title: Purification of two depressant insect neurotoxins and their gene cloning from the scorpion Buthus martensi Karsch.
abstract: Insect-specific neurotoxins are important components of scorpion venoms. In this study, two toxins from the scorpion Buthus martensi Karsch (BmK) were purified. They shared high sequence homology with other depressant insect toxins and were designated BmK ITa and BmK ITb, respectively. They were able to suppress the action potential of cockroach isolated axon, which is due to a decrease in the peak sodium current. Furthermore, the effect of BmK ITb was lower than that of BmK ITa, and some of the electrophysiological characteristics of BmK ITb even resemble that of excitatory insect toxins. Their primary structures were determined by N-terminal partial sequence determination and cDNA cloning. The differences in their structures, especially the 31st residues, may result in the unique activity of BmK ITb.
authors.affiliation: Shanghai Institute of Biochemistry and Cell Biology, Chinese Academy of Sciences, China.
authors.forename: C-G
authors.initials: CG
authors.lastname: Wang
authors.forename: M-H
authors.initials: MH
authors.lastname: Ling
authors.forename: C-W
authors.initials: CW
authors.lastname: Chi
authors.forename: D-C
authors.initials: DC
authors.lastname: Wang
authors.forename: M
authors.initials: M
authors.lastname: Pelhate
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001369:Axons / Q000187:drug effects; D003001:Cloning, Molecular; D003058:Cockroaches; D017931:DNA Primers / Q000235:genetics; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D007306:Insecticides / Q000302:isolation & purification / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D008969:Molecular Sequence Data; D009498:Neurotoxins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification* / Q000494:pharmacology; D012604:Scorpion Venoms / Q000737:chemistry*; D012605:Scorpions / Q000737:chemistry*; D017386:Sequence Homology, Amino Acid; D015222:Sodium Channels / Q000187:drug effects
chemical_list: D017931:DNA Primers; D018076:DNA, Complementary; D007306:Insecticides; D009498:Neurotoxins; D012604:Scorpion Venoms; D015222:Sodium Channels