1
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Zimmermann J, Mayer RJ, Moran J. A single phosphorylation mechanism in early metabolism - the case of phosphoenolpyruvate. Chem Sci 2023; 14:14100-14108. [PMID: 38098731 PMCID: PMC10717536 DOI: 10.1039/d3sc04116f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2023] [Accepted: 11/22/2023] [Indexed: 12/17/2023] Open
Abstract
Phosphorylation is thought to be one of the fundamental reactions for the emergence of metabolism. Nearly all enzymatic phosphorylation reactions in the anabolic core of microbial metabolism act on carboxylates to give acyl phosphates, with a notable exception - the phosphorylation of pyruvate to phosphoenolpyruvate (PEP), which involves an enolate. We wondered whether an ancestral mechanism for the phosphorylation of pyruvate to PEP could also have involved carboxylate phosphorylation rather than the modern enzymatic form. The phosphorylation of pyruvate with P4O10 as a model phosphorylating agent was found to indeed occur via carboxylate phosphorylation, as verified by mechanistic studies using model substrates, time course experiments, liquid and solid-state NMR spectroscopy, and DFT calculations. The in situ generated acyl phosphate subsequently undergoes an intramolecular phosphoryl transfer to yield PEP. A single phosphorylation mechanism acting on carboxylates appears sufficient to initiate metabolic networks that include PEP, strengthening the case that metabolism emerged from self-organized chemistry.
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Affiliation(s)
- Joris Zimmermann
- Institut de Science et d'Ingénierie Supramoléculaires (ISIS), CNRS UMR 7006, Université de Strasbourg 8 Allée Gaspard Monge 67000 Strasbourg France
| | - Robert J Mayer
- Institut de Science et d'Ingénierie Supramoléculaires (ISIS), CNRS UMR 7006, Université de Strasbourg 8 Allée Gaspard Monge 67000 Strasbourg France
| | - Joseph Moran
- Institut de Science et d'Ingénierie Supramoléculaires (ISIS), CNRS UMR 7006, Université de Strasbourg 8 Allée Gaspard Monge 67000 Strasbourg France
- Institut Universitaire de France (IUF) France
- Department of Chemistry and Biomolecular Sciences, University of Ottawa Ottawa Ontario K1N 6N5 Canada
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2
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Xu J, Wang J, Ma C, Wei Z, Zhai Y, Tian N, Zhu Z, Xue M, Li D. Embracing a low-carbon future by the production and marketing of C1 gas protein. Biotechnol Adv 2023; 63:108096. [PMID: 36621726 DOI: 10.1016/j.biotechadv.2023.108096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 12/14/2022] [Accepted: 01/03/2023] [Indexed: 01/07/2023]
Abstract
Food scarcity and environmental deterioration are two major problems that human populations currently face. Fortunately, the disruptive innovation of raw food materials has been stimulated by the rapid evolution of biomanufacturing. Therefore, it is expected that the new trends in technology will not only alter the natural resource-dependent food production systems and the traditional way of life but also reduce and assimilate the greenhouse gases released into the atmosphere. This review article summarizes the metabolic pathways associated with C1 gas conversion and the production of single-cell protein for animal feed. Moreover, the protein function, worldwide authorization, market access, and methods to overcome challenges in C1 gas assimilation microbial cell factory construction are also provided. With widespread attention and increasing policy support, the production of C1 gas protein will bring more opportunities and make tremendous contributions to our sustainable future.
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Affiliation(s)
- Jian Xu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Jie Wang
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China
| | - Chunling Ma
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; Haihe Laboratory of Synthetic Biology, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China
| | - Zuoxi Wei
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Yida Zhai
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Na Tian
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China
| | - Zhiguang Zhu
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China.
| | - Min Xue
- Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing, China.
| | - Demao Li
- Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, China; National Centre of Technology Innovation for Synthetic Biology, Tianjin, China; Tianjin Key Laboratory for Industrial Biological Systems and Bioprocessing Engineering, Tianjin, China.
