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Kang S, Song Y, Jin S, Shin J, Bae J, Kim DR, Lee JK, Kim SC, Cho S, Cho BK. Adaptive Laboratory Evolution of Eubacterium limosum ATCC 8486 on Carbon Monoxide. Front Microbiol 2020; 11:402. [PMID: 32218779 PMCID: PMC7079680 DOI: 10.3389/fmicb.2020.00402] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2019] [Accepted: 02/26/2020] [Indexed: 11/13/2022] Open
Abstract
Acetogens are naturally capable of metabolizing carbon monoxide (CO), a component of synthesis gas (syngas), for autotrophic growth in order to produce biomass and metabolites such as acetyl-CoA via the Wood–Ljungdahl pathway. However, the autotrophic growth of acetogens is often inhibited by the presence of high CO concentrations because of CO toxicity, thus limiting their biosynthetic potential for industrial applications. Herein, we implemented adaptive laboratory evolution (ALE) for growth improvement of Eubacterium limosum ATCC 8486 under high CO conditions. The strain evolved under syngas conditions with 44% CO over 150 generations, resulting in a significant increased optical density (600 nm) and growth rate by 2.14 and 1.44 folds, respectively. In addition, the evolved populations were capable of proliferating under CO concentrations as high as 80%. These results suggest that cell growth is enhanced as beneficial mutations are selected and accumulated, and the metabolism is altered to facilitate the enhanced phenotype. To identify the causal mutations related to growth improvement under high CO concentrations, we performed whole genome resequencing of each population at 50-generation intervals. Interestingly, we found key mutations in CO dehydrogenase/acetyl-CoA synthase (CODH/ACS) complex coding genes, acsA and cooC. To characterize the mutational effects on growth under CO, we isolated single clones and confirmed that the growth rate and CO tolerance level of the single clone were comparable to those of the evolved populations and wild type strain under CO conditions. Furthermore, the evolved strain produced 1.34 folds target metabolite acetoin when compared to the parental strain while introducing the biosynthetic pathway coding genes to the strains. Consequently, this study demonstrates that the mutations in the CODH/ACS complex affect autotrophic growth enhancement in the presence of CO as well as the CO tolerance of E. limosum ATCC 8486.
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Affiliation(s)
- Seulgi Kang
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Yoseb Song
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Sangrak Jin
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jongoh Shin
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Jiyun Bae
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Dong Rip Kim
- Department of Mechanical Engineering, Hanyang University, Seoul, South Korea
| | - Jung-Kul Lee
- Department of Chemical Engineering, Konkuk University, Seoul, South Korea
| | - Sun Chang Kim
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,Intelligent Synthetic Biology Center, Daejeon, South Korea
| | - Suhyung Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea
| | - Byung-Kwan Cho
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,KAIST Institute for the BioCentury, Korea Advanced Institute of Science and Technology, Daejeon, South Korea.,Intelligent Synthetic Biology Center, Daejeon, South Korea
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Metabolic response of Clostridium ljungdahlii to oxygen exposure. Appl Environ Microbiol 2015; 81:8379-91. [PMID: 26431975 DOI: 10.1128/aem.02491-15] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 09/23/2015] [Indexed: 12/31/2022] Open
Abstract
Clostridium ljungdahlii is an important synthesis gas-fermenting bacterium used in the biofuels industry, and a preliminary investigation showed that it has some tolerance to oxygen when cultured in rich mixotrophic medium. Batch cultures not only continue to grow and consume H2, CO, and fructose after 8% O2 exposure, but fermentation product analysis revealed an increase in ethanol concentration and decreased acetate concentration compared to non-oxygen-exposed cultures. In this study, the mechanisms for higher ethanol production and oxygen/reactive oxygen species (ROS) detoxification were identified using a combination of fermentation, transcriptome sequencing (RNA-seq) differential expression, and enzyme activity analyses. The results indicate that the higher ethanol and lower acetate concentrations were due to the carboxylic acid reductase activity of a more highly expressed predicted aldehyde oxidoreductase (CLJU_c24130) and that C. ljungdahlii's primary defense upon oxygen exposure is a predicted rubrerythrin (CLJU_c39340). The metabolic responses of higher ethanol production and oxygen/ROS detoxification were found to be linked by cofactor management and substrate and energy metabolism. This study contributes new insights into the physiology and metabolism of C. ljungdahlii and provides new genetic targets to generate C. ljungdahlii strains that produce more ethanol and are more tolerant to syngas contaminants.
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Bender G, Pierce E, Hill JA, Darty JE, Ragsdale SW. Metal centers in the anaerobic microbial metabolism of CO and CO2. Metallomics 2011; 3:797-815. [PMID: 21647480 PMCID: PMC3964926 DOI: 10.1039/c1mt00042j] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Carbon dioxide and carbon monoxide are important components of the carbon cycle. Major research efforts are underway to develop better technologies to utilize the abundant greenhouse gas, CO(2), for harnessing 'green' energy and producing biofuels. One strategy is to convert CO(2) into CO, which has been valued for many years as a synthetic feedstock for major industrial processes. Living organisms are masters of CO(2) and CO chemistry and, here, we review the elegant ways that metalloenzymes catalyze reactions involving these simple compounds. After describing the chemical and physical properties of CO and CO(2), we shift focus to the enzymes and the metal clusters in their active sites that catalyze transformations of these two molecules. We cover how the metal centers on CO dehydrogenase catalyze the interconversion of CO and CO(2) and how pyruvate oxidoreductase, which contains thiamin pyrophosphate and multiple Fe(4)S(4) clusters, catalyzes the addition and elimination of CO(2) during intermediary metabolism. We also describe how the nickel center at the active site of acetyl-CoA synthase utilizes CO to generate the central metabolite, acetyl-CoA, as part of the Wood-Ljungdahl pathway, and how CO is channelled from the CO dehydrogenase to the acetyl-CoA synthase active site. We cover how the corrinoid iron-sulfur protein interacts with acetyl-CoA synthase. This protein uses vitamin B(12) and a Fe(4)S(4) cluster to catalyze a key methyltransferase reaction involving an organometallic methyl-Co(3+) intermediate. Studies of CO and CO(2) enzymology are of practical significance, and offer fundamental insights into important biochemical reactions involving metallocenters that act as nucleophiles to form organometallic intermediates and catalyze C-C and C-S bond formations.
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Affiliation(s)
- Güneş Bender
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Elizabeth Pierce
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Jeffrey A. Hill
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Joseph E. Darty
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
| | - Stephen W. Ragsdale
- Department of Biological Chemistry, University of Michigan, Ann Arbor, Michigan 48109-0606, USA. Fax: +1 734-763-4581; Tel: +1 734-615-4621
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Ahmad MSA, Ashraf M. Essential roles and hazardous effects of nickel in plants. REVIEWS OF ENVIRONMENTAL CONTAMINATION AND TOXICOLOGY 2011; 214:125-167. [PMID: 21913127 DOI: 10.1007/978-1-4614-0668-6_6] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
With the world's ever increasing human population, the issues related to environmental degradation of toxicant chemicals are becoming more serious. Humans have accelerated the emission to the environment of many organic and inorganic pollutants such as pesticides, salts, petroleum products, acids, heavy metals, etc. Among different environmental heavy-metal pollutants, Ni has gained considerable attention in recent years, because of its rapidly increasing concentrations in soil, air, and water in different parts of the world. The main mechanisms by which Ni is taken up by plants are passive diffusion and active transport. Soluble Ni compounds are preferably absorbed by plants passively, through a cation transport system; chelated Ni compounds are taken up through secondary, active-transport-mediated means, using transport proteins such as permeases. Insoluble Ni compounds primarily enter plant root cells through endocytosis. Once absorbed by roots, Ni is easily transported to shoots via the xylem through the transpiration stream and can accumulate in neonatal parts such as buds, fruits, and seeds. The Ni transport and retranslocation processes are strongly regulated by metal-ligand complexes (such as nicotianamine, histidine, and organic acids) and by some proteins that specifically bind and transport Ni. Nickel, in low concentrations, fulfills a variety of essential roles in plants, bacteria, and fungi. Therefore, Ni deficiency produces an array of effects on growth and metabolism of plants, including reduced growth, and induction of senescence, leaf and meristem chlorosis, alterations in N metabolism, and reduced Fe uptake. In addition, Ni is a constituent of several metallo-enzymes such as urease, superoxide dismutase, NiFe hydrogenases, methyl coenzyme M reductase, carbon monoxide dehydrogenase, acetyl coenzyme-A synthase, hydrogenases, and RNase-A. Therefore, Ni deficiencies in plants reduce urease activity, disturb N assimilation, and reduce scavenging of superoxide free radical. In bacteria, Ni participates in several important metabolic reactions such as hydrogen metabolism, methane biogenesis, and acetogenesis. Although Ni is metabolically important in plants, it is toxic to most plant species when present at excessive amounts in soil and in nutrient solution. High Ni concentrations in growth media severely retards seed germinability of many crops. This effect of Ni is a direct one on the activities of amylases, proteases, and ribonucleases, thereby affecting the digestion and mobilization of food reserves in germinating seeds. At vegetative stages, high Ni concentrations retard shoot and root growth, affect branching development, deform various plant parts, produce abnormal flower shape, decrease biomass production, induce leaf spotting, disturb mitotic root tips, and produce Fe deficiency that leads to chlorosis and foliar necrosis. Additionally, excess Ni also affects nutrient absorption by roots, impairs plant metabolism, inhibits photosynthesis and transpiration, and causes ultrastructural modifications. Ultimately, all of these altered processes produce reduced yields of agricultural crops when such crops encounter excessive Ni exposures.
