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Larson J, Tokmina-Lukaszewska M, Payne D, Spietz RL, Fausset H, Alam MG, Brekke BK, Pauley J, Hasenoehrl EJ, Shepard EM, Boyd ES, Bothner B. Impact of mineral and non-mineral sources of iron and sulfur on the metalloproteome of Methanosarcina barkeri. Appl Environ Microbiol 2024:e0051624. [PMID: 39023267 DOI: 10.1128/aem.00516-24] [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: 03/21/2024] [Accepted: 06/27/2024] [Indexed: 07/20/2024] Open
Abstract
Methanogens often inhabit sulfidic environments that favor the precipitation of transition metals such as iron (Fe) as metal sulfides, including mackinawite (FeS) and pyrite (FeS2). These metal sulfides have historically been considered biologically unavailable. Nonetheless, methanogens are commonly cultivated with sulfide (HS-) as a sulfur source, a condition that would be expected to favor metal precipitation and thus limit metal availability. Recent studies have shown that methanogens can access Fe and sulfur (S) from FeS and FeS2 to sustain growth. As such, medium supplied with FeS2 should lead to higher availability of transition metals when compared to medium supplied with HS-. Here, we examined how transition metal availability under sulfidic (i.e., cells provided with HS- as sole S source) versus non-sulfidic (cells provided with FeS2 as sole S source) conditions impact the metalloproteome of Methanosarcina barkeri Fusaro. To achieve this, we employed size exclusion chromatography coupled with inductively coupled plasma mass spectrometry and shotgun proteomics. Significant changes were observed in the composition and abundance of iron, cobalt, nickel, zinc, and molybdenum proteins. Among the differences were alterations in the stoichiometry and abundance of multisubunit protein complexes involved in methanogenesis and electron transport chains. Our data suggest that M. barkeri utilizes the minimal iron-sulfur cluster complex and canonical cysteine biosynthesis proteins when grown on FeS2 but uses the canonical Suf pathway in conjunction with the tRNA-Sep cysteine pathway for iron-sulfur cluster and cysteine biosynthesis under sulfidic growth conditions.IMPORTANCEProteins that catalyze biochemical reactions often require transition metals that can have a high affinity for sulfur, another required element for life. Thus, the availability of metals and sulfur are intertwined and can have large impacts on an organismismal biochemistry. Methanogens often occupy anoxic, sulfide-rich (euxinic) environments that favor the precipitation of transition metals as metal sulfides, thereby creating presumed metal limitation. Recently, several methanogens have been shown to acquire iron and sulfur from pyrite, an abundant iron-sulfide mineral that was traditionally considered to be unavailable to biology. The work presented here provides new insights into the distribution of metalloproteins, and metal uptake of Methanosarcina barkeri Fusaro grown under euxinic or pyritic growth conditions. Thorough characterizations of this methanogen under different metal and sulfur conditions increase our understanding of the influence of metal availability on methanogens, and presumably other anaerobes, that inhabit euxinic environments.
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Affiliation(s)
- James Larson
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | | | - Devon Payne
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Rachel L Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Hunter Fausset
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Md Gahangir Alam
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Brooklyn K Brekke
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Jordan Pauley
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Ethan J Hasenoehrl
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Eric M Shepard
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
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Fausset H, Spietz RL, Cox S, Cooper G, Spurzem S, Tokmina-Lukaszewska M, DuBois J, Broderick JB, Shepard EM, Boyd ES, Bothner B. A shift between mineral and nonmineral sources of iron and sulfur causes proteome-wide changes in Methanosarcina barkeri. Microbiol Spectr 2024; 12:e0041823. [PMID: 38179920 PMCID: PMC10846266 DOI: 10.1128/spectrum.00418-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 11/30/2023] [Indexed: 01/06/2024] Open
Abstract
Iron (Fe) and sulfur (S) are required elements for life, and changes in their availability can limit the ecological distribution and function of microorganisms. In anoxic environments, soluble Fe typically exists as ferrous iron [Fe(II)] and S as sulfide (HS-). These species exhibit a strong affinity that ultimately drives the formation of sedimentary pyrite (FeS2). Recently, paradigm-shifting studies indicate that Fe and S in FeS2 can be made bioavailable by methanogens through a reductive dissolution process. However, the impact of the utilization of FeS2, as opposed to canonical Fe and S sources, on the phenotype of cells is not fully understood. Here, shotgun proteomics was utilized to measure changes in the phenotype of Methanosarcina barkeri MS grown with FeS2, Fe(II)/HS-, or Fe(II)/cysteine. Shotgun proteomics tracked 1,019 proteins overall, with 307 observed to change between growth conditions. Functional characterization and pathway analyses revealed these changes to be systemic and largely tangential to Fe/S metabolism. As a final step, the proteomics data were viewed with respect to previously collected transcriptomics data to deepen the analysis. Presented here is evidence that M. barkeri adopts distinct phenotypes to exploit specific sources of Fe and S in its environment. This is supported by observed protein abundance changes across broad categories of cellular biology. DNA adjacent metabolism, central carbon metabolism methanogenesis, metal trafficking, quorum sensing, and porphyrin biosynthesis pathways are all features in the phenotypic differentiation. Differences in trace metal availability attributed to complexation with HS-, either as a component of the growth medium [Fe(II)/HS-] or generated through reduction of FeS2, were likely a major factor underpinning these phenotypic differences.IMPORTANCEThe methanogenic archaeon Methanosarcina barkeri holds great potential for industrial bio-mining and energy generation technologies. Much of the biochemistry of this microbe is poorly understood, and its characterization will provide a glimpse into biological processes that evolved close to life's origin. The discovery of its ability to extract iron and sulfur from bulk, solid-phase minerals shifted a longstanding paradigm that these elements were inaccessible to biological systems. The full elucidation of this process has the potential to help scientists and engineers extract valuable metals from low-grade ore and mine waste generating energy in the form of methane while doing so.
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Affiliation(s)
- Hunter Fausset
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Rachel L. Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Savannah Cox
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Gwendolyn Cooper
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Scott Spurzem
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | | | - Jennifer DuBois
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Joan B. Broderick
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Eric M. Shepard
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
| | - Eric S. Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Brian Bothner
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, Montana, USA
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Kour M, Taborosi A, Boyd ES, Szilagyi RK. Development of molecular cluster models to probe pyrite surface reactivity. J Comput Chem 2023; 44:2486-2500. [PMID: 37650712 DOI: 10.1002/jcc.27213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2023] [Revised: 07/28/2023] [Accepted: 08/09/2023] [Indexed: 09/01/2023]
Abstract
The recent discovery that anaerobic methanogens can reductively dissolve pyrite and utilize dissolution products as a source of iron and sulfur to meet their biosynthetic demands for these elements prompted the development of atomic-scale nanoparticle models, as maquettes of reactive surface sites, for describing the fundamental redox steps that take place at the mineral surface during reduction. The given report describes our computational approach for modeling n(FeS2 ) nanoparticles originated from mineral bulk structure. These maquettes contain a comprehensive set of coordinatively unsaturated Fe(II) sites that are connected via a range of persulfide (S2 2- ) ligation. In addition to the specific maquettes with n = 8, 18, and 32 FeS2 units, we established guidelines for obtaining low-energy structures by considering the pattern of ionic, covalent, and magnetic interactions among the metal and ligand sites. The developed models serve as computational nano-reactors that can be used to describe the reductive dissolution mechanism of pyrite to better understand the reactive sites on the mineral, where microbial extracellular electron-transfer reactions can occur.
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Affiliation(s)
- Manjinder Kour
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Attila Taborosi
- Research Initiative for Supra-Materials, Faculty of Engineering, Shinshu University, Nagano, Japan
| | - Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Robert K Szilagyi
- Department of Chemistry, The University of British Columbia, Okanagan, Kelowna, British Columbia, Canada
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Chen J, Bai Q, Li Y, Liu Z, Li Y, Liang D. Coacervates Forming Coexisting Phases on a Mineral Surface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5814-5824. [PMID: 37053474 DOI: 10.1021/acs.langmuir.3c00101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Minerals played a crucial role in the chemical evolution of small molecules into biopolymers. Yet, it is still not clear how the minerals are related to the formation and the evolution of protocells on early Earth. In this work, using the coacervate formed by quaternized dextran (Q-dextran) and single-stranded oligonucleotides (ss-oligo) as the protocell model, we systematically studied the phase separation of Q-dextran and ss-oligo on the muscovite surface. Serving as rigid and 2D polyelectrolytes, the muscovite surface can be treated by Q-dextran to become negatively charged, neutral, or positively charged. We observed that Q-dextran and ss-oligo form uniform coacervates on naked and neutral muscovite surfaces, while they form biphasic coacervates containing Q-dextran-rich phases and ss-oligo-rich phases on positively or negatively charged muscovite surfaces that were pretreated by Q-dextran. The evolution of the phases is caused by the redistribution of the components as the coacervate touches the surface. Our study indicates that the mineral surface could be a potential driving force for the formation of protocells with hierarchical structures and desirable functions on prebiotic Earth.
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Affiliation(s)
- Jiaxin Chen
- Beijing National Laboratory for Molecular Sciences, and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Qingwen Bai
- Beijing National Laboratory for Molecular Sciences, and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Yanzhang Li
- Beijing Key Laboratory of Mineral Environmental Function, and the Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Science, Peking University, Beijing 100871, China
| | - Zhijun Liu
- Beijing National Laboratory for Molecular Sciences, and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
| | - Yan Li
- Beijing Key Laboratory of Mineral Environmental Function, and the Key Laboratory of Orogenic Belts and Crustal Evolution, School of Earth and Space Science, Peking University, Beijing 100871, China
| | - Dehai Liang
- Beijing National Laboratory for Molecular Sciences, and the Key Laboratory of Polymer Chemistry and Physics of the Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China
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Boyd ES, Spietz RL, Kour M, Colman DR. A naturalist perspective of microbiology: Examples from methanogenic archaea. Environ Microbiol 2023; 25:184-198. [PMID: 36367391 DOI: 10.1111/1462-2920.16285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2022] [Accepted: 11/09/2022] [Indexed: 11/13/2022]
Abstract
Storytelling has been the primary means of knowledge transfer over human history. The effectiveness and reach of stories are improved when the message is appropriate for the target audience. Oftentimes, the stories that are most well received and recounted are those that have a clear purpose and that are told from a variety of perspectives that touch on the varied interests of the target audience. Whether scientists realize or not, they are accustomed to telling stories of their own scientific discoveries through the preparation of manuscripts, presentations, and lectures. Perhaps less frequently, scientists prepare review articles or book chapters that summarize a body of knowledge on a given subject matter, meant to be more holistic recounts of a body of literature. Yet, by necessity, such summaries are often still narrow in their scope and are told from the perspective of a particular discipline. In other words, interdisciplinary reviews or book chapters tend to be the rarity rather than the norm. Here, we advocate for and highlight the benefits of interdisciplinary perspectives on microbiological subjects.
