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Wang HT, Liang ZZ, Ding J, Li G, Fu SL, Zhu D. Deciphering roles of microbiota in arsenic biotransformation from the earthworm gut and skin. JOURNAL OF HAZARDOUS MATERIALS 2023; 446:130707. [PMID: 36603428 DOI: 10.1016/j.jhazmat.2022.130707] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2022] [Revised: 12/28/2022] [Accepted: 12/28/2022] [Indexed: 06/17/2023]
Abstract
Biotransformation mediated by microbes can affect the biogeochemical cycle of arsenic. However, arsenic biotransformation mediated by earthworm-related microorganisms has not been well explored, especially the role played by earthworm skin microbiota. Herein, we reveal the profiles of arsenic biotransformation genes (ABGs) and elucidate the microbial communities of the earthworm gut, skin, and surrounding soil from five different soil environments in China. The relative abundance of ABGs in the earthworm skin microbiota, which were dominated by genes associated with arsenate reduction and transport, was approximately three times higher than that in the surrounding soil and earthworm gut microbiota. The composition and diversity of earthworm skin microbiota differed significantly from those of the soil and earthworm gut, comprising a core bacterial community with a relative abundance of 96% Firmicutes and a fungal community with relative abundances of 50% Ascomycota and 13% Mucoromycota. In addition, stochastic processes mainly contributed to the microbial community assembly across all samples. Moreover, fungal genera such as Vishniacozyma and Oomyces were important mediators of ABGs involved in the biogeochemical cycle of arsenic. This is the first study to investigate earthworm skin as a reservoir of microbial diversity in arsenic biotransformation. Our findings broaden the current scientific knowledge of the involvement of earthworms in the arsenic biogeochemical cycle.
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Affiliation(s)
- Hong-Tao Wang
- College of Geography and Environmental Science, Henan University, Kaifeng 475004, China; Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions (Henan University), Ministry of Education, Kaifeng 475004, China
| | - Zong-Zheng Liang
- Academy of Regional and Global Governance, Beijing Foreign Studies University, Beijing 100089, China
| | - Jing Ding
- School of Environmental and Material Engineering, Yantai University, Yantai 264005, China
| | - Gang Li
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China
| | - Sheng-Lei Fu
- College of Geography and Environmental Science, Henan University, Kaifeng 475004, China; Key Laboratory of Geospatial Technology for the Middle and Lower Yellow River Regions (Henan University), Ministry of Education, Kaifeng 475004, China
| | - Dong Zhu
- Key Laboratory of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, 1799 Jimei Road, Xiamen 361021, China.
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2
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Russum S, Lam KJK, Wong NA, Iddamsetty V, Hendargo KJ, Wang J, Dubey A, Zhang Y, Medrano-Soto A, Saier MH. Comparative population genomic analyses of transporters within the Asgard archaeal superphylum. PLoS One 2021; 16:e0247806. [PMID: 33770091 PMCID: PMC7997004 DOI: 10.1371/journal.pone.0247806] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2020] [Accepted: 02/15/2021] [Indexed: 01/02/2023] Open
Abstract
Upon discovery of the first archaeal species in the 1970s, life has been subdivided into three domains: Eukarya, Archaea, and Bacteria. However, the organization of the three-domain tree of life has been challenged following the discovery of archaeal lineages such as the TACK and Asgard superphyla. The Asgard Superphylum has emerged as the closest archaeal ancestor to eukaryotes, potentially improving our understanding of the evolution of life forms. We characterized the transportomes and their substrates within four metagenome-assembled genomes (MAGs), that is, Odin-, Thor-, Heimdall- and Loki-archaeota as well as the fully sequenced genome of Candidatus Prometheoarchaeum syntrophicum strain MK-D1 that belongs to the Loki phylum. Using the Transporter Classification Database (TCDB) as reference, candidate transporters encoded within the proteomes were identified based on sequence similarity, alignment coverage, compatibility of hydropathy profiles, TMS topologies and shared domains. Identified transport systems were compared within the Asgard superphylum as well as within dissimilar eukaryotic, archaeal and bacterial organisms. From these analyses, we infer that Asgard organisms rely mostly on the transport of substrates driven by the proton motive force (pmf), the proton electrochemical gradient which then can be used for ATP production and to drive the activities of secondary carriers. The results indicate that Asgard archaea depend heavily on the uptake of organic molecules such as lipid precursors, amino acids and their derivatives, and sugars and their derivatives. Overall, the majority of the transporters identified are more similar to prokaryotic transporters than eukaryotic systems although several instances of the reverse were documented. Taken together, the results support the previous suggestions that the Asgard superphylum includes organisms that are largely mixotrophic and anaerobic but more clearly define their metabolic potential while providing evidence regarding their relatedness to eukaryotes.
