Cargando…
Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1
Perfluorinated carbon atoms in a diether linkage are common in commercial anesthetics, drugs, fungicides, and insecticides. An important chemical group comprising perfluorodiethers is the 2,2-fluoro-1,3-benzodioxole (DFBD) moiety. The fluorine atoms stabilize the molecule by mitigating against metab...
Autores principales: | , , , |
---|---|
Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Society for Microbiology
2021
|
Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8593668/ https://www.ncbi.nlm.nih.gov/pubmed/34781746 http://dx.doi.org/10.1128/mBio.03001-21 |
_version_ | 1784599797241479168 |
---|---|
author | Bygd, Madison D. Aukema, Kelly G. Richman, Jack E. Wackett, Lawrence P. |
author_facet | Bygd, Madison D. Aukema, Kelly G. Richman, Jack E. Wackett, Lawrence P. |
author_sort | Bygd, Madison D. |
collection | PubMed |
description | Perfluorinated carbon atoms in a diether linkage are common in commercial anesthetics, drugs, fungicides, and insecticides. An important chemical group comprising perfluorodiethers is the 2,2-fluoro-1,3-benzodioxole (DFBD) moiety. The fluorine atoms stabilize the molecule by mitigating against metabolism by humans and microbes, as used in drugs and pesticides, respectively. Pseudomonas putida F1 catalyzed defluorination of DFBD at an initial rate of 2,100 nmol/h per mg cellular protein. This is orders of magnitude higher than previously reported microbial defluorination rates with multiply fluorinated carbon atoms. Defluorination rates declined after several hours, and the medium darkened. Significant defluorination activity was observed with cells grown on toluene but not l-arginine. Defluorination required only toluene dioxygenase. Pseudomonas and recombinant Escherichia coli cells expressing toluene dioxygenase oxidized DFBD to DFBD-4,5-dihydrodiol. The dihydrodiol could be oxidized to 4,5-dihydroxy-DFBD via the dihydrodiol dehydrogenase from P. putida F1. The dihydrodiol dehydrated with acid to yield a mixture of 4-hydroxy-DFBD and 5-hydroxy-DFBD. All those metabolites retained the difluoromethylene group; no fluoride or dark color was observed. The major route of DFBD-4,5-dihydrodiol decomposition produced fluoride and 1,2,3-trihydroxybenzene, or pyrogallol, and that was shown to be the source of the dark colors in the medium. A mechanism for DFBD-4,5-dihydrodiol transformation to two fluoride ions and pyrogallol is proposed. The Pseudomonas genome database and other databases revealed hundreds of bacteria with enzymes sharing high amino acid sequence identity to toluene dioxygenase from P. putida F1, suggesting the mechanism revealed here may apply to the defluorination of DFBD-containing compounds in the environment. |
format | Online Article Text |
id | pubmed-8593668 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | American Society for Microbiology |
record_format | MEDLINE/PubMed |
spelling | pubmed-85936682021-12-02 Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1 Bygd, Madison D. Aukema, Kelly G. Richman, Jack E. Wackett, Lawrence P. mBio Research Article Perfluorinated carbon atoms in a diether linkage are common in commercial anesthetics, drugs, fungicides, and insecticides. An important chemical group comprising perfluorodiethers is the 2,2-fluoro-1,3-benzodioxole (DFBD) moiety. The fluorine atoms stabilize the molecule by mitigating against metabolism by humans and microbes, as used in drugs and pesticides, respectively. Pseudomonas putida F1 catalyzed defluorination of DFBD at an initial rate of 2,100 nmol/h per mg cellular protein. This is orders of magnitude higher than previously reported microbial defluorination rates with multiply fluorinated carbon atoms. Defluorination rates declined after several hours, and the medium darkened. Significant defluorination activity was observed with cells grown on toluene but not l-arginine. Defluorination required only toluene dioxygenase. Pseudomonas and recombinant Escherichia coli cells expressing toluene dioxygenase oxidized DFBD to DFBD-4,5-dihydrodiol. The dihydrodiol could be oxidized to 4,5-dihydroxy-DFBD via the dihydrodiol dehydrogenase from P. putida F1. The dihydrodiol dehydrated with acid to yield a mixture of 4-hydroxy-DFBD and 5-hydroxy-DFBD. All those metabolites retained the difluoromethylene group; no fluoride or dark color was observed. The major route of DFBD-4,5-dihydrodiol decomposition produced fluoride and 1,2,3-trihydroxybenzene, or pyrogallol, and that was shown to be the source of the dark colors in the medium. A mechanism for DFBD-4,5-dihydrodiol transformation to two fluoride ions and pyrogallol is proposed. The Pseudomonas genome database and other databases revealed hundreds of bacteria with enzymes sharing high amino acid sequence identity to toluene dioxygenase from P. putida F1, suggesting the mechanism revealed here may apply to the defluorination of DFBD-containing compounds in the environment. American Society for Microbiology 2021-11-16 /pmc/articles/PMC8593668/ /pubmed/34781746 http://dx.doi.org/10.1128/mBio.03001-21 Text en Copyright © 2021 Bygd et al. https://creativecommons.org/licenses/by/4.0/This is an open-access article distributed under the terms of the Creative Commons Attribution 4.0 International license (https://creativecommons.org/licenses/by/4.0/) . |
spellingShingle | Research Article Bygd, Madison D. Aukema, Kelly G. Richman, Jack E. Wackett, Lawrence P. Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1 |
title | Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1 |
title_full | Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1 |
title_fullStr | Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1 |
title_full_unstemmed | Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1 |
title_short | Unexpected Mechanism of Biodegradation and Defluorination of 2,2-Difluoro-1,3-Benzodioxole by Pseudomonas putida F1 |
title_sort | unexpected mechanism of biodegradation and defluorination of 2,2-difluoro-1,3-benzodioxole by pseudomonas putida f1 |
topic | Research Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8593668/ https://www.ncbi.nlm.nih.gov/pubmed/34781746 http://dx.doi.org/10.1128/mBio.03001-21 |
work_keys_str_mv | AT bygdmadisond unexpectedmechanismofbiodegradationanddefluorinationof22difluoro13benzodioxolebypseudomonasputidaf1 AT aukemakellyg unexpectedmechanismofbiodegradationanddefluorinationof22difluoro13benzodioxolebypseudomonasputidaf1 AT richmanjacke unexpectedmechanismofbiodegradationanddefluorinationof22difluoro13benzodioxolebypseudomonasputidaf1 AT wackettlawrencep unexpectedmechanismofbiodegradationanddefluorinationof22difluoro13benzodioxolebypseudomonasputidaf1 |