Cargando…

Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor

Receptor binding is a prerequisite process to exert the mosquitocidal activity of the Cry4Ba toxin of Bacillus thuringiensis subsp. israelensis. The beta-sheet prism (domain II) and beta-sheet sandwich (domain III) of the Cry4Ba toxin have been implicated in receptor binding, albeit the precise bind...

Descripción completa

Detalles Bibliográficos
Autores principales: Thammasittirong, Anon, Thammasittirong, Sutticha Na-Ranong
Formato: Online Artículo Texto
Lenguaje:English
Publicado: MDPI 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9960242/
https://www.ncbi.nlm.nih.gov/pubmed/36828427
http://dx.doi.org/10.3390/toxins15020114
_version_ 1784895466560815104
author Thammasittirong, Anon
Thammasittirong, Sutticha Na-Ranong
author_facet Thammasittirong, Anon
Thammasittirong, Sutticha Na-Ranong
author_sort Thammasittirong, Anon
collection PubMed
description Receptor binding is a prerequisite process to exert the mosquitocidal activity of the Cry4Ba toxin of Bacillus thuringiensis subsp. israelensis. The beta-sheet prism (domain II) and beta-sheet sandwich (domain III) of the Cry4Ba toxin have been implicated in receptor binding, albeit the precise binding mechanisms of these remain unclear. In this work, alanine scanning was used to determine the contribution to receptor binding of some aromatic and hydrophobic residues on the surface of domains II and III that are predicted to be responsible for binding to the Aedes aegypti membrane-bound alkaline phosphatase (Aa-mALP) receptor. Larvicidal activity assays against A. aegypti larvae revealed that aromatic residues (Trp(327) on the β2 strand, Tyr(347) on the β3–β4 loop, and Tyr(359) on the β4 strand) of domain II were important to the toxicity of the Cry4Ba toxin. Quantitative binding assays using enzyme-linked immunosorbent assay (ELISA) showed similar decreasing trends in binding to the Aa-mALP receptor and in toxicity of the Cry4Ba mutants Trp327Ala, Tyr347Ala, and Tyr359Ala, suggesting that a possible function of these surface-exposed aromatic residues is receptor binding. In addition, binding assays of the Cry4Ba toxin to the mutants of the binding residues Gly(513), Ser(490), and Phe(497) of the Aa-mALP receptor supported the binding function of Trp(327), Tyr(347), and Tyr(359) of the Cry4Ba toxin, respectively. Altogether, our results showed for the first time that aromatic residues on a side surface of the Cry4Ba domain II function in receptor binding. This finding provides greater insight into the possible molecular mechanisms of the Cry4Ba toxin.
format Online
Article
Text
id pubmed-9960242
institution National Center for Biotechnology Information
language English
publishDate 2023
publisher MDPI
record_format MEDLINE/PubMed
spelling pubmed-99602422023-02-26 Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor Thammasittirong, Anon Thammasittirong, Sutticha Na-Ranong Toxins (Basel) Article Receptor binding is a prerequisite process to exert the mosquitocidal activity of the Cry4Ba toxin of Bacillus thuringiensis subsp. israelensis. The beta-sheet prism (domain II) and beta-sheet sandwich (domain III) of the Cry4Ba toxin have been implicated in receptor binding, albeit the precise binding mechanisms of these remain unclear. In this work, alanine scanning was used to determine the contribution to receptor binding of some aromatic and hydrophobic residues on the surface of domains II and III that are predicted to be responsible for binding to the Aedes aegypti membrane-bound alkaline phosphatase (Aa-mALP) receptor. Larvicidal activity assays against A. aegypti larvae revealed that aromatic residues (Trp(327) on the β2 strand, Tyr(347) on the β3–β4 loop, and Tyr(359) on the β4 strand) of domain II were important to the toxicity of the Cry4Ba toxin. Quantitative binding assays using enzyme-linked immunosorbent assay (ELISA) showed similar decreasing trends in binding to the Aa-mALP receptor and in toxicity of the Cry4Ba mutants Trp327Ala, Tyr347Ala, and Tyr359Ala, suggesting that a possible function of these surface-exposed aromatic residues is receptor binding. In addition, binding assays of the Cry4Ba toxin to the mutants of the binding residues Gly(513), Ser(490), and Phe(497) of the Aa-mALP receptor supported the binding function of Trp(327), Tyr(347), and Tyr(359) of the Cry4Ba toxin, respectively. Altogether, our results showed for the first time that aromatic residues on a side surface of the Cry4Ba domain II function in receptor binding. This finding provides greater insight into the possible molecular mechanisms of the Cry4Ba toxin. MDPI 2023-01-29 /pmc/articles/PMC9960242/ /pubmed/36828427 http://dx.doi.org/10.3390/toxins15020114 Text en © 2023 by the authors. https://creativecommons.org/licenses/by/4.0/Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https://creativecommons.org/licenses/by/4.0/).
spellingShingle Article
Thammasittirong, Anon
Thammasittirong, Sutticha Na-Ranong
Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor
title Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor
title_full Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor
title_fullStr Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor
title_full_unstemmed Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor
title_short Aromatic Residues on the Side Surface of Cry4Ba-Domain II of Bacillus thuringiensis subsp. israelensis Function in Binding to Their Counterpart Residues on the Aedes aegypti Alkaline Phosphatase Receptor
title_sort aromatic residues on the side surface of cry4ba-domain ii of bacillus thuringiensis subsp. israelensis function in binding to their counterpart residues on the aedes aegypti alkaline phosphatase receptor
topic Article
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9960242/
https://www.ncbi.nlm.nih.gov/pubmed/36828427
http://dx.doi.org/10.3390/toxins15020114
work_keys_str_mv AT thammasittironganon aromaticresiduesonthesidesurfaceofcry4badomainiiofbacillusthuringiensissubspisraelensisfunctioninbindingtotheircounterpartresiduesontheaedesaegyptialkalinephosphatasereceptor
AT thammasittirongsuttichanaranong aromaticresiduesonthesidesurfaceofcry4badomainiiofbacillusthuringiensissubspisraelensisfunctioninbindingtotheircounterpartresiduesontheaedesaegyptialkalinephosphatasereceptor