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3
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Janasch M, Crang N, Asplund-Samuelsson J, Sporre E, Bruch M, Gynnå A, Jahn M, Hudson EP. Thermodynamic limitations of PHB production from formate and fructose in Cupriavidus necator. Metab Eng 2022; 73:256-269. [PMID: 35987434 DOI: 10.1016/j.ymben.2022.08.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 06/10/2022] [Accepted: 08/06/2022] [Indexed: 11/30/2022]
Abstract
The chemolithotroph Cupriavidus necator H16 is known as a natural producer of the bioplastic-polymer PHB, as well as for its metabolic versatility to utilize different substrates, including formate as the sole carbon and energy source. Depending on the entry point of the substrate, this versatility requires adjustment of the thermodynamic landscape to maintain sufficiently high driving forces for biological processes. Here we employed a model of the core metabolism of C. necator H16 to analyze the thermodynamic driving forces and PHB yields from formate for different metabolic engineering strategies. For this, we enumerated elementary flux modes (EFMs) of the network and evaluated their PHB yields as well as thermodynamics via Max-min driving force (MDF) analysis and random sampling of driving forces. A heterologous ATP:citrate lyase reaction was predicted to increase driving force for producing acetyl-CoA. A heterologous phosphoketolase reaction was predicted to increase maximal PHB yields as well as driving forces. These enzymes were then verified experimentally to enhance PHB titers between 60 and 300% in select conditions. The EFM analysis also revealed that PHB production from formate may be limited by low driving forces through citrate lyase and aconitase, as well as cofactor balancing, and identified additional reactions associated with low and high PHB yield. Proteomics analysis of the engineered strains confirmed an increased abundance of aconitase and cofactor balancing. The findings of this study aid in understanding metabolic adaptation. Furthermore, the outlined approach will be useful in designing metabolic engineering strategies in other non-model bacteria.
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Affiliation(s)
- Markus Janasch
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden.
| | - Nick Crang
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden.
| | - Johannes Asplund-Samuelsson
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden
| | - Emil Sporre
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden
| | - Manuel Bruch
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden
| | - Arvid Gynnå
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden
| | - Michael Jahn
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden
| | - Elton P Hudson
- Science for Life Laboratory, School of Engineering Science in Chemistry, Biotechnology and Health, KTH Royal Institute of Technology, P-Box 1031, 171 21, Solna, Sweden.
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4
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Lammers M. Post-translational Lysine Ac(et)ylation in Bacteria: A Biochemical, Structural, and Synthetic Biological Perspective. Front Microbiol 2021; 12:757179. [PMID: 34721364 PMCID: PMC8556138 DOI: 10.3389/fmicb.2021.757179] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 09/10/2021] [Indexed: 12/21/2022] Open
Abstract
Ac(et)ylation is a post-translational modification present in all domains of life. First identified in mammals in histones to regulate RNA synthesis, today it is known that is regulates fundamental cellular processes also in bacteria: transcription, translation, metabolism, cell motility. Ac(et)ylation can occur at the ε-amino group of lysine side chains or at the α-amino group of a protein. Furthermore small molecules such as polyamines and antibiotics can be acetylated and deacetylated enzymatically at amino groups. While much research focused on N-(ε)-ac(et)ylation of lysine side chains, much less is known about the occurrence, the regulation and the physiological roles on N-(α)-ac(et)ylation of protein amino termini in bacteria. Lysine ac(et)ylation was shown to affect protein function by various mechanisms ranging from quenching of the positive charge, increasing the lysine side chains’ size affecting the protein surface complementarity, increasing the hydrophobicity and by interfering with other post-translational modifications. While N-(ε)-lysine ac(et)ylation was shown to be reversible, dynamically regulated by lysine acetyltransferases and lysine deacetylases, for N-(α)-ac(et)ylation only N-terminal acetyltransferases were identified and so far no deacetylases were discovered neither in bacteria nor in mammals. To this end, N-terminal ac(et)ylation is regarded as being irreversible. Besides enzymatic ac(et)ylation, recent data showed that ac(et)ylation of lysine side chains and of the proteins N-termini can also occur non-enzymatically by the high-energy molecules acetyl-coenzyme A and acetyl-phosphate. Acetyl-phosphate is supposed to be the key molecule that drives non-enzymatic ac(et)ylation in bacteria. Non-enzymatic ac(et)ylation can occur site-specifically with both, the protein primary sequence and the three dimensional structure affecting its efficiency. Ac(et)ylation is tightly controlled by the cellular metabolic state as acetyltransferases use ac(et)yl-CoA as donor molecule for the ac(et)ylation and sirtuin deacetylases use NAD+ as co-substrate for the deac(et)ylation. Moreover, the accumulation of ac(et)yl-CoA and acetyl-phosphate is dependent on the cellular metabolic state. This constitutes a feedback control mechanism as activities of many metabolic enzymes were shown to be regulated by lysine ac(et)ylation. Our knowledge on lysine ac(et)ylation significantly increased in the last decade predominantly due to the huge methodological advances that were made in fields such as mass-spectrometry, structural biology and synthetic biology. This also includes the identification of additional acylations occurring on lysine side chains with supposedly different regulatory potential. This review highlights recent advances in the research field. Our knowledge on enzymatic regulation of lysine ac(et)ylation will be summarized with a special focus on structural and mechanistic characterization of the enzymes, the mechanisms underlying non-enzymatic/chemical ac(et)ylation are explained, recent technological progress in the field are presented and selected examples highlighting the important physiological roles of lysine ac(et)ylation are summarized.
