Publication: Functional characterizations of residues Arg-158 and Tyr-170 of the mosquito-larvicidal Bacillus thuringiensis Cry4Ba
Issued Date
2014-01-01
Resource Type
ISSN
1976670X
19766696
19766696
Other identifier(s)
2-s2.0-84908879241
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Mahidol University
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SCOPUS
Bibliographic Citation
BMB Reports. Vol.47, No.10 (2014), 546-551
Suggested Citation
Somphob Leetachewa, Saengduen Moonsom, Urai Chaisri, Narumol Khomkhum, Nonglak Yoonim, Ping Wang, Chanan Angsuthanasombat Functional characterizations of residues Arg-158 and Tyr-170 of the mosquito-larvicidal Bacillus thuringiensis Cry4Ba. BMB Reports. Vol.47, No.10 (2014), 546-551. doi:10.5483/BMBRep.2014.47.10.192 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/33405
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Title
Functional characterizations of residues Arg-158 and Tyr-170 of the mosquito-larvicidal Bacillus thuringiensis Cry4Ba
Abstract
© 2014 by the The Korean Society for Biochemistry and Molecular Biology. The insecticidal activity of Bacillus thuringiensis (Bt) Cry toxins involves toxin stabilization, oligomerization, passage across the peritrophic membrane (PM), binding to midgut receptors and pore-formation. The residues Arg-158 and Tyr-170 have been shown to be crucial for the toxicity of Bt Cry4Ba. We characterized the biological function of these residues. In mosquito larvae, the mutants R158A/E/Q (R158) could hardly penetrate the PM due to a significantly reduced ability to alter PM permeability; the mutant Y170A, however, could pass through the PM, but degraded in the space between the PM and the midgut epithelium. Further characterization by oligomerization demonstrated that Arg-158 mutants failed to form correctly sized high-molecular weight oligomers. This is the first report that Arg-158 plays a role in the formation of Cry4Ba oligomers, which are essential for toxin passage across the PM. Tyr-170, meanwhile, is involved in toxin stabilization in the toxic mechanism of Cry4Ba in mosquito larvae.