title: Amino acids at N- and C-termini are required for the efficient production and folding of a cytolytic delta-endotoxin from Bacillus thuringiensis.
abstract: Bacillus thuringiensis Cyt2Aa toxin is a mosquito-larvicidal and cytolytic delta-endotoxin, which is synthesized as a protoxin and forms crystalline inclusions within the cell. These inclusions are solubilized under alkaline conditions and are activated by proteases within the larval gut. In order to assess the functions of the N-and C-terminal regions of the protoxin, several N- and C-terminal truncated forms of Cyt2Aa were constructed. It was determined that amino acid removal at the N-terminal, which disrupts the beta1 structure, might critically influence toxin production and inclusion formation. The deletion of 22 amino acids from the C-terminus reduced the production and solubility of the toxin. However, the removal of more than 22 amino acids from the C-terminus or the addition of a bulky group to this region could result in the inability of the protein to adopt the proper folding. These findings directly demonstrated the critical roles of N- and C- terminal amino acids on the production and folding of the B. thuringiensis cytolytic delta-endotoxin.
authors.affiliation: Institute of Molecular Biology and Genetics, Mahidol University, Salaya Campus, Nakhonpathom, Thailand.
authors.forename: Siriya
authors.initials: S
authors.lastname: Thammachat
authors.forename: Wanwarang
authors.initials: W
authors.lastname: Pathaichindachote
authors.forename: Chartchai
authors.initials: C
authors.lastname: Krittanai
authors.forename: Boonhiang
authors.initials: B
authors.lastname: Promdonkoy
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000494:pharmacology*; D001413:Bacillus thuringiensis / Q000737:chemistry; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D003603:Cytotoxins / Q000737:chemistry / Q000302:isolation & purification; D004526:Efficiency; D004731:Endotoxins / Q000737:chemistry* / Q000302:isolation & purification*; D005453:Fluorescence; D006460:Hemolysin Proteins / Q000737:chemistry* / Q000302:isolation & purification*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000378:metabolism; D010447:Peptide Hydrolases / Q000378:metabolism; D017510:Protein Folding / Q000187:drug effects*; D017433:Protein Structure, Secondary / Q000502:physiology; D017434:Protein Structure, Tertiary / Q000502:physiology; D013057:Spectrum Analysis
chemical_list: D000596:Amino Acids; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D003603:Cytotoxins; D004731:Endotoxins; D006460:Hemolysin Proteins; D010446:Peptide Fragments; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D010447:Peptide Hydrolases