title: Cloning and characterization of novel snake venom proteins that block smooth muscle contraction.
abstract: In this study, we isolated a 25-kDa novel snake venom protein, designated ablomin, from the venom of the Japanese Mamushi snake (Agkistrodon blomhoffi). The amino-acid sequence of this protein was determined by peptide sequencing and cDNA cloning. The deduced sequence showed high similarity to helothermine from the Mexican beaded lizard (Heloderma horridum horridum), which blocks voltage-gated calcium and potassium channels, and ryanodine receptors. Ablomin blocked contraction of rat tail arterial smooth muscle elicited by high K+-induced depolarization in the 0.1-1 microm range, but did not block caffeine-stimulated contraction. Furthermore, we isolated three other proteins from snake venoms that are homologous to ablomin and cloned the corresponding cDNAs. Two of these homologous proteins, triflin and latisemin, also inhibited high K+-induced contraction of the artery. These results indicate that several snake venoms contain novel proteins with neurotoxin-like activity.
authors.affiliation: Department of Biochemistry, Meiji Pharmaceutical University, Kiyose, Tokyo, Japan.
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Yamazaki
authors.forename: Hisashi
authors.initials: H
authors.lastname: Koike
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Sugiyama
authors.forename: Kazuko
authors.initials: K
authors.lastname: Motoyoshi
authors.forename: Taeko
authors.initials: T
authors.lastname: Wada
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hishinuma
authors.forename: Mitsuo
authors.initials: M
authors.lastname: Mita
authors.forename: Takashi
authors.initials: T
authors.lastname: Morita
mesh_terms: D017836:Agkistrodon / Q000235:genetics / Q000378:metabolism*; D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D003001:Cloning, Molecular; D003435:Crotalid Venoms / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D008969:Molecular Sequence Data; D009119:Muscle Contraction / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects / Q000502:physiology; D009498:Neurotoxins / Q000235:genetics* / Q000276:immunology / Q000378:metabolism* / Q000494:pharmacology; D016415:Sequence Alignment
chemical_list: C031442:Agkistrodon venoms; D003435:Crotalid Venoms; D009498:Neurotoxins