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Affiliation(s)
- Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Rachel L Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Manjinder Kour
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
| | - Daniel R Colman
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, Montana, USA
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Spietz RL, Payne D, Szilagyi R, Boyd ES. Reductive biomining of pyrite by methanogens. Trends Microbiol 2022; 30:1072-1083. [PMID: 35624031 DOI: 10.1016/j.tim.2022.05.005] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Revised: 05/05/2022] [Accepted: 05/06/2022] [Indexed: 01/13/2023]
Abstract
Pyrite (FeS2) is the most abundant iron sulfide mineral in Earth's crust. Until recently, FeS2 has been considered a sink for iron (Fe) and sulfur (S) at low temperature in the absence of oxygen or oxidative weathering, making these elements unavailable to biology. However, anaerobic methanogens can transfer electrons extracellularly to reduce FeS2 via direct contact with the mineral. Reduction of FeS2 occurs through a multistep process that generates aqueous sulfide (HS-) and FeS2-associated pyrrhotite (Fe1-xS). Subsequent dissolution of Fe1-xS provides Fe(II)(aq), but not HS-, that rapidly complexes with HS-(aq) generated from FeS2 reduction to form soluble iron sulfur clusters [nFeS(aq)]. Cells assimilate nFeS(aq) to meet Fe/S nutritional demands by mobilizing and hyperaccumulating Fe and S from FeS2. As such, reductive dissolution of FeS2 by methanogens has important implications for element cycling in anoxic habitats, both today and in the geologic past.
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Affiliation(s)
- Rachel L Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Devon Payne
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA
| | - Robert Szilagyi
- Department of Chemistry, University of British Columbia - Okanagan, Kelowna, BC V1V 1V7, Canada
| | - Eric S Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT 59717, USA.
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Abstract
Covering: up to 2022The report provides a broad approach to deciphering the evolution of coenzyme biosynthetic pathways. Here, these various pathways are analyzed with respect to the coenzymes required for this purpose. Coenzymes whose biosynthesis relies on a large number of coenzyme-mediated reactions probably appeared on the scene at a later stage of biological evolution, whereas the biosyntheses of pyridoxal phosphate (PLP) and nicotinamide (NAD+) require little additional coenzymatic support and are therefore most likely very ancient biosynthetic pathways.
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Affiliation(s)
- Andreas Kirschning
- Institute of Organic Chemistry, Leibniz University Hannover, Schneiderberg 1B, D-30167 Hannover, Germany.
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8
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Spietz RL, Payne D, Kulkarni G, Metcalf WW, Roden EE, Boyd ES. Investigating Abiotic and Biotic Mechanisms of Pyrite Reduction. Front Microbiol 2022; 13:878387. [PMID: 35615515 PMCID: PMC9124975 DOI: 10.3389/fmicb.2022.878387] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Accepted: 03/31/2022] [Indexed: 11/16/2022] Open
Abstract
Pyrite (FeS2) has a very low solubility and therefore has historically been considered a sink for iron (Fe) and sulfur (S) and unavailable to biology in the absence of oxygen and oxidative weathering. Anaerobic methanogens were recently shown to reduce FeS2 and assimilate Fe and S reduction products to meet nutrient demands. However, the mechanism of FeS2 mineral reduction and the forms of Fe and S assimilated by methanogens remained unclear. Thermodynamic calculations described herein indicate that H2 at aqueous concentrations as low as 10-10 M favors the reduction of FeS2, with sulfide (HS-) and pyrrhotite (Fe1- x S) as products; abiotic laboratory experiments confirmed the reduction of FeS2 with dissolved H2 concentrations greater than 1.98 × 10-4 M H2. Growth studies of Methanosarcina barkeri provided with FeS2 as the sole source of Fe and S resulted in H2 production but at concentrations too low to drive abiotic FeS2 reduction, based on abiotic laboratory experimental data. A strain of M. barkeri with deletions in all [NiFe]-hydrogenases maintained the ability to reduce FeS2 during growth, providing further evidence that extracellular electron transport (EET) to FeS2 does not involve H2 or [NiFe]-hydrogenases. Physical contact between cells and FeS2 was required for mineral reduction but was not required to obtain Fe and S from dissolution products. The addition of a synthetic electron shuttle, anthraquinone-2,6-disulfonate, allowed for biological reduction of FeS2 when physical contact between cells and FeS2 was prohibited, indicating that exogenous electron shuttles can mediate FeS2 reduction. Transcriptomics experiments revealed upregulation of several cytoplasmic oxidoreductases during growth of M. barkeri on FeS2, which may indicate involvement in provisioning low potential electrons for EET to FeS2. Collectively, the data presented herein indicate that reduction of insoluble FeS2 by M. barkeri occurred via electron transfer from the cell surface to the mineral surface resulting in the generation of soluble HS- and mineral-associated Fe1- x S. Solubilized Fe(II), but not HS-, from mineral-associated Fe1- x S reacts with aqueous HS- yielding aqueous iron sulfur clusters (FeS aq ) that likely serve as the Fe and S source for methanogen growth and activity. FeS aq nucleation and subsequent precipitation on the surface of cells may result in accelerated EET to FeS2, resulting in positive feedback between cell activity and FeS2 reduction.
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Affiliation(s)
- Rachel L. Spietz
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Devon Payne
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
| | - Gargi Kulkarni
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - William W. Metcalf
- Department of Microbiology, University of Illinois at Urbana-Champaign, Urbana, IL, United States
| | - Eric E. Roden
- Department of Geosciences, University of Wisconsin, Madison, WI, United States
| | - Eric S. Boyd
- Department of Microbiology and Cell Biology, Montana State University, Bozeman, MT, United States
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Akinyemi TS, Shao N, Lyu Z, Drake IJ, Liu Y, Whitman WB. Tuning Gene Expression by Phosphate in the Methanogenic Archaeon Methanococcus maripaludis. ACS Synth Biol 2021; 10:3028-3039. [PMID: 34665610 DOI: 10.1021/acssynbio.1c00322] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Methanococcus maripaludis is a rapidly growing, hydrogenotrophic, and genetically tractable methanogen with unique capabilities to convert formate and CO2 to CH4. The existence of genome-scale metabolic models and an established, robust system for both large-scale and continuous cultivation make it amenable for industrial applications. However, the lack of molecular tools for differential gene expression has hindered its application as a microbial cell factory to produce biocatalysts and biochemicals. In this study, a library of differentially regulated promoters was designed and characterized based on the pst promoter, which responds to the inorganic phosphate concentration in the growth medium. Gene expression increases by 4- to 6-fold when the medium phosphate drops to growth-limiting concentrations. Hence, this regulated system decouples growth from heterologous gene expression without the need for adding an inducer. The minimal pst promoter is identified and contains a conserved AT-rich region, a factor B recognition element, and a TATA box for phosphate-dependent regulation. Rational changes to the factor B recognition element and start codon had no significant impact on expression; however, changes to the transcription start site and the 5' untranslated region resulted in the differential protein production with regulation remaining intact. Compared to a previous expression system based upon the histone promoter, this regulated expression system resulted in significant improvements in the expression of a key methanogenic enzyme complex, methyl-coenzyme M reductase, and the potentially toxic arginine methyltransferase MmpX.
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Affiliation(s)
- Taiwo S. Akinyemi
- Department of Microbiology, University of Georgia, Athens, Georgia 30602, United States
| | - Nana Shao
- Department of Microbiology, University of Georgia, Athens, Georgia 30602, United States
| | - Zhe Lyu
- Department of Molecular Virology and Microbiology, Baylor College of Medicine, Houston, Texas 77030, United States
| | - Ian J. Drake
- Corporate Strategic Research, ExxonMobil Research & Engineering Company, Annandale, New Jersey 08801, United States
| | - Yuchen Liu
- Corporate Strategic Research, ExxonMobil Research & Engineering Company, Annandale, New Jersey 08801, United States
| | - William B. Whitman
- Department of Microbiology, University of Georgia, Athens, Georgia 30602, United States
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Pathways of Iron and Sulfur Acquisition, Cofactor Assembly, Destination, and Storage in Diverse Archaeal Methanogens and Alkanotrophs. J Bacteriol 2021; 203:e0011721. [PMID: 34124941 PMCID: PMC8351635 DOI: 10.1128/jb.00117-21] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Abstract
Archaeal methanogens, methanotrophs, and alkanotrophs have a high demand for iron (Fe) and sulfur (S); however, little is known of how they acquire, traffic, deploy, and store these elements. Here, we examined the distribution of homologs of proteins mediating key steps in Fe/S metabolism in model microorganisms, including iron(II) sensing/uptake (FeoAB), sulfide extraction from cysteine (SufS), and the biosynthesis of iron-sulfur [Fe-S] clusters (SufBCDE), siroheme (Pch2 dehydrogenase), protoheme (AhbABCD), cytochrome c (Cyt c) (CcmCF), and iron storage/detoxification (Bfr, FtrA, and IssA), among 326 publicly available, complete or metagenome-assembled genomes of archaeal methanogens/methanotrophs/alkanotrophs. The results indicate several prevalent but nonuniversal features, including FeoB, SufBC, and the biosynthetic apparatus for the basic tetrapyrrole scaffold, as well as its siroheme (and F430) derivatives. However, several early-diverging genomes lacked SufS and pathways to synthesize and deploy heme. Genomes encoding complete versus incomplete heme biosynthetic pathways exhibited equivalent prevalences of [Fe-S] cluster binding proteins, suggesting an expansion of catalytic capabilities rather than substitution of heme for [Fe-S] in the former group. Several strains with heme binding proteins lacked heme biosynthesis capabilities, while other strains with siroheme biosynthesis capability lacked homologs of known siroheme binding proteins, indicating heme auxotrophy and unknown siroheme biochemistry, respectively. While ferritin proteins involved in ferric oxide storage were widespread, those involved in storing Fe as thioferrate were unevenly distributed. Collectively, the results suggest that differences in the mechanisms of Fe and S acquisition, deployment, and storage have accompanied the diversification of methanogens/methanotrophs/alkanotrophs, possibly in response to differential availability of these elements as these organisms evolved. IMPORTANCE Archaeal methanogens, methanotrophs, and alkanotrophs, argued to be among the most ancient forms of life, have a high demand for iron (Fe) and sulfur (S) for cofactor biosynthesis, among other uses. Here, using comparative bioinformatic approaches applied to 326 genomes, we show that major differences in Fe/S acquisition, trafficking, deployment, and storage exist in this group. Variation in these characters was generally congruent with the phylogenetic placement of these genomes, indicating that variation in Fe/S usage and deployment has contributed to the diversification and ecology of these organisms. However, incongruency was observed among the distribution of cofactor biosynthesis pathways and known protein destinations for those cofactors, suggesting auxotrophy or yet-to-be-discovered pathways for cofactor biosynthesis.
