title: Identification of the disulfide bond pattern in albolabrin, an RGD-containing peptide from the venom of Trimeresurus albolabris: significance for the expression of platelet aggregation inhibitory activity.
abstract: Albolabrin is a 73 amino acid peptide isolated from the venom of Trimeresurus albolabris. It contains an RGD sequence and 12 cysteines and is a potent inhibitor of both platelet aggregation and fibrinogen binding to the GPIIb/IIIa complex. This protein shows a high degree of analogy (primarily due to the alignment of all cysteines and the RGD) with a number of other viper venom proteins which inhibit cell adhesion and platelet aggregation and are referred to as disintegrins: rhodostomin, trigramin, flavoridin, applagin, elegantin, and batroxostatin. In this study, we found that the reduction and vinylpyridylethylation of albolabrin and flavoridin decreased their platelet aggregation inhibitory activity approximately 40-50 times. It can be postulated that the higher potency of native and reduced flavoridin as compared to albolabrin depends on the substitution of the Asp of albolabrin with a Phe at the C-terminal end of the RGD in flavoridin. The activity of a synthetic C-terminal peptide derived from flavoridin (residues 35-65) containing four cysteines was about 75 times lower than that of the original flavoridin. The substitution of a pair of cysteine residues with alanines in this peptide resulted in further loss of activity. In order to identify the disulfide bonds in albolabrin, the molecule was digested consecutively by trypsin and porcine pancreatic elastase. Peptides resulting from this digestion were isolated by reverse-phase HPLC and identified by amino acid composition and mass spectrometry.(ABSTRACT TRUNCATED AT 250 WORDS)
authors.affiliation: Max Planck Institut für Biochemie, Martinsried/München, Federal Republic of Germany.
authors.forename: J J
authors.initials: JJ
authors.lastname: Calvete
authors.forename: W
authors.initials: W
authors.lastname: Schäfer
authors.forename: T
authors.initials: T
authors.lastname: Soszka
authors.forename: W Q
authors.initials: WQ
authors.lastname: Lu
authors.forename: J J
authors.initials: JJ
authors.lastname: Cook
authors.forename: B A
authors.initials: BA
authors.lastname: Jameson
authors.forename: S
authors.initials: S
authors.lastname: Niewiarowski
mesh_terms: D000244:Adenosine Diphosphate / Q000494:pharmacology; D000595:Amino Acid Sequence; D003435:Crotalid Venoms / Q000737:chemistry*; D004220:Disulfides / Q000737:chemistry*; D006801:Humans; D066298:In Vitro Techniques; D036341:Intercellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000737:chemistry* / Q000494:pharmacology; D010455:Peptides / Q000737:chemistry* / Q000494:pharmacology; D010974:Platelet Aggregation / Q000187:drug effects; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D012910:Snake Venoms
chemical_list: D003435:Crotalid Venoms; D004220:Disulfides; D036341:Intercellular Signaling Peptides and Proteins; D009842:Oligopeptides; D010455:Peptides; D010975:Platelet Aggregation Inhibitors; D012910:Snake Venoms; C064595:albolabrin; C069044:flavoridin protein, Trimeresurus; D000244:Adenosine Diphosphate; C047981:arginyl-glycyl-aspartic acid