title: The role of a proline-induced broken-helix motif in alpha-helix 2 of Bacillus thuringiensis delta-endotoxins.
abstract: Bacillus thuringiensis delta-endotoxins (Cry proteins), are widely used for insect control and plant protection. They are water-soluble proteins that insert into membranes forming ion channels. In most Cry toxins alpha-helix 2 is broken by a highly conserved proline residue (Pro70 in Cry1Ab), generating a broken-helix motif. The flexibility of the motif was altered through site-directed mutagenesis. It was found that increasing the flexibility of the motif decreased the stability, the ion transport ability and the toxicity of the protein. By removing the broken-helix motif, the biological properties were restored to a wild type level.
authors.affiliation: Molecular Genetics Department, The Ohio State University, 484 W. 12th Ave., Columbus, OH 43210-1292, USA.
authors.forename: S
authors.initials: S
authors.lastname: Arnold
authors.forename: A
authors.initials: A
authors.lastname: Curtiss
authors.forename: D H
authors.initials: DH
authors.lastname: Dean
authors.forename: O
authors.initials: O
authors.lastname: Alzate
mesh_terms: D000409:Alanine / Q000737:chemistry; D020816:Amino Acid Motifs; D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry*; D001427:Bacterial Toxins; D002462:Cell Membrane / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D004594:Electrophysiology; D004731:Endotoxins / Q000737:chemistry*; D005998:Glycine / Q000737:chemistry; D006460:Hemolysin Proteins; D018402:Manduca; D008871:Microvilli / Q000737:chemistry; D008958:Models, Molecular; D016297:Mutagenesis, Site-Directed; D009154:Mutation; D011392:Proline / Q000737:chemistry / Q000494:pharmacology*; D017433:Protein Structure, Secondary; D012694:Serine / Q000737:chemistry; D013696:Temperature; D013997:Time Factors
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D012694:Serine; D011392:Proline; D000409:Alanine; D005998:Glycine