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Lyu C, Meng Y, Zhang X, Yang J, Shen B. Two enzymes contribute to citrate production in the mitochondrion of Toxoplasma gondii. J Biol Chem 2024; 300:107565. [PMID: 39002675 PMCID: PMC11359734 DOI: 10.1016/j.jbc.2024.107565] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2024] [Revised: 06/27/2024] [Accepted: 07/09/2024] [Indexed: 07/15/2024] Open
Abstract
Citrate synthase catalyzes the first and the rate-limiting reaction of the tricarboxylic acid (TCA) cycle, producing citrate from the condensation of oxaloacetate and acetyl-coenzyme A. The parasitic protozoan Toxoplasma gondii has full TCA cycle activity, but its physiological roles remain poorly understood. In this study, we identified three proteins with predicted citrate synthase (CS) activities two of which were localized in the mitochondrion, including the 2-methylcitrate synthase (PrpC) that was thought to be involved in the 2-methylcitrate cycle, an alternative pathway for propionyl-CoA detoxification. Further analyses of the two mitochondrial enzymes showed that both had citrate synthase activity, but the catalytic efficiency of CS1 was much higher than that of PrpC. Consistently, the deletion of CS1 resulted in a significantly reduced flux of glucose-derived carbons into TCA cycle intermediates, leading to decreased parasite growth. In contrast, disruption of PrpC had little effect. On the other hand, simultaneous disruption of both CS1 and PrpC resulted in more severe metabolic changes and growth defects than a single deletion of either gene, suggesting that PrpC does contribute to citrate production under physiological conditions. Interestingly, deleting Δcs1 and Δprpc individually or in combination only mildly or negligibly affected the virulence of parasites in mice, suggesting that both enzymes are dispensable in vivo. The dispensability of CS1 and PrpC suggests that either the TCA cycle is not essential for the asexual reproduction of tachyzoites or there are other routes of citrate supply in the parasite mitochondrion.
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Affiliation(s)
- Congcong Lyu
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, PR China
| | - Yanan Meng
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, PR China
| | - Xin Zhang
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, PR China
| | - Jichao Yang
- College of Life Sciences, Longyan University, Longyan, Fujian, PR China
| | - Bang Shen
- State Key Laboratory of Agricultural Microbiology, College of Veterinary Medicine, Huazhong Agricultural University, Wuhan, Hubei Province, PR China; Hubei Hongshan Laboratory, Wuhan, Hubei Province, PR China; Shenzhen Institute of Nutrition and Health, Huazhong Agricultural University, Shenzhen, Guangdong Province, PR China; Shenzhen Branch, Guangdong Laboratory for Lingnan Modern Agriculture, Genome Analysis Laboratory of the Ministry of Agriculture, Agricultural Genomics Institute at Shenzhen, Chinese Academy of Agricultural Sciences, Shenzhen, Guangdong Province, PR China.
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2
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Venkat K, Hoyos M, Haycocks JR, Cassidy L, Engelmann B, Rolle-Kampczyk U, von Bergen M, Tholey A, Grainger DC, Papenfort K. A dual-function RNA balances carbon uptake and central metabolism in Vibrio cholerae. EMBO J 2021; 40:e108542. [PMID: 34612526 PMCID: PMC8672173 DOI: 10.15252/embj.2021108542] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 08/31/2021] [Accepted: 09/02/2021] [Indexed: 11/22/2022] Open
Abstract
Bacterial small RNAs (sRNAs) are well known to modulate gene expression by base pairing with trans‐encoded transcripts and are typically non‐coding. However, several sRNAs have been reported to also contain an open reading frame and thus are considered dual‐function RNAs. In this study, we discovered a dual‐function RNA from Vibrio cholerae, called VcdRP, harboring a 29 amino acid small protein (VcdP), as well as a base‐pairing sequence. Using a forward genetic screen, we identified VcdRP as a repressor of cholera toxin production and link this phenotype to the inhibition of carbon transport by the base‐pairing segment of the regulator. By contrast, we demonstrate that the VcdP small protein acts downstream of carbon transport by binding to citrate synthase (GltA), the first enzyme of the citric acid cycle. Interaction of VcdP with GltA results in increased enzyme activity and together VcdR and VcdP reroute carbon metabolism. We further show that transcription of vcdRP is repressed by CRP allowing us to provide a model in which VcdRP employs two different molecular mechanisms to synchronize central metabolism in V. cholerae.
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Affiliation(s)
- Kavyaa Venkat
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - Mona Hoyos
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany
| | - James Rj Haycocks
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Liam Cassidy
- Systematic Proteome Research & Bioanalytics, University of Kiel, Kiel, Germany
| | | | | | | | - Andreas Tholey
- Systematic Proteome Research & Bioanalytics, University of Kiel, Kiel, Germany
| | - David C Grainger
- Institute of Microbiology and Infection, University of Birmingham, Birmingham, UK
| | - Kai Papenfort
- Institute of Microbiology, Friedrich Schiller University, Jena, Germany.,Microverse Cluster, Friedrich Schiller University Jena, Jena, Germany
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Duhl KL, TerAvest MA. Shewanella oneidensis NADH dehydrogenase mutants exhibit an amino acid synthesis defect. FRONTIERS IN ENERGY RESEARCH 2019; 7:116. [PMID: 33072733 PMCID: PMC7561040 DOI: 10.3389/fenrg.2019.00116] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Shewanella oneidensis MR-1 is a dissimilatory metal reducing bacterium with a highly branched respiratory electron transport chain. The S. oneidensis MR-1 genome encodes four NADH dehydrogenases, any of which may be used during respiration. We previously determined that a double-knockout of two NADH dehydrogenases, Nuo and Nqr1, eliminated aerobic growth in minimal medium. However, the double-knockout strain was able to grow aerobically in rich medium. Here, we determined that amino acid supplementation rescued growth of the mutant strain in oxic minimal medium. To determine the mechanism of the growth defect, we monitored growth, metabolism, and total NAD(H) pools in S. oneidensis MR-1 and the NADH dehydrogenase knockout strain. We also used a genetically encoded redox sensing system and determined that NADH/NAD+ was higher in the mutant strain than in the wild-type. We observed that the double-knockout strain was able to metabolize d,l-lactate and N-acetylglucosamine when supplemented with tryptone, but excreted high concentrations of pyruvate and acetate. The requirement for amino acid supplementation, combined with an apparent inability of the mutant strain to oxidize pyruvate or acetate suggests that TCA cycle activity was inhibited in the mutant strain by a high NADH/NAD+.
