Search tips
Search criteria 


Logo of aemPermissionsJournals.ASM.orgJournalAEM ArticleJournal InfoAuthorsReviewers
Appl Environ Microbiol. 1996 January; 62(1): 279–282.
PMCID: PMC167797

Site-directed mutations in the third domain of Bacillus thuringiensis delta-endotoxin CryIAa affect its ability to increase the permeability of Bombyx mori midgut brush border membrane vesicles.


A series of mutant Bacillus thuringiensis CryIAa delta-endotoxin proteins was prepared by replacing the first, second, and last arginine residues of the conserved third-domain sequence, R-521 YRVRIR-527, with other amino acids. The stable mutant proteins were bioassayed against Bombyx mori larvae and found to all be approximately half as active as wild-type CryIAa. The toxins were also tested by means of a light-scattering assay for their ability to increase permeability of larval B. mori midgut brush border membrane vesicles. Three of the mutant toxins were as active as the wild-type toxin in the vesicle permeability assay.

Full Text

The Full Text of this article is available as a PDF (205K).

Selected References

These references are in PubMed. This may not be the complete list of references from this article.
  • Carroll J, Ellar DJ. An analysis of Bacillus thuringiensis delta-endotoxin action on insect-midgut-membrane permeability using a light-scattering assay. Eur J Biochem. 1993 Jun 15;214(3):771–778. [PubMed]
  • Chen XJ, Lee MK, Dean DH. Site-directed mutations in a highly conserved region of Bacillus thuringiensis delta-endotoxin affect inhibition of short circuit current across Bombyx mori midguts. Proc Natl Acad Sci U S A. 1993 Oct 1;90(19):9041–9045. [PubMed]
  • Ge AZ, Pfister RM, Dean DH. Hyperexpression of a Bacillus thuringiensis delta-endotoxin-encoding gene in Escherichia coli: properties of the product. Gene. 1990 Sep 1;93(1):49–54. [PubMed]
  • Ge AZ, Shivarova NI, Dean DH. Location of the Bombyx mori specificity domain on a Bacillus thuringiensis delta-endotoxin protein. Proc Natl Acad Sci U S A. 1989 Jun;86(11):4037–4041. [PubMed]
  • Harvey WR, Wolfersberger MG. Mechanism of inhibition of active potassium transport in isolated midgut of Manduca sexta by Bacillus thuringiensis endotoxin. J Exp Biol. 1979 Dec;83:293–304. [PubMed]
  • Höfte H, Whiteley HR. Insecticidal crystal proteins of Bacillus thuringiensis. Microbiol Rev. 1989 Jun;53(2):242–255. [PMC free article] [PubMed]
  • Kunkel TA. Rapid and efficient site-specific mutagenesis without phenotypic selection. Proc Natl Acad Sci U S A. 1985 Jan;82(2):488–492. [PubMed]
  • Li JD, Carroll J, Ellar DJ. Crystal structure of insecticidal delta-endotoxin from Bacillus thuringiensis at 2.5 A resolution. Nature. 1991 Oct 31;353(6347):815–821. [PubMed]
  • Nishimoto T, Yoshisue H, Ihara K, Sakai H, Komano T. Functional analysis of block 5, one of the highly conserved amino acid sequences in the 130-kDa CryIVA protein produced by Bacillus thuringiensis subsp. israelensis. FEBS Lett. 1994 Jul 18;348(3):249–254. [PubMed]
  • Rajamohan F, Alcantara E, Lee MK, Chen XJ, Curtiss A, Dean DH. Single amino acid changes in domain II of Bacillus thuringiensis CryIAb delta-endotoxin affect irreversible binding to Manduca sexta midgut membrane vesicles. J Bacteriol. 1995 May;177(9):2276–2282. [PMC free article] [PubMed]
  • Van Rie J, Jansens S, Höfte H, Degheele D, Van Mellaert H. Specificity of Bacillus thuringiensis delta-endotoxins. Importance of specific receptors on the brush border membrane of the mid-gut of target insects. Eur J Biochem. 1989 Dec 8;186(1-2):239–247. [PubMed]

Articles from Applied and Environmental Microbiology are provided here courtesy of American Society for Microbiology (ASM)