Enhanced toxicity of Bacillus thuringiensis Cry3A 8-endotoxin in coleopterans by mutagenesis in recetor binding loop

Sheng-Jiun Wu; Noah C. Koller; Deborah L. Miller; Leah Bauer; Donald H. Dean

Treesearch

Enhanced toxicity of Bacillus thuringiensis Cry3A 8-endotoxin in coleopterans by mutagenesis in recetor binding loop

Informally Refereed

Authors:

Sheng-Jiun Wu, Noah C. Koller, Deborah L. Miller, Leah Bauer, Donald H. Dean

Year:

2000

Type:

Scientific Journal

Station:

Northern Research Station

Source:

Federationof European Biochemical Societies (FEBS Letters). 473: 227-232.

Download (PDF 549 KB)

Download (PDF 549 KB): https://research.fs.usda.gov/download/treesearch/12275.pdf

Abstract

We used site-directed mutagenesis to modify the Bacillus cry3A gene in amino acid residues 350-354. Two mutant toxins, A1 (R₃₄₅A, Y₃₅₀F, Y₃₅₁F) and A2 (R₃₄₅A,DeltaY₃₅₀, DeltaY₃₅₁, showed significantly improved toxicity against Tenebrio molitor (yellow mealworm). The mutant toxin A1 was also more potent against both Leptinotarsa decemlineats (Colorado potato beetle) and Chrysomela scripta (cottonwood leaf beetle), while A2 displayed enhanced toxicity only in L. decemlineata. Competitive binding assays of L. decemlineata brush border membrane vesicles (BBMV) revealed that binding affinities for the A1 and A2 mutant toxins were ca. 2.5-fold higher than for the wild-type Cry3 toxin. Similar binding assays with C. scripta BBMV revealed a ca 5-fold lower dissociation rate for the A1 mutant as compared to that of Cry3A.

Keywords

Bacillus thuringiensis, Cry toxin, 8-Endotoxin, Coleopteran

Citation

Wu, Sheng-Jiun; Koller, Noah C.; Miller, Deborah L.; Bauer, Leah S.; Dean, Donald H. 2000. Enhanced toxicity of Bacikkus thuringiensis Cry3A 8-endotoxin in coleopterans by mutagenesis in recetor binding loop. Federationof European Biochemical Societies (FEBS Letters). 473 : p. 227-232. (2000)