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Shen J, Tang ST, Wang YN, Li XT, Chen J, Sarkarai Nadar V, Rosen BP, Zhang J, Zhao FJ. Bifunctional ArsI Dioxygenase from Acidovorax sp. ST3 with Both Methylarsenite [MAs(III)] Demethylation and MAs(III) Oxidation Activities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024. [PMID: 39226438 DOI: 10.1021/acs.est.4c04835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/05/2024]
Abstract
Methylated arsenicals, including highly toxic species, such as methylarsenite [MAs(III)], are pervasive in the environment. Certain microorganisms possess the ability to detoxify MAs(III) by ArsI-catalyzed demethylation. Here, we characterize a bifunctional enzyme encoded by the arsI gene from Acidovorax sp. ST3, which can detoxify MAs(III) through both the demethylation and oxidation pathways. Deletion of the 22 C-terminal amino acids of ArsI increased its demethylation activity while reducing the oxidation activity. Further deletion of 44 C-terminal residues enhanced the MAs(III) demethylation activity. ArsI has four vicinal cysteine pairs, with the first pair being necessary for MAs(III) demethylation, while at least one of the other three pairs contributes to MAs(III) oxidation. Molecular modeling and site-directed mutagenesis indicated that one of the C-terminal vicinal cysteine pairs is involved in modulating the switch between oxidase and demethylase activity. These findings underscore the critical role of the C-terminal region in modulating the enzymatic activities of ArsI, particularly in MAs(III) demethylation. This research reveals the structure-function relationship of the ArsI enzyme and advances our understanding of the MAs(III) metabolism in bacteria.
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Affiliation(s)
- Jie Shen
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, People's Republic of China
| | - Shi-Tong Tang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, People's Republic of China
| | - Ya-Nan Wang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, People's Republic of China
| | - Xue-Ting Li
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, People's Republic of China
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, United States
| | - Venkadesh Sarkarai Nadar
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, United States
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33199, United States
| | - Jun Zhang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, People's Republic of China
| | - Fang-Jie Zhao
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, Jiangsu 210095, People's Republic of China
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Shen J, Song XW, Bickel D, Rosen BP, Zhao FJ, Messens J, Zhang J. Arsenate reductase of Rufibacter tibetensis is a metallophosphoesterase evolved to catalyze redox reactions. Mol Microbiol 2024; 122:201-212. [PMID: 38922722 PMCID: PMC11309893 DOI: 10.1111/mmi.15289] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Revised: 05/31/2024] [Accepted: 06/07/2024] [Indexed: 06/28/2024]
Abstract
An arsenate reductase (Car1) from the Bacteroidetes species Rufibacter tibetensis 1351T was isolated from the Tibetan Plateau. The strain exhibits resistance to arsenite [As(III)] and arsenate [As(V)] and reduces As(V) to As(III). Here we shed light on the mechanism of enzymatic reduction by Car1. AlphaFold2 structure prediction, active site energy minimization, and steady-state kinetics of wild-type and mutant enzymes give insight into the catalytic mechanism. Car1 is structurally related to calcineurin-like metallophosphoesterases (MPPs). It functions as a binuclear metal hydrolase with limited phosphatase activity, particularly relying on the divalent metal Ni2+. As an As(V) reductase, it displays metal promiscuity and is coupled to the thioredoxin redox cycle, requiring the participation of two cysteine residues, Cys74 and Cys76. These findings suggest that Car1 evolved from a common ancestor of extant phosphatases by incorporating a redox function into an existing MPP catalytic site. Its proposed mechanism of arsenate reduction involves Cys74 initiating a nucleophilic attack on arsenate, leading to the formation of a covalent intermediate. Next, a nucleophilic attack of Cys76 leads to the release of As(III) and the formation of a surface-exposed Cys74-Cys76 disulfide, ready for reduction by thioredoxin.
