title: The properties conferred upon triple-helical collagen-mimetic peptides by the presence of cysteine residues.
abstract: Recently, the ability of polymeric collagen-like peptides to regulate cell behavior has generated great interest. A triple-helical peptide known as collagen-related peptide (CRP) contains the sequence (Gly-Pro-Hyp)(10). With Gly-Pro-Cys triplets appended to both of its termini, designated CRP(cys), chemical cross-linking using heterobifunctional reagents generates CRP(cys)-XL, a potent, widely used, polymeric agonist for platelet Glycoprotein VI, whereas non-cross-linked, monomeric CRP(cys) antagonizes Glycoprotein VI. Here, we describe how cysteine in these triplets may also undergo random air-induced oxidation, especially upon prolonged storage or repeated freeze-thawing, to form disulphide bonds, resulting in a lesser degree of polymerization than with chemical cross-linking. We investigated the monomeric and polymeric states of these and other cysteine-containing collagen-derived peptides, using gel filtration and dynamic light scattering, allowing the size of a CRP-XL aggregate to be estimated. The effect of cysteine thiols upon peptide adsorption to surfaces and subsequent platelet responses was investigated. This demonstrated that cysteine is required for strong binding to glass coverslips and to plastic plates used in ELISA assays.
authors.affiliation: University of Cambridge, Department of Biochemistry, Downing Site, Cambridge, UK. SlatterDA@cardiff.ac.uk
authors.forename: David A
authors.initials: DA
authors.lastname: Slatter
authors.forename: Dominique G
authors.initials: DG
authors.lastname: Bihan
authors.forename: Gavin E
authors.initials: GE
authors.lastname: Jarvis
authors.forename: Rachael
authors.initials: R
authors.lastname: Stone
authors.forename: Nicholas
authors.initials: N
authors.lastname: Pugh
authors.forename: Sumana
authors.initials: S
authors.lastname: Giddu
authors.forename: Richard W
authors.initials: RW
authors.lastname: Farndale
mesh_terms: D000327:Adsorption; D020816:Amino Acid Motifs; D000595:Amino Acid Sequence; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology; D002352:Carrier Proteins / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D002850:Chromatography, Gel; D003545:Cysteine / Q000737:chemistry*; D006801:Humans; D055767:Immobilized Proteins; D008027:Light; D008969:Molecular Sequence Data; D010084:Oxidation-Reduction; D010316:Particle Size; D010455:Peptides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D011485:Protein Binding; D017434:Protein Structure, Tertiary; D012542:Scattering, Radiation; D019809:Streptavidin / Q000737:chemistry
chemical_list: D002352:Carrier Proteins; D055767:Immobilized Proteins; D010455:Peptides; C435908:collagen-related peptide; D019809:Streptavidin; D003545:Cysteine