1
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Tóth A, Sajdik K, Gyurcsik B, Nafaee ZH, Wéber E, Kele Z, Christensen NJ, Schell J, Correia JG, Sigfridsson Clauss KGV, Pittkowski RK, Thulstrup PW, Hemmingsen L, Jancsó A. As III Selectively Induces a Disorder-to-Order Transition in the Metalloid Binding Region of the AfArsR Protein. J Am Chem Soc 2024; 146:17009-17022. [PMID: 38820242 PMCID: PMC11212059 DOI: 10.1021/jacs.3c11665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 05/22/2024] [Accepted: 05/23/2024] [Indexed: 06/02/2024]
Abstract
Arsenic is highly toxic and a significant threat to human health, but certain bacteria have developed defense mechanisms initiated by AsIII binding to AsIII-sensing proteins of the ArsR family. The transcriptional regulator AfArsR responds to AsIII and SbIII by coordinating the metalloids with three cysteines, located in a short sequence of the same monomer chain. Here, we characterize the binding of AsIII and HgII to a model peptide encompassing this fragment of the protein via solution equilibrium and spectroscopic/spectrometric techniques (pH potentiometry, UV, CD, NMR, PAC, EXAFS, and ESI-MS) combined with DFT calculations and MD simulations. Coordination of AsIII changes the peptide structure from a random-coil to a well-defined structure of the complex. A trigonal pyramidal AsS3 binding site is formed with almost exactly the same structure as observed in the crystal structure of the native protein, implying that the peptide possesses all of the features required to mimic the AsIII recognition and response selectivity of AfArsR. Contrary to this, binding of HgII to the peptide does not lead to a well-defined structure of the peptide, and the atoms near the metal binding site are displaced and reoriented in the HgII model. Our model study suggests that structural organization of the metal site by the inducer ion is a key element in the mechanism of the metalloid-selective recognition of this protein.
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Affiliation(s)
- Annamária Tóth
- Department
of Molecular and Analytical Chemistry, University
of Szeged, Dóm
tér 7-8, H-6720 Szeged, Hungary
| | - Kadosa Sajdik
- Department
of Molecular and Analytical Chemistry, University
of Szeged, Dóm
tér 7-8, H-6720 Szeged, Hungary
| | - Béla Gyurcsik
- Department
of Molecular and Analytical Chemistry, University
of Szeged, Dóm
tér 7-8, H-6720 Szeged, Hungary
| | - Zeyad H. Nafaee
- Department
of Molecular and Analytical Chemistry, University
of Szeged, Dóm
tér 7-8, H-6720 Szeged, Hungary
| | - Edit Wéber
- Department
of Medical Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary
- HUN-REN-SZTE
Biomimetic Systems Research Group, Dóm tér 8, H-6720 Szeged, Hungary
| | - Zoltan Kele
- Department
of Medical Chemistry, University of Szeged, Dóm tér 8, H-6720 Szeged, Hungary
| | - Niels Johan Christensen
- Department
of Chemistry, Faculty of Science, University
of Copenhagen, Thorvaldsensvej 40, 1871 Frederiksberg C, Denmark
| | - Juliana Schell
- Institute
for Materials Science and Center for Nanointegration Duisburg-Essen
(CENIDE), University of Duisburg-Essen, 45141 Essen, Germany
- European
Organization for Nuclear Research (CERN), CH-1211 Geneva, Switzerland
| | - Joao Guilherme Correia
- Centro de
Cięncias e Tecnologias Nucleares, Departamento de Engenharia
e Cięncias Nucleares, Instituto Superior Técnico, Universidade de Lisboa, 2695-066 Bobadela LRS, Portugal
- European
Organization for Nuclear Research (CERN), CH-1211 Geneva, Switzerland
| | | | - Rebecca K. Pittkowski
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Kobenhavn Ø, Denmark
| | - Peter Waaben Thulstrup
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Kobenhavn Ø, Denmark
| | - Lars Hemmingsen
- Department
of Chemistry, University of Copenhagen, Universitetsparken 5, 2100 Kobenhavn Ø, Denmark
| | - Attila Jancsó
- Department
of Molecular and Analytical Chemistry, University
of Szeged, Dóm
tér 7-8, H-6720 Szeged, Hungary
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2
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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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3
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Szekeres L, Maldivi P, Lebrun C, Gateau C, Mesterházy E, Delangle P, Jancsó A. Tristhiolato Pseudopeptides Bind Arsenic(III) in an AsS 3 Coordination Environment Imitating Metalloid Binding Sites in Proteins. Inorg Chem 2023; 62:6817-6824. [PMID: 37071818 PMCID: PMC10155180 DOI: 10.1021/acs.inorgchem.3c00563] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2023] [Indexed: 04/20/2023]
Abstract
The AsIII binding of two NTA-based tripodal pseudopeptides, possessing three cysteine (ligand L1) or d-penicillamine residues (ligand L2) as potential coordinating groups for soft semimetals or metal ions, was studied by experimental (UV, CD, NMR, and ESI-MS) and theoretical (DFT) methods. All of the experimental data, obtained with the variation of the AsIII:ligand concentration ratios or pH values in some instances, evidence the exclusive formation of species with an AsS3-type coordination mode. The UV-monitored titration of the ligands with arsenous acid at pH = 7.0 provided an absorbance data set that allowed for the determination of apparent stability constants of the forming species. The obtained stabilities (logK' = 5.26 (AsL1) and logK' = 3.04 (AsL2)) reflect high affinities, especially for the sterically less restricted cysteine derivative. DFT calculated structures correlate well with the spectroscopic results and, in line with the 1H NMR data, indicate a preference for the all-endo conformers resembling the AsIII environment at the semimetal binding sites in various metalloproteins.
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Affiliation(s)
- Levente
I. Szekeres
- Department
of Inorganic and Analytical Chemistry, University
of Szeged, Dóm tér 7, Szeged H-6720, Hungary
| | - Pascale Maldivi
- CEA,
CNRS, Grenoble INP, IRIG, SyMMES, Universite
Grenoble Alpes, Grenoble 38000, France
| | - Colette Lebrun
- CEA,
CNRS, Grenoble INP, IRIG, SyMMES, Universite
Grenoble Alpes, Grenoble 38000, France
| | - Christelle Gateau
- CEA,
CNRS, Grenoble INP, IRIG, SyMMES, Universite
Grenoble Alpes, Grenoble 38000, France
| | - Edit Mesterházy
- Department
of Inorganic and Analytical Chemistry, University
of Szeged, Dóm tér 7, Szeged H-6720, Hungary
- CEA,
CNRS, Grenoble INP, IRIG, SyMMES, Universite
Grenoble Alpes, Grenoble 38000, France
| | - Pascale Delangle
- CEA,
CNRS, Grenoble INP, IRIG, SyMMES, Universite
Grenoble Alpes, Grenoble 38000, France
| | - Attila Jancsó
- Department
of Inorganic and Analytical Chemistry, University
of Szeged, Dóm tér 7, Szeged H-6720, Hungary
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4
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Zhang J, Li YN, Shen J, Nadar VS, Chen J. Characterization of a novel ArsR regulates divergent ars operon in Ensifer adhaerens strain ST2. FEMS Microbiol Lett 2023; 370:fnad113. [PMID: 37881019 DOI: 10.1093/femsle/fnad113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2023] [Revised: 09/15/2023] [Accepted: 10/23/2023] [Indexed: 10/27/2023] Open
Abstract
Microbes evolved resistance determinates for coping with arsenic toxicity are commonly regulated by a variety of transcriptional repressors (ArsRs). Ensifer adhaerens strain ST2 was previously shown tolerance to environmental organoarsenical methylarsenite (MAs(III)), which has been proposed to be a primordial antibiotic. In E. adhaerens strain ST2 chromosomal ars operon, two MAs(III) resistance genes, arsZ, encoding MAs(III) oxidase, and arsK, encoding MAs(III) efflux transporter, are controlled by a novel ArsR transcriptional repressor, EaArsR. It has two conserved cysteine pairs, Cys91-92 and Cys108-109. Electrophoretic mobility shift assays (EMSAs) demonstrate that EaArsR binds to two inverted-repeat sequences within the ars promoter between arsR and arsZ to repress ars operon transcription and that DNA binding is relieved upon binding of As(III) and MAs(III). Mutation of either Cys91 or Cys92 to serine (or both) abolished these mutants binding to the ars promoter. In contrast, both C108S and C109S mutants kept responsiveness to As(III) and MAs(III). These results suggest that cysteine pair Cys91-Cys92 and either Cys108 or Cys109 contribute to form arsenic binding site. Homology modeling of EaArsR indicates the binding site consisted of Cys91-Cys92 pair from one monomer and Cys108-Cys109 pair from the other monomer, which displays the diverse evolution of arsenic binding site in the ArsR metalloregulators.
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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
| | - 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 210095, China
| | - Venkadesh Sarkarai Nadar
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, United Sates
| | - Jian Chen
- Institute of Environmental Remediation and Human Health, College of Ecology and Environment, Southwest Forestry University, Kunming 650224, China
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5
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Ranganathan S, Sethi D, Kasivisweswaran S, Ramya L, Priyadarshini R, Yennamalli RM. Structural and functional mapping of ars gene cluster in Deinococcus indicus DR1. Comput Struct Biotechnol J 2022; 21:519-534. [PMID: 36618989 PMCID: PMC9807832 DOI: 10.1016/j.csbj.2022.12.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 12/08/2022] [Accepted: 12/08/2022] [Indexed: 12/14/2022] Open
Abstract
Deinococcus indicus DR1 is a novel Gram-negative bacterium, isolated from the Dadri wetlands in Uttar Pradesh, India. In addition to being radiation-resistant, the rod-shaped, red-pigmented organism shows extraordinary resistance to arsenic. The proteins of the corresponding ars gene cluster involved in arsenic extrusion in D. indicus DR1 have not yet been characterized. Additionally, how these proteins regulate each other providing arsenic resistance is still unclear. Here, we present a computational model of the operonic structure and the corresponding characterization of the six proteins of the ars gene cluster in D. indicus DR1. Additionally, we show the expression of the genes in the presence of arsenic using qRT-PCR. The ars gene cluster consists of two transcriptional regulators (ArsR1, ArsR2), two arsenate reductases (ArsC2, ArsC3), one metallophosphatase family protein (MPase), and a transmembrane arsenite efflux pump (ArsB). The transcriptional regulators are trans-acting repressors, and the reductases reduce arsenate (As5+) ions to arsenite (As3+) ions for favourable extrusion. The proteins modelled using RoseTTAFold, and their conformationally stable coordinates obtained after MD simulation indicate their various functional roles with respect to arsenic. Excluding ArsB, all the proteins belong to the α + β class of proteins. ArsB, being a membrane protein, is fully α-helical, with 12 transmembrane helices. The results show the degree of similarity or divergence of the mechanism utilized by these proteins of ars gene cluster in D. indicus DR1 to confer high levels of arsenic tolerance. This structural characterization study of the ars genes will enable new and deeper insights of arsenic tolerance.
