title: Employing phage display to study the mode of action of Bacillus thuringiensis Cry toxins.
abstract: Phage display is an in vitro method for selecting polypeptides with desired properties from a large collection of variants. The insecticidal Cry toxins produced by Bacillus thuringiensis are highly specific to different insects. Various proteins such as cadherin, aminopeptidase-N (APN) and alkaline phosphatase (ALP) have been characterized as potential Cry-receptors. We used phage display to characterize the Cry toxin-receptor interaction(s). By employing phage-libraries that display single-chain antibodies (scFv) from humans or from immunized rabbits with Cry1Ab toxin or random 12-residues peptides, we have identified the epitopes that mediate binding of lepidopteran Cry1Ab toxin with cadherin and APN receptors from Manduca sexta and the interaction of dipteran Cry11Aa toxin with the ALP receptor from Aedes aegypti. Finally we displayed in phages the Cry1Ac toxin and discuss the potential for selecting Cry variants with improved toxicity or different specificity.
authors.affiliation: Instituto de Biotecnología, Universidad Nacional Autónoma de México, Apdo. Postal 510-3, Cuernavaca, Morelos 62250, Mexico.
authors.forename: Luisa Elena
authors.initials: LE
authors.lastname: Fernández
authors.forename: Isabel
authors.initials: I
authors.lastname: Gómez
authors.forename: Sabino
authors.initials: S
authors.lastname: Pacheco
authors.forename: Iván
authors.initials: I
authors.lastname: Arenas
authors.forename: Sarjeet S
authors.initials: SS
authors.lastname: Gilla
authors.forename: Alejandra
authors.initials: A
authors.lastname: Bravo
authors.forename: Mario
authors.initials: M
authors.lastname: Soberón
mesh_terms: D000818:Animals; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D001427:Bacterial Toxins / Q000737:chemistry / Q000378:metabolism*; D004731:Endotoxins / Q000737:chemistry / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000737:chemistry / Q000378:metabolism*; D006801:Humans; D019476:Insect Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008958:Models, Molecular; D019151:Peptide Library; D011485:Protein Binding; D011956:Receptors, Cell Surface / Q000737:chemistry / Q000235:genetics / 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; D019151:Peptide Library; D011956:Receptors, Cell Surface; C030956:insecticidal crystal protein, Bacillus Thuringiensis