Publication: Structural basis of pore formation by mosquito-larvicidal proteins from bacillus thuringiensis
Issued Date
2010-01
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eng
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Mahidol University
Bibliographic Citation
The Open Toxinology. Vol.3, 2010, 126-132
Suggested Citation
Chanan Angsuthanasombat Structural basis of pore formation by mosquito-larvicidal proteins from bacillus thuringiensis. The Open Toxinology. Vol.3, 2010, 126-132. Retrieved from: https://repository.li.mahidol.ac.th/handle/20.500.14594/1832
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Title
Structural basis of pore formation by mosquito-larvicidal proteins from bacillus thuringiensis
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Abstract
The insecticidal character of the three-domain Cry -endotoxins produced by Bacillus thuringiensis during
sporulation is believed to be caused by their capability to generate lytic pores in the target larval midgut cell membranes.
This review describes toxic mechanisms with emphasis on the structural basis of pore formation by two closely related
dipteran-specific toxins, Cry4Aa and Cry4Ba, which are highly toxic to mosquito larvae. One proposed toxic mechanism
via an “umbrella-like” structure involves membrane penetration and pore formation by the 4-5 transmembrane hairpin.
The lipid-induced -conformation of 7 could possibly serve as a lipid anchor required for an efficient insertion of the
pore-forming hairpin into the bilayer membrane. Though current electron crystallographic data are still inadequate to
provide such critical insights into the structural details of the Cry toxin-induced pore architecture, this pivotal
evidence clearly reveals that the 65-kDa active toxin in association with the lipid membrane could exist in at least two
different trimeric conformations, implying the closed and open states of a functional pore.