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Gagen EJ, Denman SE, Padmanabha J, Zadbuke S, Al Jassim R, Morrison M, McSweeney CS. Functional gene analysis suggests different acetogen populations in the bovine rumen and tammar wallaby forestomach. Appl Environ Microbiol 2010; 76:7785-95. [PMID: 20889794 PMCID: PMC2988603 DOI: 10.1128/aem.01679-10] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2010] [Accepted: 09/22/2010] [Indexed: 11/20/2022] Open
Abstract
Reductive acetogenesis via the acetyl coenzyme A (acetyl-CoA) pathway is an alternative hydrogen sink to methanogenesis in the rumen. Functional gene-based analysis is the ideal approach for investigating organisms capable of this metabolism (acetogens). However, existing tools targeting the formyltetrahydrofolate synthetase gene (fhs) are compromised by lack of specificity due to the involvement of formyltetrahydrofolate synthetase (FTHFS) in other pathways. Acetyl-CoA synthase (ACS) is unique to the acetyl-CoA pathway and, in the present study, acetyl-CoA synthase genes (acsB) were recovered from a range of acetogens to facilitate the design of acsB-specific PCR primers. fhs and acsB libraries were used to examine acetogen diversity in the bovine rumen and forestomach of the tammar wallaby (Macropus eugenii), a native Australian marsupial demonstrating foregut fermentation analogous to rumen fermentation but resulting in lower methane emissions. Novel, deduced amino acid sequences of acsB and fhs affiliated with the Lachnospiraceae in both ecosystems and the Ruminococcaeae/Blautia group in the rumen. FTHFS sequences that probably originated from nonacetogens were identified by low "homoacetogen similarity" scores based on analysis of FTHFS residues, and comprised a large proportion of FTHFS sequences from the tammar wallaby forestomach. A diversity of FTHFS and ACS sequences in both ecosystems clustered between the Lachnospiraceae and Clostridiaceae acetogens but without close sequences from cultured isolates. These sequences probably originated from novel acetogens. The community structures of the acsB and fhs libraries from the rumen and the tammar wallaby forestomach were different (LIBSHUFF, P < 0.001), and these differences may have significance for overall hydrogenotrophy in both ecosystems.
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Affiliation(s)
- Emma J Gagen
- CSIRO Livestock Industries, St. Lucia, Queensland 4067, Australia.
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Abstract
Frankly, I was surprised to receive an invitation to write a prefatory chapter for the Annual Review of Microbiology. I have read several such chapters written by outstanding researchers, many of whom I know and admire. I did not think I belonged to such a preeminent group. In my view, my contributions to the physiology and biochemistry of anaerobic thermophilic bacteria and, more lately, to anaerobic fungi are modest compared to the contribution made by other authors of prefatory chapters. I am honored to write about my life and my work, and I hope that those who read this chapter will sense how exciting and rewarding they have been.
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Affiliation(s)
- Lars G Ljungdahl
- Department of Biochemistry and Molecular Biology, The University of Georgia, Athens, Georgia 30602, USA.
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Strittmatter AW, Liesegang H, Rabus R, Decker I, Amann J, Andres S, Henne A, Fricke WF, Martinez-Arias R, Bartels D, Goesmann A, Krause L, Pühler A, Klenk HP, Richter M, Schüler M, Glöckner FO, Meyerdierks A, Gottschalk G, Amann R. Genome sequence of Desulfobacterium autotrophicum HRM2, a marine sulfate reducer oxidizing organic carbon completely to carbon dioxide. Environ Microbiol 2009; 11:1038-55. [PMID: 19187283 PMCID: PMC2702500 DOI: 10.1111/j.1462-2920.2008.01825.x] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2008] [Accepted: 10/25/2008] [Indexed: 01/23/2023]
Abstract
Sulfate-reducing bacteria (SRB) belonging to the metabolically versatile Desulfobacteriaceae are abundant in marine sediments and contribute to the global carbon cycle by complete oxidation of organic compounds. Desulfobacterium autotrophicum HRM2 is the first member of this ecophysiologically important group with a now available genome sequence. With 5.6 megabasepairs (Mbp) the genome of Db. autotrophicum HRM2 is about 2 Mbp larger than the sequenced genomes of other sulfate reducers (SRB). A high number of genome plasticity elements (> 100 transposon-related genes), several regions of GC discontinuity and a high number of repetitive elements (132 paralogous genes Mbp(-1)) point to a different genome evolution when comparing with Desulfovibrio spp. The metabolic versatility of Db. autotrophicum HRM2 is reflected in the presence of genes for the degradation of a variety of organic compounds including long-chain fatty acids and for the Wood-Ljungdahl pathway, which enables the organism to completely oxidize acetyl-CoA to CO(2) but also to grow chemolithoautotrophically. The presence of more than 250 proteins of the sensory/regulatory protein families should enable Db. autotrophicum HRM2 to efficiently adapt to changing environmental conditions. Genes encoding periplasmic or cytoplasmic hydrogenases and formate dehydrogenases have been detected as well as genes for the transmembrane TpII-c(3), Hme and Rnf complexes. Genes for subunits A, B, C and D as well as for the proposed novel subunits L and F of the heterodisulfide reductases are present. This enzyme is involved in energy conservation in methanoarchaea and it is speculated that it exhibits a similar function in the process of dissimilatory sulfate reduction in Db. autotrophicum HRM2.
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Affiliation(s)
- Axel W Strittmatter
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Heiko Liesegang
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Ralf Rabus
- Max Planck Institute for Marine MicrobiologyCelsiusstr. 1, D-28359 Bremen, Germany
- Institute for Chemistry and Biology of the Marine Environment (ICBM), Carl von Ossietzky University OldenburgCarl-von-Ossietzky Str. 9-11, D-26111 Oldenburg, Germany
| | - Iwona Decker
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Judith Amann
- Max Planck Institute for Marine MicrobiologyCelsiusstr. 1, D-28359 Bremen, Germany
| | - Sönke Andres
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Anke Henne
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Wolfgang Florian Fricke
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Rosa Martinez-Arias
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Daniela Bartels
- Center for Biotechnology (CeBiTec), Bielefeld UniversityUniversitätsstr. 37, D-33615 Bielefeld, Germany
| | - Alexander Goesmann
- Center for Biotechnology (CeBiTec), Bielefeld UniversityUniversitätsstr. 37, D-33615 Bielefeld, Germany
| | - Lutz Krause
- Center for Biotechnology (CeBiTec), Bielefeld UniversityUniversitätsstr. 37, D-33615 Bielefeld, Germany
| | - Alfred Pühler
- Lehrstuhl für Genetik, Fakultät für Biologie, Universität BielefeldD-33594 Bielefeld, Germany
| | - Hans-Peter Klenk
- DSMZ – Deutsche Sammlung von Mikroorganismen und Zellkulturen GmbHInhoffenstraße 7 B, D-38124 Braunschweig, Germany
| | - Michael Richter
- Max Planck Institute for Marine MicrobiologyCelsiusstr. 1, D-28359 Bremen, Germany
| | - Margarete Schüler
- Max Planck Institute for Marine MicrobiologyCelsiusstr. 1, D-28359 Bremen, Germany
| | | | - Anke Meyerdierks
- Max Planck Institute for Marine MicrobiologyCelsiusstr. 1, D-28359 Bremen, Germany
| | - Gerhard Gottschalk
- Göttingen Genomics Laboratory, Georg-August-UniversityGrisebachstr. 8, D-37077 Göttingen, Germany
| | - Rudolf Amann
- Max Planck Institute for Marine MicrobiologyCelsiusstr. 1, D-28359 Bremen, Germany
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Feng J, Lindahl PA. Effect of Sodium Sulfide on Ni-Containing Carbon Monoxide Dehydrogenases. J Am Chem Soc 2004; 126:9094-100. [PMID: 15264843 DOI: 10.1021/ja048811g] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structure of the active-site C-cluster in CO dehydrogenase from Carboxydothermus hydrogenoformans includes a mu(2)-sulfide ion bridged to the Ni and unique Fe, whereas the same cluster in enzymes from Rhodospirillum rubrum (CODH(Rr)) and Moorella thermoacetica (CODH(Mt)) lack this ion. This difference was investigated by exploring the effects of sodium sulfide on activity and spectral properties. Sulfide partially inhibited the CO oxidation activity of CODH(Rr) and generated a lag prior to steady-state. CODH(Mt) was inhibited similarly but without a lag. Adding sulfide to CODH(Mt) in the C(red1) state caused the g(av) = 1.82 EPR signal to decline and new features to appear, including one with g = 1.95, 1.85 and (1.70 or 1.62). Removing sulfide caused the g(av) = 1.82 signal to reappear and activity to recover. Sulfide did not affect the g(av) = 1.86 signal from the C(red2) state. A model was developed in which sulfide binds reversibly to C(red1), inhibiting catalysis. Reducing this adduct causes sulfide to dissociate, C(red2) to develop, and activity to recover. Using this model, apparent K(I) values are 40 +/- 10 nM for CODH(Rr) and 60 +/- 30 microM for CODH(Mt). Effects of sulfide are analogous to those of other anions, including the substrate hydroxyl group, suggesting that these ions also bridge the Ni and unique Fe. This proposed arrangement raises the possibility that CO binding labilizes the bridging hydroxyl and increases its nucleophilic tendency toward attacking Ni-bound carbonyl.