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Affiliation(s)
- Steven Russum
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Katie Jing Kay Lam
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Nicholas Alan Wong
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Vasu Iddamsetty
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Kevin J. Hendargo
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Jianing Wang
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Aditi Dubey
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Yichi Zhang
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
| | - Arturo Medrano-Soto
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
- * E-mail: (MHS); (AMS)
| | - Milton H. Saier
- Division of Biological Sciences, Department of Molecular Biology, University of California at San Diego, La Jolla, CA, United States of America
- * E-mail: (MHS); (AMS)
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3
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Firrincieli A, Presentato A, Favoino G, Marabottini R, Allevato E, Stazi SR, Scarascia Mugnozza G, Harfouche A, Petruccioli M, Turner RJ, Zannoni D, Cappelletti M. Identification of Resistance Genes and Response to Arsenic in Rhodococcus aetherivorans BCP1. Front Microbiol 2019; 10:888. [PMID: 31133997 PMCID: PMC6514093 DOI: 10.3389/fmicb.2019.00888] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2019] [Accepted: 04/08/2019] [Indexed: 11/28/2022] Open
Abstract
Arsenic (As) ranks among the priority metal(loid)s that are of public health concern. In the environment, arsenic is present in different forms, organic or inorganic, featured by various toxicity levels. Bacteria have developed different strategies to deal with this toxicity involving different resistance genetic determinants. Bacterial strains of Rhodococcus genus, and more in general Actinobacteria phylum, have the ability to cope with high concentrations of toxic metalloids, although little is known on the molecular and genetic bases of these metabolic features. Here we show that Rhodococcus aetherivorans BCP1, an extremophilic actinobacterial strain able to tolerate high concentrations of organic solvents and toxic metalloids, can grow in the presence of high concentrations of As(V) (up to 240 mM) under aerobic growth conditions using glucose as sole carbon and energy source. Notably, BCP1 cells improved their growth performance as well as their capacity of reducing As(V) into As(III) when the concentration of As(V) is within 30–100 mM As(V). Genomic analysis of BCP1 compared to other actinobacterial strains revealed the presence of three gene clusters responsible for organic and inorganic arsenic resistance. In particular, two adjacent and divergently oriented ars gene clusters include three arsenate reductase genes (arsC1/2/3) involved in resistance mechanisms against As(V). A sequence similarity network (SSN) and phylogenetic analysis of these arsenate reductase genes indicated that two of them (ArsC2/3) are functionally related to thioredoxin (Trx)/thioredoxin reductase (TrxR)-dependent class and one of them (ArsC1) to the mycothiol (MSH)/mycoredoxin (Mrx)-dependent class. A targeted transcriptomic analysis performed by RT-qPCR indicated that the arsenate reductase genes as well as other genes included in the ars gene cluster (possible regulator gene, arsR, and arsenite extrusion genes, arsA, acr3, and arsD) are transcriptionally induced when BCP1 cells were exposed to As(V) supplied at two different sub-lethal concentrations. This work provides for the first time insights into the arsenic resistance mechanisms of a Rhodococcus strain, revealing some of the unique metabolic requirements for the environmental persistence of this bacterial genus and its possible use in bioremediation procedures of toxic metal contaminated sites.
