetylated branched peptide with a purified unprotected 25-residue peptide, which contained Cys, 4 repeats of the triplet, Gly-Pro-Hyp, and 12 residues from the bovine macrophage scavenger receptor (residues 332 to 343). The three identical 25-residue peptides are linked at the N-terminus. CD and NMR spectra of the N-terminus cross-linked tripeptide show that it forms a collagen structure below 10-degrees-C and an extended structure at high temperature with a midpoint of 20-degrees-C.