title: Aminopeptidase-N from the Helicoverpa armigera (Hubner) brush border membrane vesicles as a receptor of Bacillus thuringiensis crylac delta-endotoxin.
abstract: Brush border membrane vesicles (BBMVs) were prepared from the 2nd instar larvae of Helicoverpa armigera. Binding of the activated Cry1Ac of Bacillus thuringiensis (Bt) toxin was shown by immunoblot. A 120-kDa protein was identified as a receptor for the Cry1Ac type delta-endotoxin. The aminopeptidase-N activity of BBMVs was measured as the hydrolysis of L-leucine p-nitroanilide. The specific activity was 35 units/mg protein. The BBMV preparation also showed low level of alkaline phosphatase activity. Zn++ chelating agents 2,2'-dipyridyl and 1,10-phenanthroline inhibited aminopeptidase activity at 10 mM concentration, indicating the presence of zinc-dependent aminopeptidase in the brush border of H. armigera. The aminopeptidase activity was increased with increasing concentration of delta-endotoxin. The purified 120-kDa binding protein was N-terminally sequenced. The first 10-amino-acid sequence showed 60-77% similarity with human cysteine-rich secretory protein-1 precursor, inhibin alpha chain precursor. Salmonella flagellar hook protein and yeast carboxypeptidase S.
authors.affiliation: Department of Microbiology and Biotechnology Centre, Faculty of Science, M.S. University of Baroda, India.
authors.forename: S S
authors.initials: SS
authors.lastname: Ingle
authors.forename: N
authors.initials: N
authors.lastname: Trivedi
authors.forename: R
authors.initials: R
authors.lastname: Prasad
authors.forename: J
authors.initials: J
authors.lastname: Kuruvilla
authors.forename: K K
authors.initials: KK
authors.lastname: Rao
authors.forename: H S
authors.initials: HS
authors.lastname: Chhatpar
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000378:metabolism*; D001427:Bacterial Toxins; D018826:CD13 Antigens / Q000737:chemistry / Q000378:metabolism*; D004731:Endotoxins / Q000378:metabolism*; D006460:Hemolysin Proteins; D006801:Humans; D019476:Insect Proteins; D007915:Lepidoptera / Q000201:enzymology*; D008871:Microvilli / Q000201:enzymology*; D008969:Molecular Sequence Data; D011956:Receptors, Cell Surface / Q000378:metabolism*
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; C095416:Cry toxin receptors; D004731:Endotoxins; D006460:Hemolysin Proteins; D019476:Insect Proteins; D011956:Receptors, Cell Surface; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D018826:CD13 Antigens