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Affiliation(s)
- Andrea Firrincieli
- Department for the Innovation in Biological Systems, Agro-Food and Forestry, University of Tuscia, Viterbo, Italy
| | - Alessandro Presentato
- Department of Biotechnology, University of Verona, Verona, Italy.,Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Giusi Favoino
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Rosita Marabottini
- Department for the Innovation in Biological Systems, Agro-Food and Forestry, University of Tuscia, Viterbo, Italy
| | - Enrica Allevato
- Department for the Innovation in Biological Systems, Agro-Food and Forestry, University of Tuscia, Viterbo, Italy
| | - Silvia Rita Stazi
- Department for the Innovation in Biological Systems, Agro-Food and Forestry, University of Tuscia, Viterbo, Italy
| | - Giuseppe Scarascia Mugnozza
- Department for the Innovation in Biological Systems, Agro-Food and Forestry, University of Tuscia, Viterbo, Italy
| | - Antoine Harfouche
- Department for the Innovation in Biological Systems, Agro-Food and Forestry, University of Tuscia, Viterbo, Italy
| | - Maurizio Petruccioli
- Department for the Innovation in Biological Systems, Agro-Food and Forestry, University of Tuscia, Viterbo, Italy
| | - Raymond J Turner
- Department of Biological Sciences, University of Calgary, Calgary, AB, Canada
| | - Davide Zannoni
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
| | - Martina Cappelletti
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna, Italy
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Hwang C, Copeland A, Lucas S, Lapidus A, Barry K, Detter JC, Glavina Del Rio T, Hammon N, Israni S, Dalin E, Tice H, Pitluck S, Chertkov O, Brettin T, Bruce D, Han C, Schmutz J, Larimer F, Land ML, Hauser L, Kyrpides N, Mikhailova N, Ye Q, Zhou J, Richardson P, Fields MW. Complete Genome Sequence of Alkaliphilus metalliredigens Strain QYMF, an Alkaliphilic and Metal-Reducing Bacterium Isolated from Borax-Contaminated Leachate Ponds. GENOME ANNOUNCEMENTS 2016; 4:e01226-16. [PMID: 27811105 PMCID: PMC5095475 DOI: 10.1128/genomea.01226-16] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 09/12/2016] [Indexed: 11/20/2022]
Abstract
Alkaliphilus metalliredigens strain QYMF is an anaerobic, alkaliphilic, and metal-reducing bacterium associated with phylum Firmicutes QYMF was isolated from alkaline borax leachate ponds. The genome sequence will help elucidate the role of metal-reducing microorganisms under alkaline environments, a capability that is not commonly observed in metal respiring-microorganisms.
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Affiliation(s)
- C Hwang
- Center for Biofilm Engineering, Montana State University, Bozeman, Montana, USA
| | - A Copeland
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - S Lucas
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - A Lapidus
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - K Barry
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - J C Detter
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | | | - N Hammon
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - S Israni
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - E Dalin
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - H Tice
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - S Pitluck
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - O Chertkov
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - T Brettin
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - D Bruce
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - C Han
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - J Schmutz
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - F Larimer
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - M L Land
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - L Hauser
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - N Kyrpides
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - N Mikhailova
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - Q Ye
- State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai, China
| | - J Zhou
- University of Oklahoma, Department of Microbiology and Plant Biology, Norman, Oklahoma, USA
| | - P Richardson
- DOE Joint Genome Institute, Walnut Creek, California, USA
| | - M W Fields
- Department of Microbiology and Immunology, Montana State University, Bozeman, Montana, USA
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5
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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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6
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Zheng W, Scifleet J, Yu X, Jiang T, Zhang R. Function of arsATorf7orf8 of Bacillus sp. CDB3 in arsenic resistance. J Environ Sci (China) 2013; 25:1386-1392. [PMID: 24218851 DOI: 10.1016/s1001-0742(12)60154-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Bacillus sp. CDB3 isolated from an arsenic contaminated cattle dip site possesses an uncommon arsenic resistance (ars) operon bearing eight genes in the order of arsRYCDATorf7orf8. We investigated the functions of arsA, arsT, orf7 and orf8 in arsenic resistance using a plasmid-based gene knockout approach in the ars gene deficient Escherichia coli strain AW3110. The CDB3 arsA gene was shown to play a significant role in resistance, suggesting that the encoded ArsA may couple with the arsenite transporter, forming an ArsAY complex that can enhance arsenite extrusion efficiency. The disruption of either arsTor orf7 was not observed to affect arsenic resistance in the heterologous E. coli host, but their involvement in arsenic resistance can not be excluded. The orf8 gene is predicted to encode a putative dual-specificity protein phosphatase which also shares certain homology to arsenate reductases. The function loss of orf8 resulted in a remarkable decrease in resistance to arsenate, though not arsenite. To examine if this effect was due to the reduction of arsenate by orf8, the arsC gene within the 8-gene operon was disrupted. The resulting abolishment of arsenate resistance suggests that the involvement of orf8 in arsenic resistance is not via reductase activity.