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Affiliation(s)
- Shrivaishnavi Ranganathan
- Department of Biotechnology, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu 613401, India
| | - Deepa Sethi
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh, India
| | - Sandhya Kasivisweswaran
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh, India
| | - L. Ramya
- Computational and Molecular Biophysics Laboratory, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu 613401, India
| | - Richa Priyadarshini
- Department of Life Sciences, School of Natural Sciences, Shiv Nadar University, Gautam Buddha Nagar, Uttar Pradesh, India,Corresponding authors.
| | - Ragothaman M. Yennamalli
- Department of Bioinformatics, School of Chemical and Biotechnology, SASTRA Deemed to be University, Thanjavur, Tamil Nadu 613401, India,Corresponding authors.
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6
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Song X, Li Y, Stirling E, Zhao K, Wang B, Zhu Y, Luo Y, Xu J, Ma B. AsgeneDB: a curated orthology arsenic metabolism gene database and computational tool for metagenome annotation. NAR Genom Bioinform 2022; 4:lqac080. [PMID: 36330044 PMCID: PMC9623898 DOI: 10.1093/nargab/lqac080] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2022] [Revised: 08/02/2022] [Accepted: 10/27/2022] [Indexed: 11/07/2022] Open
Abstract
Arsenic (As) is the most ubiquitous toxic metalloid in nature. Microbe-mediated As metabolism plays an important role in global As biogeochemical processes, greatly changing its toxicity and bioavailability. While metagenomic sequencing may advance our understanding of the As metabolism capacity of microbial communities in different environments, accurate metagenomic profiling of As metabolism remains challenging due to low coverage and inaccurate definitions of As metabolism gene families in public orthology databases. Here we developed a manually curated As metabolism gene database (AsgeneDB) comprising 400 242 representative sequences from 59 As metabolism gene families, which are affiliated with 1653 microbial genera from 46 phyla. AsgeneDB achieved 100% annotation sensitivity and 99.96% annotation accuracy for an artificial gene dataset. We then applied AsgeneDB for functional and taxonomic profiling of As metabolism in metagenomes from various habitats (freshwater, hot spring, marine sediment and soil). The results showed that AsgeneDB substantially improved the mapping ratio of short reads in metagenomes from various environments. Compared with other databases, AsgeneDB provides more accurate, more comprehensive and faster analysis of As metabolic genes. In addition, we developed an R package, Asgene, to facilitate the analysis of metagenome sequencing data. Therefore, AsgeneDB and the associated Asgene package will greatly promote the study of As metabolism in microbial communities in various environments.
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Affiliation(s)
- Xinwei Song
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310000, China,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310000, China,Hangzhou Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Yiqun Li
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310000, China,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310000, China,Hangzhou Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Erinne Stirling
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310000, China,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310000, China,Hangzhou Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Kankan Zhao
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310000, China,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310000, China,Hangzhou Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Binhao Wang
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310000, China,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310000, China,Hangzhou Innovation Center, Zhejiang University, Hangzhou 311200, China
| | - Yongguan Zhu
- State Key Laboratory of Urban and Regional Ecology, Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences, Beijing 100000, China
| | - Yongming Luo
- Key Laboratory of Soil Environment and Pollution Remediation, Institute of Soil Science, Chinese Academy of Science, Nanjing 210000, China
| | - Jianming Xu
- Institute of Soil and Water Resources and Environmental Science, College of Environmental and Resource Sciences, Zhejiang University, Hangzhou 310000, China,Zhejiang Provincial Key Laboratory of Agricultural Resources and Environment, Zhejiang University, Hangzhou 310000, China
| | - Bin Ma
- To whom correspondence should be addressed. Tel: +86 13282198979;
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7
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Chen X, Yao H, Song D, Lin J, Zhou H, Yuan W, Song P, Sun G, Xu M. A novel antimony-selective ArsR transcriptional repressor and its specific detection of antimony trioxide in environmental samples via bacterial biosensor. Biosens Bioelectron 2022; 220:114838. [DOI: 10.1016/j.bios.2022.114838] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2022] [Revised: 10/13/2022] [Accepted: 10/18/2022] [Indexed: 11/25/2022]
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8
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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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9
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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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10
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Maleki F, Shahpiri A. Efficient and specific bioaccumulation of arsenic in the transgenic Escherichia coli expressing ArsR1 from Corynebacterium glutamicum. Biometals 2022; 35:889-901. [PMID: 35767097 DOI: 10.1007/s10534-022-00412-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 06/11/2022] [Indexed: 11/02/2022]
Abstract
The toxic nature of arsenic has left a trail of disastrous health consequences around the world. Microorganisms have developed various strategies to deal with arsenic. The presence of plasmid and chromosomal ars operons is one of the most important mechanisms for the detoxification of arsenic in bacteria. ArsR is a trans-acting regulatory protein and acts as a repressor on ars operon. The gene encoding ArsR from Corynebacterium glutamicum (CgArsR1) was cloned in expression vectors pET28a. The resulting constructs were transformed into Escherichia coli strains Rosetta (DE3) and Rosetta gami 2. Following the induction with Isopropyl β-D-1-thiogalactopyranoside, the protein His-CgArsR1 was found in the soluble fraction of strain Rg-CgArsR1. For comparison, ArsR from E. coli was also overexpressed in E. coli (strain Rosetta gami 2) as His-EcArsR. A strain containing empty vector pET28a was also used as a control strain. In the medium containing either arsenite (0.5 mM) or arsenate (0.5 mM), the strain Rg-CgArsR1 and Rg-EcArsR were able to accumulate 1200 and 700 µg/g DCW As3+, respectively. In comparison, the accumulation of As5+ in these strains was 338 and 232 µg/g DCW, respectively. Whereas both strains Rg-CgArsR1 and Rg-EcArsR were able to accumulate higher amounts of As3+ and As5+ with respect to control strain, the accumulation of arsenic in the strain Rg-CgArsR1 was significantly more efficient than strain Rg-EcArsR for removing As3+ and As5+. Based on the results the gene encoding CgArsR1 is a useful and efficient target gene for the modification of bacteria for bioremediation of arsenic from polluted soil and water.
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Affiliation(s)
- Fatemeh Maleki
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, 84156-83111, Isfahan, Iran
| | - Azar Shahpiri
- Department of Biotechnology, College of Agriculture, Isfahan University of Technology, 84156-83111, Isfahan, Iran.
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11
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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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12
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Chen J, Galván AE, Nadar VS, Yoshinaga M, Rosen BP. An ArsRC fusion protein enhances arsenate sensing and detoxification. Environ Microbiol 2022; 24:1977-1987. [PMID: 35229439 DOI: 10.1111/1462-2920.15957] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 02/18/2022] [Accepted: 02/24/2022] [Indexed: 12/13/2022]
Abstract
Arsenical resistance (ars) operons encode genes for arsenic resistance and biotransformation. The majority are composed of individual genes, but fusion of ars genes is not uncommon, although it is not clear if the fused gene products are functional. Here we report identification of a four-gene ars operon from Paracoccus sp. SY that has two arsR-arsC gene fusions. ArsRC1 and ArsRC2 are related proteins that consist of an N-terminal ArsR arsenite (As(III))-responsive repressor with a C-terminal ArsC arsenate reductase. The other two genes in the operon are gapdh and arsJ. GAPDH, glyceraldehyde 3-phosphate dehydrogenase, forms 1-arseno-3-phosphoglycerate (1As3PGA) from 3-phosphoglyceraldehyde and arsenate (As(V)), ArsJ is an efflux permease for 1As3PGA that dissociates into extracellular As(V) and 3-phosphoglycerate. The net effect is As(V) extrusion and resistance. ArsRs are usually selective for As(III) and do not respond to As(V). However, the substrates and products of this operon are pentavalent, which would not be inducers of the operon. We propose that ArsRC fusions overcome this limitation by channelling the ArsC product into the ArsR binding site without diffusion through the cytosol, a de facto mechanism for As(V) induction. This novel mechanism for arsenate sensing can confer an evolutionary advantage for detoxification of inorganic arsenate.
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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
| | - Adriana E Galván
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA
| | - Venkadesh Sarkarai Nadar
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA
| | - Masafumi Yoshinaga
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA
| | - 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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13
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Zhang J, Chen J, Wu YF, Liu X, Packianathan C, Nadar VS, Rosen BP, Zhao FJ. Functional characterization of the methylarsenite-inducible arsRM operon from Noviherbaspirillum denitrificans HC18. Environ Microbiol 2022; 24:772-783. [PMID: 35049138 PMCID: PMC8881391 DOI: 10.1111/1462-2920.15909] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2021] [Revised: 01/12/2022] [Accepted: 01/14/2022] [Indexed: 02/03/2023]
Abstract
Microbial arsenic methylation by arsenite (As(III)) S-adenosylmethionine methyltransferases (ArsMs) can produce the intermediate methylarsenite (MAs(III)), which is highly toxic and is used by some microbes as an antibiotic. Other microbes have evolved mechanisms to detoxify MAs(III). In this study, an arsRM operon was identified in the genome of an MAs(III)-methylation strain Noviherbaspirillum denitrificans HC18. The arsM gene (NdarsM) is located downstream of an open reading frame encoding an MAs(III)-responsive transcriptional regulator (NdArsR). The N. denitrificans arsRM genes are co-transcribed whose expression is significantly induced by MAs(III), likely by alleviating the repressive effect of ArsR on arsRM transcription. Both in vivo and in vitro assays showed that NdArsM methylates MAs(III) to dimethyl- and trimethyl-arsenicals but does not methylate As(III). Heterologous expression of NdarsM in arsenic-sensitive Escherichia coli AW3110 conferred resistance to MAs(III) but not As(III). NdArsM has the four conserved cysteine residues present in most ArsMs, but only two of them are essential for MAs(III) methylation. The ability to methylate MAs(III) by enzymes such as NdArsM may be an evolutionary step originated from enzymes capable of methylating As(III). This finding reveals a mechanism employed by microbes such as N. denitrificans HC18 to detoxify MAs(III) by further methylation.
