title: Genetic organization of Bungarus multicinctus protease inhibitor-like proteins.
abstract: The structural organization of the genes encoding Bungarus multicinctus protease inhibitor-like proteins (PILPs), PILP-1, PILP-2 and PILP-3, are reported in this study. Unlike PILP-2 and PILP-3, recombinant PILP-1 exhibited inhibitory activity on trypsin. PILP genes and B chain genes shared identical organization with three exons interrupted by two introns in similar positions. On the contrary, intron 1 of these genes had a similar size, a notable variation with the size of intron 2 was observed. It was found that two regions at the second intron of B1 chain and B2 chain genes were absent in that of PILP genes. Noticeably, intronic insertion in the second intron of B chain genes appeared in the promoter region of PILP-1 gene, but not in that of PILP-2 and PILP-3 genes. Comparative analyses of PILP genes and B chain genes showed that the protein-coding regions of the exons are more diverse than introns, except for in the signal peptide domain. These results suggest that PILP genes and B chain genes originate from a common ancestor, and that accelerated evolution may diversify PILP and B chain genes as that proposed for snake venom phospholipase A(2), neurotoxin and cardiotoxin genes.
authors.affiliation: Institute of Biomedical Sciences, National Sun Yat-Sen University-Kaohsiung Medical University Joint Research Center, National Sun Yat-Sen University, Kaohsiung 804, Taiwan. lschang@mail.nsysu.edu.tw
authors.forename: Long-sen
authors.initials: LS
authors.lastname: Chang
authors.forename: Jeh-Jeng
authors.initials: JJ
authors.lastname: Wang
authors.forename: Yun-Ching
authors.initials: YC
authors.lastname: Cheng
authors.forename: Wen-Min
authors.initials: WM
authors.lastname: Chou
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002038:Bungarotoxins / Q000737:chemistry; D017838:Bungarus / Q000235:genetics* / Q000378:metabolism; D003001:Cloning, Molecular; D019143:Evolution, Molecular; D008969:Molecular Sequence Data; D021141:Nucleic Acid Amplification Techniques; D010802:Phylogeny; D011401:Promoter Regions, Genetic; D011480:Protease Inhibitors / Q000737:chemistry*; D011506:Proteins / Q000737:chemistry / Q000235:genetics / Q000502:physiology; D011993:Recombinant Fusion Proteins / Q000502:physiology; D016415:Sequence Alignment
chemical_list: D002038:Bungarotoxins; D011480:Protease Inhibitors; D011506:Proteins; D011993:Recombinant Fusion Proteins