N-terminal activation is an essential early step in the mechanism of action of Bacillus thuringiensis Cry1Ac insecticidal toxin

Bravo, Alejandra, Sánchez, Jorge, Kouskoura, Thaleia and Crickmore, Neil (2002) N-terminal activation is an essential early step in the mechanism of action of Bacillus thuringiensis Cry1Ac insecticidal toxin. Journal of Biological Chemistry, 277 (27). pp. 23985-23987. ISSN 0021-9258

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Abstract

A variant form of the Bacillus thuringiensis Cry1Ac toxin that is not cleaved at the N terminus during proteolytic activation with trypsin was found to be incapable of forming pores in Manduca sexta brush border membrane vesicles in vitro and had reduced insecticidal activity in vivo. Binding studies indicated an altered binding pattern of the mutant toxin in that bound toxin could not be fully displaced by a high molar excess of fully trypsin-activated toxin. These results suggest that proteolytic removal of the N-terminal peptide of Cry1Ac is an important step in toxin activation.

Item Type: Article
Additional Information: NC directed this work, mutant proteins were produced at Sussex by Kouskoura and Crickmore with specialised assays performed by collaborators in Mexico. The work describes an important role for the N-terminus of the Bt toxin with implications for GM crops which express these toxins.
Schools and Departments: School of Life Sciences > Biochemistry
Depositing User: Neil Crickmore
Date Deposited: 06 Feb 2012 21:15
Last Modified: 26 Mar 2012 11:33
URI: http://sro.sussex.ac.uk/id/eprint/30464
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