Purification and characterization of Bacillus thuringiensis var. tenebrionis insecticidal proteins produced in E. coli

• Published in: Biochemical and biophysical research communications Vol. 170; no. 2; pp. 665 - 672
• Main Authors: MacIntosh, S.C., McPherson, S.L., Perlak, F.J., Marrone, P.G., Fuchs, R.L.
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 31.07.1990; Elsevier
• Subjects: Animals; BACILLUS THURINGIENSIS; Bacillus thuringiensis - genetics; Bacillus thuringiensis tenebrionis; BACTERIA; Bacterial Proteins - genetics; Bacterial Proteins - isolation & purification; Bacterial Proteins - pharmacology; Bacterial Toxins; BACTERIE; Biological and medical sciences; Biotechnology; CHEMICAL BONDING; CISTEINA; cloning; Coleoptera - drug effects; CRYSTALS; CYSTEINE; Cysteine - genetics; disulfide; Endotoxins; ESCHERICHIA; ESCHERICHIA COLI; Escherichia coli - genetics; Fundamental and applied biological sciences. Psychology; Genes, Bacterial; Hemolysin Proteins; INDUCED MUTATION; INSECTICIDAS; INSECTICIDE; INSECTICIDES; LEPTINOTARSA; LEPTINOTARSA DECEMLINEATA; Methods. Procedures. Technologies; MUTACION INDUCIDA; Mutation; MUTATION PROVOQUEE; PLASMIDE; PLASMIDIOS; PLASMIDS; Protein engineering; PROTEINAS; PROTEINE; PROTEINS; Recombinant Proteins - genetics; Recombinant Proteins - isolation & purification; Serine - genetics; site-directed mutagenesis; RB; B.t; EDTA; DTT; TNB 2; Chrysomelidae; Purification; Coleoptera; Insecta; Bacillus thuringiensis; Escherichia coli; Site directed mutagenesis; Bacillaceae; Biological activity; Bacillales; Structure activity relation; Leptinotarsa decemlineata; Arthropoda; Bacteria; Recombinant protein; Invertebrata; Microbial insecticide; Enterobacteriaceae
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/0006-291X(90)92143-N

Native and single amino acid variants of the Bacillus thuringiensis var. tenebrionis insecticidal proteins were expressed in Escherichia coli, purified and examined for biological and biochemical properties. A novel, pH dependent, preferential precipitation method was implemented to purify Escherichia coli produced Bacillus thuringiensis var. tenebrionis proteins, which are active against Colorado potato beetle ( Leptinotarsa decemlineata) larvae. Cysteine residues of the native Bacillus thuringiensis var. tenebrionis protein were replaced by serine residues by site-directed mutagenesis to investigate the biological and structural importance of the individual cysteine residues. Sulfhydryl determination of the native and amino acid variant Bacillus thuringiensis var. tenebrionis proteins revealed that the native protein contains no disulfide bonds. Modification of the carboxyl terminal cysteine residue (amino acid 540) caused complete inactivation of the protein. Native, truncated and single amino acid variants (other than at amino acid 540) exhibited insecticidal activities comparable to each other and to solubilized crystals from the original strain.