Accelerated evolution of snake venom genes: proved by groyp IPLA2 gene

1999 Fiscal Year Final Research Report Summary

• Project/Area Number: 10640685
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Single-year Grants
• Section: 一般
• Research Field: 系統・分類
• Research Institution: Sophia University
• Principal Investigator: TAMIYA Toru Sophia University, Chemistry, Associate Professor, 理工学部, 助教授 (30119135)
• Co-Investigator(Kenkyū-buntansha): FUJIMI Takahiko Sophia University, Chemistry, Research Associate, 理工学部, 助手 ; KANZAWA Nobuyuki Sophia University, Chemistry, Research Associate, 理工学部, 助手 (40286761)
• Project Period (FY): 1998 – 1999
• Keywords: Snake venom phospholipase AィイD22ィエD2 / Snake venom gene / Laticauda / molecular evolution

Research Abstract

Many of the secreted phospholipases AィイD22ィエD2 (PLA2) from mammalian pancreas and snake venom glands have been purified and their primary structures have been determined. They consist of 120-130 amino acid residues and most of them contained seven disulfide bonds. Structural investigations based on X-ray crystallograplly and/or nuclear magnetic resonance sepectroscopy have revealed that PLA2s adopt a similar fold. PLA2s have been mainly classified into three groups, I, II and III according to their structural characteristics. Groups I and II share six disulfide bonds but the seventh is different in the two groups. Group I PLA2s (Elapidae or Hydrophiidae snake venoms and mammalian pancreas) possess and additional disulfide bond formed between half-cystines 11 and 77. Group II PLA2s (Viperidae snake venoms, mammalian platelets, and liver) are characterized by a distinct, short extension (six residues) extension at the C-terminus. Group I can be further classified into group IA and group IB PLAィイD22ィエD2 based on the presence (IB) or absence (IA) of the pancreatic loop. PLA2s from Laticauda semifasciata venom are classified into group IA.
We have been determined the structures of groups IA and IB PLA2 genes expressed in both venom glands and pancreas.
Comparing the genome structure of groups IA and IB genes, introns were highly conserved but pancreatic loop region and 3'-end of exon 4 of group IB lacked in group IA. Considering that the venom gland altered from salivary gland, group IA PLA2 genes evolved from the prototype of group IB gene as all ancestor gene.

Research Products

• [Publications] T. Tamiya et al: "Complete nucleotide sequences of cDNAs encoding long chain alpha-neurotoxins from sea krait, Laticauda semifasciate"Toxicon. 37. 181-185 (1999)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] M. Ohno et al: "Molecular evolution of snake toxins: Is the functional diversity of snake toxins associated with a mechanism of accelerated evolution?"Prog. Nucleic Acid Res. Mol. Biol.. 59. 307-364 (1998)
  • Description: 「研究成果報告書概要(和文)」より
• [Publications] Tamiya, T., Ohnom S., Nishimura, E., Fujimi, T.J., and Tsuchiya, T.: "Complete nucleotide sequences of cDNAs encoding long chain α-neurotoxins from sea krait"Toxicon. 37(1). 181-185 (1999)
  • Description: 「研究成果報告書概要(欧文)」より
• [Publications] Ohno, M., Menez, R., Ogawa, T., Danse, J.M., Shimohigashi, Y., Fromen, C., Ducancel, F., Zinn-Justin, S., Le Du, M. H., Boulain, J-C., Tamiya, T., and Menez, A.: "Molecular evolution of snake toxins: Is the functional diversity of snake toxins associated with a mechanism of accelerated evolution?"Prog. Nucleic Acid Res. Mol. Biol.. 59. 307-364 (1998)
  • Description: 「研究成果報告書概要(欧文)」より