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Affiliation(s)
- Kody L. Duhl
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
| | - Michaela A. TerAvest
- Department of Biochemistry and Molecular Biology, Michigan State University, East Lansing, MI, United States
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4
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Ge YD, Hou SL, Jiang LL, Su FZ, Wang P. Expression and characterization of a thermostable citrate synthase from Microcystis aeruginosa PCC7806. FEMS Microbiol Lett 2019; 366:5637861. [PMID: 31755935 DOI: 10.1093/femsle/fnz236] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Accepted: 11/21/2019] [Indexed: 12/13/2022] Open
Abstract
Citrate synthase (CS) is an important enzyme in energy conversion and material circulation, participating in many important biochemical processes. In the present study, CS from Microcystis aeruginosa PCC7806 (MaCS) was cloned and expressed in Escherichia coli Rosetta (DE3). The recombinant MaCS was purified and its enzymological properties were characterized. The results showed that MaCS formed dimers in native status. The optimum temperature and pH of MaCS was 30°C and 8.2, respectively. MaCS displayed relative high thermal stability. Treatment at 50°C for 20 min only decreased 11.30% activity of MaCS and the half-life of MaCS was approximately 35 min at 55°C. The kcat and Km of acetyl-CoA and oxaloacetic acid were 17.133 s-1 (kcat) and 11.62 μM (Km), 24.502 s-1 and 103.00 μM, respectively. MaCS activity was not drastically inhibited by monovalent ions and NADH but depressed by divalent ions and some small molecular compounds, especially Mg2+, Zn2+, Co2+ and DTT. Overall, these data contributed to further understanding of energy metabolism in cyanobacteria and also provided basic information for industrial application of CS.
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Affiliation(s)
- Ya-Dong Ge
- The Research Center of Life Omics and Health, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Shao-Lin Hou
- The Research Center of Life Omics and Health, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Lu-Lu Jiang
- The Research Center of Life Omics and Health, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Feng-Zhi Su
- The Research Center of Life Omics and Health, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
| | - Peng Wang
- The Research Center of Life Omics and Health, College of Life Sciences, Anhui Normal University, Wuhu 241000, China
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5
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Li D, Pang L, Yuan P, Zheng P, Huai B, Yao M, Kang Z, Liu J. A novel citrate synthase isoform contributes infection and stress resistance of the stripe rust fungus. Environ Microbiol 2018; 20:4037-4050. [PMID: 30307098 DOI: 10.1111/1462-2920.14444] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2018] [Revised: 10/05/2018] [Accepted: 10/07/2018] [Indexed: 11/30/2022]
Abstract
The early development of a rust fungus is dependent on the endogenous lipids stored in the urediniospores. After it establishes a parasitic relationship with the host, sugars absorbed from the host cells by haustoria become the primary nutrients. The tricarboxylic acid (TCA) cycle is essential to oxidize these nutrients. However, few studies have addressed the role of citrate synthase (CS), a rate-limiting enzyme of the TCA cycle, during the infection process of rust fungi. In this study, a CS gene from Puccinia striiformis f. sp. tritici (Pst), PsCS1, was cloned and characterized. Transcripts of PsCS1 and the enzyme activity of the CS were increased in the early Pst infection stage. Biochemical features and subcellular localization revealed that PsCS1 encoded a mitochondrial CS. Size exclusion chromatography, yeast two-hybrid and bimolecular fluorescence complementation experiments confirmed that PsCS1 could form a functional homo-octamer. The overexpression of PsCS1 enhanced the resistance of Escherichia coli to salt stress. The knockdown of PsCS1 using a host-induced gene silencing (HIGS) system blocked Pst growth in wheat. These results indicate that PsCS1 is required for nutrient metabolism in Pst and contributes to Pst infection by regulating ATP production and the supply of carbon sources.
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Affiliation(s)
| | | | - Pu Yuan
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
| | - Peijing Zheng
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
| | - Baoyu Huai
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Mohan Yao
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Zhensheng Kang
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Plant Protection, Northwest A&F University, Yangling, China
| | - Jie Liu
- State Key Laboratory of Crop Stress Biology for Arid Areas and College of Life Sciences, Northwest A&F University, Yangling, China
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6
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Quandt EM, Gollihar J, Blount ZD, Ellington AD, Georgiou G, Barrick JE. Fine-tuning citrate synthase flux potentiates and refines metabolic innovation in the Lenski evolution experiment. eLife 2015; 4:e09696. [PMID: 26465114 PMCID: PMC4718724 DOI: 10.7554/elife.09696] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2015] [Accepted: 10/13/2015] [Indexed: 01/20/2023] Open
Abstract
Evolutionary innovations that enable organisms to colonize new ecological niches are rare compared to gradual evolutionary changes in existing traits. We discovered that key mutations in the gltA gene, which encodes citrate synthase (CS), occurred both before and after Escherichia coli gained the ability to grow aerobically on citrate (Cit(+) phenotype) during the Lenski long-term evolution experiment. The first gltA mutation, which increases CS activity by disrupting NADH-inhibition of this enzyme, is beneficial for growth on the acetate and contributed to preserving the rudimentary Cit(+) trait from extinction when it first evolved. However, after Cit(+) was refined by further mutations, this potentiating gltA mutation became deleterious to fitness. A second wave of beneficial gltA mutations then evolved that reduced CS activity to below the ancestral level. Thus, dynamic reorganization of central metabolism made colonizing this new nutrient niche contingent on both co-opting and overcoming a history of prior adaptation.
