Open AccessDelineation of the toxin coding fragments and an insect‐specificity region of a dual toxicity Bacillus thuringiensis crystal protein gene
Author(s) -
Haider M.Z.,
Smith G.P.,
Ellar D.J.
Publication year - 1989
Publication title -
fems microbiology letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.899
H-Index - 151
eISSN - 1574-6968
pISSN - 0378-1097
DOI - 10.1111/j.1574-6968.1989.tb03037.x
Subject(s) - gene , insect , toxin , biology , dual (grammatical number) , genetics , computational biology , botany , art , literature
A series of deletion mutants have been constructed from the dual toxicity Bacillus thuringiensis aizawai IC1 ( Bta IC1) crystal protein gene. The mutant toxin genes were expressed in Escherichia coli , their protein products purified and the authenticity of these mutant proteins confirmed immunologically. Analysis of the toxicity spectra of these mutants revealed that lepidopteran toxicity is located on the N‐terminal region of the toxin between residues Ile 30 ‐Glu 595 . 3′ deletion of a further 37 residues from Glu 595 of the lepidopteran‐specific toxin abolished lepidopteran toxicity but the resulting protein consisting of residues Ile 30 ‐Gly 558 was still fully toxic to dipteran larvae and cells. Another mutant crystal protein gene truncated to encode residues between Ile 30 ‐Gly 563 was toxic only to diptera. These data indicate that the determinants of lepidopteran specificity in the Bta IC1 toxin are located between residues Gly 558 ‐Glu 595 and that the N‐terminal portion of the toxin between Ile 30 ‐Gly 558 is sufficient to express dipteran toxicity.