title: Characterization and cDNA cloning of halyxin, a heterogeneous three-chain anticoagulant protein from the venom of Agkistrodon halys brevicaudus.
abstract: We report upon the isolation, characterization, and cDNA cloning of an anticoagulant protein, halyxin from Agkistrodon halys brevicaudus venom. The protein exists as a 29kDa protein, and is separated into three chains on SDS-PAGE under reducing conditions. However, we cloned only two cDNAs encoding halyxin from the cDNA library of the snake venom gland, on the basis of the determined amino acid sequences. The complete amino acid sequences were deduced from their nucleotide sequences and named halyxin A (129 amino acid residues) and B chain (123 amino acid residues). The deduced amino acid sequence of halyxin A chain corresponds to the two smaller chains. Thus, it is considered that halyxin A chain could be synthesized as a single-chain protein that is subsequently cleaved to yield the mature two-chain protein. The amino acid sequence of halyxin is similar to that of other snake venom proteins of the C-type lectin superfamily, and prolongs plasma-clotting time. In the presence of Ca(2+) ions, halyxin binds to coagulation factors IX, X, IXa, and Xa, but not to other vitamin K-dependent coagulation factors. It also inhibits factor Xa in a non-competitive manner but does not affect other activated coagulation factors.
authors.affiliation: Department of Biochemistry, College of Science and Bioproducts Research Center, Yonsei University, Seoul 120-749, South Korea.
authors.forename: Bon-Hun
authors.initials: BH
authors.lastname: Koo
authors.forename: Young-Doug
authors.initials: YD
authors.lastname: Sohn
authors.forename: Ki-Chul
authors.initials: KC
authors.lastname: Hwang
authors.forename: Yangsoo
authors.initials: Y
authors.lastname: Jang
authors.forename: Doo-Sik
authors.initials: DS
authors.lastname: Kim
authors.forename: Kwang-Hoe
authors.initials: KH
authors.lastname: Chung
mesh_terms: D017836:Agkistrodon; D000595:Amino Acid Sequence; D000818:Animals; D000925:Anticoagulants / Q000302:isolation & purification*; D001483:Base Sequence; D001779:Blood Coagulation Factors / Q000378:metabolism; D003001:Cloning, Molecular; D003435:Crotalid Venoms / Q000235:genetics* / Q000302:isolation & purification*; D018076:DNA, Complementary / Q000302:isolation & purification*; D010450:Endopeptidases / Q000235:genetics / Q000302:isolation & purification*; D005088:Exocrine Glands / Q000378:metabolism; D006801:Humans; D019476:Insect Proteins; D008969:Molecular Sequence Data; D012471:Salivary Proteins and Peptides / Q000037:antagonists & inhibitors; D017386:Sequence Homology, Amino Acid
chemical_list: C031442:Agkistrodon venoms; D000925:Anticoagulants; D001779:Blood Coagulation Factors; D003435:Crotalid Venoms; D018076:DNA, Complementary; D019476:Insect Proteins; D012471:Salivary Proteins and Peptides; C114100:anticoagulant factor Xa protein, Aedes aegypti; C470871:halyxin, Agkistrodon halys brevicaudus; D010450:Endopeptidases