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Affiliation(s)
- Jian Feng
- Department of Chemistry, Texas A&M University, College Station, 77843-3255, USA
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Maynard EL, Tan X, Lindahl PA. Autocatalytic activation of acetyl-CoA synthase. J Biol Inorg Chem 2004; 9:316-22. [PMID: 15015040 DOI: 10.1007/s00775-004-0528-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2003] [Accepted: 02/02/2004] [Indexed: 11/30/2022]
Abstract
Acetyl-CoA synthase (ACS identical with ACS/CODH identical with CODH/ACS) from Moorella thermoacetica catalyzes the synthesis of acetyl-CoA from CO, CoA, and a methyl group of a corrinoid-iron-sulfur protein (CoFeSP). A time lag prior to the onset of acetyl-CoA production, varying from 4 to 20 min, was observed in assay solutions lacking the low-potential electron-transfer agent methyl viologen (MV). No lag was observed when MV was included in the assay. The length of the lag depended on the concentrations of CO and ACS, with shorter lags found for higher [ACS] and sub-saturating [CO]. Lag length also depended on CoFeSP. Rate profiles of acetyl-CoA synthesis, including the lag phase, were numerically simulated assuming an autocatalytic mechanism. A similar reaction profile was monitored by UV-vis spectrophotometry, allowing the redox status of the CoFeSP to be evaluated during this process. At early stages in the lag phase, Co(2+)FeSP reduced to Co(+)FeSP, and this was rapidly methylated to afford CH(3)-Co(3+)FeSP. During steady-state synthesis of acetyl-CoA, CoFeSP was predominately in the CH(3)-Co(3+)FeSP state. As the synthesis rate declined and eventually ceased, the Co(+)FeSP state predominated. Three activation reductive reactions may be involved, including reduction of the A- and C-clusters within ACS and the reduction of the cobamide of CoFeSP. The B-, C-, and D-clusters in the beta subunit appear to be electronically isolated from the A-cluster in the connected alpha subunit, consistent with the ~70 A distance separating these clusters, suggesting the need for an in vivo reductant that activates ACS and/or CoFeSP.
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Affiliation(s)
- Ernest L Maynard
- Department of Biophysics and Biophysical Chemistry, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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Loke HK, Tan X, Lindahl PA. Genetic construction of truncated and chimeric metalloproteins derived from the alpha subunit of acetyl-CoA synthase from Clostridium thermoaceticum. J Am Chem Soc 2002; 124:8667-72. [PMID: 12121109 DOI: 10.1021/ja025924w] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this study, a genetics-based method is used to truncate acetyl-coenzyme A synthase from Clostridium thermoaceticum (ACS), an alpha(2)beta(2) tetrameric 310 kDa bifunctional enzyme. ACS catalyzes the reversible reduction of CO(2) to CO and the synthesis of acetyl-CoA from CO (or CO(2) in the presence of low-potential reductants), CoA, and a methyl group bound to a corrinoid-iron sulfur protein (CoFeSP). ACS contains seven metal-sulfur clusters of four different types called A, B, C, and D. The B, C, and D clusters are located in the 72 kDa beta subunit, while the A-cluster, a Ni-X-Fe(4)S(4) cluster that serves as the active site for acetyl-CoA synthase activity, is located in the 82 kDa alpha subunit. The extent to which the essential properties of the cluster, including catalytic, redox, spectroscopic, and substrate-binding properties, were retained as ACS was progressively truncated was determined. Acetyl-CoA synthase catalytic activity remained when the entire beta subunit was removed, as long as CO, rather than CO(2) and a low-potential reductant, was used as a substrate. Truncating an approximately 30 kDa region from the N-terminus of the alpha subunit yielded a 49 kDa protein that lacked catalytic activity but exhibited A-cluster-like spectroscopic, redox, and CO-binding properties. Further truncation afforded a 23 kDa protein that lacked recognizable A-cluster properties except for UV-vis spectra typical of [Fe(4)S(4)](2+) clusters. Two chimeric proteins were constructed by fusing the gene encoding a ferredoxin from Chromatium vinosum to genes encoding the 49 and 82 kDa fragments of the alpha subunit. The chimeric proteins exhibited EPR signals that were not the simple sum of the signals from the separate proteins, suggesting magnetic interactions between clusters. This study highlights the potential for using genetics to simplify the study of complex multicentered metalloenzymes and to generate new complex metalloenzymes with interesting properties.
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Affiliation(s)
- Huay-Keng Loke
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
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Maynard EL, Lindahl PA. Catalytic coupling of the active sites in acetyl-CoA synthase, a bifunctional CO-channeling enzyme. Biochemistry 2001; 40:13262-7. [PMID: 11683635 DOI: 10.1021/bi015604+] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Acetogenic bacteria contain acetyl-CoA synthase (ACS), an enzyme with two distinct nickel-iron-sulfur active sites connected by a tunnel through which CO migrates. One site reduces CO2 to CO, while the other synthesizes acetyl-CoA from CO, CoA, and the methyl group of another protein (CH3-CP). Rapid binding of CO2 and a two-electron reduction activates ACS. When CoA and CH3-CP bind ACS, CO is rerouted through the tunnel to the synthase site, and kinetic parameters at the reductase site are altered. Under these conditions, the rates of CO2 reduction and acetyl-CoA synthesis are synchronized by an ordered catalytic mechanism.
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Affiliation(s)
- E L Maynard
- Department of Chemistry, Texas A&M University, College Station, Texas 77843-3255, USA
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Maynard EL, Sewell C, Lindahl PA. Kinetic mechanism of acetyl-CoA synthase: steady-state synthesis at variable Co/Co2 pressures. J Am Chem Soc 2001; 123:4697-703. [PMID: 11457278 DOI: 10.1021/ja004017t] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Steady-state initial rates of acetyl-CoA synthesis (upsilon/[E(tot)]) catalyzed by acetyl-CoA synthase from Clostridium thermoaceticum (ACS) were determined at various partial pressures of CO and CO2. When [CO] was varied from 0 to 100 microM in a balance of Ar, rates increased sharply from 0.3 to 100 min(-1). At [CO] > 100 microM, rates declined sharply and eventually stabilized at 10 min(-1) at 980 microM CO. Equivalent experiments carried out in CO2 revealed similar inhibitory behavior and residual activity under saturating [CO]. Plots of upsilon/[E(tot)] vs [CO2] at different fixed inhibitory [CO] revealed that Vmax/[E(tot)] (kcat) decreased with increasing [CO]. Plots of upsilon/[E(tot)] vs [CO2] at different fixed noninhibitory [CO] showed that Vmax/[E(tot)] was insensitive to changes in [CO]. Of eleven candidate mechanisms, the simplest one that fit the data best had the following key features: (a) either CO or CO2 (at a designated reductant level and pH) activate the enzyme (E' + CO right arrow over left arrow E, E' + CO2/2e-/2H+ right arrow over left arrow E); (b) CO and CO2 are both substrates that compete for the same enzyme form (E + CO right arrow over left arrow ECO, E + CO2/2e-/2H+ right arrow over left arrow ECO, and ECO --> E + P); (c) between 3 and 5 molecules of CO bind cooperatively to an enzyme form different from that to which CO2 and substrate CO bind (nCO + ECO right arrow over left arrow (CO)nECO), and this inhibits catalysis; and (d) the residual activity arises from either the (CO)nECO state or a heterogeneous form of the enzyme. Implications of these results, focusing on the roles of CO and CO2 in catalysis, are discussed.
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Affiliation(s)
- E L Maynard
- Department of Chemistry, Texas A&M University, College Station, Texas 77843, USA
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Das A, Coulter ED, Kurtz DM, Ljungdahl LG. Five-gene cluster in Clostridium thermoaceticum consisting of two divergent operons encoding rubredoxin oxidoreductase- rubredoxin and rubrerythrin-type A flavoprotein- high-molecular-weight rubredoxin. J Bacteriol 2001; 183:1560-7. [PMID: 11160086 PMCID: PMC95040 DOI: 10.1128/jb.183.5.1560-1567.2001] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
A five-gene cluster encoding four nonheme iron proteins and a flavoprotein from the thermophilic anaerobic bacterium Clostridium thermoaceticum (Moorella thermoacetica) was cloned and sequenced. Based on analysis of deduced amino acid sequences, the genes were identified as rub (rubredoxin), rbo (rubredoxin oxidoreductase), rbr (rubrerythrin), fprA (type A flavoprotein), and a gene referred to as hrb (high-molecular-weight rubredoxin). Northern blot analysis demonstrated that the five-gene cluster is organized as two subclusters, consisting of two divergently transcribed operons, rbr-fprA-hrb and rbo-rub. The rbr, fprA, and rub genes were expressed in Escherichia coli, and their encoded recombinant proteins were purified. The molecular masses, UV-visible absorption spectra, and cofactor contents of the recombinant rubrerythrin, rubredoxin, and type A flavoprotein were similar to those of respective homologs from other microorganisms. Antibodies raised against Desulfovibrio vulgaris Rbr reacted with both native and recombinant Rbr from C. thermoaceticum, indicating that this protein was expressed in the native organism. Since Rbr and Rbo have been recently implicated in oxidative stress protection in several anaerobic bacteria and archaea, we suggest a similar function of these proteins in oxygen tolerance of C. thermoaceticum.