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Affiliation(s)
- Michael Lammers
- Synthetic and Structural Biochemistry, Institute for Biochemistry, University of Greifswald, Greifswald, Germany
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5
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Fontecilla-Camps JC. Primordial bioenergy sources: The two facets of adenosine triphosphate. J Inorg Biochem 2020; 216:111347. [PMID: 33450675 DOI: 10.1016/j.jinorgbio.2020.111347] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Revised: 12/14/2020] [Accepted: 12/21/2020] [Indexed: 01/10/2023]
Abstract
Life requires energy to exist, to reproduce and to survive. Two major hypotheses have been put forward concerning the source of this energy at the very early stages of life evolution: (i) abiotic organics either brought to Earth by comets and/or meteorites, or produced at its atmosphere, and (ii) mineral surface-dependent bioinorganic catalytic reactions. Considering the latter possibility, I propose that, besides being a precursor of nucleic acids, adenosine triphosphate (ATP), which probably was used very early to improve the fidelity of nucleic acid polymerization, played an essential role in the transition between mineral-bound protocells and their free counterparts. Indeed, phosphorylation by ATP renders carboxylate groups electrophilic enough to react with nucleophiles such as amines, an effect that, thanks to their Lewis acid character, also have dehydrated metal ions on mineral surfaces. Early ATP synthesis for metabolic processes most likely depended on substrate level phosphorylation. However, the exaptation of a hexameric helicase-like ATPase and a transmembrane H+ pump (which evolved to counteract the acidity caused by fermentation reactions within the protocell) generated a much more efficient membrane-bound ATP synthase that uses chemiosmosis to make ATP.
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6
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Nguyen VH, Singh N, Medina A, Usón I, Fraser ME. Identification of the active site residues in ATP-citrate lyase's carboxy-terminal portion. Protein Sci 2019; 28:1840-1849. [PMID: 31411782 DOI: 10.1002/pro.3708] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2019] [Revised: 08/08/2019] [Accepted: 08/12/2019] [Indexed: 01/25/2023]
Abstract
ATP-citrate lyase (ACLY) catalyzes production of acetyl-CoA and oxaloacetate from CoA and citrate using ATP. In humans, this cytoplasmic enzyme connects energy metabolism from carbohydrates to the production of lipids. In certain bacteria, ACLY is used to fix carbon in the reductive tricarboxylic acid cycle. The carboxy(C)-terminal portion of ACLY shows sequence similarity to citrate synthase of the tricarboxylic acid cycle. To investigate the roles of residues of ACLY equivalent to active site residues of citrate synthase, these residues in ACLY from Chlorobium limicola were mutated, and the proteins were investigated using kinetics assays and biophysical techniques. To obtain the crystal structure of the C-terminal portion of ACLY, full-length C. limicola ACLY was cleaved, first non-specifically with chymotrypsin and subsequently with Tobacco Etch Virus protease. Crystals of the C-terminal portion diffracted to high resolution, providing structures that show the positions of active site residues and how ACLY tetramerizes.
