title: Interactions of integrin GPIIb/IIIa-derived peptides with fibrinogen investigated by NMR spectroscopy.
abstract: Three peptides derived from platelet receptor glycoprotein alphaIIbBeta3 (GPIIb/IIIa) have been identified recently as fibrinogen-binding sequences: GPIIb 300-314 and 656-667 and GPIIIa 211-223. NMR spectroscopy has been used here to investigate the interactions of these peptides with parent fibrinogen. Based on resonance broadening and chemical-shift changes of peptides in the presence and absence of fibrinogen, interactions in the fast ligand-exchange regime are apparent and interfacial residues can be proposed. Positively charged arginines and histidines, along with several hydrophobic residues, are implicated as being crucial to the binding process. Transferred nuclear Overhauser effects and distance geometry calculations allow discussion of probable conformations in peptide-'bound' states. These identifications are consistent with other biological/chemical data and provide the basis for further studies aimed at understanding fibrinogen-mediated platelet aggregation on the molecular level.
authors.affiliation: Department of Biochemistry, Biomedical Engineering Center, University of Minnesota, Minneapolis, MN 55455, U.S.A.
authors.forename: L J
authors.initials: LJ
authors.lastname: Yao
authors.forename: K H
authors.initials: KH
authors.lastname: Mayo
mesh_terms: D000595:Amino Acid Sequence; D004347:Drug Interactions; D005340:Fibrinogen / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy / Q000379:methods; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism*; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000737:chemistry / Q000378:metabolism*
chemical_list: D010446:Peptide Fragments; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D005340:Fibrinogen