Cryptic endotoxic nature of Bacillus thuringiensis Cry1Ab insecticidal crystal protein

Roberto I. Vazquez-Padron, Gustavo De La Riva, Guillermin Agüero, Yussun Silva, Si M. Pham, Mario Soberón, Alejandra Bravo, Abdelouahab Aïtouche

Research output: Contribution to journalArticlepeer-review

20 Scopus citations


Cry1Ab is one of the most studied insecticidal proteins produced by Bacillus thuringiensis during sporulation. Structurally, this protoxin has been divided in two domains: the N-terminal toxin core and the C-terminal portion. Although many studies have addressed the biochemical characteristics of the active toxin that corresponds to the N-terminal portion, there are just few reports studying the importance of the C-terminal part of the protoxin. Herein, we show that Cry1Ab protoxin has a unique natural cryptic endotoxic property that is evident when their halves are expressed individually. This toxic effect of the separate protoxin domains was found against its original host B. thuringiensis, as well as to two other bacteria, Escherichia coli and Agrobacterium tumefaciens. Interestingly, either the fusion of the C-terminal portion with the insecticidal domain-III or the whole N-terminal region reduced or neutralized such a toxic effect, while a non-Cry1A peptide such as maltose binding protein did not neutralize the toxic effect. Furthermore, the C-terminal domain, in addition to being essential for crystal formation and solubility, plays a crucial role in neutralizing the toxicity caused by a separate expression of the insecticidal domain much like a dot/anti-dot system.

Original languageEnglish (US)
Pages (from-to)30-36
Number of pages7
JournalFEBS letters
Issue number1-3
StatePublished - Jul 16 2004


  • Bacillus thuringiensis
  • Cry1A
  • Crystal toxin
  • Endotoxin
  • Insecticide

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology


Dive into the research topics of 'Cryptic endotoxic nature of Bacillus thuringiensis Cry1Ab insecticidal crystal protein'. Together they form a unique fingerprint.

Cite this