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Affiliation(s)
- Vinh H Nguyen
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Noreen Singh
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
| | - Ana Medina
- Structural Biology Unit, CSIC, Barcelona, Spain
| | - Isabel Usón
- Structural Biology Unit, CSIC, Barcelona, Spain.,ICREA, Barcelona, Spain
| | - Marie E Fraser
- Department of Biological Sciences, University of Calgary, Calgary, Alberta, Canada
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7
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Maresca D, De Filippis F, Robertiello A, Mauriello G. Metabolic Profiling and Cold-Starvation Stress Response of Oxygen-Tolerant Lactobacillus gasseri Strains Cultured in Batch Bioreactor. Microorganisms 2019; 7:microorganisms7070200. [PMID: 31311070 PMCID: PMC6680863 DOI: 10.3390/microorganisms7070200] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2019] [Revised: 07/08/2019] [Accepted: 07/10/2019] [Indexed: 11/16/2022] Open
Abstract
Phenotypic and genotypic evidence indicates that many LAB strains can grow in presence of oxygen and can shift from fermentative to aerobic and/or respiratory metabolism. The aerobic and respiratory growth of several LAB species have been studied, allowing the selection of strains showing improved biomass production, long-term survival, and resistance under oxygen and stress conditions. The aim of this work was to observe the adaptation of two Lactobacillus gasseri strains, described in a previous work, to aerobic (air injection) and respiratory (air injection plus hemin and menaquionone) conditions obtained in a batch bioreactor. One strain showed the higher biomass production and oxygen consumption as well as the lower acidification in respiratory condition. Instead, the other one grew better in aerobic condition, even though the higher resistance to cold-starvation stress was registered in respiratory condition. In silico analysis revealed notable differences between AL3 and AL5 genomes and that of the type strain. This work contributes to understanding the adaptation response of lactobacilli to aerobic and respiratory metabolism. We demonstrated that the supposed activation of respiratory metabolism may provide several modifications to cell physiology. These features may be relevant in some technological and health-promoting applications, including starter and probiotic formulations.
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Affiliation(s)
- Diamante Maresca
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, NA, Italy
| | - Francesca De Filippis
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, NA, Italy
| | - Alessandro Robertiello
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, NA, Italy
| | - Gianluigi Mauriello
- Department of Agricultural Sciences, University of Naples Federico II, 80055 Portici, NA, Italy.
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8
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Hu J, Komakula A, Fraser ME. Binding of hydroxycitrate to human ATP-citrate lyase. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2017; 73:660-671. [PMID: 28777081 DOI: 10.1107/s2059798317009871] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 07/03/2017] [Indexed: 01/20/2023]
Abstract
Hydroxycitrate from the fruit of Garcinia cambogia [i.e. (2S,3S)-2-hydroxycitrate] is the best-known inhibitor of ATP-citrate lyase. Well diffracting crystals showing how the inhibitor binds to human ATP-citrate lyase were grown by modifying the protein. The protein was modified by introducing cleavage sites for Tobacco etch virus protease on either side of a disordered linker. The protein crystallized consisted of residues 2-425-ENLYFQ and S-488-810 of human ATP-citrate lyase. (2S,3S)-2-Hydroxycitrate binds in the same orientation as citrate, but the citrate-binding domain (residues 248-421) adopts a different orientation with respect to the rest of the protein (residues 4-247, 490-746 and 748-809) from that previously seen. For the first time, electron density was evident for the loop that contains His760, which is phosphorylated as part of the catalytic mechanism. The pro-S carboxylate of (2S,3S)-2-hydroxycitrate is available to accept a phosphoryl group from His760. However, when co-crystals were grown with ATP and magnesium ions as well as either the inhibitor or citrate, Mg2+-ADP was bound and His760 was phosphorylated. The phosphoryl group was not transferred to the organic acid. This led to the interpretation that the active site is trapped in an open conformation. The strategy of designing cleavage sites to remove disordered residues could be useful in determining the crystal structures of other proteins.
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Affiliation(s)
- Jinhong Hu
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Aruna Komakula
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
| | - Marie E Fraser
- Department of Biological Sciences, University of Calgary, 2500 University Drive NW, Calgary, Alberta T2N 1N4, Canada
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9
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Jones CP, Khan K, Ingram-Smith C. Investigating the mechanism of ADP-forming acetyl-CoA synthetase from the protozoan parasite Entamoeba histolytica. FEBS Lett 2017; 591:603-612. [PMID: 28129670 DOI: 10.1002/1873-3468.12573] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 01/09/2017] [Accepted: 01/22/2017] [Indexed: 11/06/2022]
Abstract
ADP-forming acetyl-CoA synthetase (ACD) catalyzes the interconversion of acetyl-CoA and acetate. The related succinyl-CoA synthetase follows a three-step mechanism involving a single phosphoenzyme, but a novel four-step mechanism with two phosphoenzyme intermediates was proposed for Pyrococcus ACD. Characterization of enzyme variants of Entamoeba ACD in which the two proposed phosphorylated His residues were individually altered revealed that only His252 is essential for enzymatic activity. Analysis of variants altered at two residues proposed to interact with the phosphohistidine loop that swings between distinct parts of the active site are consistent with a mechanism involving a single phosphoenzyme intermediate. Our results suggest ACDs with different subunit structures may employ slightly different mechanisms to bridge the span between active sites I and II.