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Altair T, Borges LGF, Galante D, Varela H. Experimental Approaches for Testing the Hypothesis of the Emergence of Life at Submarine Alkaline Vents. Life (Basel) 2021; 11:777. [PMID: 34440521 PMCID: PMC8401828 DOI: 10.3390/life11080777] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/21/2021] [Accepted: 07/28/2021] [Indexed: 11/17/2022] Open
Abstract
Since the pioneering experimental work performed by Urey and Miller around 70 years ago, several experimental works have been developed for approaching the question of the origin of life based on very few well-constructed hypotheses. In recent years, attention has been drawn to the so-called alkaline hydrothermal vents model (AHV model) for the emergence of life. Since the first works, perspectives from complexity sciences, bioenergetics and thermodynamics have been incorporated into the model. Consequently, a high number of experimental works from the model using several tools have been developed. In this review, we present the key concepts that provide a background for the AHV model and then analyze the experimental approaches that were motivated by it. Experimental tools based on hydrothermal reactors, microfluidics and chemical gardens were used for simulating the environments of early AHVs on the Hadean Earth (~4.0 Ga). In addition, it is noteworthy that several works used techniques from electrochemistry to investigate phenomena in the vent-ocean interface for early AHVs. Their results provided important parameters and details that are used for the evaluation of the plausibility of the AHV model, and for the enhancement of it.
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Affiliation(s)
- Thiago Altair
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos 13560-970, Brazil
| | - Luiz G. F. Borges
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (L.G.F.B.); (D.G.)
| | - Douglas Galante
- Brazilian Synchrotron Light Laboratory (LNLS), Brazilian Center for Research in Energy and Materials (CNPEM), Campinas 13083-100, Brazil; (L.G.F.B.); (D.G.)
| | - Hamilton Varela
- São Carlos Institute of Chemistry, University of São Paulo, São Carlos 13560-970, Brazil
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12
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Examining pathways of iron and sulfur acquisition, trafficking, deployment, and storage in mineral-grown methanogen cells. J Bacteriol 2021; 203:e0014621. [PMID: 34251867 PMCID: PMC8516115 DOI: 10.1128/jb.00146-21] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Methanogens have a high demand for iron (Fe) and sulfur (S); however, little is known of how they acquire, deploy, and store these elements and how this, in turn, affects their physiology. Methanogens were recently shown to reduce pyrite (FeS2) generating aqueous iron-sulfide (FeS(aq)) clusters that are likely assimilated as a source of Fe and S. Here, we compare the phenotype of Methanococcus voltae when grown with FeS2 or ferrous iron (Fe(II)) and sulfide (HS-). FeS2-grown cells are 33% smaller yet have 193% more Fe than Fe(II)/HS--grown cells. Whole cell EPR revealed similar distributions of paramagnetic Fe, although FeS2-grown cells showed a broad spectral feature attributed to intracellular thioferrate-like nanoparticles. Differential proteomic analyses showed similar expression of core methanogenesis enzymes, indicating that Fe and S source does not substantively alter the energy metabolism of cells. However, a homolog of the Fe(II) transporter FeoB and its putative transcriptional regulator DtxR were up-expressed in FeS2-grown cells, suggesting that cells sense Fe(II) limitation. Two homologs of IssA, a protein putatively involved in coordinating thioferrate nanoparticles, were also up-expressed in FeS2-grown cells. We interpret these data to indicate that, in FeS2-grown cells, DtxR cannot sense Fe(II) and therefore cannot down-regulate FeoB. We suggest this is due to the transport of Fe(II) complexed with sulfide (FeS(aq)) leading to excess Fe that is sequestered by IssA as a thioferrate-like species. This model provides a framework for the design of targeted experiments aimed at further characterizing Fe acquisition and homeostasis in M. voltae and other methanogens. IMPORTANCE FeS2 is the most abundant sulfide mineral in the Earth's crust and is common in environments inhabited by methanogenic archaea. FeS2 can be reduced by methanogens, yielding aqueous FeS(aq) clusters that are thought to be a source of Fe and S. Here, we show that growth of Methanococcus voltae on FeS2 results in smaller cell size and higher Fe content per cell, with Fe likely stored intracellularly as thioferrate-like nanoparticles. Fe(II) transporters and storage proteins were up-regulated in FeS2-grown cells. These responses are interpreted to result from cells incorrectly sensing Fe(II) limitation due to assimilation of Fe(II) as FeS(aq). These findings have implications for our understanding of how Fe/S availability influences methanogen physiology and the biogeochemical cycling of these elements.
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13
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Reductive dissolution of pyrite by methanogenic archaea. ISME JOURNAL 2021; 15:3498-3507. [PMID: 34112969 PMCID: PMC8630215 DOI: 10.1038/s41396-021-01028-3] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 05/10/2021] [Accepted: 05/27/2021] [Indexed: 11/21/2022]
Abstract
The formation and fate of pyrite (FeS2) modulates global iron, sulfur, carbon, and oxygen biogeochemical cycles and has done so since early in Earth’s geological history. A longstanding paradigm is that FeS2 is stable at low temperature and is unavailable to microorganisms in the absence of oxygen and oxidative weathering. Here, we show that methanogens can catalyze the reductive dissolution of FeS2 at low temperature (≤38 °C) and utilize dissolution products to meet cellular iron and sulfur demands associated with the biosynthesis of simple and complex co-factors. Direct access to FeS2 is required to catalyze its reduction and/or to assimilate iron monosulfide that likely forms through coupled reductive dissolution and precipitation, consistent with close associations observed between cells and FeS2. These findings demonstrate that FeS2 is bioavailable to anaerobic methanogens and can be mobilized in low temperature anoxic environments. Given that methanogens evolved at least 3.46 Gya, these data indicate that the microbial contribution to the iron and sulfur cycles in ancient and contemporary anoxic environments may be more complex and robust than previously recognized, with impacts on the sources and sinks of iron and sulfur and other bio-essential and thiophilic elements such as nickel and cobalt.
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14
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Deere TM, Prakash D, Lessner FH, Duin EC, Lessner DJ. Methanosarcina acetivorans contains a functional ISC system for iron-sulfur cluster biogenesis. BMC Microbiol 2020; 20:323. [PMID: 33096982 PMCID: PMC7585200 DOI: 10.1186/s12866-020-02014-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 10/15/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The production of methane by methanogens is dependent on numerous iron-sulfur (Fe-S) cluster proteins; yet, the machinery involved in Fe-S cluster biogenesis in methanogens remains largely unknown. Methanogen genomes encode uncharacterized homologs of the core components of the ISC (IscS and IscU) and SUF (SufBC) Fe-S cluster biogenesis systems found in bacteria and eukaryotes. Methanosarcina acetivorans contains three iscSU and two sufCB gene clusters. Here, we report genetic and biochemical characterization of M. acetivorans iscSU2. RESULTS Purified IscS2 exhibited pyridoxal 5'- phosphate-dependent release of sulfur from L-cysteine. Incubation of purified IscU2 with IscS2, cysteine, and iron (Fe2+) resulted in the formation of [4Fe-4S] clusters in IscU2. IscU2 transferred a [4Fe-4S] cluster to purified M. acetivorans apo-aconitase. IscU2 also restored the aconitase activity in air-exposed M. acetivorans cell lysate. These biochemical results demonstrate that IscS2 is a cysteine desulfurase and that IscU2 is a Fe-S cluster scaffold. M. acetivorans strain DJL60 deleted of iscSU2 was generated to ascertain the in vivo importance of IscSU2. Strain DJL60 had Fe-S cluster content and growth similar to the parent strain but lower cysteine desulfurase activity. Strain DJL60 also had lower intracellular persulfide content compared to the parent strain when cysteine was an exogenous sulfur source, linking IscSU2 to sulfur metabolism. CONCLUSIONS This study establishes that M. acetivorans contains functional IscS and IscU, the core components of the ISC Fe-S cluster biogenesis system and provides the first evidence that ISC operates in methanogens.
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Affiliation(s)
- Thomas M Deere
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, AR, 72701, USA
| | - Divya Prakash
- Department of Biochemistry and Molecular Biology, The Pennsylvania State University, University Park, PA, 16802, USA
| | - Faith H Lessner
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, AR, 72701, USA
| | - Evert C Duin
- Department of Chemistry and Biochemistry, Auburn University, Auburn, AL, 36849, USA
| | - Daniel J Lessner
- Department of Biological Sciences, University of Arkansas-Fayetteville, Fayetteville, AR, 72701, USA.
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15
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Boyd ES, Amenabar MJ, Poudel S, Templeton AS. Bioenergetic constraints on the origin of autotrophic metabolism. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2020; 378:20190151. [PMID: 31902344 PMCID: PMC7015307 DOI: 10.1098/rsta.2019.0151] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 10/02/2019] [Indexed: 06/07/2023]
Abstract
Autotrophs form the base of all complex food webs and seemingly have done so since early in Earth history. Phylogenetic evidence suggests that early autotrophs were anaerobic, used CO2 as both an oxidant and carbon source, were dependent on H2 as an electron donor, and used iron-sulfur proteins (termed ferredoxins) as a primary electron carrier. However, the reduction potential of H2 is not typically low enough to efficiently reduce ferredoxin. Instead, in modern strictly anaerobic and H2-dependent autotrophs, ferredoxin reduction is accomplished using one of several recently evolved enzymatic mechanisms, including electron bifurcating and coupled ion translocating mechanisms. These observations raise the intriguing question of why anaerobic autotrophs adopted ferredoxins as central electron carriers only to have to evolve complex machinery to reduce them. Here, we report calculated reduction potentials for H2 as a function of observed environmental H2 concentration, pH and temperature. Results suggest that a combination of alkaline pH and high H2 concentration yield H2 reduction potentials low enough to efficiently reduce ferredoxins. Hyperalkaline, H2 rich environments have existed in discrete locations throughout Earth history where ultramafic minerals are undergoing hydration through the process of serpentinization. These results suggest that serpentinizing systems, which would have been common on early Earth, naturally produced conditions conducive to the emergence of H2-dependent autotrophic life. The primitive process of hydrogenotrophic methanogenesis is used to examine potential changes in methanogenesis and Fd reduction pathways as these organisms diversified away from serpentinizing environments. This article is part of a discussion meeting issue 'Serpentinite in the earth system'.