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Affiliation(s)
- Jie Shen
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Xin-Wei Song
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou, China
| | - David Bickel
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- Interuniversity Institute of Bioinformatics in Brussels, ULB-VUB, Brussels, Belgium
| | - Barry P. Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, USA
| | - Fang-Jie Zhao
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Joris Messens
- Structural Biology Brussels, Vrije Universiteit Brussel, Brussels, Belgium
- VIB-VUB Center for Structural Biology, VIB, Brussels, Belgium
- Brussels Center for Redox Biology, Brussels, Belgium
| | - Jun Zhang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
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Teng ZJ, Li J, Wang P, Li CY, Peng M, Qin QL, Chen XL, Chen Y, Fu HH, Wang N, Zhang YZ. Meta-omics analysis reveals the marine arsenic cycle driven by bacteria. JOURNAL OF HAZARDOUS MATERIALS 2024; 476:135137. [PMID: 39024770 DOI: 10.1016/j.jhazmat.2024.135137] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2024] [Revised: 06/16/2024] [Accepted: 07/05/2024] [Indexed: 07/20/2024]
Abstract
Arsenic is a toxic element widely distributed in the Earth's crust and ranked as a class I human carcinogen. Microbial metabolism makes significant contributions to arsenic detoxification, migration and transformation. Nowadays, research on arsenic is primarily in areas affected by arsenic pollution associated with human health activities. However, the biogeochemical traits of arsenic in the global marine ecosystem remain to be explicated. In this study, we revealed that seawater environments were primarily governed by the process of arsenate reduction to arsenite, while arsenite methylation was predominant in marine sediments which may serve as significant sources of arsenic emission into the atmosphere. Significant disparities existed in the distribution patterns of the arsenic cycle between surface and deep seawaters at middle and low latitudes, whereas these situations tend to be similar in the Arctic and Antarctic oceans. Significant variations were also observed in the taxonomic diversity and core microbial community of arsenic cycling across different marine environments. Specifically, γ-proteobacteria played a pivotal role in the arsenic cycle in the whole marine environment. Temperature, dissolved oxygen and phosphate were the crucial factors that related to these differentiations in seawater environments. Overall, our study contributes to a deeper understanding of the marine arsenic cycle.
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Affiliation(s)
- Zhao-Jie Teng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
| | - Jian Li
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Peng Wang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Joint Research Center for Marine Microbial Science and Technology, Shandong University and Ocean University of China, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266373, China
| | - Chun-Yang Li
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Joint Research Center for Marine Microbial Science and Technology, Shandong University and Ocean University of China, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266373, China
| | - Ming Peng
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China
| | - Qi-Long Qin
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; Joint Research Center for Marine Microbial Science and Technology, Shandong University and Ocean University of China, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266373, China
| | - Xiu-Lan Chen
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China; Joint Research Center for Marine Microbial Science and Technology, Shandong University and Ocean University of China, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266373, China
| | - Yin Chen
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; School of Life Sciences, The University of Warwick, Coventry CV4 7AL, United Kingdom
| | - Hui-Hui Fu
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Joint Research Center for Marine Microbial Science and Technology, Shandong University and Ocean University of China, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266373, China
| | - Ning Wang
- State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
| | - Yu-Zhong Zhang
- MOE Key Laboratory of Evolution and Marine Biodiversity, Frontiers Science Center for Deep Ocean Multispheres and Earth System & College of Marine Life Sciences, Ocean University of China, Qingdao 266003, China; Joint Research Center for Marine Microbial Science and Technology, Shandong University and Ocean University of China, Qingdao 266003, China; Laboratory for Marine Biology and Biotechnology, Qingdao Marine Science and Technology Center, Qingdao, 266373, China; Marine Biotechnology Research Center, State Key Laboratory of Microbial Technology, Shandong University, Qingdao 266237, China.
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Li Y, Yu Y, Yang X, Pat-Espadas AM, Vinuesa P, Herzberg M, Chen J, Rosen BP, Feng R, Rensing C. Adaptation to metal(loid)s in strain Mucilaginibacter rubeus P2 involves novel arsenic resistance genes and mechanisms. JOURNAL OF HAZARDOUS MATERIALS 2024; 462:132796. [PMID: 37865075 PMCID: PMC10699512 DOI: 10.1016/j.jhazmat.2023.132796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Revised: 09/30/2023] [Accepted: 10/14/2023] [Indexed: 10/23/2023]
Abstract
Arsenic is a ubiquitous environmental toxi substance that affects human health. Compared to inorganic arsenicals, reduced organoarsenicals are more toxic, and some of them are recognized as antibiotics, such as methylarsenite [MAs(III)] and arsinothricin (2-amino-4-(hydroxymethylarsinoyl)butanoate, or AST). To date, organoarsenicals such as MAs(V) and roxarsone [Rox(V)] are still used in agriculture and animal husbandry. How bacteria deal with both inorganic and organoarsenic species is unclear. Recently, we identified an environmental isolate Mucilaginibacter rubeus P2 that has adapted to high arsenic and antinomy levels by triplicating an arsR-mrarsUBact-arsN-arsC-(arsRhp)-hp-acr3-mrme1Bact-mrme2Bactgene cluster. Heterologous expression of mrarsMBact, mrarsUBact, mrme1Bact and mrme2Bact, encoding putative arsenic resistance determinants, in the arsenic hypersensitive strain Escherichia coli AW3110 conferred resistance to As(III), As(V), MAs(III) or Rox(III). Our data suggest that metalloid exposure promotes plasticity in arsenic resistance systems, enhancing host organism adaptation to metalloid stress.
