title: Molecular modeling and characterization of the B. thuringiensis and B. thuringiensis LDC-9 cytolytic proteins.
abstract: The Cyt toxins are able to lyse a wide range of cell types in vitro, unlike the Cry delta-endotoxins. It exerts its activity by the formation of pores within target cell membranes. The structural information available for Cyt2Aa (PDB id: 1CBY) consists of a single domain in which two outer layers of alpha-helix wrap around a mixed beta-sheet. Beta-barrel was suggested as a possible structure of the pores. Hence, this study seeks to investigate the structural properties of other Cytolytic proteins by predicting the three-dimensional (3D) model using Cyt2Aa as template. The predicted models are expected to be significantly more accurate as all the Cyt proteins showed significant similarity with the template (PDB id: 1CBY). The refined homology models revealed similar secondary structures (alpha-helices and beta-sheets) and tertiary features as Cyt2Aa. The variation in the loop regions of the tertiary structure accounts for the differential toxicity.
authors.affiliation: PG and Research Department of Zoology and Biotechnology, Lady Doak College, Madurai-625 002, TamilNadu, India. shenbagarathai@rediffmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Mahalakshmi
authors.forename: K
authors.initials: K
authors.lastname: Sujatha
authors.forename: R
authors.initials: R
authors.lastname: Shenbagarathai
mesh_terms: D000595:Amino Acid Sequence; D001413:Bacillus thuringiensis / Q000737:chemistry*; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D003198:Computer Simulation; D008958:Models, Molecular; D008969:Molecular Sequence Data; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
chemical_list: D001426:Bacterial Proteins