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Affiliation(s)
- Eric S. Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | | | - Saroj Poudel
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, USA
| | - Alexis S. Templeton
- Department of Geological Sciences, University of Colorado, Boulder, CO 80309, USA
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16
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Lyu Z, Lu Y. Metabolic shift at the class level sheds light on adaptation of methanogens to oxidative environments. ISME JOURNAL 2017; 12:411-423. [PMID: 29135970 PMCID: PMC5776455 DOI: 10.1038/ismej.2017.173] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 07/31/2017] [Accepted: 08/09/2017] [Indexed: 11/09/2022]
Abstract
Methanogens have long been considered strictly anaerobic and oxygen-sensitive microorganisms, but their ability to survive oxygen stress has also been documented. Indeed, methanogens have been found in oxidative environments, and antioxidant genes have been detected in their genomes. How methanogens adapt to oxidative environments, however, remain poorly understood. Here, we systematically predicted and annotated antioxidant features from representative genomes across six well-established methanogen orders. Based on functional gene content involved in production of reactive oxygen species, Hierarchical Clustering analyses grouped methanogens into two distinct clusters, corresponding to the Class I and II methanogens, respectively. Comparative genomics suggested a systematic shift in metabolisms across the two classes, resulting in an enrichment of antioxidant features in the Class II. Moreover, meta-analysis of 16 S rRNA gene sequences obtained from EnvDB indicated that members of Class II were more frequently recovered from microaerophilic and even oxic environments than the Class I members. Phylogenomic analysis suggested that the Class I and II methanogens might have evolved before and around the Great Oxygenation Event, respectively. The enrichment of antioxidant features in the Class II methanogens may have played a key role in the adaption of this group to oxidative environments today and historically.
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Affiliation(s)
- Zhe Lyu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, PR China.,Department of Microbiology, University of Georgia, Athens, GA, USA
| | - Yahai Lu
- College of Resources and Environmental Sciences, China Agricultural University, Beijing, PR China.,College of Urban and Environmental Sciences, Peking University, Beijing, PR China
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17
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Jennings ME, Lessner FH, Karr EA, Lessner DJ. The [4Fe-4S] clusters of Rpo3 are key determinants in the post Rpo3/Rpo11 heterodimer formation of RNA polymerase in Methanosarcina acetivorans. Microbiologyopen 2016; 6. [PMID: 27557794 PMCID: PMC5300874 DOI: 10.1002/mbo3.399] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2016] [Revised: 07/25/2016] [Accepted: 07/28/2016] [Indexed: 11/30/2022] Open
Abstract
Subunits Rpo3 and Rpb3/AC40 of RNA polymerase (RNAP) from many archaea and some eukaryotes, respectively, contain a ferredoxin‐like domain (FLD) predicted to bind one or two [4Fe‐4S] clusters postulated to play a role in regulating the assembly of RNAP. To test this hypothesis, the two [4Fe‐4S] cluster Rpo3 from Methanosarcina acetivorans was modified to generate variants that lack the FLD or each [4Fe‐4S] cluster. Viability of gene replacement mutants revealed that neither the FLD nor the ability of the FLD to bind either [4Fe‐4S] cluster is essential. Nevertheless, each mutant demonstrated impaired growth due to significantly lower RNAP activity when compared to wild type. Affinity purification of tagged Rpo3 variants from M. acetivorans strains revealed that neither the FLD nor each [4Fe‐4S] cluster is required for the formation of a Rpo3/11 heterodimer, the first step in the assembly of RNAP. However, the association of the Rpo3/11 heterodimer with catalytic subunits Rpo2′ and Rpo1″ was diminished by the removal of the FLD and each cluster, with the loss of cluster 1 having a more substantial effect than the loss of cluster 2. These results reveal that the FLD and [4Fe‐4S] clusters, particularly cluster 1, are key determinants in the post Rpo3/11 heterodimer assembly of RNAP in M. acetivorans.
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Affiliation(s)
- Matthew E Jennings
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Faith H Lessner
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
| | - Elizabeth A Karr
- Department of Microbiology and Plant Biology, University of Oklahoma, Norman, OK, USA
| | - Daniel J Lessner
- Department of Biological Sciences, University of Arkansas, Fayetteville, AR, USA
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18
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Chinta KC, Saini V, Glasgow JN, Mazorodze JH, Rahman MA, Reddy D, Lancaster JR, Steyn AJC. The emerging role of gasotransmitters in the pathogenesis of tuberculosis. Nitric Oxide 2016; 59:28-41. [PMID: 27387335 DOI: 10.1016/j.niox.2016.06.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2016] [Accepted: 06/30/2016] [Indexed: 12/17/2022]
Abstract
Mycobacterium tuberculosis (Mtb) is a facultative intracellular pathogen and the second largest contributor to global mortality caused by an infectious agent after HIV. In infected host cells, Mtb is faced with a harsh intracellular environment including hypoxia and the release of nitric oxide (NO) and carbon monoxide (CO) by immune cells. Hypoxia, NO and CO induce a state of in vitro dormancy where Mtb senses these gases via the DosS and DosT heme sensor kinase proteins, which in turn induce a set of ∼47 genes, known as the Mtb Dos dormancy regulon. On the contrary, both iNOS and HO-1, which produce NO and CO, respectively, have been shown to be important against mycobacterial disease progression. In this review, we discuss the impact of O2, NO and CO on Mtb physiology and in host responses to Mtb infection as well as the potential role of another major endogenous gas, hydrogen sulfide (H2S), in Mtb pathogenesis.
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Affiliation(s)
- Krishna C Chinta
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Vikram Saini
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; UAB Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Joel N Glasgow
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA
| | - James H Mazorodze
- KwaZulu-Natal Research Institute for TB and HIV (KRITH), Durban, South Africa
| | - Md Aejazur Rahman
- KwaZulu-Natal Research Institute for TB and HIV (KRITH), Durban, South Africa
| | - Darshan Reddy
- Department of Cardiothoracic Surgery, Nelson R Mandela School of Medicine, University of KwaZulu Natal, Durban, South Africa
| | - Jack R Lancaster
- Department of Pharmacology and Chemical Biology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Adrie J C Steyn
- Department of Microbiology, University of Alabama at Birmingham, Birmingham, AL, USA; KwaZulu-Natal Research Institute for TB and HIV (KRITH), Durban, South Africa; UAB Center for Free Radical Biology, University of Alabama at Birmingham, Birmingham, AL, USA.
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19
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Miller DV, Brown AM, Xu H, Bevan DR, White RH. Purine salvage inMethanocaldococcus jannaschii: Elucidating the role of a conserved cysteine in adenine deaminase. Proteins 2016; 84:828-40. [DOI: 10.1002/prot.25033] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 01/22/2016] [Accepted: 03/06/2016] [Indexed: 12/16/2022]
Affiliation(s)
- Danielle V. Miller
- Department of Biochemistry; Virginia Polytechnic Institute and State University; Blacksburg Virginia 24061
| | - Anne M. Brown
- Department of Biochemistry; Virginia Polytechnic Institute and State University; Blacksburg Virginia 24061
| | - Huimin Xu
- Department of Biochemistry; Virginia Polytechnic Institute and State University; Blacksburg Virginia 24061
| | - David R. Bevan
- Department of Biochemistry; Virginia Polytechnic Institute and State University; Blacksburg Virginia 24061
| | - Robert H. White
- Department of Biochemistry; Virginia Polytechnic Institute and State University; Blacksburg Virginia 24061
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20
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Sojo V, Herschy B, Whicher A, Camprubí E, Lane N. The Origin of Life in Alkaline Hydrothermal Vents. ASTROBIOLOGY 2016; 16:181-97. [PMID: 26841066 DOI: 10.1089/ast.2015.1406] [Citation(s) in RCA: 133] [Impact Index Per Article: 16.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Over the last 70 years, prebiotic chemists have been very successful in synthesizing the molecules of life, from amino acids to nucleotides. Yet there is strikingly little resemblance between much of this chemistry and the metabolic pathways of cells, in terms of substrates, catalysts, and synthetic pathways. In contrast, alkaline hydrothermal vents offer conditions similar to those harnessed by modern autotrophs, but there has been limited experimental evidence that such conditions could drive prebiotic chemistry. In the Hadean, in the absence of oxygen, alkaline vents are proposed to have acted as electrochemical flow reactors, in which alkaline fluids saturated in H2 mixed with relatively acidic ocean waters rich in CO2, through a labyrinth of interconnected micropores with thin inorganic walls containing catalytic Fe(Ni)S minerals. The difference in pH across these thin barriers produced natural proton gradients with equivalent magnitude and polarity to the proton-motive force required for carbon fixation in extant bacteria and archaea. How such gradients could have powered carbon reduction or energy flux before the advent of organic protocells with genes and proteins is unknown. Work over the last decade suggests several possible hypotheses that are currently being tested in laboratory experiments, field observations, and phylogenetic reconstructions of ancestral metabolism. We analyze the perplexing differences in carbon and energy metabolism in methanogenic archaea and acetogenic bacteria to propose a possible ancestral mechanism of CO2 reduction in alkaline hydrothermal vents. Based on this mechanism, we show that the evolution of active ion pumping could have driven the deep divergence of bacteria and archaea.