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Affiliation(s)
- Yuanping Li
- College of Tea and Food, Wuyi University, Wuyishan, China
| | - Yanshuang Yu
- Institute of Environmental Microbiology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiaojun Yang
- College of Ecology and Resource Engineering, Wuyi University, Wuyishan, China
| | - Aurora M Pat-Espadas
- CONACYT-Institute of Geology, Estación Regional del Noroeste, Universidad Nacional Autónoma de México, Luis Donaldo Colosio s/n, Hermosillo, Sonora, Mexico
| | - Pablo Vinuesa
- Centro de Ciencias Genómicas, Universidad Nacional Autónoma de México, Cuernavaca, Morelos, Mexico
| | - Martin Herzberg
- Molecular Microbiology, Institute for Biology/Microbiology, Martin-Luther-University Halle-Wittenberg, Kurt-Mothes-Str. 3, 06120 Halle, Germany
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, United States
| | - Renwei Feng
- Institute of Environmental Microbiology, Fujian Agriculture and Forestry University, Fuzhou, China.
| | - Christopher Rensing
- Institute of Environmental Microbiology, Fujian Agriculture and Forestry University, Fuzhou, China.
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Lan X, Lin W, Ning Z, Su X, Chen Y, Jia Y, Xiao E. Arsenic shapes the microbial community structures in tungsten mine waste rocks. ENVIRONMENTAL RESEARCH 2023; 216:114573. [PMID: 36243050 DOI: 10.1016/j.envres.2022.114573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2022] [Revised: 09/29/2022] [Accepted: 10/08/2022] [Indexed: 06/16/2023]
Abstract
Tungsten (W) is a critical material that is widely used in military applications, electronics, lighting technology, power engineering and the automotive and aerospace industries. In recent decades, overexploitation of W has generated large amounts of mine waste rocks, which generate elevated content of toxic elements and cause serious adverse effects on ecosystems and public health. Microorganisms are considered important players in toxic element migrations from waste rocks. However, the understanding of how the microbial community structure varies in W mine waste rocks and its key driving factors is still unknown. In this study, high-throughput sequencing methods were used to determine the microbial community profiles along a W content gradient in W mine waste rocks. We found that the microbial community structures showed clear differences across the different W levels in waste rocks. Notably, arsenic (As), instead of W and nutrients, was identified as the most important predictor influencing microbial diversity. Furthermore, our results also showed that As is the most important environmental factor that regulates the distribution patterns of ecological clusters and keystone ASVs. Importantly, we found that the dominant genera have been regulated by As and were widely involved in As biogeochemical cycling in waste rocks. Taken together, our results have provided useful information about the response of microbial communities to W mine waste rocks.
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Affiliation(s)
- Xiaolong Lan
- School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou, 521041, China
| | - Wenjie Lin
- School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou, 521041, China.
| | - Zengping Ning
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550081, China
| | - Xinyu Su
- School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou, 521041, China
| | - Yushuang Chen
- School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou, 521041, China
| | - Yanlong Jia
- School of Chemistry and Environmental Engineering, Hanshan Normal University, Chaozhou, 521041, China
| | - Enzong Xiao
- School of Environmental Science and Engineering, Guangzhou University, Guangzhou, 510006, China.
