title: Bacillus thuringiensis Cry toxins bound specifically to various proteins via domain III, which had a galactose-binding domain-like fold.
abstract: Cry toxins have been reported to bind not only to receptors on insect cells but also to several unrelated proteins. In this study, we investigated the binding properties of Bacillus thuringiensis Cry toxins, focusing on domain III, a Cry toxin region with a structure that of the galactose-binding domain-like. Cry1Aa, Cry1Ac, and Cry8Ca specifically bound to several proteins unrelated to insect midgut cells. Cry1Aa binding to Cry toxin-binding proteins was inhibited by a monoclonal antibody, 2C2, indicating that Cry1Aa binds to these Cry toxin-binding proteins through domain III. Cry1Aa binding to Bombyx mori aminopeptidase N and other Cry toxin-binding proteins was inhibited by carbonic anhydrase, a Cry toxin-binding protein. The binding regions of carbonic anhydrase and Bombyx mori aminopeptidase N were narrowed to regions of less than 20 amino acids that did not have any similarity, suggesting that Cry toxin domain III has a binding pocket for multiple proteins.
authors.affiliation: Graduate School of Bio-Applications and Systems Engineering, Tokyo University of Agriculture and Technology, Tokyo, Japan.
authors.forename: Madoka
authors.initials: M
authors.lastname: Kitami
authors.forename: Tomoyuki
authors.initials: T
authors.lastname: Kadotani
authors.forename: Kazuko
authors.initials: K
authors.lastname: Nakanishi
authors.forename: Shogo
authors.initials: S
authors.lastname: Atsumi
authors.forename: Satoshi
authors.initials: S
authors.lastname: Higurashi
authors.forename: Takahisa
authors.initials: T
authors.lastname: Ishizaka
authors.forename: Ayako
authors.initials: A
authors.lastname: Watanabe
authors.forename: Ryoichi
authors.initials: R
authors.lastname: Sato
mesh_terms: D000116:Acetylgalactosamine / Q000494:pharmacology; D000818:Animals; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D001413:Bacillus thuringiensis; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry* / Q000378:metabolism*; D012831:Bombyx / Q000201:enzymology; D018826:CD13 Antigens / Q000737:chemistry / Q000378:metabolism; D002256:Carbonic Anhydrases / Q000494:pharmacology; D002417:Cattle; D004731:Endotoxins / Q000737:chemistry / Q000378:metabolism; D004912:Erythrocytes / Q000201:enzymology; D005690:Galactose / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000737:chemistry / Q000378:metabolism; D007202:Indicators and Reagents / Q000378:metabolism; D019476:Insect Proteins / Q000378:metabolism; D008024:Ligands; D011485:Protein Binding / Q000187:drug effects; D017434:Protein Structure, Tertiary; D013379:Substrate Specificity
chemical_list: D000911:Antibodies, Monoclonal; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007202:Indicators and Reagents; D019476:Insect Proteins; D008024:Ligands; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D018826:CD13 Antigens; D002256:Carbonic Anhydrases; D000116:Acetylgalactosamine; D005690:Galactose