title: A single high-affinity binding site for von Willebrand factor in collagen III, identified using synthetic triple-helical peptides.
abstract: The essential event in platelet adhesion to the injured blood vessel wall is the binding to subendothelial collagen of plasma von Willebrand factor (VWF), a protein that interacts transiently with platelet glycoprotein Ibalpha (GPIbalpha), slowing circulating platelets to facilitate firm adhesion through collagen receptors, including integrin alpha2beta1 and GpVI. To locate the site in collagen that binds VWF, we synthesized 57 overlapping triple-helical peptides comprising the whole triple-helical domain of collagen III. Peptide no. 23 alone bound VWF, with similar affinity to that of native collagen III. Immobilized peptide no. 23 supported platelet adhesion under static and flow conditions, processes blocked by an antibody that prevents collagen from binding the VWF A3 domain. Truncated and alanine-substituted peptides derived from no. 23 either strongly interacted with both VWF and platelets or lacked both VWF and platelet binding. Thus, we identified the sequence RGQOGVMGF (O is hydroxyproline) as the minimal VWF-binding sequence in collagen III.
authors.affiliation: Department of Biochemistry, Downing Site, Cambridge CB2 1QW, United Kingdom.
authors.forename: Ton
authors.initials: T
authors.lastname: Lisman
authors.forename: Nicolas
authors.initials: N
authors.lastname: Raynal
authors.forename: Dafna
authors.initials: D
authors.lastname: Groeneveld
authors.forename: Ben
authors.initials: B
authors.lastname: Maddox
authors.forename: Anthony R
authors.initials: AR
authors.lastname: Peachey
authors.forename: Eric G
authors.initials: EG
authors.lastname: Huizinga
authors.forename: Philip G
authors.initials: PG
authors.lastname: de Groot
authors.forename: Richard W
authors.initials: RW
authors.lastname: Farndale
mesh_terms: D020816:Amino Acid Motifs; D000906:Antibodies / Q000737:chemistry / Q000378:metabolism; D001665:Binding Sites; D024061:Collagen Type III / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D038982:Integrin alpha2beta1 / Q000378:metabolism; D010455:Peptides / Q000138:chemical synthesis / Q000737:chemistry* / Q000378:metabolism; D010973:Platelet Adhesiveness / Q000502:physiology; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism; D010980:Platelet Membrane Glycoproteins / Q000378:metabolism; D011485:Protein Binding; D014841:von Willebrand Factor / Q000737:chemistry* / Q000378:metabolism
chemical_list: D000906:Antibodies; D024061:Collagen Type III; D038982:Integrin alpha2beta1; D010455:Peptides; D019038:Platelet Glycoprotein GPIb-IX Complex; D010980:Platelet Membrane Glycoproteins; C098341:platelet membrane glycoprotein VI; D014841:von Willebrand Factor