Kinetics of Bacillus thuringiensis toxin binding with brush border membrane vesicles from susceptible and resistant larvae of Plutella xylostella

L. Masson, A. Mazza, R. Brousseau, B. Tabashnik

Research output: Contribution to journalArticlepeer-review

68 Scopus citations

Abstract

An optical biosensor technology based on surface plasmon resonance was used to determine the kinetic rate constants for interactions between the CryIA(c) toxin from Bacillus thuringiensis and brush border membrane vesicles purified from susceptible and resistant larvae of diamondback moth (Plutella xylostella). CryIA(c) association and dissociation rate constants for vesicles from susceptible larvae were determined to be 4.5 x 103 M-1 s- 1 and 3.2 x 10-5 s-1, respectively, resulting in a calculated affinity constant of 7 nM. CryIE toxin did not kill susceptible or resistant larvae and did not bind to brush border vesicles. Contrary to expectations based on previous studies of binding in resistant P. xylostella, the binding kinetics for CryIA(c) did not differ significantly between susceptible larvae and those that were resistant to CryIA(c). Determination of the number of CryIA(c) receptors revealed an approximately 3-fold decrease in total CryIA(c) receptor numbers for resistant vesicles. These results suggest that factors other than binding may be altered in our resistant diamond-back moth strain. They also support the view that binding is not sufficient for toxicity.

Original languageEnglish (US)
Pages (from-to)11887-11896
Number of pages10
JournalJournal of Biological Chemistry
Volume270
Issue number20
DOIs
StatePublished - 1995
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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