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Affiliation(s)
- A Das
- Center for Biological Resource Recovery and Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia 30602-7229, USA
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15
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Loke HK, Bennett GN, Lindahl PA. Active acetyl-CoA synthase from Clostridium thermoaceticum obtained by cloning and heterologous expression of acsAB in Escherichia coli. Proc Natl Acad Sci U S A 2000; 97:12530-5. [PMID: 11050160 PMCID: PMC18798 DOI: 10.1073/pnas.220404397] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Acetyl-CoA synthase from Clostridium thermoaceticum (ACS(Ct)) is an alpha(2)beta(2) tetramer containing two novel Ni-X-Fe(4)S(4) active sites (the A and C clusters) and a standard Fe(4)S(4) cluster (the B cluster). The acsA and acsB genes encoding the enzyme were cloned into Escherichia coli strain JM109 and overexpressed at 37(o)C under anaerobic conditions with Ni supplementation. The isolated recombinant His-tagged protein (AcsAB) exhibited characteristics essentially indistinguishable from those of ACS(Ct), from which Ni had been removed from the A cluster. AcsAB migrated through nondenaturing electrophoretic gels as a single band and contained a 1:1 molar ratio of subunits and 1.0-1.6 Ni/alphabeta and 14-22 Fe/alphabeta. AcsAB exhibited 100-250 units/mg CO oxidation activity but no CO/acetyl-CoA exchange activity. Electronic absorption spectra of thionin-oxidized and CO-reduced AcsAB were similar to those of ACS(Ct), with features typical of redox-active Fe(4)S(4) clusters. Partially oxidized and CO-reduced AcsAB exhibited EPR signals with g values and low spin intensities indistinguishable from those of the B(red) state of the B cluster and the C(red1) and C(red2) states of the C cluster of ACS(Ct). Upon overnight exposure to NiCl(2), the resulting recombinant enzyme (ACS(Ec)) developed 0. 06-0.25 units/mg exchange activity. The highest of these values is typical of fully active ACS(Ct). When reduced with CO, ACS(Ec) exhibited an EPR signal indistinguishable from the NiFeC signal of Ni-replete ACS(Ct). Variability of activities and signal intensities were observed among different preparations. Issues involving the assembly of these metal centers in E. coli are discussed.
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Affiliation(s)
- H K Loke
- Departments of Chemistry and Biochemistry and Biophysics, Texas A&M University, College Station, TX 77843, USA
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16
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González JM, Robb FT. Genetic analysis of Carboxydothermus hydrogenoformans carbon monoxide dehydrogenase genes cooF and cooS. FEMS Microbiol Lett 2000; 191:243-7. [PMID: 11024270 DOI: 10.1111/j.1574-6968.2000.tb09346.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
Carboxydothermus hydrogenoformans is an extremely thermophilic, Gram-positive bacterium growing on carbon monoxide (CO) as single carbon and energy source and producing only H(2) and CO(2). Carbon monoxide dehydrogenase is a key enzyme for CO metabolism. The carbon monoxide dehydrogenase genes cooF and cooS from C. hydrogenoformans were cloned and sequenced. These genes showed the highest similarity to the cooF genes from the archaeon Archaeoglobus fulgidus and the cooS gene from the bacterium Rhodospirillum rubrum, respectively. The cooS gene was identified immediately downstream of cooF, however, the cooF and cooS genes from C. hydrogenoformans have substantially different codon usage, and the cooF gene Arg codon usage pattern, dominated by AGA and AGG, resembles the archaeal pattern. The data therefore suggest lateral transfer of these genes, possibly from different donor species.
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Affiliation(s)
- J M González
- Center of Marine Biotechnology, University of Maryland Biotechnology Institute, 701 E. Pratt St., Baltimore, MD, 21202, USA
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17
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Fraser DM, Lindahl PA. Evidence for a proposed intermediate redox state in the CO/CO(2) active site of acetyl-CoA synthase (Carbon monoxide dehydrogenase) from Clostridium thermoaceticum. Biochemistry 1999; 38:15706-11. [PMID: 10625436 DOI: 10.1021/bi990398f] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
When samples of the enzyme in the C(red1) state were reduced with Ti(3+) citrate, the C-cluster stabilized in an EPR-silent state. Subsequent treatment with CO or dithionite yielded C(red2). The EPR-silent state formed within 1 min of adding Ti(3+) citrate, while C(red2) formed after 60 min. Ti(3+) citrate appeared to slow the rate by which C(red2) formed from C(red1) and stabilize the C-cluster in the previously proposed C(int) state. This is the first strong evidence for C(int), and it supports the catalytic mechanism that required its existence. This mechanism is analogous to those used by flavins and hydrogenases to convert between n = 2 and n = 1 processes. Ti(3+) citrate had a different effect on enzyme in a CO(2) atmosphere; it shifted reduction potentials of metal centers (relative to those obtained using CO) and did not stabilize C(int). Different redox behavior was also observed when methyl viologen and benzyl viologen were used as reductants. This variability was exploited to prepare enzyme samples in which EPR from C(red2) was present without interfering signals from B(red). The saturation properties of B(red) depended upon the redox state of the enzyme. Three saturation "modes", called Sat1-Sat3, were observed. Sat1 was characterized by a sharp g = 1.94 resonance and low-intensity g = 2. 04 and 1.90 resonances, and was observed in samples poised at slightly negative potentials. Sat2 was characterized by weak intensity from all three resonances, and was strictly associated with intermediate redox states and the presence of CO(2). Sat3 was characterized by strong broad resonances with normalized intensities essentially unchanged relative to nonsaturating conditions, and was observed at the most negative potentials. Each mode probably reflects different spatial relationships among magnetic components in the enzyme.
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Affiliation(s)
- D M Fraser
- Departments of Chemistry and of Biochemistry and Biophysics, Texas A&M University, College Station, Texas 77842, USA
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18
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Staples CR, Heo J, Spangler NJ, Kerby RL, Roberts GP, Ludden PW. Rhodospirillum rubrum CO-Dehydrogenase. Part 1. Spectroscopic Studies of CODH Variant C531A Indicate the Presence of a Binuclear [FeNi] Cluster. J Am Chem Soc 1999. [DOI: 10.1021/ja990396i] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Christopher R. Staples
- Contribution from the Departments of Biochemistry and Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Jongyun Heo
- Contribution from the Departments of Biochemistry and Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Nathan J. Spangler
- Contribution from the Departments of Biochemistry and Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Robert L. Kerby
- Contribution from the Departments of Biochemistry and Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Gary P. Roberts
- Contribution from the Departments of Biochemistry and Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Paul W. Ludden
- Contribution from the Departments of Biochemistry and Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706
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19
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Fontecilla-Camps JC, Ragsdale SW. Nickel–Iron–Sulfur Active Sites: Hydrogenase and Co Dehydrogenase. ADVANCES IN INORGANIC CHEMISTRY 1999. [DOI: 10.1016/s0898-8838(08)60081-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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20
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Abstract
Methanoarchaea, the largest and most phylogenetically diverse group in the Archaea domain, have evolved energy-yielding pathways marked by one-carbon biochemistry featuring novel cofactors and enzymes. All of the pathways have in common the two-electron reduction of methyl-coenzyme M to methane catalyzed by methyl-coenzyme M reductase but deviate in the source of the methyl group transferred to coenzyme M. Most of the methane produced in nature derives from acetate in a pathway where the activated substrate is cleaved by CO dehydrogenase/acetyl-CoA synthase and the methyl group is transferred to coenzyme M via methyltetrahydromethanopterin or methyltetrahydrosarcinapterin. Electrons for reductive demethylation of the methyl-coenzyme M originate from oxidation of the carbonyl group of acetate to carbon dioxide by the synthase. In the other major pathway, formate or H2 is oxidized to provide electrons for reduction of carbon dioxide to the methyl level and reduction of methyl-coenzyme to methane. Methane is also produced from the methyl groups of methanol and methylamines. In these pathways specialized methyltransferases transfer the methyl groups to coenzyme M. Electrons for reduction of the methyl-coenzyme M are supplied by oxidation of the methyl groups to carbon dioxide by a reversal of the carbon dioxide reduction pathway. Recent progress on the enzymology of one-carbon reactions in these pathways has raised the level of understanding with regard to the physiology and molecular biology of methanogenesis. These advances have also provided a foundation for future studies on the structure/function of these novel enzymes and exploitation of the recently completed sequences for the genomes from the methanoarchaea Methanobacterium thermoautotrophicum and Methanococcus jannaschii.
