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Boden R. In memoriam: Prof Yuri Alexandrovich Trotsenko (1941-2021). FEMS Microbiol Lett 2024; 371:fnae024. [PMID: 38676918 DOI: 10.1093/femsle/fnae024] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2024] [Accepted: 04/08/2024] [Indexed: 04/29/2024] Open
Affiliation(s)
- Rich Boden
- School of Biological and Marine Sciences, Faculty of Science and Engineering, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom
- Marine Institute, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom
- Sustainable Earth Institute, University of Plymouth, Drake Circus, Plymouth PL4 8AA, United Kingdom
- Editor-In-Chief, FEMS Microbiology Letters, Delftechpark 37a, Delft 2628 XJ, Netherlands
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Yuan XJ, Chen WJ, Ma ZX, Yuan QQ, Zhang M, He L, Mo XH, Zhang C, Zhang CT, Wang MY, Xing XH, Yang S. Rewiring the native methanol assimilation metabolism by incorporating the heterologous ribulose monophosphate cycle into Methylorubrum extorquens. Metab Eng 2021; 64:95-110. [PMID: 33493644 DOI: 10.1016/j.ymben.2021.01.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Revised: 01/05/2021] [Accepted: 01/18/2021] [Indexed: 10/22/2022]
Abstract
Methanol is assimilated through the serine cycle to generate acetyl-CoA without carbon loss. However, a highly active serine cycle requires high consumption of reducing equivalents and ATP, thereby leading to the impaired efficiency of methanol conversion to reduced chemicals. In the present study, a genome-scale flux balance analysis (FBA) predicted that the introduction of the heterologous ribulose monophosphate (RuMP) cycle, a more energy-efficient pathway for methanol assimilation, could theoretically increase growth rate by 31.3% for the model alphaproteobacterial methylotroph Methylorubrum extorquens AM1. Based on this analysis, we constructed a novel synergistic assimilation pathway in vivo by incorporating the RuMP cycle into M. extroquens metabolism with the intrinsic serine cycle. We demonstrated that the operation of the synergistic pathway could increase cell growth rate by 16.5% and methanol consumption rate by 13.1%. This strategy rewired the central methylotrophic metabolism through adjusting core gene transcription, leading to a pool size increase of C2 to C5 central intermediates by 1.2- to 3.6-fold and an NADPH cofactor improvement by 1.3-fold. The titer of 3-hydroxypropionic acid (3-HP), a model product in the newly engineered chassis of M. extorquens AM1, was increased to 91.2 mg/L in shake-flask culture, representing a 3.1-fold increase compared with the control strain with only the serine cycle. The final titer of 3-HP was significantly improved to 0.857 g/L in the fed-batch bioreactor, which was more competitive compared with the other 3-HP producers using methane and CO2 as C1 sources. Collectively, our current study demonstrated that engineering the synergistic methanol assimilation pathway was a promising strategy to increase the carbon assimilation and the yields of reduced chemicals in diverse host strains for C1 microbial cell factories.
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Affiliation(s)
- Xiao-Jie Yuan
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China; Department of Molecular Biology, Qingdao Vland Biotech Inc., Qingdao, Shandong Province, People's Republic of China
| | - Wen-Jing Chen
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Zeng-Xin Ma
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Qian-Qian Yuan
- Key Laboratory of Systems Microbial Biotechnology, Tianjin Institute of Industrial Biotechnology, Chinese Academy of Sciences, Tianjin, People's Republic of China
| | - Min Zhang
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Lian He
- Department of Chemical Engineering, University of Washington, Seattle, WA, USA
| | - Xu-Hua Mo
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Chong Zhang
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, People's Republic of China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, People's Republic of China
| | - Chang-Tai Zhang
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Meng-Ying Wang
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China
| | - Xin-Hui Xing
- Key Laboratory of Industrial Biocatalysis, Ministry of Education, Department of Chemical Engineering, Tsinghua University, Beijing, People's Republic of China; Center for Synthetic and Systems Biology, Tsinghua University, Beijing, People's Republic of China; Institute of Biopharmaceutical and Health Engineering, Tsinghua Shenzhen International Graduate School, And Institute of Biomedical Health Technology and Engineering, Shenzhen Bay Laboratory, Shenzhen, China
| | - Song Yang
- School of Life Sciences, Shandong Province Key Laboratory of Applied Mycology, And Qingdao International Center on Microbes Utilizing Biogas, Qingdao Agricultural University, Qingdao, Shandong Province, People's Republic of China; Key Laboratory of Systems Bioengineering, Ministry of Education, Tianjin University, Tianjin, People's Republic of China.