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Affiliation(s)
- Erik M Quandt
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, United States
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, United States
| | - Jimmy Gollihar
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, United States
| | - Zachary D Blount
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, United States
- Department of Microbiology and Molecular Genetics, Michigan State University, East Lansing, United States
| | - Andrew D Ellington
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, United States
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, United States
| | - George Georgiou
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
- Department of Chemical Engineering, The University of Texas at Austin, Austin, United States
- Department of Biomedical Engineering, The University of Texas at Austin, Austin, United States
| | - Jeffrey E Barrick
- Institute for Cellular and Molecular Biology, The University of Texas at Austin, Austin, United States
- BEACON Center for the Study of Evolution in Action, Michigan State University, East Lansing, United States
- Department of Molecular Biosciences, The University of Texas at Austin, Austin, United States
- Center for Systems and Synthetic Biology, The University of Texas at Austin, Austin, United States
- Center for Computational Biology and Bioinformatics, The University of Texas at Austin, Austin, United States
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7
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Ge Y, Cao Z, Song P, Zhu G. Identification and characterization of a novel citrate synthase fromStreptomyces diastaticusNo. 7 strain M1033. Biotechnol Appl Biochem 2015; 62:300-8. [DOI: 10.1002/bab.1372] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Accepted: 03/14/2015] [Indexed: 11/06/2022]
Affiliation(s)
- Yadong Ge
- Institute of Molecular Biology and Biotechnology, Key Laboratory of Molecular Evolution and Biodiversity; Key Laboratory of the Biotic Environment and Ecological Safety in Anhui Province, Anhui Normal University; Wuhu Anhui People's Republic of China
| | - Zhengyu Cao
- Institute of Molecular Biology and Biotechnology, Key Laboratory of Molecular Evolution and Biodiversity; Key Laboratory of the Biotic Environment and Ecological Safety in Anhui Province, Anhui Normal University; Wuhu Anhui People's Republic of China
| | - Ping Song
- Institute of Molecular Biology and Biotechnology, Key Laboratory of Molecular Evolution and Biodiversity; Key Laboratory of the Biotic Environment and Ecological Safety in Anhui Province, Anhui Normal University; Wuhu Anhui People's Republic of China
| | - Guoping Zhu
- Institute of Molecular Biology and Biotechnology, Key Laboratory of Molecular Evolution and Biodiversity; Key Laboratory of the Biotic Environment and Ecological Safety in Anhui Province, Anhui Normal University; Wuhu Anhui People's Republic of China
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8
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Liao CH, Yao LL, Ye BC. Three genes encoding citrate synthases in Saccharopolyspora erythraea are regulated by the global nutrient-sensing regulators GlnR, DasR, and CRP. Mol Microbiol 2014; 94:1065-1084. [PMID: 25294017 DOI: 10.1111/mmi.12818] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/30/2014] [Indexed: 02/06/2023]
Abstract
Saccharopolyspora erythraea has three citrate synthases encoded by gltA-2, citA, and citA4. Here, we characterized and identified the expression and regulatory properties of these synthases. Three pleiotropic global regulatory proteins of S. erythraea - CRP, GlnR, and DasR - are involved in carbon metabolism, nitrogen metabolism, and amino-sugar (chitin and GlcNAc) metabolism. Using electrophoretic mobility shift assays (EMSAs), we identified these regulators as proteins that bind directly to the promoter regions of all citrate synthase genes (gltA-2, citA, and citA4). Footprinting assays indicated the exact protect sequences of CRP, GlnR, and DasR on the promoter region of gltA-2, revealing binding competition between GlnR and DasR. Moreover, by comparing the transcription levels of citrate synthase genes between parental and glnR mutant or dasR mutant strains, or by comparing the transcription response of citrate synthases under various nutrient conditions, we found that GlnR and DasR negatively regulated citA and citA4 transcription but had no regulatory effects on the gltA-2 gene. Although no CRP mutant was available, the results indicated that CRP was a cAMP-binding receptor affecting gltA-2 transcription when the intracellular cAMP concentration increased. Thus, an overall model of CS regulation by C and/or N metabolism regulators and cAMP receptor protein was proposed.
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Affiliation(s)
- Cheng-Heng Liao
- Lab of Biosystems and Microanalysis, State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai, 200237, China
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9
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Zinsser VL, Moore CM, Hoey EM, Trudgett A, Timson DJ. Citrate synthase from the liver fluke Fasciola hepatica. Parasitol Res 2013; 112:2413-7. [PMID: 23494154 DOI: 10.1007/s00436-013-3363-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2013] [Accepted: 02/18/2013] [Indexed: 12/01/2022]
Abstract
Citrate synthase catalyses the first step of the Krebs' tricarboxylic acid cycle. A sequence encoding citrate synthase from the common liver fluke, Fasciola hepatica, has been cloned. The encoded protein sequence is predicted to fold into a largely α-helical protein with high structural similarity to mammalian citrate synthases. Although a hexahistidine-tagged version of the protein could be expressed in Escherichia coli, it was not possible to purify it by nickel-affinity chromatography. Similar results were obtained with a version of the protein which lacks the putative mitochondrial targeting sequence (residues 1 to 29). However, extracts from bacterial cells expressing this version had additional citrate synthase activity after correcting for the endogenous, bacterial activity. The apparent K m for oxaloacetate was found to be 0.22 mM, which is higher than that observed in mammalian citrate synthases. Overall, the sequence and structure of F. hepatica citrate synthase are similar to ones from other eukaryotes, but there are enzymological differences which merit further investigation.
