title: Is an amphiphilic region responsible for the haemolytic activity of Bacillus thuringiensis toxin?
abstract: The amino acid sequence of the 27 kDa protein responsible for the haemolytic activity of Bacillus thuringiensis subsp. israelensis toxin has been analysed by secondary structure prediction, helical wheel/net diagrams and molecular mechanics calculations. We found that segment 116-126 presumably forms a strongly amphiphilic alpha-helix. This is supported by the findings that the synthesized segment 116-126 (a) has a significant alpha-helical content in water, and (b) displays an in vitro haemolytic activity comparable to that of bee venom peptide melittin. As segment 116-126 is present in the haemolyzing, but not present in the non-haemolyzing proteins from B. thuringiensis toxins, we suggest that this segment is responsible for the lytic potential of the B. thuringiensis subsp. israelensis protein.
authors.affiliation: Institute for Biochemistry and Protein Research, ABC, Gödöllö, Hungary.
authors.forename: E
authors.initials: E
authors.lastname: Szabó
authors.forename: J
authors.initials: J
authors.lastname: Murvai
authors.forename: P
authors.initials: P
authors.lastname: Fábián
authors.forename: F
authors.initials: F
authors.lastname: Fábián
authors.forename: M
authors.initials: M
authors.lastname: Hollósi
authors.forename: J
authors.initials: J
authors.lastname: Kajtár
authors.forename: Z
authors.initials: Z
authors.lastname: Buzás
authors.forename: M
authors.initials: M
authors.lastname: Sajgó
authors.forename: S
authors.initials: S
authors.lastname: Pongor
authors.forename: B
authors.initials: B
authors.lastname: Asbóth
mesh_terms: D000595:Amino Acid Sequence; D001413:Bacillus thuringiensis / Q000737:chemistry*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry*; D001427:Bacterial Toxins / Q000737:chemistry*; D002942:Circular Dichroism; D004731:Endotoxins / Q000737:chemistry*; D006460:Hemolysin Proteins / Q000737:chemistry*; D008555:Melitten / Q000737:chemistry; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017386:Sequence Homology, Amino Acid; D013056:Spectrophotometry, Ultraviolet
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D001427:Bacterial Toxins; D004731:Endotoxins; D006460:Hemolysin Proteins; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D008555:Melitten