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Zhou Q, Zhang J, Chen J. Methylation of arsenic differs with substrates in Arcticibacter tournemirensis R1 from an As-contaminated paddy soil. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:156527. [PMID: 35679924 DOI: 10.1016/j.scitotenv.2022.156527] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 05/24/2022] [Accepted: 06/02/2022] [Indexed: 06/15/2023]
Abstract
Arsenic can be methylated by arsenite (As(III)) S-adenosylmethionine methyltransferases (ArsMs) among various kingdoms of life. The intermediate product methylarsenite (MAs(III)) is highly toxic and can be utilized as an antibiotic by some microbes. ArsM gene is widely distributed in the members of every kingdom from bacteria to humans and displays a high diversity of sequence. Based on arsenic methylating capacity, ArsM proteins can be divided into two phylogenetically distinct clades (Groups 1 and 2). In this study, we show that Arcticibacter tournemirensis R1 isolated from arsenic contaminated paddy soil is resistant to both As(III) and MAs(III), but exhibits different methylation activities for As(III) and MAs(III). The A. tournemirensis R1 shows low As(III) methylation activity and produces an unknown arsenic compound. In contrast, it shows high methylation activity with MAs(III), with the main product of dimethylarsenate (DMAs(V)). An AtarsM gene is found in ars operon of A. tournemirensis R1 genome and is regulated by an atypical transcriptional repressor ArsR. Expressed in Escherichia coli AtArsM confers resistance to As(III) and MAs(III). Both in vivo and in vitro assays show that AtArsM methylates As(III) and MAs(III) to dimethyl- and trimethyl‑arsenicals. AtArsM has four conserved cysteine residues, which are present in most ArsMs and can be classified into phylogenetic group 2 family, producing trimethylated arsenic metabolites. The high arsenic methylation and volatilization activity of AtArsM provides a potential strategy for arsenic bioremediation. The methylation activity differs with As(III) and MAs(III) in A. tournemirensis R1 indicates that there may have different detoxification mechanisms for As(III) and MAs(III), which are worth investigating in the future.
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Affiliation(s)
- Qiang Zhou
- College of Biology and Environmental Sciences, Jishou University, Jishou, Hunan 416000, China
| | - Jun Zhang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing 210095, China.
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, United States.
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Zhang J, Wu YF, Tang ST, Chen J, Rosen BP, Zhao FJ. A PadR family transcriptional repressor controls transcription of a trivalent metalloid resistance operon of Azospirillum halopraeferens strain Au 4. Environ Microbiol 2022; 24:5139-5150. [PMID: 35880613 DOI: 10.1111/1462-2920.16147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2022] [Revised: 07/18/2022] [Accepted: 07/20/2022] [Indexed: 11/28/2022]
Abstract
Methylarsenite [MAs(III)] is a highly toxic arsenical produced by some microbes as an antibiotic. In this study, we demonstrate that a PadR family transcriptional regulator, PadRars , from Azospirillum halopraeferens strain Au 4 directly binds to the promoter region of the arsenic resistance (ars) operon (consisting of padRars , arsV, and arsW) and represses transcription of arsV and arsW genes involved in MAs(III) resistance. Quantitative reverse transcriptase PCR and transcriptional reporter assays showed that transcription of the ars operon is induced strongly by MAs(III) and less strongly by arsenite and antimonite. Electrophoretic mobility shift assays with recombinant PadRars showed that it represses transcription of the ars operon by binding to two inverted-repeat sequences within the ars promoter. PadRars has two conserved cysteine pairs, Cys56/57 and Cys133/134; mutation of the first pair to serine abolished the transcriptional response of the ars operon to trivalent metalloids, suggesting that Cys56/57 form a binding site for trivalent metalloids. Either C133S or C134S derivative responses to MAs(III) but not As(III) or Sb(III), suggesting that it is a third ligand to trivalent metalloids. PadRars represents a new type of repressor proteins regulating transcription of an ars operon involved in the resistance to trivalent metalloids, especially MAs(III). This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jun Zhang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Yi-Fei Wu
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Shi-Tong Tang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Fang-Jie Zhao
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, China
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Characterization of Two Highly Arsenic-Resistant Caulobacteraceae Strains of Brevundimonas nasdae: Discovery of a New Arsenic Resistance Determinant. Int J Mol Sci 2022; 23:ijms23105619. [PMID: 35628430 PMCID: PMC9144182 DOI: 10.3390/ijms23105619] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 05/12/2022] [Accepted: 05/13/2022] [Indexed: 02/07/2023] Open