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Affiliation(s)
- Wei Zheng
- State Key Laboratory of Tree Genetics and Breeding, Northeast Forestry University, Harbin 150040, China.
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Hamamura N, Fukushima K, Itai T. Identification of antimony- and arsenic-oxidizing bacteria associated with antimony mine tailing. Microbes Environ 2013; 28:257-63. [PMID: 23666539 PMCID: PMC4070671 DOI: 10.1264/jsme2.me12217] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Antimony (Sb) is a naturally occurring toxic element commonly associated with arsenic (As) in the environment and both elements have similar chemistry and toxicity. Increasing numbers of studies have focused on microbial As transformations, while microbial Sb interactions are still not well understood. To gain insight into microbial roles in the geochemical cycling of Sb and As, soils from Sb mine tailing were examined for the presence of Sb- and As-oxidizing bacteria. After aerobic enrichment culturing with AsIII (10 mM) or SbIII (100 μM), pure cultures of Pseudomonas- and Stenotrophomonas-related isolates with SbIII oxidation activities and a Sinorhizobium-related isolate capable of AsIII oxidation were obtained. The AsIII-oxidizing Sinorhizobium isolate possessed the aerobic arsenite oxidase gene (aioA), the expression of which was induced in the presence of AsIII or SbIII. However, no SbIII oxidation activity was detected from the Sinorhizobium-related isolate, suggesting the involvement of different mechanisms for Sb and As oxidation. These results demonstrate that indigenous microorganisms associated with Sb mine soils are capable of Sb and As oxidation, and potentially contribute to the speciation and mobility of Sb and As in situ.
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Affiliation(s)
- Natsuko Hamamura
- Center for Marine Environmental Studies, Ehime University, Matsuyama 790–8577, Japan.
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8
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Villadangos AF, Fu HL, Gil JA, Messens J, Rosen BP, Mateos LM. Efflux permease CgAcr3-1 of Corynebacterium glutamicum is an arsenite-specific antiporter. J Biol Chem 2011; 287:723-735. [PMID: 22102279 DOI: 10.1074/jbc.m111.263335] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Resistance to arsenite (As(III)) by cells is generally accomplished by arsenite efflux permeases from Acr3 or ArsB unrelated families. We analyzed the function of three Acr3 proteins from Corynebacterium glutamicum, CgAcr3-1, CgAcr3-2, and CgAcr3-3. CgAcr3-1 conferred the highest level of As(III) resistance and accumulation in vivo. CgAcr3-1 was also the most active when everted membranes vesicles from Escherichia coli or C. glutamicum mutants were assayed for efflux with different energy sources. As(III) and antimonite (Sb(III)) resistance and accumulation studies using E. coli or C. glutamicum arsenite permease mutants clearly show that CgAcr3-1 is specific for As(III). In everted membrane vesicles expressing CgAcr3-1, dissipation of either the membrane potential or the pH gradient of the proton motive force did not prevent As(III) uptake, whereas dissipation of both components eliminated uptake. Further, a mutagenesis study of CgAcr3-1 suggested that a conserved cysteine and glutamate are involved in active transport. Therefore, we propose that CgAcr3-1 is an antiporter that catalyzes arsenite-proton exchange with residues Cys129 and Glu305 involved in efflux.