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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
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - 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 210095, China
| | - Xia Liu
- College of Life Sciences, Nanjing Agricultural University, Nanjing 210095, China
| | - Charles Packianathan
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - Venkadesh S. Nadar
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - Barry P. Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA,Co-corresponding authors: Fangjie Zhao () and Barry P. Rosen ()
| | - 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,Co-corresponding authors: Fangjie Zhao () and Barry P. Rosen ()
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14
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Zhang J, Chen J, Wu YF, Wang ZP, Qiu JG, Li XL, Cai F, Xiao KQ, Sun XX, Rosen BP, Zhao FJ. Oxidation of organoarsenicals and antimonite by a novel flavin monooxygenase widely present in soil bacteria. Environ Microbiol 2022; 24:752-761. [PMID: 33769668 PMCID: PMC8862597 DOI: 10.1111/1462-2920.15488] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 03/21/2021] [Accepted: 03/24/2021] [Indexed: 02/03/2023]
Abstract
Arsenic can be biomethylated to form a variety of organic arsenicals differing in toxicity and environmental mobility. Trivalent methylarsenite (MAs(III)) produced in the methylation process is more toxic than inorganic arsenite (As(III)). MAs(III) also serves as a primitive antibiotic and, consequently, some environmental microorganisms have evolved mechanisms to detoxify MAs(III). However, the mechanisms of MAs(III) detoxification are not well understood. In this study, we identified an arsenic resistance (ars) operon consisting of three genes, arsRVK, that contribute to MAs(III) resistance in Ensifer adhaerens ST2. ArsV is annotated as an NADPH-dependent flavin monooxygenase with unknown function. Expression of arsV in the arsenic hypersensitive Escherichia coli strain AW3110Δars conferred resistance to MAs(III) and the ability to oxidize MAs(III) to MAs(V). In the presence of NADPH and either FAD or FMN, purified ArsV protein was able to oxidize both MAs(III) to MAs(V) and Sb(III) to Sb(V). Genes with arsV-like sequences are widely present in soils and environmental bacteria. Metagenomic analysis of five paddy soils showed the abundance of arsV-like sequences of 0.12-0.25 ppm. These results demonstrate that ArsV is a novel enzyme for the detoxification of MAs(III) and Sb(III) and the genes encoding ArsV are widely present in soil bacteria.
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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
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida, 33199
| | - 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, 210095, China
| | - Zi-Ping 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, 210095, China
| | - Ji-Guo Qiu
- College of Life Sciences, Nanjing Agricultural University, Nanjing, 210095, China
| | - Xiao-Long 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
| | - Feng Cai
- 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
| | - Ke-Qing Xiao
- School of Earth and Environment, University of Leeds, Leeds, LS2 9JT, UK
| | - Xiao-Xu Sun
- Guangdong Institute of Eco-environmental Science & Technology, Guangdong Academy of Sciences, Guangzhou, 510650, 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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15
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Naughton KL, Boedicker JQ. Simulations to Aid in the Design of Microbes for Synthesis of Metallic Nanomaterials. ACS Synth Biol 2021; 10:3475-3488. [PMID: 34807578 DOI: 10.1021/acssynbio.1c00412] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Microbes are champions of nanomaterial synthesis. By virtue of their incredible native range─from thermal vents to radioactive soil─microbes evolved tools to thrive on inorganic material, and, in their normal course of living, forge nanomaterials. In recent decades, synthetic biologists have engineered a vast array of functional nanomaterials using genetic tools that control the natural ability of bacteria to perform complex redox chemistry, maintain steep chemical gradients, and express biomolecular scaffolds. Leveraging microbial biology can lead to intricate nanomaterial architectures whose design and assembly exists beyond the ken of inorganic methods. Theories enumerating microbial nanomaterial synthesis are spare, however, despite the advantage they could offer. Here, we describe a theoretical approach to simulating biogenic nanomaterial synthesis that incorporates key features and parameters of Gram-negative bacteria. By adapting previously verified inorganic theories of nanoparticle synthesis, we recapitulate past biogenic experiments, such as the ability to localize nanoparticle synthesis or regulate nucleation of specific nanomaterials. Moreover, the simulation offers direction in the design of future experiments. Our results demonstrate the promise of marrying experimental and theoretical approaches to microbial nanomaterial synthesis.
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Affiliation(s)
- Kyle L. Naughton
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, United States
| | - James Q. Boedicker
- Department of Physics and Astronomy, University of Southern California, Los Angeles, California 90089-0484, United States
- Department of Biological Sciences, University of Southern California, Los Angeles, California 90089-0371, United States
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16
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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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17
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Design and Prototyping of Genetically Encoded Arsenic Biosensors Based on Transcriptional Regulator AfArsR. Biomolecules 2021; 11:biom11091276. [PMID: 34572489 PMCID: PMC8470949 DOI: 10.3390/biom11091276] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 08/13/2021] [Accepted: 08/18/2021] [Indexed: 12/12/2022] Open
Abstract
Genetically encoded biosensors based on engineered fluorescent proteins (FPs) are essential tools for monitoring the dynamics of specific ions and molecules in biological systems. Arsenic ion in the +3 oxidation state (As3+) is highly toxic to cells due to its ability to bind to protein thiol groups, leading to inhibition of protein function, disruption of protein–protein interactions, and eventually to cell death. A genetically encoded biosensor for the detection of As3+ could potentially facilitate the investigation of such toxicity both in vitro and in vivo. Here, we designed and developed two prototype genetically encoded arsenic biosensors (GEARs), based on a bacterial As3+ responsive transcriptional factor AfArsR from Acidithiobacillus ferrooxidans. We constructed FRET-based GEAR biosensors by insertion of AfArsR between FP acceptor/donor FRET pairs. We further designed and engineered single FP-based GEAR biosensors by insertion of AfArsR into GFP. These constructs represent prototypes for a new family of biosensors based on the ArsR transcriptional factor scaffold. Further improvements of the GEAR biosensor family could lead to variants with suitable performance for detection of As3+ in various biological and environmental systems.
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18
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High arsenic levels increase activity rather than diversity or abundance of arsenic metabolism genes in paddy soils. Appl Environ Microbiol 2021; 87:e0138321. [PMID: 34378947 DOI: 10.1128/aem.01383-21] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Arsenic (As) metabolism genes are generally present in soils but their diversity, relative abundance, and transcriptional activity in response to different As concentrations remain unclear, limiting our understanding of the microbial activities that control the fate of an important environmental pollutant. To address this issue, we applied metagenomics and metatranscriptomics to paddy soils showing a gradient of As concentrations to investigate As resistance genes (ars) including arsR, acr3, arsB, arsC, arsM, arsI, arsP, and arsH as well as energy-generating As respiratory oxidation (aioA) and reduction (arrA) genes. Somewhat unexpectedly, the relative DNA abundances and diversity of ars, aioA, and arrA genes were not significantly different between low and high (∼10 vs ∼100 mg kg-1) As soils. By comparison to available metagenomes from other soils, geographic distance rather than As levels drove the different compositions of microbial communities. Arsenic significantly increased ars genes abundance only when its concentration was higher than 410 mg kg-1. In contrast, between low and high As soils, metatranscriptomics revealed a significant increase in transcription of ars and aioA genes, which are induced by arsenite, the dominant As species in paddy soils, but not arrA genes, which are induced by arsenate. These patterns appeared to be community-wide as opposed to taxon-specific. Collectively, our findings advance understanding of how microbes respond to high As levels and the diversity of As metabolism genes in paddy soils and indicated that future studies of As metabolism in soil, or other environments, should include the function (transcriptome) level. IMPORTANCE Arsenic (As) is a toxic metalloid pervasively present in the environment. Microorganisms have evolved the capacity to metabolize As, and As metabolism genes are ubiquitously present in the environment even in the absence of high concentrations of As. However, these previous studies were carried out at the DNA level and thus, the activity of the As metabolism genes detected remains essentially speculative. Here, we show that the high As levels in paddy soils increased the transcriptional activity rather than the relative DNA abundance and diversity of As metabolism genes. These findings advance our understanding of how microbes respond to and cope with high As levels and have implications for better monitoring and managing an important toxic metalloid in agricultural soils and possibly other ecosystems.
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19
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Yang M, Jia SH, Tao HL, Zhu C, Jia WZ, Hu LH, Gao CH. Cd(II)-binding transcriptional regulator interacts with isoniazid and regulates drug susceptibility in mycobacteria. J Biochem 2021; 169:43-53. [PMID: 32706888 DOI: 10.1093/jb/mvaa086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2020] [Accepted: 07/16/2020] [Indexed: 02/03/2023] Open
Abstract
It is urgent to understand the regulatory mechanism of drug resistance in widespread bacterial pathogens. In Mycobacterium tuberculosis, several transcriptional regulators have been found to play essential roles in regulating its drug resistance. In this study, we found that an ArsR family transcription regulator encoded by Rv2642 (CdiR) responds to isoniazid (INH), a widely used anti-tuberculosis (TB) drug. CdiR negatively regulates self and adjacent genes, including arsC (arsenic-transport integral membrane protein ArsC). CdiR directly interacts with INH and Cd(II). The binding of INH and Cd(II) both reduce its DNA-binding activity. Disrupting cdiR increased the drug susceptibility to INH, whereas overexpressing cdiR decreased the susceptibility. Strikingly, overexpressing arsC increased the drug susceptibility as well as cdiR. Additionally, both changes in cdiR and arsC expression caused sensitivity to other drugs such as rifamycin and ethambutol, where the minimal inhibitory concentrations in the cdiR deletion strain were equal to those of the arsC-overexpressing strain, suggesting that the function of CdiR in regulating drug resistance primarily depends on arsC. Furthermore, we found that Cd(II) enhances bacterial resistance to INH in a CdiR-dependent manner. As a conclusion, CdiR has a critical role in directing the interplay between Cd(II) metal ions and drug susceptibility in mycobacteria.