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Affiliation(s)
- Veronika L Zinsser
- School of Biological Sciences, Queen's University Belfast, Medical Biology Centre, 97 Lisburn Road, Belfast, BT9 7BL, UK
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10
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Discovery of an Iron-Regulated Citrate Synthase in Staphylococcus aureus. ACTA ACUST UNITED AC 2012; 19:1568-78. [DOI: 10.1016/j.chembiol.2012.10.003] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 09/06/2012] [Accepted: 10/03/2012] [Indexed: 11/21/2022]
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11
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van Ooyen J, Emer D, Bussmann M, Bott M, Eikmanns BJ, Eggeling L. Citrate synthase in Corynebacterium glutamicum is encoded by two gltA transcripts which are controlled by RamA, RamB, and GlxR. J Biotechnol 2011; 154:140-8. [DOI: 10.1016/j.jbiotec.2010.07.004] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2009] [Revised: 01/18/2010] [Accepted: 07/01/2010] [Indexed: 11/15/2022]
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12
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Müller-Kraft G, Babel W. Regulation der Citratsynthase bei fakultativ methylotrophen Bakterien. J Basic Microbiol 2007. [DOI: 10.1002/jobm.19830230306] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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14
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Mitchell CG, Anderson SC, el-Mansi EM. Purification and characterization of citrate synthase isoenzymes from Pseudomonas aeruginosa. Biochem J 1995; 309 ( Pt 2):507-11. [PMID: 7626013 PMCID: PMC1135760 DOI: 10.1042/bj3090507] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Two types of citrate synthase (CS) have been purified from Pseudomonas aeruginosa, a 'large' form (CSI) and a 'small' form (CSII). The M(r)s of the CSI and CSII isoenzymes were determined to be 240,000 +/- 16,000 (mean +/- S.E.M.) and 80,300 +/- 3800 respectively. Chemical cross-linking of the native enzymes with either dimethyl suberimidate or glutaraldehyde followed by electrophoretic analysis by SDS/PAGE showed that CSI is a hexamer and CSII is a dimer. SDS/PAGE showed that CSI and CSII each consist of a single subunit type, of M(r) 42,000 +/- 2000 and M(r) 36,500 +/- 2000 respectively. CSI and CSII were also shown to be distinct kinetically, immunologically and in terms of their regulatory properties. It is suggested that the CS isoenzymes are products of different structural genes.
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Affiliation(s)
- C G Mitchell
- Department of Biological Sciences, Napier University, Edinburgh, U.K
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15
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Asai T, Takahashi R, Fujioka T, Tokuyama T. Purification and properties of a citrate synthase from Nitrosomonas sp. TK794 and a comparison with the enzymes of another nitrifying bacteria. ACTA ACUST UNITED AC 1995. [DOI: 10.1016/0922-338x(95)92747-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
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16
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Takahashi R, Usui K, Sakuraba T, Tokuyama T. Purification and some properties of citrate synthase from a nitrite-oxidizing chemoautotroph, Nitrobacter agilis ATCC 14123. ACTA ACUST UNITED AC 1994. [DOI: 10.1016/0922-338x(94)90217-8] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Molgat GF, Donald LJ, Duckworth HW. Chimeric allosteric citrate synthases: construction and properties of citrate synthases containing domains from two different enzymes. Arch Biochem Biophys 1992; 298:238-46. [PMID: 1524432 DOI: 10.1016/0003-9861(92)90118-g] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The citrate synthases of the gram-negative bacteria, Escherichia coli and Acinetobacter anitratum, are allosterically inhibited by NADH. The kinetic properties, however, suggest that the equilibrium between active (R) and inactive (T) conformational states is shifted toward the T state in the E. coli enzyme. We have now manipulated the cloned genes for the two bacterial enzymes to produce two chimeric proteins, in which one folding domain of each subunit is derived from each enzyme. One chimera (the large domain from A. anitratum and the small domain from the E. coli enzyme) is designated CS ACI::eco; the other is called CS ECO::aci. Both chimeras are roughly as active as the wild type parents, but their Km values for both substrates are lower than those for the E. coli enzyme, and NADH inhibition is markedly sigmoid, while that for E. coli citrate synthases is hyperbolic. Curve-fitting to the allosteric equation suggests that these differences are the result of the destabilization of the T state in the chimeras. The ACI::eco chimera exists almost entirely as a hexamer, like the A. anitratum enzyme, while the ECO::aci chimera, like the E. coli synthase, forms three major bands on nondenaturing polyacrylamide gels, two of them hexamers of different net charge, and one a dimer. These findings indicate that subunit interactions leading to hexamer formation in allosteric citrate synthases of gram-negative bacteria involve mainly the large domains. The chimeras are also used to show that the NADH binding site of E. coli citrate synthase is located entirely in the large domain. Sensitivity of the chimeras to denaturation by urea, to which the A. anitratum enzyme is much more resistant than the E. coli enzyme, is determined by the large domains. Sensitivity to inactivation by subtilisin is intermediate between those shown by the E. coli (very sensitive) and A. anitratum (quite resistant) synthases. This result suggests that digestibility by subtilisin is determined by conformational factors as well as the amino acid sequences of the target regions.