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Affiliation(s)
- Cheryl P Jones
- Department of Genetics and Biochemistry and the Eukaryotic Pathogens Innovation Center, Clemson University, SC, USA
| | - Kirin Khan
- Department of Genetics and Biochemistry and the Eukaryotic Pathogens Innovation Center, Clemson University, SC, USA
| | - Cheryl Ingram-Smith
- Department of Genetics and Biochemistry and the Eukaryotic Pathogens Innovation Center, Clemson University, SC, USA
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10
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Filippov S, Pinkosky SL, Newton RS. LDL-cholesterol reduction in patients with hypercholesterolemia by modulation of adenosine triphosphate-citrate lyase and adenosine monophosphate-activated protein kinase. Curr Opin Lipidol 2014; 25:309-15. [PMID: 24978142 PMCID: PMC4162331 DOI: 10.1097/mol.0000000000000091] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
PURPOSE OF REVIEW To review the profile of ETC-1002, as shown in preclinical and clinical studies, including LDL-cholesterol (LDL-C)-lowering activity and beneficial effects on other cardiometabolic risk markers as they relate to the inhibition of adenosine triphosphate-citrate lyase and the activation of adenosine monophosphate-activated protein kinase. RECENT FINDINGS ETC-1002 is an adenosine triphosphate-citrate lyase inhibitor/adenosine monophosphate-activated protein kinase activator currently in Phase 2b clinical development. In seven Phase 1 and Phase 2a clinical studies, ETC-1002 dosed once daily for 2-12 weeks has lowered LDL-C and reduced high-sensitivity C-reactive protein by up to 40%, with neutral to positive effects on glucose levels, blood pressure, and body weight. Importantly, use of ETC-1002 in statin-intolerant patients has shown statin-like lowering of LDL-C without the muscle pain and weakness responsible for discontinuation of statin use by many patients. ETC-1002 has also been shown to produce an incremental benefit, lowering LDL-C as an add-on therapy to a low-dose statin. In over 300 individuals in studies of up to 12 weeks, ETC-1002 has been well tolerated with no serious adverse effects. SUMMARY Because adenosine triphosphate-citrate lyase and adenosine monophosphate-activated protein kinase play central roles in regulating lipid and glucose metabolism, pharmacological modulation of these two enzymes could provide an important therapeutic alternative for statin-intolerant patients with hypercholesterolemia.
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11
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Fan F, Williams HJ, Boyer JG, Graham TL, Zhao H, Lehr R, Qi H, Schwartz B, Raushel FM, Meek TD. On the catalytic mechanism of human ATP citrate lyase. Biochemistry 2012; 51:5198-211. [PMID: 22657152 DOI: 10.1021/bi300611s] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
ATP citrate lyase (ACL) catalyzes an ATP-dependent biosynthetic reaction which produces acetyl-coenzyme A and oxaloacetate from citrate and coenzyme A (CoA). Studies were performed with recombinant human ACL to ascertain the nature of the catalytic phosphorylation that initiates the ACL reaction and the identity of the active site residues involved. Inactivation of ACL by treatment with diethylpyrocarbonate suggested the catalytic role of an active site histidine (i.e., His760), which was proposed to form a phosphohistidine species during catalysis. The pH-dependence of the pre-steady-state phosphorylation of ACL with [γ-(33)P]-ATP revealed an ionizable group with a pK(a) value of ~7.5, which must be unprotonated for the catalytic phosphorylation of ACL to occur. Mutagenesis of His760 to an alanine results in inactivation of the biosynthetic reaction of ACL, in good agreement with the involvement of a catalytic histidine. The nature of the formation of the phospho-ACL was further investigated by positional isotope exchange using [γ-(18)O(4)]-ATP. The β,γ-bridge to nonbridge positional isotope exchange rate of [γ-(18)O(4)]-ATP achieved its maximal rate of 14 s(-1) in the absence of citrate and CoA. This rate decreased to 5 s(-1) when citrate was added, and was found to be 10 s(-1) when both citrate and CoA were present. The rapid positional isotope exchange rates indicated the presence of one or more catalytically relevant, highly reversible phosphorylated intermediates. Steady-state measurements in the absence of citrate and CoA showed that MgADP was produced by both wild type and H760A forms of ACL, with rates at three magnitudes lower than that of k(cat) for the full biosynthetic reaction. The ATPase activity of ACL, along with the small yet significant positional isotope exchange rate observed in H760A mutant ACL (~150 fold less than wild type), collectively suggested the presence of a second, albeit unproductive, phosphoryl transfer in ACL. Mathematical analysis and computational simulation suggested that the desorption of MgADP at a rate of ~7 s(-1) was the rate-limiting step in the biosynthesis of AcCoA and oxaloacetate.
