| Literature DB >> 15050842 |
Aliou Bah1, Kees van Frankenhuyzen, Roland Brousseau, Luke Masson.
Abstract
The objective of the present work was to create an active Cry1Aa toxin showing enhanced resistance to degradation by spruce budworm (Choristoneura fumiferana) midgut proteases by mutating potential chymotrypsin and trypsin sites. Fourteen Cry1Aa mutants were created in an Escherichia coli-Bacillus shuttle vector and expressed in a crystal minus Bacillus thuringiensis host. Using spruce budworm gut juice, commercial bovine trypsin and chymotrypsin we performed protease resistance assays with Cry1Aa wild type and mutant toxins. Although many mutants showed little or no change, several mutants showed a > 2-fold increase (R543S, R566G, and F570S) up to a > 4-fold increase in toxicity (F576S), in bioassay studies against C. fumiferana. The in vitro protease resistance assay results indicated a possible involvement of other gut juice components in toxin overdigestion.Entities:
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Year: 2004 PMID： 15050842 DOI： 10.1016/j.jip.2004.02.002
Source DB: PubMed Journal: J Invertebr Pathol ISSN： 0022-2011 Impact factor: 2.841