title: Identification of a major GpVI-binding locus in human type III collagen.
abstract: We have analyzed the adhesion of human and murine platelets, and of recombinant human and murine GpVI ectodomains, to synthetic triple-helical collagen-like peptides. These included 57 peptides derived from the sequence of human type III collagen and 9 peptides derived from the cyanogen bromide fragment of bovine type III collagen, alpha1(III)CB4. We have identified several peptides that interact with GpVI, in particular a peptide designated III-30 with the sequence GAOGLRGGAGPOGPEGGKGAAGPOGPO. Both human and murine platelets bound to peptide III-30 in a GpVI-dependent manner. III-30 also supported binding of recombinant GpVI ectodomains. Cross-linked III-30 induced aggregation of human and murine platelets, although with a lower potency than collagen-related peptide. Modifications of the peptide sequence indicated that the hydroxyproline residues play a significant role in supporting its GpVI reactivity. However, many peptides containing OGP/GPO motifs did not support adhesion to GpVI. These data indicate that the ability of a triple-helical peptide to bind GpVI is not solely determined by the presence or spatial arrangement of these OGP/GPO motifs within the peptides.
authors.affiliation: Departments of Biochemistry, University of Cambridge, Downing Site, Cambridge CB2 1QW, United Kingdom. gej1000@cam.ac.uk
authors.forename: Gavin E
authors.initials: GE
authors.lastname: Jarvis
authors.forename: Nicolas
authors.initials: N
authors.lastname: Raynal
authors.forename: Jonathan P
authors.initials: JP
authors.lastname: Langford
authors.forename: David J
authors.initials: DJ
authors.lastname: Onley
authors.forename: Allen
authors.initials: A
authors.lastname: Andrews
authors.forename: Peter A
authors.initials: PA
authors.lastname: Smethurst
authors.forename: Richard W
authors.initials: RW
authors.lastname: Farndale
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D001792:Blood Platelets / Q000378:metabolism; D002417:Cattle; D024061:Collagen Type III / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D051379:Mice; D010446:Peptide Fragments; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry; D010974:Platelet Aggregation; D010980:Platelet Membrane Glycoproteins / Q000737:chemistry / Q000378:metabolism*; D011485:Protein Binding
chemical_list: D024061:Collagen Type III; D010446:Peptide Fragments; D010455:Peptides; D010980:Platelet Membrane Glycoproteins; C098341:platelet membrane glycoprotein VI