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Affiliation(s)
- Min Yang
- College of Life Science and Technology, Huazhong University of Science and Technology, Wuhan 430074, China
| | - Shi-Hua Jia
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Hui-Ling Tao
- International Agricultural Institute, Yunnan Academy of Agricultural Sciences, Kunming 650224, China
| | - Chen Zhu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Wan-Zhong Jia
- The State Key Laboratory of Veterinary Etiological Biology, Lanzhou Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Lanzhou 730046, China
| | - Li-Hua Hu
- College of Life Science and Technology, Huazhong Agricultural University, Wuhan 430070, China
| | - Chun-Hui Gao
- College of Resources and Environment, Huazhong Agricultural University, Wuhan 430070, China
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20
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Viswanathan T, Chen J, Wu M, An L, Kandavelu P, Sankaran B, Radhakrishnan M, Li M, Rosen BP. Functional and structural characterization of AntR, an Sb(III) responsive transcriptional repressor. Mol Microbiol 2021; 116:427-437. [PMID: 33786926 DOI: 10.1111/mmi.14721] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 03/21/2021] [Accepted: 03/25/2021] [Indexed: 12/01/2022]
Abstract
The ant operon of the antimony-mining bacterium Comamonas testosterone JL40 confers resistance to Sb(III). The operon is transcriptionally regulated by the product of the first gene in the operon, antR. AntR is a member of ArsR/SmtB family of metal/metalloid-responsive repressors resistance. We purified and characterized C. testosterone AntR and demonstrated that it responds to metalloids in the order Sb(III) = methylarsenite (MAs(III) >> As(III)). The protein was crystallized, and the structure was solved at 2.1 Å resolution. The homodimeric structure of AntR adopts a classical ArsR/SmtB topology architecture. The protein has five cysteine residues, of which Cys103a from one monomer and Cys113b from the other monomer, are proposed to form one Sb(III) binding site, and Cys113a and Cys103b forming a second binding site. This is the first report of the structure and binding properties of a transcriptional repressor with high selectivity for environmental antimony.
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Affiliation(s)
- Thiruselvam Viswanathan
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Jian Chen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Minghan Wu
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Lijin An
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Palani Kandavelu
- SER-CAT and the Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Banumathi Sankaran
- Molecular Biophysics and Integrated Bioimaging, Lawrence Berkeley Laboratory, Berkeley Center for Structural Biology, Berkeley, CA, USA
| | - Manohar Radhakrishnan
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
| | - Mingshun Li
- State Key Laboratory of Agricultural Microbiology, College of Life Science and Technology, Huazhong Agricultural University, Wuhan, P.R. China
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, USA
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21
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Flagellin-based electrochemical sensing layer for arsenic detection in water. Sci Rep 2021; 11:3497. [PMID: 33568718 PMCID: PMC7876115 DOI: 10.1038/s41598-021-83053-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 01/27/2021] [Indexed: 11/08/2022] Open
Abstract
Regular monitoring of arsenic concentrations in water sources is essential due to the severe health effects. Our goal was to develop a rapidly responding, sensitive and stable sensing layer for the detection of arsenic. We have designed flagellin-based arsenic binding proteins capable of forming stable filament structures with high surface binding site densities. The D3 domain of Salmonella typhimurium flagellin was replaced with an arsenic-binding peptide motif of different bacterial ArsR transcriptional repressor factors. We have shown that the fusion proteins developed retain their polymerization ability and have thermal stability similar to that of wild-type filament. The strong arsenic binding capacity of the monomeric proteins was confirmed by isothermal titration calorimetry (ITC), and dissociation constants (Kd) of a few hundred nM were obtained for all three variants. As-binding fibers were immobilized on the surface of a gold electrode and used as a working electrode in cyclic voltammetry (CV) experiments to detect inorganic arsenic near the maximum allowable concentration (MAC) level. Based on these results, it can be concluded that the stable arsenic-binding flagellin variant can be used as a rapidly responding, sensitive, but simple sensing layer in a field device for the MAC-level detection of arsenic in natural waters.
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22
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The Great Oxidation Event expanded the genetic repertoire of arsenic metabolism and cycling. Proc Natl Acad Sci U S A 2020; 117:10414-10421. [PMID: 32350143 PMCID: PMC7229686 DOI: 10.1073/pnas.2001063117] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
The rise of oxygen on the early Earth about 2.4 billion years ago reorganized the redox cycle of harmful metal(loids), including that of arsenic, which doubtlessly imposed substantial barriers to the physiology and diversification of life. Evaluating the adaptive biological responses to these environmental challenges is inherently difficult because of the paucity of fossil records. Here we applied molecular clock analyses to 13 gene families participating in principal pathways of arsenic resistance and cycling, to explore the nature of early arsenic biogeocycles and decipher feedbacks associated with planetary oxygenation. Our results reveal the advent of nascent arsenic resistance systems under the anoxic environment predating the Great Oxidation Event (GOE), with the primary function of detoxifying reduced arsenic compounds that were abundant in Archean environments. To cope with the increased toxicity of oxidized arsenic species that occurred as oxygen built up in Earth's atmosphere, we found that parts of preexisting detoxification systems for trivalent arsenicals were merged with newly emerged pathways that originated via convergent evolution. Further expansion of arsenic resistance systems was made feasible by incorporation of oxygen-dependent enzymatic pathways into the detoxification network. These genetic innovations, together with adaptive responses to other redox-sensitive metals, provided organisms with novel mechanisms for adaption to changes in global biogeocycles that emerged as a consequence of the GOE.
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23
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Durante-Rodríguez G, Fernández-Llamosas H, Alonso-Fernandes E, Fernández-Muñiz MN, Muñoz-Olivas R, Díaz E, Carmona M. ArxA From Azoarcus sp. CIB, an Anaerobic Arsenite Oxidase From an Obligate Heterotrophic and Mesophilic Bacterium. Front Microbiol 2019; 10:1699. [PMID: 31417512 PMCID: PMC6683785 DOI: 10.3389/fmicb.2019.01699] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Accepted: 07/10/2019] [Indexed: 11/13/2022] Open
Abstract
Arsenic is a toxic element widely distributed in nature, but numerous bacteria are able to resist its toxicity mainly through the ars genes encoding an arsenate reductase and an arsenite efflux pump. Some “arsenotrophic” bacteria are also able to use arsenite as energy supplier during autotrophic growth by coupling anaerobic arsenite oxidation via the arx gene products to nitrate respiration or photosynthesis. Here, we have demonstrated that Azoarcus sp. CIB, a facultative anaerobic β-proteobacterium, is able to resist arsenic oxyanions both under aerobic and anaerobic conditions. Genome mining, gene expression, and mutagenesis studies revealed the presence of a genomic island that harbors the ars and arx clusters involved in arsenic resistance in strain CIB. Orthologous ars clusters are widely distributed in the genomes of sequenced Azoarcus strains. Interestingly, genetic and metabolic approaches showed that the arx cluster of the CIB strain encodes an anaerobic arsenite oxidase also involved in the use of arsenite as energy source. Hence, Azoarcus sp. CIB represents the prototype of an obligate heterotrophic bacterium able to use arsenite as an extra-energy source for anaerobic cell growth. The arsenic island of strain CIB supports the notion that metabolic and energetic skills can be gained by genetic mobile elements.
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Affiliation(s)
| | | | - Elena Alonso-Fernandes
- Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas-CSIC, Madrid, Spain
| | | | - Riansares Muñoz-Olivas
- Departamento de Química Analítica, Facultad de Químicas, Universidad Complutense Madrid, Madrid, Spain
| | - Eduardo Díaz
- Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas-CSIC, Madrid, Spain
| | - Manuel Carmona
- Biotecnología Microbiana y de Plantas, Centro de Investigaciones Biológicas-CSIC, Madrid, Spain
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24
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Chen X, Jiang X, Tie C, Yoo J, Wang Y, Xu M, Sun G, Guo J, Li X. Contribution of nonconsensus base pairs within ArsR binding sequences toward ArsR-DNA binding and arsenic-mediated transcriptional induction. J Biol Eng 2019; 13:53. [PMID: 31182975 PMCID: PMC6555750 DOI: 10.1186/s13036-019-0181-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2019] [Accepted: 05/27/2019] [Indexed: 11/30/2022] Open
Abstract
Background A transcriptional reporter is the key component in bacterial biosensors which are employed to monitor the induction or repression of a reporter gene corresponding to environmental change. Interaction of a transcription factor with its consensus sequence generated by using a position weight matrix (PWM) model is crucial for its sensitivity of the reporter. However, recent studies suggest that PWM model based on independent contribution of individual consensus base pairs to protein interaction is often insufficient to explain complex regulation, such as the effect of nonconsensus sequences on the protein-DNA binding affinity. In the present study, we employed a simpler prokaryotic arsenic repressor (ArsR) regulation system to access the protein-DNA recognition. Contribution of nonconsensus base pairs within ArsR binding sequences toward ArsR-DNA binding and arsenic-mediated transcriptional induction was studied. Results We constructed a series of arsenic responsive reporters, each comprising two copies of the ArsR binding sequences from different resources. We found that high arsenic-mediated induction specifically requires the binding sequence from Escherichia coli to be placed at the first binding sequence; however, no such preference was observed for the second binding sequence, which could be from Acidithiobacillus ferrooxidans, plasmid R773, Synechococcus, or a core binding sequence of arsR. By creating a series of reporters differed at the nonconsensus base pairs of the second binding sequence, we observed that some constructs bound weakly while others strongly to ArsR. Most interestingly, although a number of these reporters showed similar binding affinity to ArsR, their arsenic-dependent induction differed significantly. Conclusions The results indicated that nonconsensus base pairs could have profound influence on protein binding and may also modulate post-binding function. These findings provide new insights into the complex regulation of gene expression and facilitate the development of transcriptional reporter-based biosensors.
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Affiliation(s)
- Xingjuan Chen
- 1Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Xin Jiang
- 4Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA USA
| | - Cuijuan Tie
- 4Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA USA
| | - Jinnon Yoo
- 4Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA USA
| | - Yan Wang
- 3Science and Technology Library of Guangdong Province, Guangdong Institute of Science and Technology Information and Development Strategy, Guangzhou, China
| | - Meiying Xu
- 1Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Guoping Sun
- 1Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Jun Guo
- 1Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Xianqiang Li
- 1Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China.,4Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA USA
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25
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Prabaharan C, Kandavelu P, Packianathan C, Rosen BP, Thiyagarajan S. Structures of two ArsR As(III)-responsive transcriptional repressors: Implications for the mechanism of derepression. J Struct Biol 2019; 207:209-217. [PMID: 31136796 DOI: 10.1016/j.jsb.2019.05.009] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 05/23/2019] [Accepted: 05/24/2019] [Indexed: 10/26/2022]
Abstract
ArsR As(III)-responsive transcriptional repressors, members of the ArsR/SmtB family of metalloregulatory proteins, have been characterized biochemically but, to date, no As(III)-bound structure has been solved. Here we report two crystal structures of ArsR repressors from Acidithiobacillus ferrooxidans (AfArsR) and Corynebacterium glutamicum (CgArsR) in the As(III)-bound form. AfArsR crystallized in P21 space group and diffracted up to 1.86 Å. CgArsR crystallized in P212121 and diffracted up to 1.6 Å. AfArsR showed one As(III) bound in one subunit of the homodimer, while the CgArsR structure showed two As(III) bound with S3 coordination, one in each monomer. Previous studies indicated that in AfArsR As(III) binds to Cys95, Cys96 and Cys102 from the same monomer, while, in CgArsR, to Cys15, Cys16 from one monomer and Cys55 from the other monomer. The dimer interfaces of these structures showed distinct differences from other members of the ArsR/SmtB family of proteins, which potentially renders multiple options for evolving metal(loid) binding sites in this family of proteins. Also, CgArsR presents a new α2-N binding site, not the previously predicted α3-N site. Despite differences in the location of the binding cysteines in the primary sequences of these proteins, the two metal binding sites are almost congruent on their structures, an example of convergent evolution. Analyses of the electrostatic surface of the proteins at the DNA binding domain indicate that there two different modes of derepression in the ArsR/SmtB family of metalloregulatory proteins.
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Affiliation(s)
| | - Palani Kandavelu
- SER-CAT, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA 30602, USA.
| | - Charles Packianathan
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA.
| | - 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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26
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Castro NS, Moura I, Carepo MS, Laia CA. Fluorescence anisotropy of fluorescein derivative varies according to pH: Lessons for binding studies. J Photochem Photobiol A Chem 2019. [DOI: 10.1016/j.jphotochem.2018.12.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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27
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Szekeres LI, Gyurcsik B, Kiss T, Kele Z, Jancsó A. Interaction of Arsenous Acid with the Dithiol-Type Chelator British Anti-Lewisite (BAL): Structure and Stability of Species Formed in an Unexpectedly Complex System. Inorg Chem 2018; 57:7191-7200. [PMID: 29856616 DOI: 10.1021/acs.inorgchem.8b00894] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
British anti-Lewisite (2,3-dimerkaptopropan-1-ol, dimercaprol, BAL) is one of the best-known chelator-type therapeutic agents against toxic metal ions and metalloids, especially arsenicals. Surprisingly, the mechanisms of action at the molecular level, as well as the coordination features of this traditional drug toward various arsenicals, are still poorly revealed. The present study on the interaction of arsenous acid (H3AsO3) with BAL, involving UV and NMR titrations, electrospray ionization mass spectrometry, and 2D NMR experiments combined with MP2 calculations, demonstrates that the reaction of H3AsO3 with BAL at pH = 7.0 results in a more complex speciation than was assumed before. The three reactive hydroxyl groups of H3AsO3 allow for interaction with three thiol moieties via condensation reaction, leading to the observed AsBAL2 and As2BAL3 complexes besides the AsBAL species. This indicates the strong propensity of inorganic As(III) to saturate its coordination sphere with thiolate groups. The alcoholic hydroxyl group of the ligand may also directly bind to As(III) in AsBAL. Compared to dithiothreitol or dithioeritritol, the preference of BAL to form complexes with such a tridentate binding mode is much lower owing to the more strained bridged bicyclic structure with an αAsSC < 90° bond angle and an unfavorable condensed boat-type six-membered ring. On the basis of the NMR data, the predominating, bidentately bound AsBAL species, including a five-membered chelate ring, exists in rapidly interconverting envelope forms of E and Z stereoisomers. The conditional stability constants calculated for the three macrospecies from a series of UV data [log βpH=7.0 = 6.95 (AsBAL), 11.56 (AsBAL2), and 22.73 (As2BAL3)] reflect that BAL is still the most efficient, known, dithiol-type chelator of H3AsO3.
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Affiliation(s)
- Levente I Szekeres
- Department of Inorganic and Analytical Chemistry , University of Szeged , Dóm tér 7 , Szeged H-6720 , Hungary
| | - Béla Gyurcsik
- Department of Inorganic and Analytical Chemistry , University of Szeged , Dóm tér 7 , Szeged H-6720 , Hungary
| | - Tamás Kiss
- Department of Inorganic and Analytical Chemistry , University of Szeged , Dóm tér 7 , Szeged H-6720 , Hungary
| | - Zoltán Kele
- Department of Medical Chemistry , University of Szeged , Dóm tér 8 , Szeged H-6720 , Hungary
| | - Attila Jancsó
- Department of Inorganic and Analytical Chemistry , University of Szeged , Dóm tér 7 , Szeged H-6720 , Hungary
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28
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Characterization of recombinant E. coli expressing arsR from Rhodopseudomonas palustris CGA009 that displays highly selective arsenic adsorption. Appl Microbiol Biotechnol 2018; 102:6247-6255. [DOI: 10.1007/s00253-018-9080-8] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2018] [Revised: 04/13/2018] [Accepted: 04/16/2018] [Indexed: 11/27/2022]
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29
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Fang Y, Zhu C, Chen X, Wang Y, Xu M, Sun G, Guo J, Yoo J, Tie C, Jiang X, Li X. Copy number of ArsR reporter plasmid determines its arsenite response and metal specificity. Appl Microbiol Biotechnol 2018; 102:5753-5761. [PMID: 29766244 DOI: 10.1007/s00253-018-9042-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2018] [Revised: 04/19/2018] [Accepted: 04/19/2018] [Indexed: 10/16/2022]
Abstract
The key component in bacteria-based biosensors is a transcriptional reporter employed to monitor induction or repression of a reporter gene corresponding to environmental change. In this study, we made a series of reporters in order to achieve highly sensitive detection of arsenite. From these reporters, two biosensors were developed by transformation of Escherichia coli DH5α with pLHPars9 and pLLPars9, consisting of either a high or low copy number plasmid, along with common elements of ArsR-luciferase fusion and addition of two binding sequences, one each from E. coli and Acidithiobacillus ferrooxidans chromosome, in front of the R773 ArsR operon. Both of them were highly sensitive to arsenite, with a low detection limit of 0.04 μM arsenite (~ 5 μg/L). They showed a wide dynamic range of detection up to 50 μM using high copy number pLHPars9 and 100 μM using low copy number pLLPars9. Significantly, they differ in metal specificity, pLLPars9 more specific to arsenite, while pLHPars9 to both arsenite and antimonite. The only difference between pLHPars9 and pLLPars9 is their copy numbers of plasmid and corresponding ratios of ArsR to its binding promoter/operator sequence. Therefore, we propose a working model in which DNA bound-ArsR is different from its free form in metal specificity.
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Affiliation(s)
- Yun Fang
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, 100 Central Xianlie Road, Guangzhou, 510070, Guangdong, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Chunjie Zhu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, 100 Central Xianlie Road, Guangzhou, 510070, Guangdong, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Xingjuan Chen
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, 100 Central Xianlie Road, Guangzhou, 510070, Guangdong, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Yan Wang
- Science and Technology Library of Guangdong Province, Guangdong Institute of Science and Technology Information and Development Strategy, Guangzhou, China
| | - Meiying Xu
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, 100 Central Xianlie Road, Guangzhou, 510070, Guangdong, China. .,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China.
| | - Guoping Sun
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, 100 Central Xianlie Road, Guangzhou, 510070, Guangdong, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Jun Guo
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, 100 Central Xianlie Road, Guangzhou, 510070, Guangdong, China.,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China
| | - Jinnon Yoo
- Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA, USA
| | - Cuijuan Tie
- Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA, USA
| | - Xin Jiang
- Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA, USA
| | - Xianqiang Li
- Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, 100 Central Xianlie Road, Guangzhou, 510070, Guangdong, China. .,State Key Laboratory of Applied Microbiology Southern China, Guangzhou, China. .,Signosis Inc., 1700 Wyatt Drive, suite10-12, Santa Clara, CA, USA.
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30
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LaVoie SP, Summers AO. Transcriptional responses of Escherichia coli during recovery from inorganic or organic mercury exposure. BMC Genomics 2018; 19:52. [PMID: 29338696 PMCID: PMC5769350 DOI: 10.1186/s12864-017-4413-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Accepted: 12/22/2017] [Indexed: 12/22/2022] Open
Abstract
Background The protean chemical properties of mercury have long made it attractive for diverse applications, but its toxicity requires great care in its use, disposal, and recycling. Mercury occurs in multiple chemical forms, and the molecular basis for the distinct toxicity of its various forms is only partly understood. Global transcriptomics applied over time can reveal how a cell recognizes a toxicant and what cellular subsystems it marshals to repair and recover from the damage. The longitudinal effects on the transcriptome of exponential phase E. coli were compared during sub-acute exposure to mercuric chloride (HgCl2) or to phenylmercuric acetate (PMA) using RNA-Seq. Results Differential gene expression revealed common and distinct responses to the mercurials throughout recovery. Cultures exhibited growth stasis immediately after each mercurial exposure but returned to normal growth more quickly after PMA exposure than after HgCl2 exposure. Correspondingly, PMA rapidly elicited up-regulation of a large number of genes which continued for 30 min, whereas fewer genes were up-regulated early after HgCl2 exposure only some of which overlapped with PMA up-regulated genes. By 60 min gene expression in PMA-exposed cells was almost indistinguishable from unexposed cells, but HgCl2 exposed cells still had many differentially expressed genes. Relative expression of energy production and most metabolite uptake pathways declined with both compounds, but nearly all stress response systems were up-regulated by one or the other mercurial during recovery. Conclusions Sub-acute exposure influenced expression of ~45% of all genes with many distinct responses for each compound, reflecting differential biochemical damage by each mercurial and the corresponding resources available for repair. This study is the first global, high-resolution view of the transcriptional responses to any common toxicant in a prokaryotic model system from exposure to recovery of active growth. The responses provoked by these two mercurials in this model bacterium also provide insights about how higher organisms may respond to these ubiquitous metal toxicants. Electronic supplementary material The online version of this article (10.1186/s12864-017-4413-z) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Stephen P LaVoie
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA.
| | - Anne O Summers
- Department of Microbiology, University of Georgia, Athens, GA, 30602, USA.
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31
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Chen J, Nadar VS, Rosen BP. A novel MAs(III)-selective ArsR transcriptional repressor. Mol Microbiol 2017; 106:469-478. [PMID: 28861914 DOI: 10.1111/mmi.13826] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/28/2017] [Indexed: 11/29/2022]
Abstract
Microbial expression of genes for resistance to heavy metals and metalloids is usually transcriptionally regulated by the toxic ions themselves. Arsenic is a ubiquitous, naturally occurring toxic metalloid widely distributed in soil and groundwater. Microbes biotransform both arsenate (As(V)) and arsenite (As(III)) into more toxic methylated metabolites methylarsenite (MAs(III)) and dimethylarsenite (DMAs(III)). Environmental arsenic is sensed by members of the ArsR/SmtB family. The arsR gene is autoregulated and is typically part of an operon that contains other ars genes involved in arsenic detoxification. To date every identified ArsR is regulated by inorganic As(III). Here we described a novel ArsR from Shewanella putrefaciens selective for MAs(III). SpArsR orthologs control expression of two MAs(III) resistance genes, arsP that encodes the ArsP MAs(III) efflux permease, and arsH encoding the ArsH MAs(III) oxidase. SpArsR has two conserved cysteine residues, Cys101 and Cys102. Mutation of either resulted in loss of MAs(III) binding, indicating that they form an MAs(III) binding site. SpArsR can be converted into an As(III)-responsive repressor by introduction of an additional cysteine that allows for three-coordinate As(III) binding. Our results indicate that SpArsR evolved selectivity for MAs(III) over As(III) in order to control expression of genes for MAs(III) detoxification.
