Publication: Functional characterizations of residues Arg-158 and Tyr-170 of the mosquito-larvicidal Bacillus thuringiensis Cry4Ba
Accepted Date
2013-10-28
Issued Date
2014
Resource Type
Language
eng
ISSN
1976-670X (electronic)
Rights
Mahidol University
Rights Holder(s)
Korean Society for Biochemistry and Molecular Biology
Bibliographic Citation
BMB Rep. Vol.47, No.10 (2014), 546-551.
Suggested Citation
Somphob Leetachewa, Saengduen Moonsom, Urai Chaisri, Narumol Khomkhum, Nonglak Yoonim, Wang Ping, Chanan Angsuthanasombat Functional characterizations of residues Arg-158 and Tyr-170 of the mosquito-larvicidal Bacillus thuringiensis Cry4Ba. BMB Rep. Vol.47, No.10 (2014), 546-551.. doi:10.5483/BMBRep.2014.47.10.192 Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/1849
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Title
Functional characterizations of residues Arg-158 and Tyr-170 of the mosquito-larvicidal Bacillus thuringiensis Cry4Ba
Abstract
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. [BMB
Reports 2014; 47(10): 546-551]