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3
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Nguyen AD, Nam G, Kim D, Lee EY. Metabolic role of pyrophosphate-linked phosphofructokinase pfk for C1 assimilation in Methylotuvimicrobium alcaliphilum 20Z. Microb Cell Fact 2020; 19:131. [PMID: 32546161 PMCID: PMC7298851 DOI: 10.1186/s12934-020-01382-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2019] [Accepted: 05/30/2020] [Indexed: 01/02/2023] Open
Abstract
BACKGROUND Methanotrophs is a promising biocatalyst in biotechnological applications with their ability to utilize single carbon (C1) feedstock to produce high-value compounds. Understanding the behavior of biological networks of methanotrophic bacteria in different parameters is vital to systems biology and metabolic engineering. Interestingly, methanotrophic bacteria possess the pyrophosphate-dependent 6-phosphofructokinase (PPi-PFK) instead of the ATP-dependent 6-phosphofructokinase, indicating their potentials to serve as promising model for investigation the role of inorganic pyrophosphate (PPi) and PPi-dependent glycolysis in bacteria. Gene knockout experiments along with global-omics approaches can be used for studying gene functions as well as unraveling regulatory networks that rely on the gene product. RESULTS In this study, we performed gene knockout and RNA-seq experiments in Methylotuvimicrobium alcaliphilum 20Z to investigate the functional roles of PPi-PFK in C1 metabolism when cells were grown on methane and methanol, highlighting its metabolic importance in C1 assimilation in M. alcaliphilum 20Z. We further conducted adaptive laboratory evolution (ALE) to investigate regulatory architecture in pfk knockout strain. Whole-genome resequencing and RNA-seq approaches were performed to characterize the genetic and metabolic responses of adaptation to pfk knockout. A number of mutations, as well as gene expression profiles, were identified in pfk ALE strain to overcome insufficient C1 assimilation pathway which limits the growth in the unevolved strain. CONCLUSIONS This study first revealed the regulatory roles of PPi-PFK on C1 metabolism and then provided novel insights into mechanism of adaptation to the loss of this major metabolic enzyme as well as an improved basis for future strain design in type I methanotrophs.
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Affiliation(s)
- Anh Duc Nguyen
- Department of Chemical Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104, South Korea
| | - Gayoung Nam
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea
| | - Donghyuk Kim
- School of Energy and Chemical Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, South Korea.
| | - Eun Yeol Lee
- Department of Chemical Engineering, Kyung Hee University, Yongin-si, Gyeonggi-do, 17104, South Korea.
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Koendjbiharie JG, Hon S, Pabst M, Hooftman R, Stevenson DM, Cui J, Amador-Noguez D, Lynd LR, Olson DG, van Kranenburg R. The pentose phosphate pathway of cellulolytic clostridia relies on 6-phosphofructokinase instead of transaldolase. J Biol Chem 2020; 295:1867-1878. [PMID: 31871051 PMCID: PMC7029132 DOI: 10.1074/jbc.ra119.011239] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Revised: 12/16/2019] [Indexed: 01/24/2023] Open
Abstract
The genomes of most cellulolytic clostridia do not contain genes annotated as transaldolase. Therefore, for assimilating pentose sugars or for generating C5 precursors (such as ribose) during growth on other (non-C5) substrates, they must possess a pathway that connects pentose metabolism with the rest of metabolism. Here we provide evidence that for this connection cellulolytic clostridia rely on the sedoheptulose 1,7-bisphosphate (SBP) pathway, using pyrophosphate-dependent phosphofructokinase (PPi-PFK) instead of transaldolase. In this reversible pathway, PFK converts sedoheptulose 7-phosphate (S7P) to SBP, after which fructose-bisphosphate aldolase cleaves SBP into dihydroxyacetone phosphate and erythrose 4-phosphate. We show that PPi-PFKs of Clostridium thermosuccinogenes and Clostridium thermocellum indeed can convert S7P to SBP, and have similar affinities for S7P and the canonical substrate fructose 6-phosphate (F6P). By contrast, (ATP-dependent) PfkA of Escherichia coli, which does rely on transaldolase, had a very poor affinity for S7P. This indicates that the PPi-PFK of cellulolytic clostridia has evolved the use of S7P. We further show that C. thermosuccinogenes contains a significant SBP pool, an unusual metabolite that is elevated during growth on xylose, demonstrating its relevance for pentose assimilation. Last, we demonstrate that a second PFK of C. thermosuccinogenes that operates with ATP and GTP exhibits unusual kinetics toward F6P, as it appears to have an extremely high degree of cooperative binding, resulting in a virtual on/off switch for substrate concentrations near its K½ value. In summary, our results confirm the existence of an SBP pathway for pentose assimilation in cellulolytic clostridia.