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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
| | - Venkadesh Sarkarai Nadar
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
| | - 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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32
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Saha RP, Samanta S, Patra S, Sarkar D, Saha A, Singh MK. Metal homeostasis in bacteria: the role of ArsR-SmtB family of transcriptional repressors in combating varying metal concentrations in the environment. Biometals 2017; 30:459-503. [PMID: 28512703 DOI: 10.1007/s10534-017-0020-3] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2017] [Accepted: 05/09/2017] [Indexed: 02/02/2023]
Abstract
Bacterial infections cause severe medical problems worldwide, resulting in considerable death and loss of capital. With the ever-increasing rise of antibiotic-resistant bacteria and the lack of development of new antibiotics, research on metal-based antimicrobial therapy has now gained pace. Metal ions are essential for survival, but can be highly toxic to organisms if their concentrations are not strictly controlled. Through evolution, bacteria have acquired complex metal-management systems that allow them to acquire metals that they need for survival in different challenging environments while evading metal toxicity. Metalloproteins that controls these elaborate systems in the cell, and linked to key virulence factors, are promising targets for the anti-bacterial drug development. Among several metal-sensory transcriptional regulators, the ArsR-SmtB family displays greatest diversity with several distinct metal-binding and nonmetal-binding motifs that have been characterized. These prokaryotic metolloregulatory transcriptional repressors represses the expression of operons linked to stress-inducing concentrations of metal ions by directly binding to the regulatory regions of DNA, while derepression results from direct binding of metal ions by these homodimeric proteins. Many bacteria, e.g., Mycobacterium tuberculosis, Bacillus anthracis, etc., have evolved to acquire multiple metal-sensory motifs which clearly demonstrate the importance of regulating concentrations of multiple metal ions. Here, we discussed the mechanisms of how ArsR-SmtB family regulates the intracellular bioavailability of metal ions both inside and outside of the host. Knowledge of the metal-challenges faced by bacterial pathogens and their survival strategies will enable us to develop the next generation drugs.
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Affiliation(s)
- Rudra P Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India.
| | - Saikat Samanta
- Department of Microbiology, School of Science, Adamas University, Kolkata, 700126, India
| | - Surajit Patra
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Diganta Sarkar
- Department of Biotechnology, Techno India University, Kolkata, 700091, India
| | - Abinit Saha
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
| | - Manoj Kumar Singh
- Department of Biotechnology, School of Biotechnology, Adamas University, Kolkata, 700126, India
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33
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The Arsenic Detoxification System in Corynebacteria: Basis and Application for Bioremediation and Redox Control. ADVANCES IN APPLIED MICROBIOLOGY 2017; 99:103-137. [PMID: 28438267 DOI: 10.1016/bs.aambs.2017.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Arsenic (As) is widespread in the environment and highly toxic. It has been released by volcanic and anthropogenic activities and causes serious health problems worldwide. To survive arsenic-rich environments, soil and saprophytic microorganisms have developed molecular detoxification mechanisms to survive arsenic-rich environments, mainly by the enzymatic conversion of inorganic arsenate (AsV) to arsenite (AsIII) by arsenate reductases, which is then extruded by arsenite permeases. One of these Gram-positive bacteria, Corynebacterium glutamicum, the workhorse of biotechnological research, is also resistant to arsenic. To sanitize contaminated soils and waters, C. glutamicum strains were modified to work as arsenic "biocontainers." Two chromosomally encoded ars operons (ars1 and ars2) are responsible for As resistance. The genes within these operons encode for metalloregulatory proteins (ArsR1/R2), arsenite permeases (Acr3-1/-2), and arsenate reductases (ArsC1/C2/C1'). ArsC1/C2 arsenate reductases are coupled to the low molecular weight thiol mycothiol (MSH) and to the recently discovered mycoredoxin-1 (Mrx-1) present in most Actinobacteria. This MSH/Mrx-1 redox system protects cells against different forms of stress, including reactive oxygen species (ROS), metals, and antibiotics. ROS can modify functional sulfur cysteines by oxidizing the thiol (-SH) to a sulfenic acid (-SOH). These oxidation-sensitive protein cysteine thiols are redox regulated by the MSH/Mrx-1 couple in Corynebacterium and Mycobacterium. In summary, the molecular mechanisms involved in arsenic resistance system in C. glutamicum have paved the way for understanding the cellular response against oxidative stress in Actinobacteria.
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Arruda LM, Monteiro LMO, Silva-Rocha R. The Chromobacterium violaceum ArsR Arsenite Repressor Exerts Tighter Control on Its Cognate Promoter Than the Escherichia coli System. Front Microbiol 2016; 7:1851. [PMID: 27917165 PMCID: PMC5116461 DOI: 10.3389/fmicb.2016.01851] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Accepted: 11/03/2016] [Indexed: 11/13/2022] Open
Abstract
Environmental bacteria are endowed with several regulatory systems that have potential applications in biotechnology. In this report, we characterize the arsenic biosensing features of the ars response system from Chromobacterium violaceum in the heterologous host Escherichia coli. We show that the native Pars/arsR system of C. violaceum outperforms the chromosomal ars copy of E. coli when exposed to micromolar concentrations of arsenite. To understand the molecular basis of this phenomenon, we analyzed the interaction between ArsR regulators and their promoter target sites as well as induction of the system at saturating concentrations of the regulators. In vivo titration experiments indicate that ArsR from C. violaceum has stronger binding affinity for its target promoter than the regulator from E. coli does. Additionally, arsenite induction experiments at saturating regulator concentration demonstrates that although the Pars/arsR system from E. coli displays a gradual response to increasing concentration of the inducer, the system from C. violaceum has a steeper response with a stronger promoter induction after a given arsenite threshold. Taken together, these data demonstrate the characterization of a novel arsenic response element from an environmental bacterium with potentially enhanced performance that could be further explored for the construction of an arsenic biosensor.
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Affiliation(s)
- Letícia M Arruda
- Systems and Synthetic Biology Lab, Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo Ribeirão Preto, Brazil
| | - Lummy M O Monteiro
- Systems and Synthetic Biology Lab, Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo Ribeirão Preto, Brazil
| | - Rafael Silva-Rocha
- Systems and Synthetic Biology Lab, Department of Cell and Molecular Biology, Ribeirão Preto Medical School, University of São Paulo Ribeirão Preto, Brazil
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Paralogous Regulators ArsR1 and ArsR2 of Pseudomonas putida KT2440 as a Basis for Arsenic Biosensor Development. Appl Environ Microbiol 2016; 82:4133-4144. [PMID: 27208139 DOI: 10.1128/aem.00606-16] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2016] [Accepted: 04/25/2016] [Indexed: 11/20/2022] Open
Abstract
UNLABELLED The remarkable metal resistance of many microorganisms is related to the presence of multiple metal resistance operons. Pseudomonas putida KT2440 can be considered a model for these microorganisms since its arsenic resistance is due to the action of proteins encoded by the two paralogous arsenic resistance operons ARS1 and ARS2. Both operons contain the genes encoding the transcriptional regulators ArsR1 and ArsR2 that control operon expression. We show here that purified ArsR1 and ArsR2 bind the trivalent salt of arsenic (arsenite) with similar affinities (~30 μM), whereas no binding is observed for the pentavalent salt (arsenate). Furthermore, trivalent salts of bismuth and antimony showed binding to both paralogues. The positions of cysteines, found to bind arsenic in other homologues, indicate that ArsR1 and ArsR2 employ different modes of arsenite recognition. Both paralogues are dimeric and possess significant thermal stability. Both proteins were used to construct whole-cell, lacZ-based biosensors. Whereas responses to bismuth were negligible, significant responses were observed for arsenite, arsenate, and antimony. Biosensors based on the P. putida arsB1 arsB2 arsenic efflux pump double mutant were significantly more sensitive than biosensors based on the wild-type strain. This sensitivity enhancement by pump mutation may be a convenient strategy for the construction of other biosensors. A frequent limitation found for other arsenic biosensors was their elevated background signal and interference by inorganic phosphate. The constructed biosensors show no interference by inorganic phosphate, are characterized by a very low background signal, and were found to be suitable to analyze environmental samples. IMPORTANCE Arsenic is at the top of the priority list of hazardous compounds issued by the U.S. Agency for Toxic Substances and Disease. The reason for the stunning arsenic resistance of many microorganisms is the existence of paralogous arsenic resistance operons. Pseudomonas putida KT2440 is a model organism for such bacteria, and their duplicated ars operons and in particular their ArsR transcription regulators have been studied in depth by in vivo approaches. Here we present an analysis of both purified ArsR paralogues by different biophysical techniques, and data obtained provide valuable insight into their structure and function. Particularly insightful was the comparison of ArsR effector profiles determined by in vitro and in vivo experimentation. We also report the use of both paralogues to construct robust and highly sensitive arsenic biosensors. Our finding that the deletion of both arsenic efflux pumps significantly increases biosensor sensitivity is of general relevance in the biosensor field.
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Li J, Mandal G, Rosen BP. Expression of arsenic resistance genes in the obligate anaerobe Bacteroides vulgatus ATCC 8482, a gut microbiome bacterium. Anaerobe 2016; 39:117-23. [PMID: 27040269 PMCID: PMC4984537 DOI: 10.1016/j.anaerobe.2016.03.012] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2016] [Revised: 03/27/2016] [Accepted: 03/28/2016] [Indexed: 11/26/2022]
Abstract
The response of the obligate anaerobe Bacteroides vulgatus ATCC 8482, a common human gut microbiota, to arsenic was determined. B. vulgatus ATCC 8482 is highly resistant to pentavalent As(V) and methylarsenate (MAs(V)). It is somewhat more sensitive to trivalent inorganic As(III) but 100-fold more sensitive to methylarsenite (MAs(III)) than to As(III). B. vulgatus ATCC 8482 has eight continuous genes in its genome that we demonstrate form an arsenical-inducible transcriptional unit. The first gene of this ars operon, arsR, encodes a putative ArsR As(III)-responsive transcriptional repressor. The next three genes encode proteins of unknown function. The remaining genes, arsDABC, have well-characterized roles in detoxification of inorganic arsenic, but there are no known genes for MAs(III) resistance. Expression of each gene after exposure to trivalent and pentavalent inorganic and methylarsenicals was analyzed. MAs(III) was the most effective inducer. The arsD gene was the most highly expressed of the ars operon genes. These results demonstrate that this anaerobic microbiome bacterium has arsenic-responsive genes that confer resistance to inorganic arsenic and may be responsible for the organism's ability to maintain its prevalence in the gut following dietary exposure to inorganic arsenic.