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Affiliation(s)
- J G Ferry
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park 16801, USA.
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21
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Arendsen AF, Lindley PF. The Search for A “Prismane” Fe–S Protein. ADVANCES IN INORGANIC CHEMISTRY 1999. [DOI: 10.1016/s0898-8838(08)60079-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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DiRusso CC, Tsvetnitsky V, Højrup P, Knudsen J. Fatty acyl-CoA binding domain of the transcription factor FadR. Characterization by deletion, affinity labeling, and isothermal titration calorimetry. J Biol Chem 1998; 273:33652-9. [PMID: 9837950 DOI: 10.1074/jbc.273.50.33652] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Escherichia coli transcription factor FadR regulates genes required for fatty acid biosynthesis and degradation in an opposing manner. It is acting as an activator of biosynthetic genes and a repressor of degradative genes. The DNA binding of FadR to regions within the promoters of responsive genes and operons is inhibited by long chain acyl-CoA thioesters but not free fatty acids or coenzyme A. The acyl-CoA binding domain of FadR was localized by affinity labeling of the full-length protein and an amino-terminal deletion derivative, FadRDelta1-167, with a palmitoyl-CoA analogue, 9-p-azidophenoxy[9-3H]nonanoic acid-CoA ester. Analysis of labeled peptides generated by tryptic digestion of the affinity-labeled proteins identified one peptide common to both the full-length protein and the deletion derivative. The amino-terminal sequence of the labeled peptide was SLALGFYHK, which corresponds to amino acids 187-195 in FadR. Isothermal titration calorimetry was used to estimate affinity of the wild-type full-length FadR, a His-tagged derivative, and FadRDelta1-167 for acyl-CoA. The binding was characterized by a large negative DeltaH0, -16 to -20 kcal mol-1. No binding was detected for the medium chain ligand C8-CoA. Full-length wild-type FadR and His6-FadR bound oleoyl-CoA and myristoyl-CoA with similar affinities, Kd of 45 and 63 nM and 68 and 59 nM, respectively. The Kd for palmitoyl-CoA binding was about 5-fold higher despite the fact that palmitoyl-CoA is 50-fold more efficient in inhibiting FadR binding to DNA than myristoyl-CoA. The results indicate that both acyl-CoA chain length and the presence of double bonds in the acyl chain affect FadR ligand binding.
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Affiliation(s)
- C C DiRusso
- Department of Biochemistry and Molecular Biology, Albany Medical College, Albany, New York 12208, USA
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23
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Spangler NJ, Meyers MR, Gierke KL, Kerby RL, Roberts GP, Ludden PW. Substitution of valine for histidine 265 in carbon monoxide dehydrogenase from Rhodospirillum rubrum affects activity and spectroscopic states. J Biol Chem 1998; 273:4059-64. [PMID: 9461598 DOI: 10.1074/jbc.273.7.4059] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
In carbon monoxide dehydrogenase (CODH) from Rhodospirillum rubrum, histidine 265 was replaced with valine by site-directed mutagenesis of the cooS gene. The altered form of CODH (H265V) had a low nickel content and a dramatically reduced level of catalytic activity. Although treatment with NiCl2 and CoCl2 increased the activity of H265V CODH by severalfold, activity levels remained more than 1000-fold lower than that of wild-type CODH. Histidine 265 was not essential for the formation and stability of the Fe4S4 clusters. The Km and KD for CO as well as the KD for cyanide were relatively unchanged as a result of the amino acid substitution in CODH. The time-dependent reduction of the [Fe4S4]2+ clusters by CO occurred on a time scale of hours, suggesting that, as a consequence of the mutation, a rate-limiting step had been introduced prior to the transfer of electrons from CO to the cubanes in centers B and C. EPR spectra of H265V CODH lacked the gav = 1.86 and gav = 1.87 signals characteristic of reduced forms of the active site (center C) of wild-type CODH. This indicates that the electronic properties of center C have been modified possibly by the disruption or alteration of the ligand-mediated interaction between the nickel site and Fe4S4 chromophore.
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Affiliation(s)
- N J Spangler
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin-Madison, Madison, Wisconsin 53706, USA
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24
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Das A, Ljungdahl LG. Composition and primary structure of the F1F0 ATP synthase from the obligately anaerobic bacterium Clostridium thermoaceticum. J Bacteriol 1997; 179:3746-55. [PMID: 9171425 PMCID: PMC179173 DOI: 10.1128/jb.179.11.3746-3755.1997] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The subunit composition and primary structure of the proton-translocating F1F0 ATP synthase have been determined in Clostridium thermoaceticum. The isolated enzyme has a subunit composition identical to that of the F1F0 ATP synthase purified from Clostridium thermoautotrophicum (A. Das, D. M. Ivey, and L. G. Ljungdahl, J. Bacteriol. 179:1714-1720, 1997), both having six different polypeptides. The molecular masses of the six subunits were 60, 50, 32, 17, 19, and 8 kDa, and they were identified as alpha, beta, gamma, delta, epsilon, and c, respectively, based on their reactivity with antibodies against the F1 ATPase purified from C. thermoautotrophicum and by comparing their N-terminal amino acid sequences with that deduced from the cloned genes of the C. thermoaceticum atp operon. The subunits a and b found in many bacterial ATP synthases could not be detected either in the purified ATP synthase or crude membranes of C. thermoaceticum. The C. thermoaceticum atp operon contained nine genes arranged in the order atpI (i), atpB (a), atpE (c), atpF (b), atpH (delta), atpA (alpha), atpG (gamma), atpD (beta), and atpC (epsilon). The deduced protein sequences of the C. thermoaceticum ATP synthase subunits were comparable with those of the corresponding subunits from Escherichia coli, thermophilic Bacillus strain PS3, Rhodospirillum rubrum, spinach chloroplasts, and the cyanobacterium Synechococcus strain PCC 6716. The analysis of total RNA by Northern hybridization experiments reveals the presence of transcripts (mRNA) of the genes i, a, and b subunits not found in the isolated enzyme. Analysis of the nucleotide sequence of the atp genes reveals overlap of the structural genes for the i and a subunits and the presence of secondary structures (in the b gene) which could influence the posttranscriptional regulation of the corresponding genes.
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Affiliation(s)
- A Das
- Center for Biological Resource Recovery and Department of Biochemistry and Molecular Biology, University of Georgia, Athens 30602, USA
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25
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Barondeau DP, Lindahl PA. Methylation of Carbon Monoxide Dehydrogenase fromClostridium thermoaceticumand Mechanism of Acetyl Coenzyme A Synthesis. J Am Chem Soc 1997. [DOI: 10.1021/ja963597k] [Citation(s) in RCA: 92] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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26
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Abstract
Biologically-produced CH4 derives from either the reduction of CO2 or the methyl group of acetate by two separate pathways present in anaerobic mierobes from the Archaea domain. Elucidation of the pathway for CO2 reduction to CH4, the first to be investigated, has yielded several novel enzymes and cofactors. Most of the CH4 produced in nature derives from the methyl group of acetate. Methanosarcina thermophila is a moderate thermophile which ferments acetate by reducing the methyl group to CH4 with electrons derived from oxidation of the carbonyl group to CO2. The pathway in M. thermophila is now understood on a biochemical and genetic level comparable to understanding of the CO2-reducing pathway. Enzymes have been purified and characterized. The genes encoding these enzymes have been cloned, sequenced, transcriptionally mapped, and their regulation defined on a molecular level. This review emphasizes recent developments concerning the enzymes which are unique to the acetate fermentation pathway in M. thermophila.
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Affiliation(s)
- J G Ferry
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park 16802-4500, USA
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27
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Maupin-Furlow JA, Ferry JG. Analysis of the CO dehydrogenase/acetyl-coenzyme A synthase operon of Methanosarcina thermophila. J Bacteriol 1996; 178:6849-56. [PMID: 8955306 PMCID: PMC178585 DOI: 10.1128/jb.178.23.6849-6856.1996] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
The cdhABC genes encoding the respective alpha, epsilon, and beta subunits of the five-subunit (alpha, beta, gamma, delta, and epsilon) CO dehydrogenase/acetyl-coenzyme synthase (CODH/ACS) complex from Methanosarcina thermophila were cloned and sequenced. Northern (RNA) blot analyses indicated that the cdh genes encoding the five subunits and an open reading frame (ORF1) with unknown function are cotranscribed during growth on acetate. Northern blot and primer extension analyses suggested that mRNA processing and multiple promoters may be involved in cdh transcript synthesis. The putative CdhA (alpha subunit) and CdhB (epsilon subunit) proteins each have 40% identity to CdhA and CdhB of the CODH/ACS complex from Methanosaeta soehngenii. The cdhC gene encodes the beta subunit (CdhC) of the CODH/ACS complex from M. thermophila. The N-terminal 397 amino acids of CdhC are 42% identical to the C-terminal half of the alpha subunit of CODH/ACS from the acetogenic anaerobe Clostridium thermoaceticum. Sequence analysis suggested potential structures and functions for the previously uncharacterized beta subunit from M. thermophila. The deduced protein sequence of ORF1, located between the cdhC and cdhD genes, has 29% identity to NifH2 from Methanobacterium ivanovii.
