title: Cyt1Ca from Bacillus thuringiensis subsp. israelensis: production in Escherichia coli and comparison of its biological activities with those of other Cyt-like proteins.
abstract: The larvicidal activity of Bacillus thuringiensis subsp. israelensis against dipteran larvae is determined by four major polypeptides of the parasporal crystalline body produced during sporulation. Cyt1Aa shows the lowest toxicity when used alone but is the most synergistic with any of the other proteins. The sequence of the plasmid pBtoxis, which contains all the toxin genes in this subspecies, revealed a new cyt-like coding sequence named cyt1Ca. In addition to the Cyt-like region, the predicted Cyt1Ca contained an extra domain at the C terminus, which appeared to be a beta-trefoil carbohydrate-binding motif, as found in several ricin-like toxins. The gene was PCR-amplified from pBtoxis and cloned in several vectors, allowing high-level expression in Escherichia coli. Cyt1Ca was purified by nickel-nitrilotriacetic acid affinity chromatography, characterized, and its biological activity was determined. Toxicity against larvae of Aedes aegypti of Cyt1Ca in recombinant E. coli cells was compared with that of Cyt1Aa and Cyt2Ba, and the ability of these proteins to enhance the activity of Cry4Aa was assessed. Although Cyt2Ba appeared able to interact with Cry4Aa, no activity for Cyt1Ca was observed, even when produced in truncated form. Furthermore, in contrast to Cyt1Aa, Cyt1Ca did not lyse sheep erythrocytes, and it was not bactericidal to the host cell.
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva 84105, Israel.
authors.forename: Robert
authors.initials: R
authors.lastname: Manasherob
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva 84105, Israel.
authors.forename: Mark
authors.initials: M
authors.lastname: Itsko
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva 84105, Israel.
authors.forename: Nadine
authors.initials: N
authors.lastname: Sela-Baranes
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva 84105, Israel.
authors.forename: Eitan
authors.initials: E
authors.lastname: Ben-Dov
authors.affiliation: Cardiff School of Biosciences, Cardiff University, Museum Avenue, Cardiff CF10 3US, UK.
authors.forename: Colin
authors.initials: C
authors.lastname: Berry
authors.affiliation: Department of Chemical Engineering and Biotechnology, College of Judea and Samaria, Ariel 44837, Israel.|Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva 84105, Israel.
authors.forename: Shmuel
authors.initials: S
authors.lastname: Cohen
authors.affiliation: Department of Life Sciences, Ben-Gurion University of the Negev, PO Box 653, Be'er-Sheva 84105, Israel.
authors.forename: Arieh
authors.initials: A
authors.lastname: Zaritsky
mesh_terms: D000330:Aedes / Q000254:growth & development; D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology*; D001427:Bacterial Toxins / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology*; D004731:Endotoxins / Q000096:biosynthesis* / Q000302:isolation & purification / Q000494:pharmacology*; D004926:Escherichia coli / Q000235:genetics; D005798:Genes, Bacterial; D006460:Hemolysin Proteins; D007814:Larva / Q000187:drug effects; D008018:Life Cycle Stages; D010572:Pest Control, Biological; D017434:Protein Structure, Tertiary
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis