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Publication Metadata only Bacillus thuringiensis Cry4Aa insecticidal protein: Functional importance of the intrinsic stability of the unique α4-α5 loop comprising the Pro-rich sequence(2014-01-01) Chompounoot Imtong; Chalermpol Kanchanawarin; Gerd Katzenmeier; Chanan Angsuthanasombat; Mahidol University; Biophysics Institute for Research and Development (BIRD); Kasetsart UniversityThe long loop connecting transmembrane α4 and α5 of the Bacillus thuringiensis Cry4Aa toxin possesses a unique feature with Pro-rich sequence (Pro193Pro194-Pro196) which was shown to be crucial for toxicity. Here, the structural role... equal to the wild-type. Bioassays demonstrated that all mutants, particularly P193V and P193F whose inclusions were hardly soluble in carbonate buffer (pH 9.0), exhibited reduced toxicity, suggesting an essential role in toxin function by the specificPublication Open Access Structural basis of pore formation by mosquito-larvicidal proteins from bacillus thuringiensis(2010-01) Chanan Angsuthanasombat; Mahidol University. Institute of Molecular BiosciencesThe insecticidal character of the three-domain Cry -endotoxins produced by Bacillus thuringiensis during sporulation is believed to be caused by their capability to generate lytic pores in the target larval midgut cell membranes. This review... describes toxic mechanisms with emphasis on the structural basis of pore formation by two closely related dipteran-specific toxins, Cry4Aa and Cry4Ba, which are highly toxic to mosquito larvae. One proposed toxic mechanism via an “umbrella-like” structurePublication Metadata only Insertion behavior of the Bacillus thuringiensis Cry4Ba insecticidal protein into lipid monolayers(2005-10-15) Yodsoi Kanintronkul; Toemsak Srikhirin; Chanan Angsuthanasombat; Teerakiat Kerdcharoen; Mahidol UniversityToxicity mechanisms of Bacillus thuringiensis Cry insecticidal proteins involve membrane insertion and lytic pore formation in lipid bilayers of the target larval midgut cell membranes. The B. thuringiensis Cry4Ba mosquito-larvicidal protein hasPublication Metadata only Asn183 in α5 is essential for oligomerisation and toxicity of the Bacillus thuringiensis Cry4Ba toxin(2006-01-01) Supaporn Likitvivatanavong; Gerd Katzenmeier; Chanan Angsuthanasombat; Mahidol UniversityThe proposed toxicity mechanism of the Bacillus thuringiensis Cry insecticidal proteins involves membrane penetration and lytic pore formation of the α4-α5 hairpins in the target larval midgut cell membranes. In this study, alanine substitutions...183A mutant was almost completely abolished whereas the four other mutants showed only a small reduction in toxicity. Additionally, replacements of this critical residue with various amino acids revealed that the uncharged polar residue at position 183Publication Metadata only Bacillus thuringiensis cry4ba insecticidal toxinexploits leu615 in its c‐terminal domain to interact with a target receptor—aedes aegypti membrane‐bound alkaline phosphatase(2021-08-01) Anon Thammasittirong; Sutticha Na Ranong Thammasittirong; Chompounoot Imtong; Sathapat Charoenjotivadhanakul; Somsri Sakdee; Hui Chun Li; Siriporn Okonogi; Chanan Angsuthanasombat; Kasetsart University, Kamphaeng Saen Campus; Tzu Chi University; Institute of Molecular Biosciences, Mahidol University; Prince of Songkla University; Chiang Mai University; Biophysics Institute for Research and Development (BIRD)In addition to the receptor‐binding domain (DII), the C‐terminal domain (DIII) of threedomain Cry insecticidal δ‐endotoxins from Bacillus thuringiensis has been implicated in target insect specificity, yet its precise mechanistic role remains... toxicity.Publication Metadata only Functional characterizations of residues Arg-158 and Tyr-170 of the mosquito-larvicidal Bacillus thuringiensis Cry4Ba(2014-01-01) Somphob Leetachewa; Saengduen Moonsom; Urai Chaisri; Narumol Khomkhum; Nonglak Yoonim; Ping Wang; Chanan Angsuthanasombat; Mahidol University; Western University; Cornell University New York State Agricultural Experiment Station© 2014 by the The Korean Society for Biochemistry and Molecular Biology. The insecticidal activity of Bacillus thuringiensis (Bt) Cry toxins involves toxin stabilization, oligomerization, passage across the peritrophic membrane (PM), binding... to midgut receptors and pore-formation. The residues Arg-158 and Tyr-170 have been shown to be crucial for the toxicity of Bt Cry4Ba. We characterized the biological function of these residues. In mosquito larvae, the mutants R158A/E/Q (R158) could hardlyPublication Metadata only Ex vivo cytotoxicity of the Bacillus thuringiensis Cry4B δ-endotoxin to isolated midguts of Aedes aegypti larvae(2003-05-31) Sahawat Barusrux; Issara Sramala; Gerd Katzenmeier; Ahnond Bunyaratvej; Sakol Panyim; Chanan Angsuthanasombat; Mahidol University; The Institute of Science and Technology for Research and Development, Mahidol UniversityThe pathological effect of the Bacillus thuringiensis Cry δ-endotoxins on susceptible insect larvae had extensive damage on the midgut epithelial cells. In this study, an ex vivo assay was devised for assessing the insecticidal potency of the cloned... Cry4B mosquito-larvicidal protein that is expressed in Escherichia coli. Determination of toxicity was carried out by using a cell viability assay on the midguts that were dissected from 5-day old Aedes aegypti mosquito larvae. After incubationPublication Metadata only Functional expression in insect cells of glycosylphosphatidylinositol-linked alkaline phosphatase from Aedes aegypti larval midgut: A Bacillus thuringiensis Cry4Ba toxin receptor(2011-03-01) Manasave Dechklar; Kasorn Tiewsiri; Chanan Angsuthanasombat; Kusol Pootanakit; Mahidol UniversityBacillus thuringiensis produces insecticidal crystal (Cry) proteins which bind to cell surface receptors on the brush border membrane of susceptible midgut larvae. The toxin-receptor interaction generates pores in midgut epithelial cells resulting... treated with Cry4Ba. Overall results indicated that Aa-mALP protein was responsible for mediating Cry4Ba toxicity against Sf9 cells, suggesting its role as a receptor for Cry4Ba toxin in A. aegypti mosquito larvae. © 2010 Elsevier Ltd.Publication Metadata only The C-terminal domain of the Bacillus thuringiensis Cry4Ba mosquito-specific toxin serves as a potential membrane anchor(2019-01-01) Anon Thammasittirong; Chompounoot Imtong; Wilaiwan Sriwimol; Somsri Sakdee; Chanan Angsuthanasombat; Kasetsart University, Kamphaeng Saen Campus; Faculty of Medicine, Prince of Songkia University; Mahidol University; Prince of Songkla University; Biophysics Institute for Research and Development (BIRD)© 2019 by the authors. Licensee MDPI, Basel, Switzerland. Although the C-terminal domain (DIII) of three-domain Cry insecticidal toxins from Bacillus thuringiensis has been implicated in various biological functions, its exact role still remains...-forming moiety of the Cry4Ba mosquito-active toxin, highlighting its potential mechanistic contribution to the interaction of the full-length toxin with lipid membranes in mediating toxicity.Publication Metadata only Targeted mutagenesis of loop residues in the receptor-binding domain of the Bacillus thuringiensis Cry4Ba toxin affects larvicidal activity(2005-01-15) Tipparat Tuntitippawan; Panadda Boonserm; Gerd Katzenmeier; Chanan Angsuthanasombat; Mahidol UniversityLoop residues in domain II of Bacillus thuringiensis Cry δ-endotoxins have been demonstrated to be involved in insecticidal specificity. In this study, selected residues in loops β6-β7 (S387SPS390), β8-β9 (S410, N411, T413, T415, E417and G418) and β... comparable to the wild type. Only E. coli cells that express the P389A, S410A, E417A, Y455A or N456A mutants exhibited a loss in toxicity against Aedes aegypti mosquito larvae of approximately 30% when compared to the wild type. In addition, E. coli cells