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Affiliation(s)
- J A Maupin-Furlow
- Department of Biochemistry and Molecular Biology, Pennsylvania State University, University Park 16802-4500, USA
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28
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Ragsdale SW, Kumar M. Nickel-Containing Carbon Monoxide Dehydrogenase/Acetyl-CoA Synthase(,). Chem Rev 1996; 96:2515-2540. [PMID: 11848835 DOI: 10.1021/cr950058+] [Citation(s) in RCA: 263] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Stephen W. Ragsdale
- Department of Biochemistry, Beadle Center, University of Nebraska, Lincoln, Nebraska 68588-0664
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29
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Anderson ME, Lindahl PA. Spectroscopic states of the CO oxidation/CO2 reduction active site of carbon monoxide dehydrogenase and mechanistic implications. Biochemistry 1996; 35:8371-80. [PMID: 8679595 DOI: 10.1021/bi952902w] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
CO dehydrogenases catalyze the reversible oxidation of CO to CO2, at an active site (called the C-cluster) composed of an Fe4S4 cube with what appears to be a 5-coordinate Fe (called FCII), linked to a Ni (Hu, Z., Spangler, N. J., Anderson, M. E., Xia, J., Ludden, P. W., Lindahl, P. A., & Münck, E. (1996) J. Am. Chem. Soc. 118, 830-845). During catalysis, electrons are transferred from the C-cluster to an [Fe4S4]2+/1+ electron-transfer cluster called the B-cluster. An S = 1/2 form of the C-cluster (called Cred1) converts to another S = 1/2 form (called Cred2) upon reduction with CO, at a rate well within the turnover frequency of the enzyme (Kumar, M., Lu, W.-P., Liu, L., & Ragsdale, S. W. (1993) J. Am. Chem. Soc. 115, 11646-11647). This suggests that the conversion is part of the catalytic mechanism. Dithionite is reported in this paper to effect this conversion as well, but at a much slower rate (kso = 5.3 x 10(-2) M-1 s-1 for dithionite vs 4.4 x 10(6) M-1 s-1 for CO). By contrast, dithionite reduces the oxidized B-cluster much faster, possibly within the turnover frequency of the enzyme. Dithionite apparently effects the Cred1/Cred2 conversion directly, rather than through an intermediate. The conversion rate varies with dithionite concentration. The Cred1/Cred2 conversion occurs at least 10(2) times faster in the presence of CO2 than in its absence. CO2 alters the g values of the gav = 1.82 signal, indicating that CO2 binds to a C-cluster-sensitive site at mild potentials. CN- inhibits CO oxidation by binding to FCII (Hu et al., 1996), and CO, CO2 in the presence of dithionite, or CS2 in dithionite accelerate CN- dissociation from this site (Anderson, M. E., & Lindahl, P. A. (1994) Biochemistry 33, 8702-8711). The effect of CO, CO2, and CS2 on CN- dissociation suggested that these molecules bind at a site (called the modulator) other than that to which CN- binds. The effects of CO2, CS2, CO, and dithionite on the Cred1/Cred2 conversion rate followed a similar pattern, suggesting that this rate is also influenced by modulator binding. Some batches of enzyme cannot convert to the Cred2 form using dithionite, but pretreatment with CO or CO2/dithionite effectively "cures" such batches of this disability. The results presented suggest that the Ni of the C-cluster is the modulator and the substrate binding site for CO/CO2. The inhibitor CS2 in the presence of dithionite also accelerates the decline of Cred1, leading first to an EPR-silent state of the C-cluster, and eventually to a state yielding an EPR signal with gav = 1.66. CS2 binding thus shares some resemblance to CO2 binding. Approximately 90% of the absorbance changes at 420 nm that occur when oxidized CODHCt is reduced by dithionite occur within 2 min at 10 degrees C. This absorbance change occurs in concert with the gav = 1.94 signal development. The remaining 10% of the A420 changes occur over the course of approximately 50 min, apparently coincident with the Cred1/Cred2 conversion. One possibility is that the conversion involves reduction of an (unidentified) Fe-S cluster. A three-state model of catalysis is proposed in which Cred1 binds and oxidizes CO, Cred2 is two electrons more reduced than Cred1 and is the state that binds and reduces CO2, and Cint is a one-electron-reduced state that is proposed to exist because of constraints imposed by the nature of the CO/CO2 reaction and the properties of the clusters involved in catalysis.
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Affiliation(s)
- M E Anderson
- Department of Chemistry, Texas A & M University, College Station 77843, USA
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Eggen RI, van Kranenburg R, Vriesema AJ, Geerling AC, Verhagen MF, Hagen WR, de Vos WM. Carbon monoxide dehydrogenase from Methanosarcina frisia Gö1. Characterization of the enzyme and the regulated expression of two operon-like cdh gene clusters. J Biol Chem 1996; 271:14256-63. [PMID: 8662887 DOI: 10.1074/jbc.271.24.14256] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Carbon monoxide dehydrogenase (Cdh) has been anaerobically purified from Methanosarcina frisia Gö1. The enzyme is a Ni2+-, Fe2+-, and S2--containing alpha2beta2 heterotetramer of 214 kDa with a pI of 5.2 and subunits of 94 and 19 kDa. It has a Vmax of 0.3 mmol of CO min-1 mg-1 and Km values for CO and methyl viologen of approximately 0.9 mM and 0.12 mM, respectively. EPR spectroscopy on the reduced enzyme showed two overlapping signals: one indicative for 2 (4Fe-4S)+ clusters and a second signal that is atypical for standard Fe/S clusters. The latter was, together with high-spin EPR signals of the oxidized enzyme tentatively assigned to an Fe/S cluster of high nuclearity.
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Affiliation(s)
- R I Eggen
- Department of Microbiology, Wageningen Agricultural University, Wageningen 6703 CT, The Netherlands
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31
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Spangler NJ, Lindahl PA, Bandarian V, Ludden PW. Spectroelectrochemical characterization of the metal centers in carbon monoxide dehydrogenase (CODH) and nickel-deficient CODH from Rhodospirillum rubrum. J Biol Chem 1996; 271:7973-7. [PMID: 8626477 DOI: 10.1074/jbc.271.14.7973] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
Carbon-monoxide dehydrogenase (CODH) from Rhodospirillum rubrum contains two metal centers: a Ni-X-[Fe4S4]2+/1+ cluster (C-center) that serves as the COoxidation site and a standard [Fe4S4]2+/1+ cluster (B-center) that mediates electron flow from the C-center to external electron acceptors. Four states of the C-center were previously identified in electron paramagnetic resonance (EPR) and Mössbauer studies. In this report, EPR-redox titrations demonstrate that the fully oxidized, diamagnetic form of the C-center (Cox) undergoes a one-electron reduction to the Cred1 state (gav = 1.87) with a midpoint potential of -110 mV. The reduction of Cox to Cred1 is shown to coincide with the reduction of an [Fe4S4]2+/1+ cluster in redox-titration experiments monitored by UV-visible spectroscopy. Nickel-deficient CODH, which is devoid of nickel yet contains both [Fe4S4]2+/1+ clusters, does not exhibit EPR-active states or reduced Fe4S4 clusters at potentials more positive than -350 mV.
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Affiliation(s)
- N J Spangler
- Department of Biochemistry, College of Agricultural and Life Sciences, University of Wisconsin, Madison, Wisconsin 53706, USA
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32
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Xia J, Sinclair JF, Baldwin TO, Lindahl PA. Carbon monoxide dehydrogenase from Clostridium thermoaceticum: quaternary structure, stoichiometry of its SDS-induced dissociation, and characterization of the faster-migrating form. Biochemistry 1996; 35:1965-71. [PMID: 8639680 DOI: 10.1021/bi9511853] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The molecular mass (M(r)) of the nickel- and iron-sulfur-containing enzyme CO dehydrogenase from Clostridium thermoaceticum was determined by sedimentation equilibrium ultracentrifugation to be 300,000 +/- 30,000 Da. Since the enzyme is known to contain equal numbers of two types of subunits (M(r) = 82,000 Da for alpha and 73,000 Da for beta), this indicates an alpha 2 beta 2 quaternary structure. The enzyme was previously thought to have an alpha 3 beta 3 structure because it migrates through calibrated size-exclusion chromatographic columns with an apparent M(r) of about 420,000 Da. The disproportionately fast migration rate suggests that the enzyme is nonspherical. SDS induces the dissociation of an alpha subunit, yielding a stable species called FM-CODH. FM-CODH had a molecular mass of 210,000 +/- 30,000 Da, indicating an alpha 1 beta 2 structure. It contained 2.1 +/- 0.3 Ni and 16 +/- 3 Fe per alpha 1 beta 2, exhibited S-->Fe charge-transfer transitions typical of Fe-S proteins, and afforded the gav = 1.82, 1.86, and 1.94 EPR signals. Quantitation of the 1.82 and (1.94 +/- 1.86) signals afforded 0.35 and 1.9 spin/alpha 1 beta 2, respectively. FM-CODH samples exhibited CO oxidation activity, but little CO/acetyl-CoA exchange activity. Some FM-CODH samples exhibited CO oxidation activities as high as native enzyme. These results, along with the quantified spin intensities of the EPR signals, indicate that FM-CODH contains the B- and C-clusters and suggest that these clusters are located in the beta subunit. The alpha subunit that dissociated during formation of FM-CODH is not required for CO oxidation activity. FM-CODH is either devoid of A-clusters, or if such clusters are present, they have lost their ability to exhibit substantial NiFeC signals and CO/acetyl-CoA exchange activity. Incubating FM-CODH and alpha yielded a species that migrated through polyacrylamide gels at the same rate as native enzyme, and had a molecular mass indicating an alpha 2 beta 2 structure. Thus, the SDS-induced dissociation of the enzyme appears to be reversible.