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Affiliation(s)
- Almudena F Villadangos
- Departamento de Biología Molecular, Área de Microbiología, Facultad de Biología-Ambientales, Universidad de León, 24071 León, Spain
| | - Hsueh-Liang Fu
- Department of Biochemistry and Molecular Biology, Wayne State University School of Medicine, Detroit, Michigan 48201
| | - Jose A Gil
- Departamento de Biología Molecular, Área de Microbiología, Facultad de Biología-Ambientales, Universidad de León, 24071 León, Spain
| | - Joris Messens
- Department of Structural Biology, Vlaams Instituut voor Biotechnologie; Structural Biology Brussels, Vrije Universiteit Brussels, 1050 Brussels, Belgium; Brussels Center for Redox Biology, 1050 Brussels, Belgium
| | - Barry P Rosen
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, Florida 33099.
| | - Luis M Mateos
- Departamento de Biología Molecular, Área de Microbiología, Facultad de Biología-Ambientales, Universidad de León, 24071 León, Spain.
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Ajees AA, Yang J, Rosen BP. The ArsD As(III) metallochaperone. Biometals 2010; 24:391-9. [PMID: 21188475 DOI: 10.1007/s10534-010-9398-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2010] [Accepted: 12/14/2010] [Indexed: 01/19/2023]
Abstract
Arsenic, a toxic metalloid widely existing in the environment, causes a variety of health problems. The ars operon encoded by Escherichia coli plasmid R773 has arsD and arsA genes, where ArsA is an ATPase that is the catalytic subunit of the ArsAB As(III) extrusion pump, and ArsD is an arsenic chaperone for ArsA. ArsD transfers As(III) to ArsA and increases the affinity of ArsA for As(III), allowing resistance to environmental concentrations of arsenic. Cys12, Cys13 and Cys18 in ArsD form a three sulfur-coordinated As(III) binding site that is essential for metallochaperone activity. ATP hydrolysis by ArsA is required for transfer of As(III) from ArsD to ArsA, suggesting that transfer occurs with a conformation of ArsA that transiently forms during the catalytic cycle. The 1.4 Å x-ray crystal structure of ArsD shows a core of four β-strands flanked by four α-helices in a thioredoxin fold. Docking of ArsD with ArsA was modeled in silico. Independently ArsD mutants exhibiting either weaker or stronger interaction with ArsA were selected. The locations of the mutations mapped on the surface of ArsD are consistent with the docking model. The results suggest that the interface with ArsA involves one surface of α1 helix and metalloid binding site of ArsD.
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Affiliation(s)
- A Abdul Ajees
- Department of Cellular Biology and Pharmacology, Herbert Wertheim College of Medicine, Florida International University, Miami, FL 33199, USA
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10
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Castillo R, Saier MH. Functional Promiscuity of Homologues of the Bacterial ArsA ATPases. Int J Microbiol 2010; 2010:187373. [PMID: 20981284 PMCID: PMC2963123 DOI: 10.1155/2010/187373] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2010] [Accepted: 09/07/2010] [Indexed: 11/30/2022] Open
Abstract
The ArsA ATPase of E. coli plays an essential role in arsenic detoxification. Published evidence implicates ArsA in the energization of As(III) efflux via the formation of an oxyanion-translocating complex with ArsB. In addition, eukaryotic ArsA homologues have several recognized functions unrelated to arsenic resistance. By aligning ArsA homologues, constructing phylogenetic trees, examining ArsA encoding operons, and estimating the probable coevolution of these homologues with putative transporters and auxiliary proteins unrelated to ArsB, we provide evidence for new functions for ArsA homologues. They may play roles in carbon starvation, gas vesicle biogenesis, and arsenic resistance. The results lead to the proposal that ArsA homologues energize four distinct and nonhomologous transporters, ArsB, ArsP, CstA, and Acr3.
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Affiliation(s)
- Rostislav Castillo
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
| | - Milton H. Saier
- Division of Biological Sciences, University of California at San Diego, La Jolla, CA 92093-0116, USA
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