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Affiliation(s)
- G F Molgat
- Department of Chemistry, University of Manitoba, Winnipeg, Canada
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18
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Affiliation(s)
- P A Srere
- Department of Veterans Affairs Medical Center, University of Texas Southwestern Medical Center, Dallas 75216
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19
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Heinzen RA, Frazier ME, Mallavia LP. Sequence and linkage analysis of the Coxiella burnetii citrate synthase-encoding gene. Gene X 1991; 109:63-9. [PMID: 1756983 DOI: 10.1016/0378-1119(91)90589-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022] Open
Abstract
The nucleotide (nt) sequence of the Coxiella burnetii citrate synthase-encoding gene (gltA), previously cloned in Escherichia coli, was determined. The nt sequence analysis revealed an open reading frame (ORF) of 1290 bp capable of coding for a protein of 430 amino acids (aa) with a deduced Mr of 48,633. Preceding an ATG start codon, a possible transcription start point (tsp) with homology to the E. coli promoter consensus was detected. A poly-purine-rich region occurred immediately upstream from the gltA reading frame and potentially serves as a ribosome-binding site. Additionally, a G + C-rich region of dyad symmetry 3' to the translational stop codon was found that could possibly function as a Rho-independent transcriptional termination signal. A large, nearly perfect, inverted repeat was identified upstream from the gltA tsp and was shown by Southern analysis to be present in multiple copies in the C. burnetii genome. The deduced aa sequence of C. burnetii GltA was optimally aligned with enzymes from various prokaryotic sources and one eukaryotic source (pig heart). Using perfect aa identity, the C. burnetii enzyme demonstrated the greatest homology with GltA from Acinetobacter anitratum (65%). Although only 26% aa identity was seen with the pig heart enzyme, many of the residues identified in ligand binding appear to be conserved. Sequencing studies of a region centered approx. 5.6 kb upstream from gltA revealed an ORF read with opposite polarity that encodes a peptide highly homologous to the C terminus of the flavoprotein subunit of E. coli succinate dehydrogenase. This report represents the first nt sequence analysis of a gene of known function from the obligate intracellular parasite, C. burnetii.
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Affiliation(s)
- R A Heinzen
- Department of Microbiology, Washington State University, Pullman 99164-4340
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[53] Citrate synthases from methylotrophs. Methods Enzymol 1990. [DOI: 10.1016/0076-6879(90)88055-f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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21
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Toerien DF, Gerber A, Lötter LH, Cloete TE. Enhanced Biological Phosphorus Removal in Activated Sludge Systems. ADVANCES IN MICROBIAL ECOLOGY 1990. [DOI: 10.1007/978-1-4684-7612-5_5] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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22
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McDermott TR, Griffith SM, Vance CP, Graham PH. Carbon metabolism inBradyrhizobium japonicumbacteroids. FEMS Microbiol Lett 1989. [DOI: 10.1111/j.1574-6968.1989.tb03403.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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23
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Abstract
The microbial polymer poly-3-hydroxybutyrate (PHB) and related poly-hydroxyalkanoates, such as poly-3-hydroxyvalerate and poly-3-hydroxyoctanoate, are unique biodegradable thermoplastics of considerable commercial importance. The structure, properties and regulation of synthesis and degradation of PHB are reviewed and the microbial production of copolymers of 3-hydroxybutyrate and 3-hydroxyvalerate, with properties varying according to copolymer composition, is discussed.
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Affiliation(s)
- E A Dawes
- Department of Biochemistry, University of Hull, U.K
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24
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Anderson DH, Duckworth HW. In vitro mutagenesis of Escherichia coli citrate synthase to clarify the locations of ligand binding sites. J Biol Chem 1988. [DOI: 10.1016/s0021-9258(18)69186-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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25
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Danson MJ. Archaebacteria: the comparative enzymology of their central metabolic pathways. Adv Microb Physiol 1988; 29:165-231. [PMID: 3132816 DOI: 10.1016/s0065-2911(08)60348-3] [Citation(s) in RCA: 83] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Affiliation(s)
- M J Danson
- Department of Biochemistry, University of Bath, England
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26
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Heinzen RA, Mallavia LP. Cloning and functional expression of the Coxiella burnetii citrate synthase gene in Escherichia coli. Infect Immun 1987; 55:848-55. [PMID: 3104207 PMCID: PMC260428 DOI: 10.1128/iai.55.4.848-855.1987] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
The citrate synthase gene from the obligate intracellular rickettsial parasite Coxiella burnetii was cloned and expressed in Escherichia coli. Transduction into E. coli with a C. burnetii gene library constructed in the cosmid vector pHK17 resulted in the functional complementation of the gltA mutation of E. coli MOB154. A GltA+ clone carrying 16.4 kilobase pairs of C. burnetii DNA and designated pJCC959 was isolated and characterized. Southern hybridization analysis confirmed that the pJCC959 cloned insert consists of C. burnetii DNA and that homology exists with the Rickettsia prowazekii citrate synthase gene. Subcloning analysis with the multicopy expression vector pUC8 revealed that citrate synthase expression was under control of a C. burnetti promoter. In vitro transcription-translation of subclones pLPM20 and pLPM30 established a molecular weight of ca. 46,000 for the monomer form of the cloned enzyme. Transposon Tn5 mutagenesis of pLPM30 defined the coding region to approximately 1.2 kilobase pairs of C. burnetii DNA. Maxicell analysis of selected pLPM30::Tn5 insertion derivatives identified the direction of transcription and the relative translational start and stop sites and substantiated the molecular weight value calculated from the in vitro analysis. Inhibition studies showed that citrate synthase activity in crude cell extracts obtained from strain MOB154 transformed with the cloned C. burnetii gene was markedly inhibited by 4 mM ATP, while 4 mM alpha-ketoglutarate had virtually no effect. These data indicate that the C. burnetii enzyme displays regulatory behavior characteristic of the small gram-positive bacterial and eucaryotic enzyme.
