title: The 20-kDa chaperone-like protein of Bacillus thuringiensis ssp. israelensis enhances yield, crystal size and solubility of Cry3A.
abstract: OBJECTIVE
  To determine whether the 20-kDa chaperone-like protein of Bacillus thuringiensis ssp. israelensis enhances synthesis, crystallization and solubility of the Cry3A coleopteran toxin and whether the crystalline inclusions produced are toxic to neonates of the Colorado potato beetle, Leptinotarsa decemlineata.
  
  
  RESULTS
  The cry3A gene was expressed in the 4Q7 strain of B. thuringiensis ssp. israelensis in the absence or presence of the 20-kDa gene. The 20-kDa protein enhanced Cry3A yield by 2·7-fold per unit of fermentation medium. Crystal volumes averaged 2·123 and 0·964 μm(3) when synthesized in, respectively, the presence or absence of the 20-kDa protein. Both crystals were soluble at pH 5 and pH 6; however, the larger crystal was 1·7× and 1·5× more soluble at, respectively, pH 7 and pH 10. No significant difference in toxicity against L. decemlineata neonates was observed.
  
  
  CONCLUSIONS
  This report demonstrated that the 20-kDa chaperone-like protein enhances yield, volume and solubility of the coleopteran Cry3A crystalline inclusions per unit crystal/spore mixture.
  
  
  CONCLUSIONS
  This is the first report showing that an accessory protein (20-kDa) could enhance synthesis and crystallization of Cry3A, a finding that could be beneficial for commercial production of this coleopteran-specific insecticidal protein for microbial insecticides and possibly even for transgenic crops.
authors.affiliation: Department of Entomology, University of California-Riverside, CA 92521, USA.
authors.forename: M
authors.initials: M
authors.lastname: Diaz-Mendoza
authors.forename: D K
authors.initials: DK
authors.lastname: Bideshi
authors.forename: F
authors.initials: F
authors.lastname: Ortego
authors.forename: G P
authors.initials: GP
authors.lastname: Farinós
authors.forename: B A
authors.initials: BA
authors.lastname: Federici
mesh_terms: D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D001517:Coleoptera / Q000382:microbiology; D003120:Colorado; D004731:Endotoxins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism* / Q000648:ultrastructure; D007814:Larva / Q000382:microbiology; D018832:Molecular Chaperones / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D010572:Pest Control, Biological; D012995:Solubility; D013171:Spores, Bacterial / Q000502:physiology
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D018832:Molecular Chaperones; C030956:insecticidal crystal protein, Bacillus Thuringiensis