title: Characterization of Bacillus thuringiensis Cry1 class proteins in relation to their insecticidal action.
abstract: Thirty nine Bt Cry1 subgroup protein sequences were retrieved from NCBI and analyzed for physicochemical properties, active site and relationship in relation to their variations in toxicity. Cry1 proteins were found to be hydrophilic and stable. SOSUI server predicted presence of two transmembrane regions in Ag and a single transmembrane region from Aa to Ae. EMBOSS PepWheel tool analysis of the transmembrane regions showed that there were 23 highly conserved residues towards the N terminal which are hydrophobic and more than half of the residues were neutrally charged. No signal peptide was detected which classifies the Cry1 group proteins as non-secretory proteins. Cry1 proteins have very high composition of neutral amino acids and might transform into negative charge after solubilization in alkaline environment (insect midgut). The negatively charged protein might misfold causing difficultly to digest and thereby be toxic to lepidopteran. Active sites of Cry1 proteins with more than 50% neutral amino acids showed wide insecticidal spectrum and further positive correlation (r = 0.7731) was observed between neutral amino acids and insect species affected (Y = -138.21 + 2.907X). Similarity of sequences was found between Cry1 proteins based on their high or low spectrum of insecticidal activity.
authors.affiliation: Department of Biotechnology, Mizoram University, Aizawl 796004, Mizoram, India.
authors.forename: Brindha
authors.initials: B
authors.lastname: Senthil Kumar
authors.forename: Zothansanga
authors.initials: Z
authors.lastname: Ralte
authors.forename: Ajit Kumar
authors.initials: AK
authors.lastname: Passari
authors.forename: Vineet Kumar
authors.initials: VK
authors.lastname: Mishra
authors.forename: Biku Moni
authors.initials: BM
authors.lastname: Chutia
authors.forename: Bhim Pratap
authors.initials: BP
authors.lastname: Singh
authors.forename: Gurusubramanian
authors.initials: G
authors.lastname: Guruswami
authors.forename: Senthil Kumar
authors.initials: SK
authors.lastname: Nachimuthu
mesh_terms: D000595:Amino Acid Sequence; D000596:Amino Acids / Q000737:chemistry; D000818:Animals; D001413:Bacillus thuringiensis / Q000737:chemistry*; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins / Q000737:chemistry / Q000633:toxicity*; D020134:Catalytic Domain; D004731:Endotoxins / Q000737:chemistry / Q000633:toxicity*; D019143:Evolution, Molecular; D006460:Hemolysin Proteins / Q000737:chemistry / Q000633:toxicity*; D007313:Insecta / Q000187:drug effects; D007306:Insecticides / Q000737:chemistry / Q000633:toxicity*; D008969:Molecular Sequence Data; D021382:Protein Sorting Signals; D016415:Sequence Alignment; D012995:Solubility
chemical_list: D000596:Amino Acids; D000083722:Bacillus thuringiensis Toxins; D001426:Bacterial Proteins; D004731:Endotoxins; D006460:Hemolysin Proteins; D007306:Insecticides; D021382:Protein Sorting Signals; C030956:insecticidal crystal protein, Bacillus Thuringiensis