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Affiliation(s)
| | - Shuen Hon
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755; Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830
| | - Martin Pabst
- Cell Systems Engineering, Delft University of Technology, 2629 HZ Delft, The Netherlands
| | - Robert Hooftman
- Laboratory of Microbiology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands
| | - David M Stevenson
- Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Jingxuan Cui
- Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830; Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, 03755
| | - Daniel Amador-Noguez
- Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830; Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin 53706
| | - Lee R Lynd
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755; Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830; Department of Biological Sciences, Dartmouth College, Hanover, New Hampshire, 03755
| | - Daniel G Olson
- Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755; Center for Bioenergy Innovation, Oak Ridge National Laboratories, Oak Ridge, Tennessee 37830
| | - Richard van Kranenburg
- Corbion, 4206 AC Gorinchem, The Netherlands; Laboratory of Microbiology, Wageningen University & Research, 6708 WE Wageningen, The Netherlands.
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5
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Hu L, Yang Y, Yan X, Zhang T, Xiang J, Gao Z, Chen Y, Yang S, Fei Q. Molecular Mechanism Associated With the Impact of Methane/Oxygen Gas Supply Ratios on Cell Growth of Methylomicrobium buryatense 5GB1 Through RNA-Seq. Front Bioeng Biotechnol 2020; 8:263. [PMID: 32318556 PMCID: PMC7154130 DOI: 10.3389/fbioe.2020.00263] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2020] [Accepted: 03/13/2020] [Indexed: 11/13/2022] Open
Abstract
The methane (CH4)/oxygen (O2) gas supply ratios significantly affect the cell growth and metabolic pathways of aerobic obligate methanotrophs. However, few studies have explored the CH4/O2 ratios of the inlet gas, especially for the CH4 concentrations within the explosion range (5∼15% of CH4 in air). This study thoroughly investigated the molecular mechanisms associated with the impact of different CH4/O2 ratios on cell growth of a model type I methanotroph Methylomicrobium buryatense 5GB1 cultured at five different CH4/O2 supply molar ratios from 0.28 to 5.24, corresponding to CH4 content in gas mixture from 5% to 50%, using RNA-Seq transcriptomics approach. In the batch cultivation, the highest growth rate of 0.287 h-1 was achieved when the CH4/O2 supply molar ratio was 0.93 (15% CH4 in air), and it is crucial to keep the availability of carbon and oxygen levels balanced for optimal growth. At this ratio, genes related to methane metabolism, phosphate uptake system, and nitrogen fixation were significantly upregulated. The results indicated that the optimal CH4/O2 ratio prompted cell growth by increasing genes involved in metabolic pathways of carbon, nitrogen and phosphate utilization in M. buryatense 5GB1. Our findings provided an effective gas supply strategy for methanotrophs, which could enhance the production of key intermediates and enzymes to improve the performance of bioconversion processes using CH4 as the only carbon and energy source. This research also helps identify genes associated with the optimal CH4/O2 ratio for balancing energy metabolism and carbon flux, which could be candidate targets for future metabolic engineering practice.