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27
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Donald LJ, Duckworth HW. Molecular cloning of the structural gene for Acinetobacter citrate synthase. Biochem Biophys Res Commun 1986; 141:797-803. [PMID: 3026391 DOI: 10.1016/s0006-291x(86)80243-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
The structural gene for citrate synthase of Acinetobacter anitratum has been cloned in Escherichia coli in a form which expresses the enzyme. A library of EcoRI fragments of Acinetobacter genomic DNA was prepared in the vector lambda gt10, and clones were screened by hybridization with an E. coli citrate synthase clone under conditions of reduced stringency. A 6.5 kbp clone was obtained which was subcloned into pBR322, and shown to direct the formation of Acinetobacter citrate synthase in E. coli hosts. The promoter was located within a BglII fragment, and from this information the orientation of the gene was deduced.
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28
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Reusch RN, Hiske TW, Sadoff HL. Poly-beta-hydroxybutyrate membrane structure and its relationship to genetic transformability in Escherichia coli. J Bacteriol 1986; 168:553-62. [PMID: 3536850 PMCID: PMC213516 DOI: 10.1128/jb.168.2.553-562.1986] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
The effects of competence-inducing treatments on the composition and organization of membrane lipids in Escherichia coli K-12, DH1, DH5, HB101, and RR1 were investigated for two widely used protocols in which transformability is developed at low temperatures in Ca2+ buffers. At stages during each procedure, the lipid compositions of the cells were determined, and the thermotropic lipid phase transitions were observed in whole cell culture by fluorescence assay with the hydrophobic probe N-phenyl-1-naphthylamine. Competence was evaluated by determining transformation efficiencies with plasmid pBR322 DNA. The competence-inducing procedures effected only slight changes in phospholipid compositions which did not correlate with transformability. However, the induction of competence was coincident with de novo synthesis and incorporation of poly-beta-hydroxybutyrate into the cytoplasmic membranes and with the appearance of a sharp lipid phase transition above physiological temperatures. Transformation efficiencies correlated with poly-beta-hydroxybutyrate concentrations and with the intensity of the new phase transition. Transformability, poly-beta-hydroxybutyrate synthesis and the new phase transition were not significantly affected by inhibition of protein synthesis with chloramphenicol or inhibition of respiration or ATP synthesis with azide, cyanide, arsenate, or 2,4-dinitrophenol; however, when poly-beta-hydroxybutyrate synthesis was inhibited with acetaldehyde, the new phase transition was not observed, and competence failed to develop. These studies suggest that genetic transformability in E. coli may be physiologically regulated.
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29
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Schmidt SK, Alexander M. Effects of dissolved organic carbon and second substrates on the biodegradation of organic compounds at low concentrations. Appl Environ Microbiol 1985; 49:822-7. [PMID: 3890738 PMCID: PMC238452 DOI: 10.1128/aem.49.4.822-827.1985] [Citation(s) in RCA: 107] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Pseudomonas acidovorans and Pseudomonas sp. strain ANL but not Salmonella typhimurium grew in an inorganic salts solution. The growth of P. acidovorans in this solution was not enhanced by the addition of 2.0 micrograms of phenol per liter, but the phenol was mineralized. Mineralization of 2.0 micrograms of phenol per liter by P. acidovorans was delayed 16 h by 70 micrograms of acetate per liter, and the delay was lengthened by increasing acetate concentrations, whereas phenol and acetate were utilized simultaneously at concentrations of 2.0 and 13 micrograms/liter, respectively. Growth of Pseudomonas sp. in the inorganic salts solution was not affected by the addition of 3.0 micrograms each of glucose and aniline per liter, nor was mineralization of the two compounds detected during the initial period of growth. However, mineralization of both substrates by this organism occurred simultaneously during the latter phases of growth and after growth had ended at the expense of the uncharacterized dissolved organic compounds in the salts solution. In contrast, when Pseudomonas sp. was grown in the salts solution supplemented with 300 micrograms each of glucose and aniline, the sugar was mineralized first, and aniline was mineralized only after much of the glucose carbon was converted to CO2. S. typhimurium failed to multiply in the salts solution with 1.0 micrograms of glucose per liter. It grew slightly but mineralized little of the sugar at 5.0 micrograms/liter, but its population density rose at 10 micrograms of glucose per liter or higher. The hexose could be mineralized at 0.5 micrograms/liter, however, if the solution contained 5.0 mg of arabinose per liter.(ABSTRACT TRUNCATED AT 250 WORDS)
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30
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Pullen AM, Budgen N, Danson MJ, Hough DW. Citrate synthase: an immunochemical investigation of interspecies diversity. FEBS Lett 1985; 182:163-6. [PMID: 2578989 DOI: 10.1016/0014-5793(85)81175-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Rabbit antibodies have been raised to pig heart citrate synthase. Using purified IgG, competitive enzyme-linked immunoassays and assays of citrate synthase activity indicate the presence of antibodies to a number of antigenic sites on the enzyme, only some of which are essential for catalytic activity. From a comparison of citrate synthases from prokaryotic and eukaryotic organisms, the degree of interaction between antibody and enzyme was in the order: pig heart greater than pigeon breast greater than Bacillus megaterium greater than Escherichia coli. These findings are discussed in terms of the known interspecies diversity of the enzyme.