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Affiliation(s)
- J Xia
- Department of Chemistry, Texas A&M University, College Station 77843, USA
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33
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Hu Z, Spangler NJ, Anderson ME, Xia J, Ludden PW, Lindahl PA, Münck E. Nature of the C-Cluster in Ni-Containing Carbon Monoxide Dehydrogenases. J Am Chem Soc 1996. [DOI: 10.1021/ja9528386] [Citation(s) in RCA: 83] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Zhengguo Hu
- Contribution from the Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Texas A & M University, College Station, Texas 77843, and Department of Biochemistry, College of Agricultural and Life Sciences, University of WisconsinMadison, Madison, Wisconsin 53706
| | - Nathan J. Spangler
- Contribution from the Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Texas A & M University, College Station, Texas 77843, and Department of Biochemistry, College of Agricultural and Life Sciences, University of WisconsinMadison, Madison, Wisconsin 53706
| | - Mark E. Anderson
- Contribution from the Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Texas A & M University, College Station, Texas 77843, and Department of Biochemistry, College of Agricultural and Life Sciences, University of WisconsinMadison, Madison, Wisconsin 53706
| | - Jinqiang Xia
- Contribution from the Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Texas A & M University, College Station, Texas 77843, and Department of Biochemistry, College of Agricultural and Life Sciences, University of WisconsinMadison, Madison, Wisconsin 53706
| | - Paul W. Ludden
- Contribution from the Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Texas A & M University, College Station, Texas 77843, and Department of Biochemistry, College of Agricultural and Life Sciences, University of WisconsinMadison, Madison, Wisconsin 53706
| | - Paul A. Lindahl
- Contribution from the Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Texas A & M University, College Station, Texas 77843, and Department of Biochemistry, College of Agricultural and Life Sciences, University of WisconsinMadison, Madison, Wisconsin 53706
| | - Eckard Münck
- Contribution from the Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, Department of Chemistry, Texas A & M University, College Station, Texas 77843, and Department of Biochemistry, College of Agricultural and Life Sciences, University of WisconsinMadison, Madison, Wisconsin 53706
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34
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Xia J, Lindahl PA. Assembly of an Exchange-Coupled [Ni:Fe4S4] Cluster in the α Metallosubunit of Carbon Monoxide Dehydrogenase from Clostridium thermoaceticum with Spectroscopic Properties and CO-Binding Ability Mimicking Those of the Acetyl-CoA Synthase Active Site. J Am Chem Soc 1996. [DOI: 10.1021/ja952845u] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Jinqiang Xia
- Department of Chemistry, Texas A & M University College Station, Texas 77843
| | - Paul A. Lindahl
- Department of Chemistry, Texas A & M University College Station, Texas 77843
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35
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Raman N, DiRusso CC. Analysis of acyl coenzyme A binding to the transcription factor FadR and identification of amino acid residues in the carboxyl terminus required for ligand binding. J Biol Chem 1995; 270:1092-7. [PMID: 7836365 DOI: 10.1074/jbc.270.3.1092] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The Escherichia coli FadR protein regulates the transcription of many unlinked genes and operons encoding proteins required for fatty acid synthesis and degradation. Previously, we demonstrated that the ability of purified FadR to bind DNA in vitro is inhibited by long chain acyl coenzyme A esters (DiRusso, D. D., Heimert, T. L., and Metzger, A. K. (1992) J. Biol. Chem. 267, 8685-8691). In the present work, we show that FadR binds acyl-CoA directly. Ligand binding resulted in a shift in the apparent pI of FadR from 6.9 to 6.2 and in a marked decrease in intrinsic fluorescence. The Km for FadR binding of oleoyl coenzyme A was determined to be 12.1 nM using the fluorescence quenching assay. The binding site for acyl-CoA was identified by selection of non-inducible mutations in the FadR gene. One altered protein carrying the change Ser219 to Asn (S219N) was purified and shown to have a reduced affinity for oleoyl coenzyme A as evidenced by a Km of 257 nM. S219N retained the ability to bind DNA and to repress or activate transcription. Alanine substitution of amino acid residues 215 through 230 identified Gly216 and Trp223 as also required specifically for induction. This region of FadR shares amino acid identities and similarities with the coenzyme A-binding site of Clostridium thermoaceticum CO dehydrogenase/acetyl-coenzyme A synthase. Due to the alteration in binding affinity of the purified S219N protein, the non-inducible phenotype of several proteins carrying alanine substitutions and similarities to CO dehydrogenase/acetyl-coenzyme A synthase we propose this region of FadR forms part of the acyl-CoA-binding domain.
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Affiliation(s)
- N Raman
- Department of Biochemistry, University of Tennessee, Memphis 38163
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36
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Roberts DL, Zhao S, Doukov T, Ragsdale SW. The reductive acetyl coenzyme A pathway: sequence and heterologous expression of active methyltetrahydrofolate:corrinoid/iron-sulfur protein methyltransferase from Clostridium thermoaceticum. J Bacteriol 1994; 176:6127-30. [PMID: 7928975 PMCID: PMC196833 DOI: 10.1128/jb.176.19.6127-6130.1994] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
The methyltransferase (MeTr) from Clostridium thermoaceticum transfers the N5-methyl group of (6S)-methyltetrahydrofolate to the cobalt center of a corrinoid/iron-sulfur protein in the acetyl coenzyme A pathway. MeTr was purified to homogeneity and shown to lack metals. The acsE gene encoding MeTr was sequenced and actively expressed in Escherichia coli at a level of 9% of cell protein. Regions in the sequence of MeTr and the E. coli cobalamin-dependent methionine synthase were found to share significant homology, suggesting that they may represent tetrahydrofolate-binding domains.
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Affiliation(s)
- D L Roberts
- Department of Biochemistry, University of Nebraska, Lincoln 68583-0718
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37
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Abstract
Four microbial enzymes are known to require nickel: hydrogenase, methyl coenzyme M reductase, carbon monoxide dehydrogenase, and urease. Recent biochemical and molecular biological experiments have provided clear evidence for the existence of multiple auxiliary genes that facilitate nickel incorporation into urease and hydrogenase. Similarly, accessory factors are also likely to be required for the other two enzymes. One of the urease-related genes (ureE) encodes a cytoplasmic protein that has been purified and shown to bind nickel reversibly. We propose that the UreE protein serves as a nickel donor to urease apoprotein. A second urease-related auxiliary gene (ureG) possesses a sequence motif that is found in ATP- and GTP-binding proteins. We have shown that nickel incorporation into urease requires energy and speculate that the UreG protein may serve as an energy transducer, coupling the energy of NTP hydrolysis to metallocenter incorporation. The UreG protein is related in sequence to HypB, a protein that has been proposed to function in nickel processing in hydrogenases. Hence, the mechanisms for metallocenter biosynthesis in these two dissimilar enzymes may have evolved from a common nickel incorporation system.
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Affiliation(s)
- R P Hausinger
- Department of Microbiology, Michigan State University, East Lansing 48824
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38
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Characterization of the metal centers of the Ni/Fe-S component of the carbon-monoxide dehydrogenase enzyme complex from Methanosarcina thermophila. J Biol Chem 1994. [DOI: 10.1016/s0021-9258(17)36944-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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39
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Shanmugasundaram T, Sundaresh CS, Kumar GK. Identification of a cysteine involved in the interaction between carbon monoxide dehydrogenase and corrinoid/Fe-S protein from Clostridium thermoaceticum. FEBS Lett 1993; 326:281-4. [PMID: 8325380 DOI: 10.1016/0014-5793(93)81808-d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
In Clostridium thermoaceticum, the synthesis of acetyl-CoA from methyl tetrahydrofolate occurs via a series of enzymatic reactions involving methyl transferase, corrinoid/Fe-S protein (corrinoid), carbon monoxide dehydrogenase (CODH) and ferredoxin. We have investigated the possibility of one or more of these proteins existing as multi-enzyme complexes in vivo with higher catalytic activity. A protein complex consisting of CODH and corrinoid was isolated from the cell-free extracts of Clostridium thermoaceticum. The acetyl-CoA synthesis was found to be approximately 1.8-fold higher with the complex than that observed with the isolated protein components. HPLC gel filtration analyses of the native and DTE reduced complex suggested that the CODH:corrinoid complex is held together primarily by an inter disulfide bond. By differential labeling of thiols with [14C]N-ethylmaleimide it was found that Cys-506 of the alpha subunit of CODH was involved in the disulfide linkage with the corrinoid of the complex.