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Affiliation(s)
- Victor Sojo
- 1 Department of Genetics, Evolution and Environment, University College London , London, UK
- 2 CoMPLEX, University College London , London, UK
| | - Barry Herschy
- 1 Department of Genetics, Evolution and Environment, University College London , London, UK
| | - Alexandra Whicher
- 1 Department of Genetics, Evolution and Environment, University College London , London, UK
| | - Eloi Camprubí
- 1 Department of Genetics, Evolution and Environment, University College London , London, UK
| | - Nick Lane
- 1 Department of Genetics, Evolution and Environment, University College London , London, UK
- 2 CoMPLEX, University College London , London, UK
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21
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Herschy B, Whicher A, Camprubi E, Watson C, Dartnell L, Ward J, Evans JRG, Lane N. An origin-of-life reactor to simulate alkaline hydrothermal vents. J Mol Evol 2014; 79:213-27. [PMID: 25428684 PMCID: PMC4247476 DOI: 10.1007/s00239-014-9658-4] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 11/21/2014] [Indexed: 11/25/2022]
Abstract
Chemiosmotic coupling is universal: practically all cells harness electrochemical proton gradients across membranes to drive ATP synthesis, powering biochemistry. Autotrophic cells, including phototrophs and chemolithotrophs, also use proton gradients to power carbon fixation directly. The universality of chemiosmotic coupling suggests that it arose very early in evolution, but its origins are obscure. Alkaline hydrothermal systems sustain natural proton gradients across the thin inorganic barriers of interconnected micropores within deep-sea vents. In Hadean oceans, these inorganic barriers should have contained catalytic Fe(Ni)S minerals similar in structure to cofactors in modern metabolic enzymes, suggesting a possible abiotic origin of chemiosmotic coupling. The continuous supply of H2 and CO2 from vent fluids and early oceans, respectively, offers further parallels with the biochemistry of ancient autotrophic cells, notably the acetyl CoA pathway in archaea and bacteria. However, the precise mechanisms by which natural proton gradients, H2, CO2 and metal sulphides could have driven organic synthesis are uncertain, and theoretical ideas lack empirical support. We have built a simple electrochemical reactor to simulate conditions in alkaline hydrothermal vents, allowing investigation of the possibility that abiotic vent chemistry could prefigure the origins of biochemistry. We discuss the construction and testing of the reactor, describing the precipitation of thin-walled, inorganic structures containing nickel-doped mackinawite, a catalytic Fe(Ni)S mineral, under prebiotic ocean conditions. These simulated vent structures appear to generate low yields of simple organics. Synthetic microporous matrices can concentrate organics by thermophoresis over several orders of magnitude under continuous open-flow vent conditions.
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Affiliation(s)
- Barry Herschy
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Alexandra Whicher
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Eloi Camprubi
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Cameron Watson
- Department of Genetics, Evolution and Environment, University College London, London, UK
| | - Lewis Dartnell
- Space Research Centre, Department of Physics and Astronomy, University of Leicester, Leicester, UK
| | - John Ward
- Department of Biochemical Engineering, University College London, London, UK
| | | | - Nick Lane
- Department of Genetics, Evolution and Environment, University College London, London, UK
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22
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Pierella Karlusich JJ, Lodeyro AF, Carrillo N. The long goodbye: the rise and fall of flavodoxin during plant evolution. JOURNAL OF EXPERIMENTAL BOTANY 2014; 65:5161-78. [PMID: 25009172 PMCID: PMC4400536 DOI: 10.1093/jxb/eru273] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 05/27/2014] [Accepted: 05/28/2014] [Indexed: 05/18/2023]
Abstract
Ferredoxins are electron shuttles harbouring iron-sulfur clusters that connect multiple oxido-reductive pathways in organisms displaying different lifestyles. Some prokaryotes and algae express an isofunctional electron carrier, flavodoxin, which contains flavin mononucleotide as cofactor. Both proteins evolved in the anaerobic environment preceding the appearance of oxygenic photosynthesis. The advent of an oxygen-rich atmosphere proved detrimental to ferredoxin owing to iron limitation and oxidative damage to the iron-sulfur cluster, and many microorganisms induced flavodoxin expression to replace ferredoxin under stress conditions. Paradoxically, ferredoxin was maintained throughout the tree of life, whereas flavodoxin is absent from plants and animals. Of note is that flavodoxin expression in transgenic plants results in increased tolerance to multiple stresses and iron deficit, through mechanisms similar to those operating in microorganisms. Then, the question remains open as to why a trait that still confers plants such obvious adaptive benefits was not retained. We compare herein the properties of ferredoxin and flavodoxin, and their contrasting modes of expression in response to different environmental stimuli. Phylogenetic analyses suggest that the flavodoxin gene was already absent in the algal lineages immediately preceding land plants. Geographical distribution of phototrophs shows a bias against flavodoxin-containing organisms in iron-rich coastal/freshwater habitats. Based on these observations, we propose that plants evolved from freshwater macroalgae that already lacked flavodoxin because they thrived in an iron-rich habitat with no need to back up ferredoxin functions and therefore no selective pressure to keep the flavodoxin gene. Conversely, ferredoxin retention in the plant lineage is probably related to its higher efficiency as an electron carrier, compared with flavodoxin. Several lines of evidence supporting these contentions are presented and discussed.
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Affiliation(s)
- Juan J Pierella Karlusich
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Anabella F Lodeyro
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
| | - Néstor Carrillo
- Instituto de Biología Molecular y Celular de Rosario (IBR-CONICET), Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, S2002LRK Rosario, Argentina
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23
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Estellon J, Ollagnier de Choudens S, Smadja M, Fontecave M, Vandenbrouck Y. An integrative computational model for large-scale identification of metalloproteins in microbial genomes: a focus on iron-sulfur cluster proteins. Metallomics 2014; 6:1913-30. [PMID: 25117543 DOI: 10.1039/c4mt00156g] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Metalloproteins represent a ubiquitous group of molecules which are crucial to the survival of all living organisms. While several metal-binding motifs have been defined, it remains challenging to confidently identify metalloproteins from primary protein sequences using computational approaches alone. Here, we describe a comprehensive strategy based on a machine learning approach to design and assess a penalized generalized linear model. We used this strategy to detect members of the iron-sulfur cluster protein family. A new category of descriptors, whose profile is based on profile hidden Markov models, encoding structural information was combined with public descriptors into a linear model. The model was trained and tested on distinct datasets composed of well-characterized iron-sulfur protein sequences, and the resulting model provided higher sensitivity compared to a motif-based approach, while maintaining a good level of specificity. Analysis of this linear model allows us to detect and quantify the contribution of each descriptor, providing us with a better understanding of this complex protein family along with valuable indications for further experimental characterization. Two newly-identified proteins, YhcC and YdiJ, were functionally validated as genuine iron-sulfur proteins, confirming the prediction. The computational model was then applied to over 550 prokaryotic genomes to screen for iron-sulfur proteomes; the results are publicly available at: . This study represents a proof-of-concept for the application of a penalized linear model to identify metalloprotein superfamilies on a large-scale. The application employed here, screening for iron-sulfur proteomes, provides new candidates for further biochemical and structural analysis as well as new resources for an extensive exploration of iron-sulfuromes in the microbial world.
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Affiliation(s)
- Johan Estellon
- Univ. Grenoble Alpes, iRTSV-BGE, F-38000 Grenoble, France.
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24
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Sheng Y, Abreu IA, Cabelli DE, Maroney MJ, Miller AF, Teixeira M, Valentine JS. Superoxide dismutases and superoxide reductases. Chem Rev 2014; 114:3854-918. [PMID: 24684599 PMCID: PMC4317059 DOI: 10.1021/cr4005296] [Citation(s) in RCA: 587] [Impact Index Per Article: 58.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2013] [Indexed: 11/30/2022]
Affiliation(s)
- Yuewei Sheng
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
| | - Isabel A. Abreu
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
- Instituto
de Biologia Experimental e Tecnológica, Av. da República,
Qta. do Marquês, Estação Agronómica Nacional,
Edificio IBET/ITQB, 2780-157, Oeiras, Portugal
| | - Diane E. Cabelli
- Chemistry
Department, Brookhaven National Laboratory, Upton, New York 11973, United States
| | - Michael J. Maroney
- Department
of Chemistry, University of Massachusetts
Amherst, Amherst, Massachusetts 01003, United States
| | - Anne-Frances Miller
- Department
of Chemistry, University of Kentucky, Lexington, Kentucky 40506-0055, United States
| | - Miguel Teixeira
- Instituto
de Tecnologia Química e Biológica António Xavier, Universidade Nova de Lisboa, Av. da República, 2780-157, Oeiras, Portugal
| | - Joan Selverstone Valentine
- Department
of Chemistry and Biochemistry, University
of California Los Angeles, Los
Angeles, California 90095, United States
- Department
of Bioinspired Sciences, Ewha Womans University, Seoul 120-750, Republic of Korea
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25
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Sousa FL, Martin WF. Biochemical fossils of the ancient transition from geoenergetics to bioenergetics in prokaryotic one carbon compound metabolism. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2014; 1837:964-81. [PMID: 24513196 DOI: 10.1016/j.bbabio.2014.02.001] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/26/2013] [Revised: 01/31/2014] [Accepted: 02/03/2014] [Indexed: 12/27/2022]
Abstract
The deep dichotomy of archaea and bacteria is evident in many basic traits including ribosomal protein composition, membrane lipid synthesis, cell wall constituents, and flagellar composition. Here we explore that deep dichotomy further by examining the distribution of genes for the synthesis of the central carriers of one carbon units, tetrahydrofolate (H4F) and tetrahydromethanopterin (H4MPT), in bacteria and archaea. The enzymes underlying those distinct biosynthetic routes are broadly unrelated across the bacterial-archaeal divide, indicating that the corresponding pathways arose independently. That deep divergence in one carbon metabolism is mirrored in the structurally unrelated enzymes and different organic cofactors that methanogens (archaea) and acetogens (bacteria) use to perform methyl synthesis in their H4F- and H4MPT-dependent versions, respectively, of the acetyl-CoA pathway. By contrast, acetyl synthesis in the acetyl-CoA pathway - from a methyl group, CO2 and reduced ferredoxin - is simpler, uniform and conserved across acetogens and methanogens, and involves only transition metals as catalysts. The data suggest that the acetyl-CoA pathway, while being the most ancient of known CO2 assimilation pathways, reflects two phases in early evolution: an ancient phase in a geochemically confined and non-free-living universal common ancestor, in which acetyl thioester synthesis proceeded spontaneously with the help of geochemically supplied methyl groups, and a later phase that reflects the primordial divergence of the bacterial and archaeal stem groups, which independently invented genetically-encoded means to synthesize methyl groups via enzymatic reactions. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
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Affiliation(s)
- Filipa L Sousa
- Institute for Molecular Evolution,University of Düsseldorf, 40225 Düsseldorf, Germany
| | - William F Martin
- Institute for Molecular Evolution,University of Düsseldorf, 40225 Düsseldorf, Germany.