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31
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Miles JS, Guest JR. Complete nucleotide sequence of the fumarase gene (citG) of Bacillus subtilis 168. Nucleic Acids Res 1985; 13:131-40. [PMID: 3923430 PMCID: PMC340979 DOI: 10.1093/nar/13.1.131] [Citation(s) in RCA: 45] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
The nucleotide sequence of a 2.14 kb fragment of Bacillus subtilis DNA containing the citG gene encoding fumarase was determined using the dideoxy chain termination method. The citG coding region of 1392 base pairs (464 codons) was identified, and the deduced Mr (50425) is in good agreement with that of the protein identified from expression in Escherichia coli maxicells. There is no sequence homology between the B. subtilis and E. coli fumarases. Overlapping potential promoter sequences have been identified for sigma 28, sigma 37 and sigma 55 RNA polymerase holoenzymes. The DNA fragment also contains the proximal part of the gerA locus, responsible for L-alanine-sensitive spore germination.
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32
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Beeckmans S. Some structural and regulatory aspects of citrate synthase. THE INTERNATIONAL JOURNAL OF BIOCHEMISTRY 1984; 16:341-51. [PMID: 6370751 DOI: 10.1016/0020-711x(84)90131-9] [Citation(s) in RCA: 35] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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33
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Robinson MS, Danson MJ, Weitzman PD. Citrate synthase from a Gram-positive bacterium. Purification and characterization of the Bacillus megaterium enzyme. Biochem J 1983; 213:53-9. [PMID: 6412681 PMCID: PMC1152089 DOI: 10.1042/bj2130053] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Citrate synthase was purified to homogeneity from a Gram-positive bacterium (Bacillus megaterium) for the first time. The Mr of the native enzyme was determined to be 84 000 (S.E.M. +/- 5000). Sodium dodecyl sulphate/polyacrylamide-gel electrophoresis and gel filtration in guanidinium chloride revealed a single protein species of Mr 40 300 (S.E.M. +/- 4400), indicating a dimeric enzyme. This dimeric structure was confirmed by cross-linking the native enzyme with dimethyl suberimidate and with glutaraldehyde, followed by electrophoretic analysis. The enzyme follows Michaelis-Menten kinetics with respect to both substrates, acetyl-CoA and oxaloacetate, and is sensitive to non-specific inhibition by a range of adenine nucleotides. In both molecular and catalytic properties the citrate synthase closely resembles the enzyme from eukaryotic sources and contrasts markedly with the larger, hexameric, enzyme from Gram-negative bacteria.
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34
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Weitzman PD, Ridley J. Affinity chromatography of acyl-CoA utilizing enzymes on Procion Red-agarose. Biochem Biophys Res Commun 1983; 112:1021-6. [PMID: 6847676 DOI: 10.1016/0006-291x(83)91720-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
The dye Procion Red HE3B immobilized on agarose and available as Matrex Gel Red A is shown to bind citrate synthase and succinate thiokinase from a number of diverse organisms. Salt-gradient elution removes the enzymes in high yields and with substantial purification. The elution profiles follow a pattern similar to that of the molecular size variations of the enzymes.
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35
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Robinson MS, Easom RA, Danson MJ, Weitzman PD. Citrate synthase of Escherichia coli. Characterisation of the enzyme from a plasmid-cloned gene and amplification of the intracellular levels. FEBS Lett 1983; 154:51-4. [PMID: 6339275 DOI: 10.1016/0014-5793(83)80873-4] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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36
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Fabregat I, Satrústegui J, Machado A. Citrate synthase of Tetrahymena pyriformis: evolutionary and regulatory aspects. Arch Biochem Biophys 1983; 220:354-60. [PMID: 6401983 DOI: 10.1016/0003-9861(83)90424-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Citrate synthase (EC 4.1.3.7) from Tetrahymena pyriformis has been purified 185-fold. The molecular weight of the native enzyme was determined to be 120,000. The enzyme is labile at low ionic strength, but can be stabilized by KCl and glycerol. It is activated by KCl at low (below 60 mM) or high concentrations, and inhibited by divalent cations (Mn2+, Mg2+, Ca2+). The Michaelis constants are 0.1 mM for oxalacetate and 0.01 mM for acetyl-CoA. The kinetics with oxalacetate exhibit negative cooperativity, with a nH = 0.66. Among the metabolites tested, only ATP and GTP can inhibit the enzyme but Mg2+ relieves the ATP inhibition. Incubation with sulfhydryl reagents (DTNB) in the absence of its substrates results in a rapid inactivation of the enzyme. It is concluded that Tetrahymena citrate synthase is closer to the enzyme from Gram-positive bacteria than to those of eucaryotes.
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37
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Müller-Kraft G, Babel W. [Regulation of citrate synthase in facultative methylotrophic bacteria]. ZEITSCHRIFT FUR ALLGEMEINE MIKROBIOLOGIE 1983; 23:181-7. [PMID: 6880250 DOI: 10.1002/jobm.3630230306] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Commonly the TCA cycle fulfils an anabolic and a catabolic function in case of aerobic chemoorganoheterotrophic nutrition. In methylotrophic growth the TCA cycle is dispensable as a bioenergetic pathway. This is reflected by properties of citrate synthase in facultative methylotrophic bacteria. Two citrate synthases, a "chemoorganoheterotrophic" one, which is inhibited by NADH (or ATP in Acetobacter MB 58), and a "methylotrophic" one, which is not or less affected by energy indicators, were found in Pseudomonas oleovorans, Pseudomonas MS, Pseudomonas MA, and Acetobacter MB 58. The concentration of these citrate synthases depends on the manner of nutrition. Bacteria with ICL-negative-variant of the serine pathway and with ribulosebisphosphate pathway seem to possess only a "chemoorganoheterotrophic" citrate synthase. Possibly the anabolic function of this citrate synthase can be realized by metabolites.