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Affiliation(s)
- Fan Fan
- Biological Reagents and Assay Development, GlaxoSmithKline, Collegeville, Pennsylvania 19426, USA.
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12
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Torres R, Chim N, Sankaran B, Pujol C, Bliska JB, Goulding CW. Structural insights into RipC, a putative citrate lyase β subunit from a Yersinia pestis virulence operon. Acta Crystallogr Sect F Struct Biol Cryst Commun 2012; 68:2-7. [PMID: 22232161 PMCID: PMC3253824 DOI: 10.1107/s1744309111048056] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2011] [Accepted: 11/11/2011] [Indexed: 05/26/2024]
Abstract
Yersinia pestis remains a threat, with outbreaks of plague occurring in rural areas and its emergence as a weapon of bioterrorism; thus, an improved understanding of its various pathogenicity pathways is warranted. The rip (required for intracellular proliferation) virulence operon is required for Y. pestis survival in interferon-γ-treated macrophages and has been implicated in lowering macrophage-produced nitric oxide levels. RipC, one of three gene products from the rip operon, is annotated as a citrate lyase β subunit. Furthermore, the Y. pestis genome lacks genes that encode citrate lyase α and γ subunits, suggesting a unique functional role of RipC in the Y. pestis rip-mediated survival pathway. Here, the 2.45 Å resolution crystal structure of RipC revealed a homotrimer in which each monomer consists of a (β/α)(8) TIM-barrel fold. Furthermore, the trimeric state was confirmed in solution by size-exclusion chromatography. Through sequence and structure comparisons with homologous proteins, it is proposed that RipC is a putative CoA- or CoA-derivative binding protein.
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Affiliation(s)
- Rodrigo Torres
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
| | - Nicholas Chim
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
| | - Banumathi Sankaran
- Berkeley Center for Structural Biology, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - Céline Pujol
- Department of Molecular Genetics and Microbiology and Center for Infectious Diseases, State University of New York, Stony Brook, NY 11794, USA
| | - James B. Bliska
- Department of Molecular Genetics and Microbiology and Center for Infectious Diseases, State University of New York, Stony Brook, NY 11794, USA
| | - Celia W. Goulding
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697, USA
- Department of Pharmaceutical Sciences, University of California, Irvine, CA 92697, USA
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13
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Tang KH, Blankenship RE. Both forward and reverse TCA cycles operate in green sulfur bacteria. J Biol Chem 2010; 285:35848-54. [PMID: 20650900 DOI: 10.1074/jbc.m110.157834] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The anoxygenic green sulfur bacteria (GSBs) assimilate CO(2) autotrophically through the reductive (reverse) tricarboxylic acid (RTCA) cycle. Some organic carbon sources, such as acetate and pyruvate, can be assimilated during the phototrophic growth of the GSBs, in the presence of CO(2) or HCO(3)(-). It has not been established why the inorganic carbonis required for incorporating organic carbon for growth and how the organic carbons are assimilated. In this report, we probed carbon flux during autotrophic and mixotrophic growth of the GSB Chlorobaculum tepidum. Our data indicate the following: (a) the RTCA cycle is active during autotrophic and mixotrophic growth; (b) the flux from pyruvate to acetyl-CoA is very low and acetyl-CoA is synthesized through the RTCA cycle and acetate assimilation; (c) pyruvate is largely assimilated through the RTCA cycle; and (d) acetate can be assimilated via both of the RTCA as well as the oxidative (forward) TCA (OTCA) cycle. The OTCA cycle revealed herein may explain better cell growth during mixotrophic growth with acetate, as energy is generated through the OTCA cycle. Furthermore, the genes specific for the OTCA cycle are either absent or down-regulated during phototrophic growth, implying that the OTCA cycle is not complete, and CO(2) is required for the RTCA cycle to produce metabolites in the TCA cycle. Moreover, CO(2) is essential for assimilating acetate and pyruvate through the CO(2)-anaplerotic pathway and pyruvate synthesis from acetyl-CoA.