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Affiliation(s)
- Jiaojiao Li
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, United States
| | - Goutam Mandal
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, United States
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, United States.
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Regulatory Activities of Four ArsR Proteins in Agrobacterium tumefaciens 5A. Appl Environ Microbiol 2016; 82:3471-3480. [PMID: 27037117 DOI: 10.1128/aem.00262-16] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/28/2016] [Indexed: 02/08/2023] Open
Abstract
UNLABELLED ArsR is a well-studied transcriptional repressor that regulates microbe-arsenic interactions. Most microorganisms have an arsR gene, but in cases where multiple copies exist, the respective roles or potential functional overlap have not been explored. We examined the repressors encoded by arsR1 and arsR2 (ars1 operon) and by arsR3 and arsR4 (ars2 operon) in Agrobacterium tumefaciens 5A. ArsR1 and ArsR4 are very similar in their primary sequences and diverge phylogenetically from ArsR2 and ArsR3, which are also quite similar to one another. Reporter constructs (lacZ) for arsR1, arsR2, and arsR4 were all inducible by As(III), but expression of arsR3 (monitored by reverse transcriptase PCR) was not influenced by As(III) and appeared to be linked transcriptionally to an upstream lysR-type gene. Experiments using a combination of deletion mutations and additional reporter assays illustrated that the encoded repressors (i) are not all autoregulatory as is typically known for ArsR proteins, (ii) exhibit variable control of each other's encoding genes, and (iii) exert variable control of other genes previously shown to be under the control of ArsR1. Furthermore, ArsR2, ArsR3, and ArsR4 appear to have an activator-like function for some genes otherwise repressed by ArsR1, which deviates from the well-studied repressor role of ArsR proteins. The differential regulatory activities suggest a complex regulatory network not previously observed in ArsR studies. The results indicate that fine-scale ArsR sequence deviations of the reiterated regulatory proteins apparently translate to different regulatory roles. IMPORTANCE Given the significance of the ArsR repressor in regulating various aspects of microbe-arsenic interactions, it is important to assess potential regulatory overlap and/or interference when a microorganism carries multiple copies of arsR This study explores this issue and shows that the four arsR genes in A. tumefaciens 5A, associated with two separate ars operons, encode proteins exhibiting various degrees of functional overlap with respect to autoregulation and cross-regulation, as well as control of other functional genes. In some cases, differences in regulatory activity are associated with only limited differences in protein primary structure. The experiments summarized herein also present evidence that ArsR proteins appear to have activator functions, representing novel regulatory activities for ArsR, previously known only to be a repressor.
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Chen J, Yoshinaga M, Garbinski LD, Rosen BP. Synergistic interaction of glyceraldehydes-3-phosphate dehydrogenase and ArsJ, a novel organoarsenical efflux permease, confers arsenate resistance. Mol Microbiol 2016; 100:945-53. [PMID: 26991003 DOI: 10.1111/mmi.13371] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/12/2016] [Indexed: 11/28/2022]
Abstract
Microbial biotransformations are major contributors to the arsenic biogeocycle. In parallel with transformations of inorganic arsenic, organoarsenicals pathways have recently been recognized as important components of global cycling of arsenic. The well-characterized pathway of resistance to arsenate is reduction coupled to arsenite efflux. Here, we describe a new pathway of arsenate resistance involving biosynthesis and extrusion of an unusual pentavalent organoarsenical. A number of arsenic resistance (ars) operons have two genes of unknown function that are linked in these operons. One, gapdh, encodes the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase. The other, arsJ, encodes a major facilitator superfamily (MFS) protein. The two genes were cloned from the chromosome of Pseudomonas aeruginosa. When expressed together, but not alone, in Escherichia coli, gapdh and arsJ specifically conferred resistance to arsenate and decreased accumulation of As(V). Everted membrane vesicles from cells expressing arsJ accumulated As(V) in the presence of purified GAPDH, D-glceraldehylde 3-phosphate (G3P) and NAD(+) . GAPDH forms the unstable organoarsenical 1-arseno-3-phosphoglycerate (1As3PGA). We propose that ArsJ is an efflux permease that extrudes 1As3PGA from cells, where it rapidly dissociates into As(V) and 3-phosphoglycerate (3PGA), creating a novel pathway of arsenate 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
| | - Masafumi Yoshinaga
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA
| | - Luis D Garbinski
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL, 33199, USA
| | - 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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Arsenic Directly Binds to and Activates the Yeast AP-1-Like Transcription Factor Yap8. Mol Cell Biol 2015; 36:913-22. [PMID: 26711267 DOI: 10.1128/mcb.00842-15] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Accepted: 12/23/2015] [Indexed: 11/20/2022] Open
Abstract
The AP-1-like transcription factor Yap8 is critical for arsenic tolerance in the yeast Saccharomyces cerevisiae. However, the mechanism by which Yap8 senses the presence of arsenic and activates transcription of detoxification genes is unknown. Here we demonstrate that Yap8 directly binds to trivalent arsenite [As(III)] in vitro and in vivo and that approximately one As(III) molecule is bound per molecule of Yap8. As(III) is coordinated by three sulfur atoms in purified Yap8, and our genetic and biochemical data identify the cysteine residues that form the binding site as Cys132, Cys137, and Cys274. As(III) binding by Yap8 does not require an additional yeast protein, and Yap8 is regulated neither at the level of localization nor at the level of DNA binding. Instead, our data are consistent with a model in which a DNA-bound form of Yap8 acts directly as an As(III) sensor. Binding of As(III) to Yap8 triggers a conformational change that in turn brings about a transcriptional response. Thus, As(III) binding to Yap8 acts as a molecular switch that converts inactive Yap8 into an active transcriptional regulator. This is the first report to demonstrate how a eukaryotic protein couples arsenic sensing to transcriptional activation.
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Complete genome sequence of Microbacterium sp. CGR1, bacterium tolerant to wide abiotic conditions isolated from the Atacama Desert. J Biotechnol 2015; 216:149-50. [PMID: 26521698 DOI: 10.1016/j.jbiotec.2015.10.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 10/22/2015] [Indexed: 01/10/2023]
Abstract
Microbacterium sp. CGR1 (RGM2230) is an isolate from the Atacama Desert that displays a wide pH, salinity and temperature tolerance. This strain exhibits riboflavin overproducer features and traits for developing an environmental arsenic biosensor. Here, we report the complete genome sequence of this strain, which represents the first genome of the genus Microbacterium sequenced and assembled in a single contig. The genome contains 3,634,864bp, 3299 protein-coding genes, 45 tRNAs, six copies of 5S-16S-23S rRNA and a high genome average GC-content of 68.04%.
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Yu X, Zheng W, Bhat S, Aquilina JA, Zhang R. Transcriptional and posttranscriptional regulation of Bacillus sp. CDB3 arsenic-resistance operon ars1. PeerJ 2015; 3:e1230. [PMID: 26355338 PMCID: PMC4562236 DOI: 10.7717/peerj.1230] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2015] [Accepted: 08/16/2015] [Indexed: 11/24/2022] Open
Abstract
Bacillus sp. CDB3 possesses a novel eight-gene ars cluster (ars1, arsRYCDATorf7orf8) with some unusual features in regard to expression regulation. This study demonstrated that the cluster is a single operon but can also produce a short three-gene arsRYC transcript. A hairpin structure formed by internal inverted repeats between arsC and arsD was shown to diminish the expression of the full operon, thereby probably acting as a transcription attenuator. A degradation product of the arsRYC transcript was also identified. Electrophoretic mobility shift analysis demonstrated that ArsR interacts with the ars1 promoter forming a protein-DNA complex that could be impaired by arsenite. However, no interaction was detected between ArsD and the ars1 promoter, suggesting that the CDB3 ArsD protein may not play a regulatory role. Compared to other ars gene clusters, regulation of the Bacillus sp. CDB3 ars1 operon is more complex. It represents another example of specific mRNA degradation in the transporter gene region and possibly the first case of attenuator-mediated regulation of ars operons.
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Affiliation(s)
- Xuefei Yu
- School of Biological Sciences, University of Wollongong , Wollongong, NSW , Australia
| | - Wei Zheng
- Current affiliation: Research Center on Life Sciences and Environmental Sciences, Harbin University of Commerce , Harbin , China
| | - Somanath Bhat
- Current affiliation: National Measurement Institute of Australia , Lindfield, NSW , Australia
| | - J Andrew Aquilina
- School of Biological Sciences, University of Wollongong , Wollongong, NSW , Australia
| | - Ren Zhang
- School of Biological Sciences, University of Wollongong , Wollongong, NSW , Australia
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Hirano S, Tadano M, Kobayashi Y, Udagawa O, Kato A. Solubility shift and SUMOylaltion of promyelocytic leukemia (PML) protein in response to arsenic(III) and fate of the SUMOylated PML. Toxicol Appl Pharmacol 2015; 287:191-201. [DOI: 10.1016/j.taap.2015.05.018] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2015] [Revised: 04/17/2015] [Accepted: 05/29/2015] [Indexed: 12/16/2022]
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ArsC3 from Desulfovibrio alaskensis G20, a cation and sulfate-independent highly efficient arsenate reductase. J Biol Inorg Chem 2014; 19:1277-85. [DOI: 10.1007/s00775-014-1184-8] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2014] [Accepted: 08/03/2014] [Indexed: 12/24/2022]
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An ArsR/SmtB family member is involved in the regulation by arsenic of the arsenite oxidase operon in Thiomonas arsenitoxydans. Appl Environ Microbiol 2014; 80:6413-26. [PMID: 25107975 DOI: 10.1128/aem.01771-14] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The genetic organization of the aioBA operon, encoding the arsenite oxidase of the moderately acidophilic and facultative chemoautotrophic bacterium Thiomonas arsenitoxydans, is different from that of the aioBA operon in the other arsenite oxidizers, in that it encodes AioF, a metalloprotein belonging to the ArsR/SmtB family. AioF is stabilized by arsenite, arsenate, or antimonite but not molybdate. Arsenic is tightly attached to AioF, likely by cysteine residues. When loaded with arsenite or arsenate, AioF is able to bind specifically to the regulatory region of the aio operon at two distinct positions. In Thiomonas arsenitoxydans, the promoters of aioX and aioB are convergent, suggesting that transcriptional interference occurs. These results indicate that the regulation of the aioBA operon is more complex in Thiomonas arsenitoxydans than in the other aioBA containing arsenite oxidizers and that the arsenic binding protein AioF is involved in this regulation. On the basis of these data, a model to explain the tight control of aioBA expression by arsenic in Thiomonas arsenitoxydans is proposed.