Abstract
Arsenic (As), distributed widely in the natural environment, is a toxic substance which can severely impair the normal functions in living cells. Research on the genetic determinants conferring functions in arsenic resistance and metabolism is of great importance for remediating arsenic-contaminated environments. Many organisms, including bacteria, have developed various strategies to tolerate arsenic, by either detoxifying this harmful element or utilizing it for energy generation. More and more new arsenic resistance (ars) determinants have been identified to be conferring resistance to diverse arsenic compounds and encoded in ars operons. There is a hazard in mobilizing arsenic during gold-mining activities due to gold- and arsenic-bearing minerals coexisting. In this study, we isolated 8 gold enrichment strains from the Zijin gold and copper mine (Longyan, Fujian Province, China) wastewater treatment site soil, at an altitude of 192 m. We identified two Brevundimonas nasdae strains, Au-Bre29 and Au-Bre30, among these eight strains, having a high minimum inhibitory concentration (MIC) for As(III). These two strains contained the same ars operons but displayed differences regarding secretion of extra-polymeric substances (EPS) upon arsenite (As(III)) stress. B. nasdae Au-Bre29 contained one extra plasmid but without harboring any additional ars genes compared to B. nasdae Au-Bre30. We optimized the growth conditions for strains Au-Bre29 and Au-Bre30. Au-Bre30 was able to tolerate both a lower pH and slightly higher concentrations of NaCl. We also identified folE, a folate synthesis gene, in the ars operon of these two strains. In most organisms, folate synthesis begins with a FolE (GTP-Cyclohydrolase I)-type enzyme, and the corresponding gene is typically designated folE (in bacteria) or gch1 (in mammals). Heterologous expression of folE, cloned from B. nasdae Au-Bre30, in the arsenic-hypersensitive strain Escherichia coli AW3110, conferred resistance to As(III), arsenate (As(V)), trivalent roxarsone (Rox(III)), pentavalent roxarsone (Rox(V)), trivalent antimonite (Sb(III)), and pentavalent antimonate (Sb(V)), indicating that folate biosynthesis is a target of arsenite toxicity and increased production of folate confers increased resistance to oxyanions. Genes encoding Acr3 and ArsH were shown to confer resistance to As(III), Rox(III), Sb(III), and Sb(V), and ArsH also conferred resistance to As(V). Acr3 did not confer resistance to As(V) and Rox(V), while ArsH did not confer resistance to Rox(V).
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Zhang J, Li YN, Chen J, Yan Y, Rosen BP, Zhao FJ. ArsZ from Ensifer adhaerens ST2 is a novel methylarsenite oxidase. Environ Microbiol 2022; 24:3013-3021. [PMID: 35355385 DOI: 10.1111/1462-2920.15983] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 03/09/2022] [Accepted: 03/21/2022] [Indexed: 11/30/2022]
Abstract
Trivalent methylarsenite (MAs(III)) produced by biomethylation is more toxic than inorganic arsenite (As(III)). Hence, MAs(III) has been proposed to be a primordial antibiotic. Other bacteria evolved mechanisms to detoxify MAs(III). In this study, the molecular mechanisms of MAs(III) resistance of Ensifer adhaerens ST2 were investigated. In the chromosome of E. adhaerens ST2 is a gene encoding a protein of unknown function. Here we show that this gene, designated arsZ, encodes a novel MAs(III) oxidase that confers resistance by oxidizing highly toxic MAs(III) to relatively nontoxic MAs(V). Two other genes, arsRK, are adjacent to arsZ but are divergently encoded in the opposite direction. Heterologous expression of arsZ in Escherichia coli confers resistance to MAs(III) but not to As(III). Purified ArsZ catalyzes thioredoxin- and NAPD+ -dependent oxidation of MAs(III). Mutational analysis of ArsZ suggests that Cys59 and Cys123 are involved in oxidation of MAs(III). Expression of arsZ, arsR and arsK genes is induced by MAs(III) and As(III), and is likely controlled by the ArsR transcriptional repressor. These results demonstrate that ArsZ is a novel MAs(III) oxidase that contributes to E. adhaerens tolerance to environmental organoarsenicals. The arsZRK operon is widely present in bacteria within the Rhizobiaceae family. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Jun Zhang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yan-Ning Li
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, 33199
| | - Yu Yan
- Department of Environmental Science and Engineering, Huaqiao University, Xiamen, 361021, China
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, 33199
| | - Fang-Jie Zhao
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Center for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
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Identification of a MarR Subfamily That Regulates Arsenic Resistance Genes. Appl Environ Microbiol 2021; 87:e0158821. [PMID: 34613763 DOI: 10.1128/aem.01588-21] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
