Protease-resistant core form of Bacillus thuringiensis Cry1Ie: monomeric and oligomeric forms in solution

• Published in: Biotechnology letters Vol. 31; no. 11; pp. 1769 - 1774
• Main Authors: Guo, Shuyuan, Zhang, Yancai, Song, Fuping, Zhang, Jie, Huang, Dafang
• Format: Journal Article
• Language: English
• Published: Dordrecht Dordrecht : Springer Netherlands 01.11.2009; Springer Netherlands; Springer Nature B.V
• Subjects: Aggregates; Animals; Applied Microbiology; Bacillus thuringiensis; Bacillus thuringiensis - chemistry; Bacteria; Bacterial Proteins - chemistry; Bacterial Proteins - isolation & purification; Bacterial Proteins - pharmacology; Biochemistry; Biological Assay; Biomedical and Life Sciences; Biotechnology; Chromatography, Gel; E coli; Electrophoresis, Polyacrylamide Gel; Endotoxins - chemistry; Endotoxins - isolation & purification; Endotoxins - pharmacology; Escherichia coli; Gene expression; Genes; Hemolysin Proteins - chemistry; Hemolysin Proteins - isolation & purification; Hemolysin Proteins - pharmacology; Larva - drug effects; Lepidoptera - drug effects; Life Sciences; Microbiology; Molecular weight; Monomers; Oligomers; Original Research Paper; Plutella xylostella; Proteases; Protein Structure, Quaternary; Solutions; Trypsin - metabolism; Oligomer; Protease-resistant core form; Cry1Ie protein
• ISSN: 0141-5492; 1573-6776
• DOI: 10.1007/s10529-009-0078-2

Cry1Ie is encoded by cry1Ie, a gene that is silent in Bacillus thuringiensis strains but can be over-expressed in Escherichia coli. A protease-resistant core form of Cry1Ie with a molecular weight of approx. 55 kDa was found among the products of trypsin digestion. The oligomer and monomer of the protease-resistant core form were purified separately. The oligomer fraction contained a small quantity of dimer and a large amount of aggregates larger than tetramers. The 50% lethal concentrations (LC₅₀) of the full-length Cry1Ie and both the monomer and oligomer fractions of the protease-resistant core form against Plutella xylostella were 14, 21 and 1400 μg/ml, respectively.