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Affiliation(s)
- Kuo-Hsiang Tang
- Department of Biology and Chemistry, Washington University, St Louis, Missouri 63130, USA
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Bräsen C, Schmidt M, Grötzinger J, Schönheit P. Reaction mechanism and structural model of ADP-forming Acetyl-CoA synthetase from the hyperthermophilic archaeon Pyrococcus furiosus: evidence for a second active site histidine residue. J Biol Chem 2008; 283:15409-18. [PMID: 18372246 DOI: 10.1074/jbc.m710218200] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
In Archaea, acetate formation and ATP synthesis from acetyl-CoA is catalyzed by an unusual ADP-forming acetyl-CoA synthetase (ACD) (acetyl-CoA + ADP + P(i) acetate + ATP + HS-CoA) catalyzing the formation of acetate from acetyl-CoA and concomitant ATP synthesis by the mechanism of substrate level phosphorylation. ACD belongs to the protein superfamily of nucleoside diphosphate-forming acyl-CoA synthetases, which also include succinyl-CoA synthetases (SCSs). ACD differs from SCS in domain organization of subunits and in the presence of a second highly conserved histidine residue in the beta-subunit, which is absent in SCS. The influence of these differences on structure and reaction mechanism of ACD was studied with heterotetrameric ACD (alpha(2)beta(2)) from the hyperthermophilic archaeon Pyrococcus furiosus in comparison with heterotetrameric SCS. A structural model of P. furiosus ACD was constructed suggesting a novel spatial arrangement of the subunits different from SCS, however, maintaining a similar catalytic site. Furthermore, kinetic and molecular properties and enzyme phosphorylation as well as the ability to catalyze arsenolysis of acetyl-CoA were studied in wild type ACD and several mutant enzymes. The data indicate that the formation of enzyme-bound acetyl phosphate and enzyme phosphorylation at His-257alpha, respectively, proceed in analogy to SCS. In contrast to SCS, in ACD the phosphoryl group is transferred from the His-257alpha to ADP via transient phosphorylation of a second conserved histidine residue in the beta-subunit, His-71beta. It is proposed that ACD reaction follows a novel four-step mechanism including transient phosphorylation of two active site histidine residues:
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Affiliation(s)
- Christopher Bräsen
- Institut für Allgemeine Mikrobiologie, Christian-Albrechts Universität Kiel, Am Botanischen Garten 1-9, Kiel, Germany
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Kim W, Tabita FR. Both subunits of ATP-citrate lyase from Chlorobium tepidum contribute to catalytic activity. J Bacteriol 2006; 188:6544-52. [PMID: 16952946 PMCID: PMC1595482 DOI: 10.1128/jb.00523-06] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
ATP-citrate lyase (ACL) is an essential enzyme of the reductive tricarboxylic acid (RTCA) pathway of CO(2) assimilation. The RTCA pathway occurs in several groups of autotrophic prokaryotes, including the green sulfur bacteria. ACL catalyzes the coenzyme A (CoA)-dependent and MgATP-dependent cleavage of citrate into oxaloacetate and acetyl-CoA, representing a key step in the RTCA pathway. To characterize this enzyme from the green sulfur bacterium Chlorobium tepidum and determine the role of its two distinct polypeptide chains, recombinant holo-ACL as well as its two individual subunit polypeptides were synthesized in Escherichia coli. The recombinant holoenzyme, prepared from coexpressed large and small ACL genes, and the individual large and small subunit polypeptides, prepared from singly expressed genes, were all purified to homogeneity to high yield. Purified recombinant holo-ACL was isolated at high specific activity, and its k(cat) was comparable to that of previously prepared native C. tepidum ACL. Moreover, the purified recombinant large and small subunit polypeptides were able to reconstitute the holo-ACL in vitro, with activity levels approaching that of recombinant holo-ACL prepared from coexpressed genes. Stoichiometric amounts of each subunit protein were required to maximize the activity and form the most stable structure of reconstituted holo-ACL. These results suggested that this reconstitution system could be used to discern the catalytic role of specific amino acid residues on each subunit. Reconstitution and mutagenesis studies together indicated that residues of each subunit contributed to different aspects of the catalytic mechanism, suggesting that both subunit proteins contribute to the active site of C. tepidum ACL.
