Northern Research Station
11 Campus Blvd., Suite 200
Newtown Square, PA 19073
(610) 557-4132 TTY/TDD
Title: Enhanced toxicity of Bacillus thuringiensis Cry3A 8-endotoxin in coleopterans by mutagenesis in recetor binding loop
Author: Wu, Sheng-Jiun; Koller, Noah C.; Miller, Deborah L.; Bauer, Leah S.; Dean, Donald H.
Publication: Federationof European Biochemical Societies (FEBS Letters). 473: 227-232.
Key Words: Bacillus thuringiensis, Cry toxin, 8-Endotoxin, Coleopteran
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.
This document is in PDF format. You can obtain a free PDF reader from Adobe.
Forest Service Home | USDA.gov | recreation.gov