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A C⋅As lyase for degradation of environmental organoarsenical herbicides and animal husbandry growth promoters. Proc Natl Acad Sci U S A 2014; 111:7701-6. [PMID: 24821808 DOI: 10.1073/pnas.1403057111] [Citation(s) in RCA: 98] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Arsenic is the most widespread environmental toxin. Substantial amounts of pentavalent organoarsenicals have been used as herbicides, such as monosodium methylarsonic acid (MSMA), and as growth enhancers for animal husbandry, such as roxarsone (4-hydroxy-3-nitrophenylarsonic acid) [Rox(V)]. These undergo environmental degradation to more toxic inorganic arsenite [As(III)]. We previously demonstrated a two-step pathway of degradation of MSMA to As(III) by microbial communities involving sequential reduction to methylarsonous acid [MAs(III)] by one bacterial species and demethylation from MAs(III) to As(III) by another. In this study, the gene responsible for MAs(III) demethylation was identified from an environmental MAs(III)-demethylating isolate, Bacillus sp. MD1. This gene, termed arsenic inducible gene (arsI), is in an arsenic resistance (ars) operon and encodes a nonheme iron-dependent dioxygenase with C ⋅ As lyase activity. Heterologous expression of ArsI conferred MAs(III)-demethylating activity and MAs(III) resistance to an arsenic-hypersensitive strain of Escherichia coli, demonstrating that MAs(III) demethylation is a detoxification process. Purified ArsI catalyzes Fe(2+)-dependent MAs(III) demethylation. In addition, ArsI cleaves the C ⋅ As bond in trivalent roxarsone and other aromatic arsenicals. ArsI homologs are widely distributed in prokaryotes, and we propose that ArsI-catalyzed organoarsenical degradation has a significant impact on the arsenic biogeocycle. To our knowledge, this is the first report of a molecular mechanism for organoarsenic degradation by a C ⋅ As lyase.
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Chen J, Sun S, Li CZ, Zhu YG, Rosen BP. Biosensor for organoarsenical herbicides and growth promoters. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2014; 48:1141-7. [PMID: 24359149 PMCID: PMC3939449 DOI: 10.1021/es4038319] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
The toxic metalloid arsenic is widely distributed in food, water, and soil. While inorganic arsenic enters the environment primarily from geochemical sources, methylarsenicals either result from microbial biotransformation of inorganic arsenic or are introduced anthropogenically. Methylarsenicals such as monosodium methylarsonic acid (MSMA) have been extensively utilized as herbicides, and aromatic arsenicals such as roxarsone (Rox) are used as growth promoters for poultry and swine. Organoarsenicals are degraded to inorganic arsenic. The toxicological effects of arsenicals depend on their oxidation state, chemical composition, and bioavailability. Here we report that the active forms are the trivalent arsenic-containing species. We constructed a whole-cell biosensor utilizing a modified ArsR repressor that is highly selective toward trivalent methyl and aromatic arsenicals, with essentially no response to inorganic arsenic. The biosensor was adapted for in vitro detection of organoarsenicals using fluorescence anisotropy of ArsR-DNA interactions. It detects bacterial biomethylation of inorganic arsenite both in vivo and in vitro with detection limits of 10(-7) M and linearity to 10(-6) M for phenylarsenite and 5 × 10(-6) M for methylarsenite. The biosensor detects reduced forms of MSMA and roxarsone and offers a practical, low cost method for detecting activate forms and breakdown products of organoarsenical herbicides and growth promoters.
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Affiliation(s)
- Jian Chen
- Department of Cellular Biology and Pharmacology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL 33199, USA
- State Key Lab of Regional and Urban Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
| | - Samio Sun
- Nanobioengineering/Nanobioelectronics Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA
| | - Chen-Zhong Li
- Nanobioengineering/Nanobioelectronics Laboratory, Department of Biomedical Engineering, Florida International University, Miami, FL 33174, USA
| | - Yong-Guan Zhu
- State Key Lab of Regional and Urban Ecology, Research Center for Eco-environmental Sciences, Chinese Academy of Sciences, Beijing 100085, China
- Key Lab of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen 361021, People's Republic of China
| | - Barry P. Rosen
- Department of Cellular Biology and Pharmacology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL 33199, USA
- Correspondence: Barry P. Rosen, Herbert Wertheim Florida International University College of Medicine, 11200 SW 8th Street, HLS II 693 Miami, FL 33199 Tel: (+1) 305-348-0657, Fax: (+1) 305-348-0651,
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Affiliation(s)
- Shengwen Shen
- Department
of Laboratory Medicine
and Pathology, 10-102 Clinical Sciences Building, University
of Alberta, Edmonton, Alberta, Canada, T6G 2G3
| | - Xing-Fang Li
- Department
of Laboratory Medicine
and Pathology, 10-102 Clinical Sciences Building, University
of Alberta, Edmonton, Alberta, Canada, T6G 2G3
| | - William R. Cullen
- Department of Chemistry, University of British Columbia, 2036 Main Mall, Vancouver,
British Columbia, Canada, V6T 1Z1
| | - Michael Weinfeld
- Department of Oncology, Cross
Cancer Institute, University of Alberta, 11560 University Avenue, Edmonton, Alberta, Canada, T6G 1Z2
| | - X. Chris Le
- Department
of Laboratory Medicine
and Pathology, 10-102 Clinical Sciences Building, University
of Alberta, Edmonton, Alberta, Canada, T6G 2G3
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Yang HC, Fu HL, Lin YF, Rosen BP. Pathways of arsenic uptake and efflux. CURRENT TOPICS IN MEMBRANES 2013; 69:325-58. [PMID: 23046656 DOI: 10.1016/b978-0-12-394390-3.00012-4] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Arsenic is the most prevalent environmental toxic substance and ranks first on the U.S. Environmental Protection Agency's Superfund List. Arsenic is a carcinogen and a causative agent of numerous human diseases. Paradoxically arsenic is used as a chemotherapeutic agent for treatment of acute promyelocytic leukemia. Inorganic arsenic has two biological important oxidation states: As(V) (arsenate) and As(III) (arsenite). Arsenic uptake is adventitious because the arsenate and arsenite are chemically similar to required nutrients. Arsenate resembles phosphate and is a competitive inhibitor of many phosphate-utilizing enzymes. Arsenate is taken up by phosphate transport systems. In contrast, at physiological pH, the form of arsenite is As(OH)(3), which resembles organic molecules such as glycerol. Consequently, arsenite is taken into cells by aquaglyceroporin channels. Arsenic efflux systems are found in nearly every organism and evolved to rid cells of this toxic metalloid. These efflux systems include members of the multidrug resistance protein family and the bacterial exchangers Acr3 and ArsB. ArsB can also be a subunit of the ArsAB As(III)-translocating ATPase, an ATP-driven efflux pump. The ArsD metallochaperone binds cytosolic As(III) and transfers it to the ArsA subunit of the efflux pump. Knowledge of the pathways and transporters for arsenic uptake and efflux is essential for understanding its toxicity and carcinogenicity and for rational design of cancer chemotherapeutic drugs.
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Affiliation(s)
- Hung-Chi Yang
- Department of Medical Biotechnology and Laboratory Sciences, Chang-Gung University, Tao-Yuan, Taiwan
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Slyemi D, Bonnefoy V. How prokaryotes deal with arsenic(†). ENVIRONMENTAL MICROBIOLOGY REPORTS 2012; 4:571-586. [PMID: 23760928 DOI: 10.1111/j.1758-2229.2011.00300.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Arsenic is a notorious poison classified as a carcinogen, a teratogen and a clastogen that ranks number one on the Environmental Protection Agency's priority list of drinking water contaminants. It is ubiquitous and relatively abundant in the Earth's crust. Its mobilization in waters by weathering, volcanic, anthropogenic or biological activities represents a major hazard to public health, exemplified in India and Bangladesh where 50 million people are acutely at risk. Since basically the origin of life, microorganisms have been exposed to this toxic compound and have evolved a variety of resistance mechanisms, such as extracellular precipitation, chelation, intracellular sequestration, active extrusion from the cell or biochemical transformation (redox or methylation). Arsenic efflux systems are widespread and are found in nearly all organisms. Some microorganisms are also able to utilize this metalloid as a metabolic energy source through either arsenite oxidation or arsenate reduction. The energy metabolism involving redox reactions of arsenic has been suggested to have evolved during early life on Earth. This review highlights the different systems evolved by prokaryotes to cope with arsenic and how they participate in its biogeochemical cycle.
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Affiliation(s)
- Djamila Slyemi
- Laboratoire de Chimie Bactérienne, UPR-CNRS 9043, Institut de Microbiologie de la Méditerranée, 31 chemin Joseph Aiguier, 13402, Marseille, Cedex 20, France. Aix-Marseille Université, Marseille, France
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Kang YS, Heinemann J, Bothner B, Rensing C, McDermott TR. Integrated co-regulation of bacterial arsenic and phosphorus metabolisms. Environ Microbiol 2012; 14:3097-109. [PMID: 23057575 DOI: 10.1111/j.1462-2920.2012.02881.x] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2012] [Revised: 08/19/2012] [Accepted: 08/20/2012] [Indexed: 11/30/2022]
Abstract
Arsenic ranks first on the US Environmental Protection Agency Superfund List of Hazardous Substances. Its mobility and toxicity depend upon chemical speciation, which is significantly driven by microbial redox transformations. Genome sequence-enabled surveys reveal that in many microorganisms genes essential to arsenite (AsIII) oxidation are located immediately adjacent to genes coding for functions associated with phosphorus (Pi) acquisition, implying some type of functional importance to the metabolism of As, Pi or both. We extensively document how expression of genes key to AsIII oxidation and the Pi stress response are intricately co-regulated in the soil bacterium Agrobacterium tumefaciens. These observations significantly expand our understanding of how environmental factors influence microbial AsIII metabolism and contribute to the current discussion of As and P metabolism in the microbial cell.
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Affiliation(s)
- Yoon-Suk Kang
- Department of Land Resources and Environmental Sciences, Montana State University, Bozeman, MT 59717, USA
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