title: Cytolytic peptide fragments of Cyt1Aa from Bacillus thuringiensis subsp. israelensis.
abstract: Cyt1Aa is the major and most active component of the parasporal crystal of the Gram-positive soil entomopathogenic bacterium Bacillus thuringiensis subsp. israelensis. The Cyt1Aa protoxin exhibits some hemolytic and cytolytic activity. However, highly active 22-25 kDa toxins are obtained after proteolysis of Cyt1Aa from both the N- and the C-termini. As shown in this study, preliminary binding of the protoxin to polylamellary liposomes or partial denaturation of Cyt1Aa and further processing by several exogenous proteases yielded short 4.9-11.5 kDa cytolytic peptide fragments of Cyt1Aa. The shortest 51 amino acid peptide was obtained after pre-incubation of Cyt1Aa with SDS and proteolysis with proteinase K. This peptide was purified, identified as the Ile87-Asp137 fragment of Cyt1Aa and was shown to exhibit more than 30 % hemolysis of rabbit erythrocytes.
authors.affiliation: Department of Chemical Engineering, Biotechnology and Materials, Ariel University Center of Samaria, Ariel, Israel. marinan@ariel.ac.il
authors.forename: Marina
authors.initials: M
authors.lastname: Nisnevitch
authors.forename: Svetlana
authors.initials: S
authors.lastname: Nikonov
authors.forename: Yeshayahu
authors.initials: Y
authors.lastname: Nitzan
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001413:Bacillus thuringiensis / Q000378:metabolism*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism*; D004591:Electrophoresis, Polyacrylamide Gel; D019286:Endopeptidase K / Q000378:metabolism; D004731:Endotoxins / Q000737:chemistry / Q000378:metabolism*; D006460:Hemolysin Proteins / Q000737:chemistry / Q000378:metabolism*; D006461:Hemolysis / Q000187:drug effects; D008081:Liposomes / Q000378:metabolism; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000302:isolation & purification / Q000378:metabolism* / Q000494:pharmacology; D011485:Protein Binding; D059748:Proteolysis; D011817:Rabbits
chemical_list: D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D008081:Liposomes; D010446:Peptide Fragments; C030956:insecticidal crystal protein, Bacillus Thuringiensis; D019286:Endopeptidase K