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26
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Dufour V, Stahl M, Rosenfeld E, Stintzi A, Baysse C. Insights into the mode of action of benzyl isothiocyanate on Campylobacter jejuni. Appl Environ Microbiol 2013; 79:6958-68. [PMID: 24014524 PMCID: PMC3811535 DOI: 10.1128/aem.01967-13] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2013] [Accepted: 08/28/2013] [Indexed: 12/24/2022] Open
Abstract
Campylobacter jejuni is a widespread pathogen responsible for most of the food-borne gastrointestinal diseases in Europe. The use of natural antimicrobial molecules is a promising alternative to antibiotic treatments for pathogen control in the food industry. Isothiocyanates are natural antimicrobial compounds, which also display anticancer activity. Several studies described the chemoprotective effect of isothiocyanates on eukaryotic cells, but the antimicrobial mechanism is still poorly understood. We investigated the early cellular response of C. jejuni to benzyl isothiocyanate by both transcriptomic and physiological approaches. The transcriptomic response of C. jejuni to benzyl isothiocyanate showed upregulation of heat shock response genes and an impact on energy metabolism. Oxygen consumption was progressively impaired by benzyl isothiocyanate treatment, as revealed by high-resolution respirometry, while the ATP content increased soon after benzyl isothiocyanate exposition, which suggests a shift in the energy metabolism balance. Finally, benzyl isothiocyanate induced intracellular protein aggregation. These results indicate that benzyl isothiocyanate affects C. jejuni by targeting proteins, resulting in the disruption of major metabolic processes and eventually leading to cell death.
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Affiliation(s)
- Virginie Dufour
- EA1254 Microbiologie et Risques Infectieux, University of Rennes 1, Rennes, France
| | - Martin Stahl
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | | | - Alain Stintzi
- Ottawa Institute of Systems Biology, Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, ON, Canada
| | - Christine Baysse
- EA1254 Microbiologie et Risques Infectieux, University of Rennes 1, Rennes, France
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27
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Sousa FL, Thiergart T, Landan G, Nelson-Sathi S, Pereira IAC, Allen JF, Lane N, Martin WF. Early bioenergetic evolution. Philos Trans R Soc Lond B Biol Sci 2013; 368:20130088. [PMID: 23754820 PMCID: PMC3685469 DOI: 10.1098/rstb.2013.0088] [Citation(s) in RCA: 148] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Life is the harnessing of chemical energy in such a way that the energy-harnessing device makes a copy of itself. This paper outlines an energetically feasible path from a particular inorganic setting for the origin of life to the first free-living cells. The sources of energy available to early organic synthesis, early evolving systems and early cells stand in the foreground, as do the possible mechanisms of their conversion into harnessable chemical energy for synthetic reactions. With regard to the possible temporal sequence of events, we focus on: (i) alkaline hydrothermal vents as the far-from-equilibrium setting, (ii) the Wood-Ljungdahl (acetyl-CoA) pathway as the route that could have underpinned carbon assimilation for these processes, (iii) biochemical divergence, within the naturally formed inorganic compartments at a hydrothermal mound, of geochemically confined replicating entities with a complexity below that of free-living prokaryotes, and (iv) acetogenesis and methanogenesis as the ancestral forms of carbon and energy metabolism in the first free-living ancestors of the eubacteria and archaebacteria, respectively. In terms of the main evolutionary transitions in early bioenergetic evolution, we focus on: (i) thioester-dependent substrate-level phosphorylations, (ii) harnessing of naturally existing proton gradients at the vent-ocean interface via the ATP synthase, (iii) harnessing of Na(+) gradients generated by H(+)/Na(+) antiporters, (iv) flavin-based bifurcation-dependent gradient generation, and finally (v) quinone-based (and Q-cycle-dependent) proton gradient generation. Of those five transitions, the first four are posited to have taken place at the vent. Ultimately, all of these bioenergetic processes depend, even today, upon CO2 reduction with low-potential ferredoxin (Fd), generated either chemosynthetically or photosynthetically, suggesting a reaction of the type 'reduced iron → reduced carbon' at the beginning of bioenergetic evolution.
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Affiliation(s)
- Filipa L. Sousa
- Institute of Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Thorsten Thiergart
- Institute of Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Giddy Landan
- Institute of Genomic Microbiology, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Shijulal Nelson-Sathi
- Institute of Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany
| | - Inês A. C. Pereira
- Instituto de Tecnologia Química e Biológica, Universidade Nova de Lisboa, Oeiras, Portugal
| | - John F. Allen
- School of Biological and Chemical Sciences, Queen Mary, University of London, London, UK
- Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London, UK
| | - Nick Lane
- Research Department of Genetics, Evolution and Environment, University College London, Gower Street, London, UK
| | - William F. Martin
- Institute of Molecular Evolution, University of Düsseldorf, 40225 Düsseldorf, Germany
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28
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Iron sulfur cluster proteins and microbial regulation: implications for understanding tuberculosis. Curr Opin Chem Biol 2012; 16:45-53. [PMID: 22483328 DOI: 10.1016/j.cbpa.2012.03.004] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2012] [Revised: 03/05/2012] [Accepted: 03/07/2012] [Indexed: 11/22/2022]
Abstract
All pathogenic and nonpathogenic microbes are continuously exposed to environmental or endogenous reactive oxygen and nitrogen species, which can critically effect survival and disease. Iron-sulfur [Fe-S] cluster containing prosthetic groups provide the microbial cell with a unique capacity to sense and transcriptionally respond to diatomic gases (e.g. NO and O2) and redox-cycling agents. Recent advances in our understanding of the mechanisms for how the FNR and SoxR [Fe-S] cluster proteins respond to NO and O2 have provided new insights into the biochemical mechanism of action of the Mycobacterium tuberculosis (Mtb) family of WhiB [Fe-S] cluster proteins. These insights have provided the basis for establishing a unifying paradigm for the Mtb WhiB family of proteins. Mtb is the etiological agent for tuberculosis (TB), a disease that affects nearly one-third of the world's population.
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Lessner FH, Jennings ME, Hirata A, Duin EC, Lessner DJ. Subunit D of RNA polymerase from Methanosarcina acetivorans contains two oxygen-labile [4Fe-4S] clusters: implications for oxidant-dependent regulation of transcription. J Biol Chem 2012; 287:18510-23. [PMID: 22457356 DOI: 10.1074/jbc.m111.331199] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Subunit D of multisubunit RNA polymerase from many species of archaea is predicted to bind one to two iron-sulfur (Fe-S) clusters, the function of which is unknown. A survey of encoded subunit D in the genomes of sequenced archaea revealed six distinct groups based on the number of complete or partial [4Fe-4S] cluster motifs within domain 3. Only subunit D from strictly anaerobic archaea, including all members of the Methanosarcinales, are predicted to bind two [4Fe-4S] clusters. We report herein the purification and characterization of Methanosarcina acetivorans subunit D in complex with subunit L. Expression of subunit D and subunit L in Escherichia coli resulted in the purification of a D-L heterodimer with only partial [4Fe-4S] cluster content. Reconstitution in vitro with iron and sulfide revealed that the M. acetivorans D-L heterodimer is capable of binding two redox-active [4Fe-4S] clusters. M. acetivorans subunit D deleted of domain 3 (DΔD3) was still capable of co-purifying with subunit L but was devoid of [4Fe-4S] clusters. Affinity purification of subunit D or subunit DΔD3 from M. acetivorans resulted in the co-purification of endogenous subunit L with each tagged subunit D. Overall, these results suggest that domain 3 of subunit D is required for [4Fe-4S] cluster binding, but the [4Fe-4S] clusters and domain 3 are not required for the formation of the D-L heterodimer. However, exposure of two [4Fe-4S] cluster-containing D-L heterodimer to oxygen resulted in loss of the [4Fe-4S] clusters and subsequent protein aggregation, indicating that the [4Fe-4S] clusters influence the stability of the D-L heterodimer and therefore have the potential to regulate the assembly and/or activity of RNA polymerase in an oxidant-dependent manner.
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Affiliation(s)
- Faith H Lessner
- Department of Biological Sciences, University of Arkansas, Fayetteville, Arkansas 72701, USA
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30
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Liu Y, Beer LL, Whitman WB. Methanogens: a window into ancient sulfur metabolism. Trends Microbiol 2012; 20:251-8. [PMID: 22406173 DOI: 10.1016/j.tim.2012.02.002] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2011] [Revised: 01/29/2012] [Accepted: 02/06/2012] [Indexed: 11/26/2022]
Abstract
Methanogenesis is an ancient metabolism that originated on the early anoxic Earth. The buildup of O(2) about 2.4 billion years ago led to formation of a large oceanic sulfate pool, the onset of widespread sulfate reduction and the marginalization of methanogens to anoxic and sulfate-poor niches. Contemporary methanogens are restricted to anaerobic habitats and may have retained some metabolic relics that were common in early anaerobic life. Consistent with this hypothesis, methanogens do not utilize sulfate as a sulfur source, Cys is not utilized as a sulfur donor for Fe-S cluster and Met biosynthesis, and Cys biosynthesis uses an unusual tRNA-dependent pathway.
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Affiliation(s)
- Yuchen Liu
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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31
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Atkinson GC, Hauryliuk V, Tenson T. An ancient family of SelB elongation factor-like proteins with a broad but disjunct distribution across archaea. BMC Evol Biol 2011; 11:22. [PMID: 21255425 PMCID: PMC3037878 DOI: 10.1186/1471-2148-11-22] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2010] [Accepted: 01/21/2011] [Indexed: 02/05/2023] Open
Abstract
Background SelB is the dedicated elongation factor for delivery of selenocysteinyl-tRNA to the ribosome. In archaea, only a subset of methanogens utilizes selenocysteine and encodes archaeal SelB (aSelB). A SelB-like (aSelBL) homolog has previously been identified in an archaeon that does not encode selenosysteine, and has been proposed to be a pyrrolysyl-tRNA-specific elongation factor (EF-Pyl). However, elongation factor EF-Tu is capable of binding archaeal Pyl-tRNA in bacteria, suggesting the archaeal ortholog EF1A may also be capable of delivering Pyl-tRNA to the ribosome without the need of a specialized factor. Results We have phylogenetically characterized the aSelB and aSelBL families in archaea. We find the distribution of aSelBL to be wider than both selenocysteine and pyrrolysine usage. The aSelBLs also lack the carboxy terminal domain usually involved in recognition of the selenocysteine insertion sequence in the target mRNA. While most aSelBL-encoding archaea are methanogenic Euryarchaea, we also find aSelBL representatives in Sulfolobales and Thermoproteales of Crenarchaea, and in the recently identified phylum Thaumarchaea, suggesting that aSelBL evolution has involved horizontal gene transfer and/or parallel loss. Severe disruption of the GTPase domain suggests that some family members may employ a hitherto unknown mechanism of nucleotide hydrolysis, or have lost their GTPase ability altogether. However, patterns of sequence conservation indicate that aSelBL is still capable of binding the ribosome and aminoacyl-tRNA. Conclusions Although it is closely related to SelB, aSelBL appears unlikely to either bind selenocysteinyl-tRNA or function as a classical GTP hydrolyzing elongation factor. We propose that following duplication of aSelB, the resultant aSelBL was recruited for binding another aminoacyl-tRNA. In bacteria, aminoacylation with selenocysteine is essential for efficient thermodynamic coupling of SelB binding to tRNA and GTP. Therefore, change in tRNA specificity of aSelBL could have disrupted its GTPase cycle, leading to relaxation of selective pressure on the GTPase domain and explaining its apparent degradation. While the specific role of aSelBL is yet to be experimentally tested, its broad phylogenetic distribution, surpassing that of aSelB, indicates its importance.
