Structure and function of Bacillus thuringiensis pore-forming insecticidal toxins

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TypeArticle
Journal titlePhysics in Canada
Volume60
Pages2024; # of pages: 5
AbstractThe Gram-positive bacterium Bacillus thuringiensis is the most extensively used environment-friendly bioinsecticide worldwide. It produces a variety of crystalline proteins which are specifically lethal to different insect species. Following solubilization in the midgut lumen of susceptible insect larvae and binding to specific receptors located on the surface of the luminal membrane of midgut epithelial cells, the toxins insert into the membrane and form pores that abolish transmembrane ionic gradients which are vital for cellular functions. The three-dimensional structures of four B. thuringiensis Cry toxins have been elucidated. They share a similar three-domain structure in which domain I, composed of amphipathic α-helices, plays a crucial role in pore formation. The other two domains are composed of β-sheets and are responsible for receptor binding and toxin specificity. The mechanism by which these toxins insert into the cell membrane remains one of the most challenging biophysical questions regarding their mode of action. It involves extensive conformational changes in the toxin molecule and assembly of an oligomeric structure composed of a yet undetermined number of toxin subunits. A better understanding of these events is gradually emerging from the analysis of the functional properties of genetically engineered mutant toxins using a variety of biophysical techniques.
Publication date
LanguageEnglish
AffiliationNRC Biotechnology Research Institute; National Research Council Canada
Peer reviewedNo
NRC numberBCENV27
NPARC number3539477
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Record identifier732f49a8-461c-4d50-90e5-d4cb7534ba54
Record created2009-03-01
Record modified2016-05-09
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