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38
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Weitzman PD, Jaskowska-Hodges H. Patterns of nucleotide utilisation in bacterial succinate thiokinases. FEBS Lett 1982; 143:237-40. [PMID: 6811321 DOI: 10.1016/0014-5793(82)80107-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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39
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40
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Weitzman PDJ. PATTERNS OF ENZYME DIVERSITY AND ORGANELLE EVOLUTION. Ann N Y Acad Sci 1981. [DOI: 10.1111/j.1749-6632.1981.tb54388.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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41
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42
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43
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Babel W, Müller-Kraft G. [Regulation of citrate synthase during methylotrophic and chemoorganoheterotrophic nutrition of bacteria]. ZEITSCHRIFT FUR ALLGEMEINE MIKROBIOLOGIE 1979; 19:687-93. [PMID: 232798 DOI: 10.1002/jobm.3630191003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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44
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Danson MJ, Weitzman PD. Thiol groups of Escherichia coli citrate synthase and their influence on activity and regulation. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 485:452-64. [PMID: 200273 DOI: 10.1016/0005-2744(77)90181-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The modification of Escherichia coli citrate synthase (citrate oxaloacetatelyase(pro-3S-CH2.COO- leads to acetyl-CoA, EC 4.1.3.7) with 5,5'-dithiobis-(2-nitrobenzoic acid) has been investigated. (1) In low ionic strength (20 mM Tris.HCl, pH 8.0): (A) Eight thiol groups per tetramer of the native enzyme reacted with Nbs2. (b) Two of the eight accessible thiols were modified rapidly with the loss of 26% enzyme activity but with no change in the NADH inhibition. The remaining six were modified more slowly, resulting in a further 60% loss of activity and complete densensitization to NADH. (c) The 2nd-order rate constant for the modification of the rapidly reacting thiols is 2.5.10(4) M-1.min-1. At the reagent concentrations used (0.1 to 0.2 mM) the modification of the six thiols in the slow kinetic set appeared to be 1st-order; at 0.1 mM dithionitrobenzoic acid their rate of modification was approximately 30 times slower than the thiols in the fast kinetic set. (2) In high ionic strength (20 mM Tris.HCl, pH 8.0, 0.1 M KCl): (a) Four thiol groups were modified in a single kinetic set and it appeared that these thiols are four of the six slowly modified in the absence of KCl. (b) The modification resulted in 70% loss of enzyme activity and complete loss of NADH inhibition. (3) From the kinetic analysis it is proposed that the four thiol groups accessible to dithionitrobenzoic acid in the absence and presence of 0.1 M KCl are those involved in the response of NADH. Modification of any one of these four groups produced no reduction in the inhibition; instead, loss of NADH sensitivity was coincident with the appearance of tetrameric protein possessing three substituted thiols, whereas enzyme with one or two modified groups was still fully inhibited by NADH.
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45
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Lucas C, Weitzman PD. Regulation of citrate synthase from blue-green bacteria by succinyl coenzyme A. Arch Microbiol 1977; 114:55-60. [PMID: 410381 DOI: 10.1007/bf00429630] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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46
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Brown J, Payne BL, Smith TM, Sulya L. Effects of ATP, NADH and aldosterone on citrate synthase from bovine kidney cortex. ACTA ACUST UNITED AC 1977. [DOI: 10.1016/0020-711x(77)90043-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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47
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Harford S, Jones D, Weitzman PD. Rapid techniques for the examination of bacterial citrate synthases. THE JOURNAL OF APPLIED BACTERIOLOGY 1976; 41:465-71. [PMID: 190201 DOI: 10.1111/j.1365-2672.1976.tb00659.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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48
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Higa AI, Cazzulo JJ. The citrate synthase from Bacillus Stearothermophilus. EXPERIENTIA 1976; 32:1373-4. [PMID: 991973 DOI: 10.1007/bf01937381] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Citrate synthase has been purified to apparent homogeneity from Bacillus stearothermophilus. Its kinetic and regulatory properties, and molecular weight, are similar to those of the enzymes from suitable mesophilic counterparts, but its thermal stability is considerably greater.
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49
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Berndt H, Ostwal KP, Lalucat J, Schumann C, Mayer F, Schlegel HG. Identification and physiological characterization of the nitrogen fixing bacterium Corynebacterium autotrophicum GZ 29. Arch Microbiol 1976; 108:17-26. [PMID: 1275646 DOI: 10.1007/bf00425088] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The coryneform hydrogen bacterium strain GZ 29, assigned to Corynebacterium autotrophicum fixed molecular nitrogen under autotrophic (H2, CO2) as well as under heterotrophic (sucrose) conditions. Physiological parameters of nitrogen fixation were measured under heterotrophic conditions. The optimal dissolved oxygen concentration for cells grown in a fermenter with N2 was rather low (0.14 mg O2/l) compared with cells grown in the presence of NH+4 (4.45 mg O2/l). C. autotrophicum GZ 29 had a doubling time of 3.7 h at 30 degrees C with N2 as N-source and sucrose as carbon source and at optimal pO2. Acetylene reduction reached values of 12 nmoles of ethylene produced/min X mg protein. Although the oxygen concentration in the growing culture was kept constant, the optimal dissolved oxygen tension for the acetylene reduction assay shifted to higher pO2-values. The overall efficiency of nitrogen fixation amounted to 22 mg N fixed/g sucrose consumed; it reached a maximal value of 65 mg N fixed/g sucrose consumed at the beginning of the exponential growth phase. Intact cells reduced acetylene even under anaerobic test conditions; further anaerobic metabolic activity could not be ascertained so far.
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50
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Massarini E, Higa AI, Cazzulo JJ. Regulatory properties of the citrate synthase from Rhodospirillum rubrum. EXPERIENTIA 1976; 32:426-8. [PMID: 178526 DOI: 10.1007/bf01920775] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Citrate synthase, purified 600-fold from Rhodospirillum rubrum, is activated by KCl and inhibited by ATP and NADH; the effect of the latter inhibitor is completely counteracted by AMP and partially counteracted by KCl.
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