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Substitutions in Spodoptera exigua topoisomerase I modulate its relaxation activity and camptothecin sensitivity
Author(s) -
Zhang Pei,
Zhang Lan,
Zhang Yanning,
Mao Liangang,
Jiang Hongyun
Publication year - 2017
Publication title -
pest management science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.296
H-Index - 125
eISSN - 1526-4998
pISSN - 1526-498X
DOI - 10.1002/ps.4440
Subject(s) - exigua , spodoptera , camptothecin , topoisomerase , mutant , biology , plasmid , relaxation (psychology) , dna , biochemistry , chemistry , gene , recombinant dna , neuroscience
BACKGROUND Topoisomerase I (Top I) is referred as the cellular target of the camptothecins ( CPTs ) which are now being explored as potential pesticides for insect control. Three amino acid substitutions, including L530P , A653T and S729T , in Top Is of insects were found in our previous studies. In order to investigate the effect of these three substitutions, a comparative analysis was conducted between the wild‐type and mutant Top Is in Spodoptera exigua Hübner. RESULTS The optimal salt concentration of A653T and S729T was 150 m m , which is consistent with that of the wild‐type Top I, while the mutant L530P showed maximum relaxation activity at a lower KCl concentration (100 m m ). The mutated L530P and A653T Top Is showed a higher relaxation efficiency owing to an increased relaxation velocity toward the negatively supercoiled plasmid pBR322 DNA , which rendered L530P and A653T resistant to CPTs , whereas mutant S729T exhibited sensitivity to CPTs as a result of a decreased relaxation activity toward plasmid pBR322 DNA . CONCLUSIONS These results suggested that the polymorphism in Top I of insects was related to the biological activity of CPTs , which provided the basic information for reasonable usage of CPTs to control insect pests. © 2016 Society of Chemical Industry