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Affiliation(s)
- T Shanmugasundaram
- Department of Biochemistry, Case Western Reserve University, Cleveland, OH 44106
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40
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Lu W, Schiau I, Cunningham J, Ragsdale S. Sequence and expression of the gene encoding the corrinoid/iron-sulfur protein from Clostridium thermoaceticum and reconstitution of the recombinant protein to full activity. J Biol Chem 1993. [DOI: 10.1016/s0021-9258(18)53364-0] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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41
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Shin W, Lindahl PA. Low spin quantitation of NiFeC EPR signal from carbon monoxide dehydrogenase is not due to damage incurred during protein purification. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1161:317-22. [PMID: 8381672 DOI: 10.1016/0167-4838(93)90231-f] [Citation(s) in RCA: 29] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Evidence is presented that the O2-sensitive, nickel- and iron-containing enzyme carbon monoxide dehydrogenase from Clostridium thermoaceticum was purified without significantly inactivating either its CO oxidation or CO/acetyl-CoA exchange activities. All CO oxidation activity from the crude extract was recovered in the purified enzyme (and side fractions). The exchange activity could not be quantified similarly, because the crude extract and early purification step fractions exhibited little or no exchange activity. Later purification fractions exhibited much more exchange activity, suggesting that an inhibitor was present in the impure fractions. The NiFeC EPR signal intensity was used as an indicator of the enzyme's capacity to catalyze exchange. This signal was extremely sensitive to oxygen; exposure to as little as 0.5 equiv/mol enzyme dimer resulted in substantial loss of intensity. The NiFeC intensities at each step in the purification were virtually invariant, indicating that the enzyme had not been exposed to oxygen and had not been inactivated towards catalyzing exchange. The ability to purify carbon monoxide dehydrogenase (CODH) without inactivating nearly any of the molecules suggests that it is quite stable under anaerobic conditions. The purified enzyme, which could not have lost functional metal ions during purification, contained 1.9 Ni and 11.3 Fe, similar to previous reports. The NiFeC EPR signal intensity from each purification fraction (0.2 spins/mol enzyme dimer) was as low as from previous preparations, indicating that its low spin quantitation is not the result of damage incurred during purification. If the low intensity arises from heterogeneity as proposed earlier, the heterogeneity must originate prior to purification.
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Affiliation(s)
- W Shin
- Department of Chemistry, Texas A&M University, College Station 77843
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42
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Shin W, Lindahl PA. Function and CO binding properties of the NiFe complex in carbon monoxide dehydrogenase from Clostridium thermoaceticum. Biochemistry 1992; 31:12870-5. [PMID: 1334436 DOI: 10.1021/bi00166a023] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Adding 1,10-phenanthroline to carbon monoxide dehydrogenase from Clostridium thermoaceticum results in the complete loss of the NiFeC EPR signal and the CO/acetyl-CoA exchange activity. Other EPR signals characteristic of the enzyme (the gav = 1.94 and gav = 1.86 signals) and the CO oxidation activity are completely unaffected by the 1,10-phenanthroline treatment. This indicates that there are two catalytic sites on the enzyme; the NiFe complex is required for catalyzing the exchange and acetyl-CoA synthase reactions, while some other site is responsible for CO oxidation. The strength of CO binding to the NiFe complex was examined by titrating dithionite-reduced enzyme with CO. During the titration, the NiFeC EPR signal developed to a final spin intensity of 0.23 spin/alpha beta. The resulting CO titration curve (NiFeC spins/alpha beta vs CO pha beta) was fitted using two reactions: binding of CO to the oxidized NiFe complex, and reduction of the CO-bound species to a form that exhibits the NiFeC signal. Best fits yielded apparent binding constants between 6000 and 14,000 M-1 (Kd = 70-165 microM). This sizable range is due to uncertainty whether CO binds to all or only a small fraction (approximately 23%) of the NiFe complexes. Reduction of the CO-bound NiFe complex is apparently required to activate it for catalysis. The electron used for this reduction originates from the CO oxidation site, suggesting that delivery of a low-potential electron to the CO-bound NiFe complex is the physiological function of the CO oxidation reaction catalyzed by this enzyme.
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Affiliation(s)
- W Shin
- Department of Chemistry, Texas A&M University, College Station 77843
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43
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Stokkermans JP, Pierik AJ, Wolbert RB, Hagen WR, Van Dongen WM, Veeger C. The primary structure of a protein containing a putative [6Fe-6S] prismane cluster from Desulfovibrio vulgaris (Hildenborough). EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 208:435-42. [PMID: 1339351 DOI: 10.1111/j.1432-1033.1992.tb17205.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The gene encoding a protein containing a putative [6Fe-6S] prismane cluster has been cloned from Desulfovibrio vulgaris (Hildenborough) and sequenced. The gene encodes a polypeptide composed of 553 amino acids (60,161 Da). The DNA-derived amino acid sequence was partly confirmed by N-terminal sequencing of the purified protein and of fragments of the protein generated by CNBr cleavage. Furthermore, the C-terminal sequence was verified by digestion with carboxypeptidases A and B. The polypeptide contains nine Cys residues. Four of these residues are gathered in a Cys-Xaa2-Cys-Xaa7-Cys-Xaa5-Cys motif located towards the N-terminus of the protein. No relevant sequence similarity was found with other proteins, including those with high-spin Fe-S clusters (nitrogenase, hydrogenase), with one significant exception: the stretch containing the first four Cys residues spans two submotifs, Cys-Xaa2-Cys and Lys-Gly-Xaa-Cys-Gly, separated by 11 residues, that are also present in high-spin Fe-S cluster containing CO dehydrogenase. Western-blot analysis demonstrates cross-reactivity of antibodies raised against the purified protein both in Desulfovibrio strains and other sulfate-reducing bacteria. Hybridization of the cloned gene with genomic DNA of several other Desulfovibrio species indicates that homologous sequences are generally present in the genus Desulfovibrio.
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Affiliation(s)
- J P Stokkermans
- Department of Biochemistry, Agricultural University, Wageningen, The Netherlands
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44
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Stokkermans JP, van den Berg WA, van Dongen WM, Veeger C. The primary structure of a protein containing a putative [6Fe-6S] prismane cluster from Desulfovibrio desulfuricans (ATCC 27774). BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1132:83-7. [PMID: 1511014 DOI: 10.1016/0167-4781(92)90057-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The gene encoding a protein containing a novel iron sulfur cluster ([6Fe-6S]) has been cloned from Desulfovibrio desulfuricans ATCC 27774 and sequenced. An open reading frame was found encoding a 545 amino acid protein (M(r) 58,496). The amino acid sequence is highly homologous with that of the corresponding protein from D. vulgaris (Hildenborough) and contains a Cys-motif that may be involved in coordination of the Fe-S cluster.
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Affiliation(s)
- J P Stokkermans
- Department of Biochemistry, Agricultural University, Wageningen, Netherlands
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45
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Kerby RL, Hong SS, Ensign SA, Coppoc LJ, Ludden PW, Roberts GP. Genetic and physiological characterization of the Rhodospirillum rubrum carbon monoxide dehydrogenase system. J Bacteriol 1992; 174:5284-94. [PMID: 1644755 PMCID: PMC206364 DOI: 10.1128/jb.174.16.5284-5294.1992] [Citation(s) in RCA: 124] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
A 3.7-kb DNA region encoding part of the Rhodospirillum rubrum CO oxidation (coo) system was identified by using oligonucleotide probes. Sequence analysis of the cloned region indicated four complete or partial open reading frames (ORFs) with acceptable codon usage. The complete ORFs, the 573-bp cooF and the 1,920-bp cooS, encode an Fe/S protein and the Ni-containing carbon monoxide dehydrogenase (CODH), respectively. The four 4-cysteine motifs encoded by cooF are typical of a class of proteins associated with other oxidoreductases, including formate dehydrogenase, nitrate reductase, dimethyl sulfoxide reductase, and hydrogenase activities. The R. rubrum CODH is 67% similar to the beta subunit of the Clostridium thermoaceticum CODH and 47% similar to the alpha subunit of the Methanothrix soehngenii CODH; an alignment of these three peptides shows relatively limited overall conservation. Kanamycin cassette insertions into cooF and cooS resulted in R. rubrum strains devoid of CO-dependent H2 production with little (cooF::kan) or no (cooS::kan) methyl viologen-linked CODH activity in vitro, but did not dramatically alter their photoheterotrophic growth on malate in the presence of CO. Upstream of cooF is a 567-bp partial ORF, designated cooH, that we ascribe to the CO-induced hydrogenase, based on sequence similarity with other hydrogenases and the elimination of CO-dependent H2 production upon introduction of a cassette into this region. From mutant characterizations, we posit that cooH and cooFS are not cotranscribed. The second partial ORF starts 67 bp downstream of cooS and would be capable of encoding 35 amino acids with an ATP-binding site motif.
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Affiliation(s)
- R L Kerby
- Department of Bacteriology, College of Agricultural and Life Sciences, University of Wisconsin-Madison 53706
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