Polymerization site in the beta chain of fibrin: mapping of the B beta 1-55 sequence.
The formation of a fibrin clot occurs through binding of putative complementary sites, called fibrin polymerization sites, located in the NH2- and COOH-terminal domains of fibrin monomer molecules. In this study, we have investigated the structure of the NH2-terminal fibrin polymerization site by using fibrinogen-derived peptides and fragments. Fibrinogen was digested with Crotalus atrox protease III, to two major molecular species: a Mr 325,000 derivative (Fg325) and a peptide of Mr 5000. The peptide and its thrombin-cleavage product were purified by ion-exchange and reverse-phase HPLC; the authenticity of the B beta 1-42 and beta 15-42 peptides, respectively, was confirmed by amino acid sequencing. Since Fg325 had decreased thrombin coagulability, we addressed the question of whether the peptide B beta 1-42 contained a fibrin polymerization site. In order to identify and map the site, the peptides B beta 1-42 and beta 15-42 were tested for their ability to inhibit fibrin monomer polymerization. In addition the following peptides prepared by chemical synthesis were also tested: beta 15-18, beta 15-26, beta 24-42, beta 40-54, beta 50-55, and alpha 17-19-Pro. While B beta 1-42 had no inhibitory activity, the peptide devoid of fibrinopeptide B, beta 15-42, was a strong inhibitor. The peptides beta 15-18, beta 15-26, and beta 15-42 decreased the rate of fibrin polymerization by 50% at a molar excess of the peptide to fibrin monomer of 500, 430, and 50, respectively. The peptides beta 24-42, beta 40-54, and beta 50-55 were inactive.(ABSTRACT TRUNCATED AT 250 WORDS)
Pandya
B V
BV
Department of Biochemistry, Kirksville College of Osteopathic Medicine, Missouri 63501.
Gabriel
J L
JL
O'Brien
J
J
Budzynski
A Z
AZ
D000595:Amino Acid Sequence; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D005337:Fibrin / Q000378:metabolism*; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D046911:Macromolecular Substances; D008958:Models, Molecular; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010446:Peptide Fragments / Q000302:isolation & purification; D010449:Peptide Mapping; D011487:Protein Conformation; D013917:Thrombin / Q000378:metabolism
D046911:Macromolecular Substances; D010446:Peptide Fragments; D005337:Fibrin; D005340:Fibrinogen; D013917:Thrombin