In this study, comprehensive analyses were performed to determine the function of an atypical MarR homolog in Achromobacter sp. strain As-55. Genomic analyses of Achromobacter sp. As-55 showed that this marR is located adjacent to an arsV gene. ArsV is a flavin-dependent monooxygenase that confers resistance to the antibiotic methylarsenite [MAs(III)], the organoarsenic compound roxarsone(III) [Rox(III)], and the inorganic antimonite [Sb(III)]. Similar marR genes are widely distributed in arsenic-resistant bacteria. Phylogenetic analyses showed that these MarRs are found in operons predicted to be involved in resistance to inorganic and organic arsenic species, so the subfamily was named MarRars. MarRars orthologs have three conserved cysteine residues, which are Cys36, Cys37, and Cys157 in Achromobacter sp. As-55, mutation of which compromises the response to MAs(III)/Sb(III). GFP-fluorescent biosensor assays show that AdMarRars (MarR protein of Achromobacter deleyi As-55) responds to trivalent As(III) and Sb(III) but not to pentavalent As(V) or Sb(V). The results of RT-qPCR assays show that arsV is expressed constitutively in a marR deletion mutant, indicating that marR represses transcription of arsV. Moreover, electrophoretic mobility shift assays (EMSAs) demonstrate that AdMarRars binds to the promoters of both marR and arsV in the absence of ligands and that DNA binding is relieved upon binding of As(III) and Sb(III). Our results demonstrate that AdMarRars is a novel As(III)/Sb(III)-responsive transcriptional repressor that controls expression of arsV, which confers resistance to MAs(III), Rox(III), and Sb(III). AdMarRars and its orthologs form a subfamily of MarR proteins that regulate genes conferring resistance to arsenic-containing antibiotics. IMPORTANCE In this study, a MarR family member, AdMarRars was shown to regulate the arsV gene, which confers resistance to arsenic-containing antibiotics. It is a founding member of a distinct subfamily that we refer to as MarRars, regulating genes conferring resistance to arsenic and antimony antibiotic compounds. AdMarRars was shown to be a repressor containing conserved cysteine residues that are required to bind As(III) and Sb(III), leading to a conformational change and subsequent derepression. Here we show that members of the MarR family are involved in regulating arsenic-containing compounds.
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Chen J, Zhang J, Wu YF, Zhao FJ, Rosen BP. ArsV and ArsW provide synergistic resistance to the antibiotic methylarsenite. Environ Microbiol 2021; 23:7550-7562. [PMID: 34676971 DOI: 10.1111/1462-2920.15817] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 09/23/2021] [Accepted: 10/07/2021] [Indexed: 11/29/2022]
Abstract
Toxic organoarsenicals enter the environment from biogenic and anthropogenic activities such as microbial methylation of inorganic arsenic and pentavalent herbicides such as monosodium methylarsenate (MSMA or MAs(V)). Trivalent MAs(III) is considerably more toxic than arsenite or arsenate. Microbes have evolved mechanisms to detoxify organoarsenicals. We previously identified ArsV, a flavin-linked monooxygenase and demonstrated that it confers resistance to methylarsenite by oxidation to methylarsenate. The arsV gene is usually in an arsenic resistance (ars) operon controlled by an ArsR repressor and adjacent to a methylarsenite efflux gene, either arsK or a gene for a putative transporter. Here we show that Paracoccus sp. SY oxidizes methylarsenite. It has an ars operon with three genes, arsR, arsV and a transport gene termed arsW. Heterologous expression of arsV in Escherichia coli conferred resistance to MAs(III), while arsW did not. Co-expression of arsV and arsW increased resistance compared with either alone. The cells oxidized methylarsenite and accumulated less methylarsenate. Everted membrane vesicles from E. coli cells expressing arsW-accumulated methylarsenate. We propose that ArsV is a monooxygenase that oxidizes methylarsenite to methylarsenate, which is extruded by ArsW, one of only a few known pentavalent organoarsenical efflux permeases, a novel pathway of organoarsenical resistance.
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Affiliation(s)
- Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA.,Institute of Environment Remediation and Human Health, and College of Ecology and Environment, Southwest Forestry University, Kunming, 650224, China
| | - Jun Zhang
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Yi-Fei Wu
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Fang-Jie Zhao
- Jiangsu Key Laboratory for Organic Waste Utilization, Jiangsu Collaborative Innovation Centre for Solid Organic Waste Resource Utilization, College of Resources and Environmental Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA
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