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Affiliation(s)
- Wonduck Kim
- Department of Microbiology, The Ohio State University, 484 12th Ave., Columbus, OH 42310-1292, USA
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Goulding CW, Bowers PM, Segelke B, Lekin T, Kim CY, Terwilliger TC, Eisenberg D. The structure and computational analysis of Mycobacterium tuberculosis protein CitE suggest a novel enzymatic function. J Mol Biol 2006; 365:275-83. [PMID: 17064730 DOI: 10.1016/j.jmb.2006.09.086] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2006] [Revised: 09/13/2006] [Accepted: 09/18/2006] [Indexed: 10/24/2022]
Abstract
Fatty acid biosynthesis is essential for the survival of Mycobacterium tuberculosis and acetyl-coenzyme A (acetyl-CoA) is an essential precursor in this pathway. We have determined the 3-D crystal structure of M. tuberculosis citrate lyase beta-subunit (CitE), which as annotated should cleave protein bound citryl-CoA to oxaloacetate and a protein-bound CoA derivative. The CitE structure has the (beta/alpha)(8) TIM barrel fold with an additional alpha-helix, and is trimeric. We have determined the ternary complex bound with oxaloacetate and magnesium, revealing some of the conserved residues involved in catalysis. While the bacterial citrate lyase is a complex with three subunits, the M. tuberculosis genome does not contain the alpha and gamma subunits of this complex, implying that M. tuberculosis CitE acts differently from other bacterial CitE proteins. The analysis of gene clusters containing the CitE protein from 168 fully sequenced organisms has led us to identify a grouping of functionally related genes preserved in M. tuberculosis, Rattus norvegicus, Homo sapiens, and Mus musculus. We propose a novel enzymatic function for M. tuberculosis CitE in fatty acid biosynthesis that is analogous to bacterial citrate lyase but producing acetyl-CoA rather than a protein-bound CoA derivative.
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Affiliation(s)
- Celia W Goulding
- Institute for Genomics and Proteomics, UCLA, Los Angeles, CA 90095-1570, USA
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Atomi H. Microbial enzymes involved in carbon dioxide fixation. J Biosci Bioeng 2005; 94:497-505. [PMID: 16233341 DOI: 10.1016/s1389-1723(02)80186-4] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2002] [Accepted: 09/17/2002] [Indexed: 11/26/2022]
Abstract
This review focuses on the enzymes involved in two microbial carbon dioxide fixation pathways, the Calvin-Benson-Bassham cycle and the reductive tricarboxylic acid cycle. The function, structural features, and gene regulation of microbial ribulose 1,5-bisphosphate carboxylase/oxygenase (Rubisco), a key enzyme of the Calvin-Benson-Bassham cycle, is described. Some recent findings on Rubisco from archaea and Rubisco-like proteins are also outlined. In the final section, biochemical features of the key enzymes in the reductive tricarboxylic acid cycle are reviewed.
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Affiliation(s)
- Haruyuki Atomi
- Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Yoshida-Honmachi, Sakyo-ku, Kyoto 606-8501, Japan.
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Abeliovich H. An empirical extremum principle for the hill coefficient in ligand-protein interactions showing negative cooperativity. Biophys J 2005; 89:76-9. [PMID: 15834004 PMCID: PMC1366580 DOI: 10.1529/biophysj.105.060194] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2005] [Accepted: 04/04/2005] [Indexed: 11/18/2022] Open
Abstract
The Hill coefficient (nH) is a central parameter in the study of ligand-protein interactions, which measures the degree of cooperativity between subunits that bind the ligand in multisubunit proteins. The most common usage of nH is as an estimate of the minimal number of interacting binding sites in positively cooperating systems. In the present study, a statistical interpretation of nH for a generalized system of multiple identical binding sites is developed. This interpretation is then applied to the derivation of an empirical extremum principle for nH in negatively cooperating systems of identical binding sites, which can be used for the estimation of the minimal number of interacting sites in such systems.
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Affiliation(s)
- Hagai Abeliovich
- Department of Biochemistry and Food Science, Hebrew University of Jerusalem, Rehovot, Israel.
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