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32
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Liu Y, Sieprawska-Lupa M, Whitman WB, White RH. Cysteine is not the sulfur source for iron-sulfur cluster and methionine biosynthesis in the methanogenic archaeon Methanococcus maripaludis. J Biol Chem 2010; 285:31923-9. [PMID: 20709756 DOI: 10.1074/jbc.m110.152447] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three multiprotein systems are known for iron-sulfur (Fe-S) cluster biogenesis in prokaryotes and eukaryotes as follows: the NIF (nitrogen fixation), the ISC (iron-sulfur cluster), and the SUF (mobilization of sulfur) systems. In all three, cysteine is the physiological sulfur source, and the sulfur is transferred from cysteine desulfurase through a persulfidic intermediate to a scaffold protein. However, the biochemical nature of the sulfur source for Fe-S cluster assembly in archaea is unknown, and many archaea lack homologs of cysteine desulfurases. Methanococcus maripaludis is a methanogenic archaeon that contains a high amount of protein-bound Fe-S clusters (45 nmol/mg protein). Cysteine in this archaeon is synthesized primarily via the tRNA-dependent SepRS/SepCysS pathway. When a ΔsepS mutant (a cysteine auxotroph) was grown with (34)S-labeled sulfide and unlabeled cysteine, <8% of the cysteine, >92% of the methionine, and >87% of the sulfur in the Fe-S clusters in proteins were labeled, suggesting that the sulfur in methionine and Fe-S clusters was derived predominantly from exogenous sulfide instead of cysteine. Therefore, this investigation challenges the concept that cysteine is always the sulfur source for Fe-S cluster biosynthesis in vivo and suggests that Fe-S clusters are derived from sulfide in those organisms, which live in sulfide-rich habitats.
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Affiliation(s)
- Yuchen Liu
- Department of Microbiology, University of Georgia, Athens, Georgia 30602-2605, USA
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Lane N, Allen JF, Martin W. How did LUCA make a living? Chemiosmosis in the origin of life. Bioessays 2010; 32:271-80. [PMID: 20108228 DOI: 10.1002/bies.200900131] [Citation(s) in RCA: 181] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Despite thermodynamic, bioenergetic and phylogenetic failings, the 81-year-old concept of primordial soup remains central to mainstream thinking on the origin of life. But soup is homogeneous in pH and redox potential, and so has no capacity for energy coupling by chemiosmosis. Thermodynamic constraints make chemiosmosis strictly necessary for carbon and energy metabolism in all free-living chemotrophs, and presumably the first free-living cells too. Proton gradients form naturally at alkaline hydrothermal vents and are viewed as central to the origin of life. Here we consider how the earliest cells might have harnessed a geochemically created proton-motive force and then learned to make their own, a transition that was necessary for their escape from the vents. Synthesis of ATP by chemiosmosis today involves generation of an ion gradient by means of vectorial electron transfer from a donor to an acceptor. We argue that the first donor was hydrogen and the first acceptor CO2.
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Affiliation(s)
- Nick Lane
- Department of Genetics, Evolution and Environment, University College London, London, UK
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Louvel H, Kanai T, Atomi H, Reeve JN. The Fur iron regulator-like protein is cryptic in the hyperthermophilic archaeon Thermococcus kodakaraensis. FEMS Microbiol Lett 2009; 295:117-28. [PMID: 19484827 DOI: 10.1111/j.1574-6968.2009.01594.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Archaea, which regroup organisms with extreme living conditions, possess many predicted iron-containing proteins that may be metabolically critical; however, their need for iron remains poorly documented. In this report, iron acquisition mechanisms were investigated in the hyperthermophilic archaeon Thermococcus kodakaraensis. Thermococcus kodakaraensis requires iron for its growth and possesses many putative iron uptake systems, including several ATP-binding cassette-like transporters and two FeoAB-like receptors, showing that this organism shares similar features with bacteria. One homolog of the major bacterial iron regulator, ferric uptake regulator (Fur), with about 50% similarity to Escherichia coli Fur was also identified. Thermococcus kodakaraensis Fur was found to be able to specifically bind to a Fur-binding site consensus-like sequence of its own gene promoter. However, its expression has been hindered by a -1 frameshift mutation and the chromosomal repair of this mutation did not affect T. kodakaraensis in vivo phenotypes. Microarrays analyses helped to further characterize T. kodakaraensis iron-dependent growth and revealed no role for the Fur homolog in the global regulatory response of the cells to iron. In contrast, additional evidences indicated that the T. kodakaraensis diphtheria toxin regulator (DtxR) homolog may control the expression of the major iron acquisition effectors, while its inactivation enabled higher resistance to iron deficiency.
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Affiliation(s)
- Hélène Louvel
- Department of Microbiology, Ohio State University, Columbus, OH, USA.
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35
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Hauenstein SI, Perona JJ. Redundant synthesis of cysteinyl-tRNACys in Methanosarcina mazei. J Biol Chem 2008; 283:22007-17. [PMID: 18559341 PMCID: PMC2494925 DOI: 10.1074/jbc.m801839200] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2008] [Revised: 05/19/2008] [Indexed: 11/06/2022] Open
Abstract
A subset of methanogenic archaea synthesize the cysteinyl-tRNA(Cys) (Cys-tRNA(Cys)) needed for protein synthesis using both a canonical cysteinyl-tRNA synthetase (CysRS) as well as a set of two enzymes that operate via a separate indirect pathway. In the indirect route, phosphoseryl-tRNA(Cys) (Sep-tRNA(Cys)) is first synthesized by phosphoseryl-tRNA synthetase (SepRS), and this misacylated intermediate is then converted to Cys-tRNA(Cys) by Sep-tRNA:Cys-tRNA synthase (SepCysS) via a pyridoxal phosphate-dependent mechanism. Here, we explore the function of all three enzymes in the mesophilic methanogen Methanosarcina mazei. The genome of M. mazei also features three distinct tRNA(Cys) isoacceptors, further indicating the unusual and complex nature of Cys-tRNA(Cys) synthesis in this organism. Comparative aminoacylation kinetics by M. mazei CysRS and SepRS reveals that each enzyme prefers a distinct tRNA(Cys) isoacceptor or pair of isoacceptors. Recognition determinants distinguishing the tRNAs are shown to reside in the globular core of the molecule. Both enzymes also require the S-adenosylmethione-dependent formation of (m1)G37 in the anticodon loop for efficient aminoacylation. We further report a new, highly sensitive assay to measure the activity of SepCysS under anaerobic conditions. With this approach, we demonstrate that SepCysS functions as a multiple-turnover catalyst with kinetic behavior similar to bacterial selenocysteine synthase and the archaeal/eukaryotic SepSecS enzyme. Together, these data suggest that both metabolic routes and all three tRNA(Cys) species in M. mazei play important roles in the cellular physiology of the organism.
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Affiliation(s)
- Scott I Hauenstein
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, USA
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Abstract
The accurate formation of cognate aminoacyl-transfer RNAs (aa-tRNAs) is essential for the fidelity of translation. Most amino acids are esterified onto their cognate tRNA isoacceptors directly by aa-tRNA synthetases. However, in the case of four amino acids (Gln, Asn, Cys and Sec), aminoacyl-tRNAs are made through indirect pathways in many organisms across all three domains of life. The process begins with the charging of noncognate amino acids to tRNAs by a specialized synthetase in the case of Cys-tRNA(Cys) formation or by synthetases with relaxed specificity, such as the non-discriminating glutamyl-tRNA, non-discriminating aspartyl-tRNA and seryl-tRNA synthetases. The resulting misacylated tRNAs are then converted to cognate pairs through transformation of the amino acids on the tRNA, which is catalyzed by a group of tRNA-dependent modifying enzymes, such as tRNA-dependent amidotransferases, Sep-tRNA:Cys-tRNA synthase, O-phosphoseryl-tRNA kinase and Sep-tRNA:Sec-tRNA synthase. The majority of these indirect pathways are widely spread in all domains of life and thought to be part of the evolutionary process.
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Affiliation(s)
- Jing Yuan
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520-8114, USA
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Sheppard K, Yuan J, Hohn MJ, Jester B, Devine KM, Söll D. From one amino acid to another: tRNA-dependent amino acid biosynthesis. Nucleic Acids Res 2008; 36:1813-25. [PMID: 18252769 PMCID: PMC2330236 DOI: 10.1093/nar/gkn015] [Citation(s) in RCA: 138] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
Aminoacyl-tRNAs (aa-tRNAs) are the essential substrates for translation. Most aa-tRNAs are formed by direct aminoacylation of tRNA catalyzed by aminoacyl-tRNA synthetases. However, a smaller number of aa-tRNAs (Asn-tRNA, Gln-tRNA, Cys-tRNA and Sec-tRNA) are made by synthesizing the amino acid on the tRNA by first attaching a non-cognate amino acid to the tRNA, which is then converted to the cognate one catalyzed by tRNA-dependent modifying enzymes. Asn-tRNA or Gln-tRNA formation in most prokaryotes requires amidation of Asp-tRNA or Glu-tRNA by amidotransferases that couple an amidase or an asparaginase to liberate ammonia with a tRNA-dependent kinase. Both archaeal and eukaryotic Sec-tRNA biosynthesis and Cys-tRNA synthesis in methanogens require O-phosophoseryl-tRNA formation. For tRNA-dependent Cys biosynthesis, O-phosphoseryl-tRNA synthetase directly attaches the amino acid to the tRNA which is then converted to Cys by Sep-tRNA: Cys-tRNA synthase. In Sec-tRNA synthesis, O-phosphoseryl-tRNA kinase phosphorylates Ser-tRNA to form the intermediate which is then modified to Sec-tRNA by Sep-tRNA:Sec-tRNA synthase. Complex formation between enzymes in the same pathway may protect the fidelity of protein synthesis. How these tRNA-dependent amino acid biosynthetic routes are integrated into overall metabolism may explain why they are still retained in so many organisms.
