title: Effect of a 20-kilodalton protein from Bacillus thuringiensis subsp. israelensis on production of the CytA protein by Escherichia coli.
abstract: CytA, a 27-kDa cytolytic crystal protein of Bacillus thuringiensis subsp. israelensis, is produced only at very low levels by recombinant Escherichia coli cells unless a 20-kDa B. thuringiensis subsp. israelensis protein is also present (K. M. McLean and H. R. Whiteley, J. Bacteriol. 169:1017-1023, 1987; L. F. Adams, J. E. Visick, and H. R. Whiteley, J. Bacteriol. 171:521-530, 1989). However, the data reported here demonstrate that the 20-kDa protein is not required for high-level CytA production in E. coli strains carrying mutations in rpoH, groEL, or dnaK, all of which affect the proteolytic ability of the cells. The 20-kDa protein also increases the amount of CryIVD (another B. thuringiensis subsp. israelensis crystal protein) and LacZX90 (a mutant of beta-galactosidase) made by E. coli. The latter phenomenon is attributable to an increase in the half-life of LacZX90, suggesting that the 20-kDa protein may stabilize this protein. The effect of the 20-kDa protein was also examined in vitro and in a T7 RNA polymerase expression system, and the possible significance of these results for the timing of proteolysis and of 20-kDa protein activity is discussed. Finally, the ability of a single antibody to coimmunoprecipitate CytA and the 20-kDa protein from E. coli extracts provides evidence for a protein-protein interaction that may be related to the mechanism of action of the 20-kDa protein.
authors.affiliation: Department of Microbiology, University of Washington, Seattle 98195.
authors.forename: J E
authors.initials: JE
authors.lastname: Visick
authors.forename: H R
authors.initials: HR
authors.lastname: Whiteley
mesh_terms: D001413:Bacillus thuringiensis / Q000235:genetics*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D001427:Bacterial Toxins; D003001:Cloning, Molecular; D004731:Endotoxins; D004926:Escherichia coli / Q000235:genetics / Q000378:metabolism*; D006460:Hemolysin Proteins; D006358:Hot Temperature; D007700:Kinetics; D008970:Molecular Weight; D016296:Mutagenesis; D010957:Plasmids; D014176:Protein Biosynthesis; D011993:Recombinant Fusion Proteins / Q000302:isolation & purification / Q000378:metabolism; D014158:Transcription, Genetic; D001616:beta-Galactosidase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D011993:Recombinant Fusion Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D001616:beta-Galactosidase