Cloning, co-expression with an amidating enzyme, and activity of the scorpion toxin BmK ITa1 cDNA in insect cells.
BmK ITa1 is an insect-specific neurotoxin from the Chinese scorpion Buthus martensi Karsch (Bmk). We succeeded in obtaining biologically active recombinant BmK ITa1 protein by simultaneous expression in insect cells of BmK ITa1 cDNA with an amidating enzyme expressed by the rat peptidylglycine alpha-amidating monooxygenase (PAM) gene. We investigated the insecticidal efficacy of recombinant BmK ITa1/W (without coexpression of PAM), and of BmK ITa1/A (with coexpression of PAM) in 5th instar Bombyx mori, by injecting these recombinant toxins into larvae. The lethal time for 50% of larvae (LT50) was 9 h for BmK ITa1/A and 17 h for BmK ITa1/W. At 19 h after injection all of the larvae exposed to BmK ITa1/A had been killed, whereas only half of the larvae exposed to BmK ITa1/W had been killed. These results show that the simultaneous expression of an amidating enzyme can result in apparently higher insecticidal activity of BmK ITa1.
Liu
Zhen
Z
State Key Laboratory of Molecular Biology, Shanghai Institute of Biochemistry and Cell Biology, Shanghiai Institutes for Biological Sciences, Chinese Academy of Sciences, 320 Yueyang Road, Shanghai 200031, Peoples Republic of China.
Yang
Guanzhen
G
Li
Boliang
B
Chi
Chengwu
C
Wu
Xiangfu
X
D000818:Animals; D016367:Baculoviridae / Q000235:genetics / Q000378:metabolism; D012831:Bombyx / Q000187:drug effects*; D003001:Cloning, Molecular; D004305:Dose-Response Relationship, Drug; D005786:Gene Expression Regulation / Q000235:genetics; D007814:Larva / Q000187:drug effects; D007928:Lethal Dose 50; D006899:Mixed Function Oxygenases / Q000096:biosynthesis* / Q000235:genetics; D009097:Multienzyme Complexes / Q000096:biosynthesis* / Q000235:genetics; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology; D012604:Scorpion Venoms / Q000096:biosynthesis* / Q000235:genetics / Q000302:isolation & purification / Q000494:pharmacology*
C471081:BmK Ita1 toxin, Buthus martensii; D009097:Multienzyme Complexes; D011994:Recombinant Proteins; D012604:Scorpion Venoms; D006899:Mixed Function Oxygenases; C035189:peptidylglycine monooxygenase