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Affiliation(s)
- Kelly Sheppard
- Department of Molecular Biophysics, Yale University, New Haven, CT 06520-8114, USA
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Klipcan L, Frenkel-Morgenstern M, Safro MG. Presence of tRNA-dependent pathways correlates with high cysteine content in methanogenic Archaea. Trends Genet 2008; 24:59-63. [DOI: 10.1016/j.tig.2007.11.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Revised: 11/02/2007] [Accepted: 11/21/2007] [Indexed: 10/22/2022]
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Lessner DJ, Ferry JG. The archaeon Methanosarcina acetivorans contains a protein disulfide reductase with an iron-sulfur cluster. J Bacteriol 2007; 189:7475-84. [PMID: 17675382 PMCID: PMC2168450 DOI: 10.1128/jb.00891-07] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Methanosarcina acetivorans, a strictly anaerobic methane-producing species belonging to the domain Archaea, contains a gene cluster annotated with homologs encoding oxidative stress proteins. One of the genes (MA3736) is annotated as a gene encoding an uncharacterized carboxymuconolactone decarboxylase, an enzyme required for aerobic growth with aromatic compounds by species in the domain Bacteria. Methane-producing species are not known to utilize aromatic compounds, suggesting that MA3736 is incorrectly annotated. The product of MA3736, overproduced in Escherichia coli, had protein disulfide reductase activity dependent on a C(67)XXC(70) motif not found in carboxymuconolactone decarboxylase. We propose that MA3736 be renamed mdrA (methanosarcina disulfide reductase). Further, unlike carboxymuconolactone decarboxylase, MdrA contained an Fe-S cluster. Binding of the Fe-S cluster was dependent on essential cysteines C(67) and C(70), while cysteines C(39) and C(107) were not required. Loss of the Fe-S cluster resulted in conversion of MdrA from an inactive hexamer to a trimer with protein disulfide reductase activity. The data suggest that MdrA is the prototype of a previously unrecognized protein disulfide reductase family which contains an intermolecular Fe-S cluster that controls oligomerization as a mechanism to regulate protein disulfide reductase activity.
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Affiliation(s)
- Daniel J Lessner
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park, PA 16802, USA
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Kaakoush NO, Sterzenbach T, Miller WG, Suerbaum S, Mendz GL. Identification of disulfide reductases in Campylobacterales: a bioinformatics investigation. Antonie Van Leeuwenhoek 2007; 92:429-41. [PMID: 17588128 DOI: 10.1007/s10482-007-9171-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2007] [Accepted: 04/11/2007] [Indexed: 11/26/2022]
Abstract
Disulfide reductases of host-colonising bacteria are involved in the expression of virulence factors, resistance to drugs, and elimination of toxic compounds. Large-scale genome analyses of 281 prokaryotes identified CXXC and CXXC-derived motifs in each microorganism. The total number of these motifs showed correlations with genome size and oxygen tolerance of the prokaryotes. Specific bioinformatic analyses served to identify putative disulfide reductases in the Campylobacterales Campylobacter jejuni, Helicobacter pylori, Wolinella succinogenes and Arcobacter butzleri which colonise the gastrointestinal tract of higher animals. Three filters applied to the genomes of these species yielded 35, 25, 28 and 34 genes, respectively, encoding proteins with the characteristics of disulfide reductases. Ten proteins were common to the four species, including four belonging to the thioredoxin system. The presence of thioredoxin reductase activities was detected in the four bacterial species by observing dithiobis-2-nitrobenzoic acid reduction with beta-nicotinamide adenine dinucleotide phosphate as cofactor. Phylogenetic analyses of the thioredoxin reductases TrxB(1) and TrxB(2) of the four Campylobacterales were performed. Their TrxB(1) proteins were more closely related to those of Firmicutes than to the corresponding proteins of other Proteobacteria. The Campylobacterales TrxB(2) proteins were closer to glutathione reductases of other organisms than to their respective TrxB(1) proteins. The phylogenetic features of the Campylobacterales thioredoxin reductases suggested a special role for these enzymes in the physiology of these bacteria.
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Affiliation(s)
- Nadeem O Kaakoush
- School of Medical Sciences, The University of New South Wales, Sydney, NSW 2052, Australia
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Ferrer M, Golyshina OV, Beloqui A, Golyshin PN, Timmis KN. The cellular machinery of Ferroplasma acidiphilum is iron-protein-dominated. Nature 2007; 445:91-4. [PMID: 17203061 DOI: 10.1038/nature05362] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2006] [Accepted: 10/20/2006] [Indexed: 11/09/2022]
Abstract
Ferroplasma is a genus of the Archaea, one of the three branches of the tree of life, and belongs to the order Thermoplasmatales (Euryarchaeota), which contains the most acidophilic microbes yet known. Ferroplasma species live in acid mine drainage, acidic pools and environments containing sulphidic ores such as pyrite and characterized by pH values of 0-2 and high concentrations of ferrous iron and other heavy metals. F. acidiphilum strain Y(T) is a chemoautotroph that grows optimally at pH 1.7 and gains energy by oxidizing ferrous iron and carbon by the fixation of carbon dioxide. Here we show that 86% of 189 investigated cellular proteins of F. acidiphilum are iron-metalloproteins. These include proteins with deduced structural, chaperone and catalytic roles, not described as iron-metalloproteins in any other organism so far investigated. The iron atoms in the proteins seem to organize and stabilize their three-dimensional structures, to act as 'iron rivets'. Analysis of proteins of the phylogenetic neighbour Picrophilus torridus and of the habitat neighbour Acidithiobacillus ferrooxidans revealed far fewer and only typical metalloproteins. F. acidiphilum therefore has a currently unique iron-protein-dominated cellular machinery and biochemical phylogeny.
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Affiliation(s)
- Manuel Ferrer
- CSIC, Institute of Catalysis, Cantoblanco, 28049 Madrid, Spain.
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Bragg JG, Thomas D, Baudouin-Cornu P. Variation among species in proteomic sulphur content is related to environmental conditions. Proc Biol Sci 2006; 273:1293-300. [PMID: 16720405 PMCID: PMC1560280 DOI: 10.1098/rspb.2005.3441] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2005] [Accepted: 12/04/2005] [Indexed: 11/12/2022] Open
Abstract
The elemental composition of proteins influences the quantities of different elements required by organisms. Here, we considered variation in the sulphur content of whole proteomes among 19 Archaea, 122 Eubacteria and 10 eukaryotes whose genomes have been fully sequenced. We found that different species vary greatly in the sulphur content of their proteins, and that average sulphur content of proteomes and genome base composition are related. Forces contributing to variation in proteomic sulphur content appear to operate quite uniformly across the proteins of different species. In particular, the sulphur content of orthologous proteins was frequently correlated with mean proteomic sulphur contents. Among prokaryotes, proteomic sulphur content tended to be greater in anaerobes, relative to non-anaerobes. Thermophiles tended to have lower proteomic sulphur content than non-thermophiles, consistent with the thermolability of cysteine and methionine residues. This work suggests that persistent environmental growth conditions can influence the evolution of elemental composition of whole proteomes in a manner that may have important implications for the amount of sulphur used by living organisms to build proteins. It extends previous studies that demonstrated links between transient changes in environmental conditions and the elemental composition of subsets of proteins expressed under these conditions.
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Affiliation(s)
- Jason G Bragg
- Department of Biology, University of New MexicoMSC03 2020, Albuquerque, NM 87131-0001, USA
| | - Dominique Thomas
- Centre de Génétique Moléculaire, Centre National de la Recherche Scientifique91198 Gif-sur-Yvette, France
- Cytomics Systems SABâtiment 5, 1 avenue de la Terrasse, 91190 Gif sur Yvette, France
| | - Peggy Baudouin-Cornu
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital600 University Avenue, Toronto, ON M5G 1X5, Canada
- LPG, SBGM/DBJCbât 144, CEA Saclay, F-91191 Gif-sur-Yvette Cedex, France
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Affiliation(s)
- Marc Fontecave
- Laboratoire de Chimie et Biochimie des Centres Rédox Biologiques, DRDC/CB, CEA/CNRS/Université Joseph Fourier, CEA-Grenoble, UMR 5047, 17 Avenue des Martyrs, 38504 Grenoble Cedex 09, France.
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O'Donoghue P, Sethi A, Woese CR, Luthey-Schulten ZA. The evolutionary history of Cys-tRNACys formation. Proc Natl Acad Sci U S A 2005; 102:19003-8. [PMID: 16380427 PMCID: PMC1323144 DOI: 10.1073/pnas.0509617102] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The recent discovery of an alternate pathway for indirectly charging tRNA(Cys) has stimulated a re-examination of the evolutionary history of Cys-tRNA(Cys) formation. In the first step of the pathway, O-phosphoseryl-tRNA synthetase charges tRNA(Cys) with O-phosphoserine (Sep), a precursor of the cognate amino acid. In the following step, Sep-tRNA:Cys-tRNA synthase (SepCysS) converts Sep to Cys in a tRNA-dependent reaction. The existence of such a pathway raises several evolutionary questions, including whether the indirect pathway is a recent evolutionary invention, as might be implied from its localization to the Euryarchaea, or, as evidence presented here indicates, whether this pathway is more ancient, perhaps already in existence at the time of the last universal common ancestral state. A comparative phylogenetic approach is used, combining evolutionary information from protein sequences and structures, that takes both the signature of horizontal gene transfer and the recurrence of the full canonical phylogenetic pattern into account, to document the complete evolutionary history of cysteine coding and understand the nature of this process in the last universal common ancestral state. Resulting from the historical study of tRNA(Cys) aminoacylation and the integrative perspective of sequence, structure, and function are 3D models of O-phosphoseryl-tRNA synthetase and SepCysS, which provide experimentally testable predictions regarding the identity and function of key active-site residues in these proteins. The model of SepCysS is used to suggest a sulfhydrylation reaction mechanism, which is predicted to occur at the interface of a SepCysS dimer.
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Affiliation(s)
- Patrick O'Donoghue
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
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