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Affiliation(s)
- Lizhen Hu
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, China
| | - Yongfu Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Xin Yan
- Key Laboratory of Agricultural Environmental Microbiology, Ministry of Agriculture, College of Life Sciences, Nanjing Agricultural University, Nanjing, China
| | - Tianqing Zhang
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, China
| | - Jing Xiang
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, China
| | - Zixi Gao
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, China
| | - Yunhao Chen
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
| | - Shihui Yang
- State Key Laboratory of Biocatalysis and Enzyme Engineering, Environmental Microbial Technology Center of Hubei Province, and School of Life Sciences, Hubei University, Wuhan, China
- *Correspondence: Shihui Yang,
| | - Qiang Fei
- School of Chemical Engineering and Technology, Xi’an Jiaotong University, Xi’an, China
- Shaanxi Key Laboratory of Energy Chemical Process Intensification, Xi’an Jiaotong University, Xi’an, China
- Qiang Fei,
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Methane utilization in Methylomicrobium alcaliphilum 20Z R: a systems approach. Sci Rep 2018; 8:2512. [PMID: 29410419 PMCID: PMC5802761 DOI: 10.1038/s41598-018-20574-z] [Citation(s) in RCA: 57] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Accepted: 01/22/2018] [Indexed: 12/20/2022] Open
Abstract
Biological methane utilization, one of the main sinks of the greenhouse gas in nature, represents an attractive platform for production of fuels and value-added chemicals. Despite the progress made in our understanding of the individual parts of methane utilization, our knowledge of how the whole-cell metabolic network is organized and coordinated is limited. Attractive growth and methane-conversion rates, a complete and expert-annotated genome sequence, as well as large enzymatic, 13C-labeling, and transcriptomic datasets make Methylomicrobium alcaliphilum 20ZR an exceptional model system for investigating methane utilization networks. Here we present a comprehensive metabolic framework of methane and methanol utilization in M. alcaliphilum 20ZR. A set of novel metabolic reactions governing carbon distribution across central pathways in methanotrophic bacteria was predicted by in-silico simulations and confirmed by global non-targeted metabolomics and enzymatic evidences. Our data highlight the importance of substitution of ATP-linked steps with PPi-dependent reactions and support the presence of a carbon shunt from acetyl-CoA to the pentose-phosphate pathway and highly branched TCA cycle. The diverged TCA reactions promote balance between anabolic reactions and redox demands. The computational framework of C1-metabolism in methanotrophic bacteria can represent an efficient tool for metabolic engineering or ecosystem modeling.
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7
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Christoffersen TE, Olsen Hult LT, Solberg H, Bakke A, Kuczkowska K, Huseby E, Jacobsen M, Lea T, Kleiveland CR. Effects of the non-commensal Methylococcus capsulatus Bath on mammalian immune cells. Mol Immunol 2015; 66:107-16. [PMID: 25771177 DOI: 10.1016/j.molimm.2015.02.019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Revised: 01/27/2015] [Accepted: 02/19/2015] [Indexed: 12/21/2022]
Abstract
Dietary inclusions of a bacterial meal consisting mainly of the non-commensal, methanotrophic bacteria Methylococcus capsulatus Bath have been shown to ameliorate symptoms of intestinal inflammation in different animal models. In order to investigate the molecular mechanisms causing these effects, we have studied the influence of this strain on different immune cells central for the regulation of inflammatory responses. Effects were compared to those induced by the closely related strain M. capsulatus Texas and the well-described probiotic strain Escherichia coli Nissle 1917. M. capsulatus Bath induced macrophage polarization toward a pro-inflammatory phenotype, but not to the extent observed after exposure to E. coli Nissle 1917. Likewise, dose-dependent abilities to activate NF-κB transcription in U937 cells were observed, with E. coli Nissle 1917 being most potent. High levels of CD141 on human primary monocyte-derived dendritic cells (moDCs) were only detected after exposure to E. coli Nissle 1917, which collectively indicate a superior capacity to induce Th1 cell responses for this strain. On the other hand, the M. capsulatus strains were more potent in increasing the expression of the maturation markers CD80, CD83 and CD86 than E. coli Nissle 1917. M. capsulatus Bath induced the highest levels of IL-6, IL-10 and IL-12 secretion from dendritic cells, suggesting that this strain generally the post potent inducer of cytokine secretion. These results show that M. capsulatus Bath exhibit immunogenic properties in mammalian in vitro systems which diverge from that of E. coli Nissle 1917. This may provide clues to how M. capsulatus Bath influence the adaptive immune system in vivo. However, further in vivo experiments are required for a complete understanding of how this strain ameliorates intestinal inflammation in animal models.
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Affiliation(s)
| | | | - Henriette Solberg
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Aas, Norway.
| | - Anne Bakke
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Aas, Norway.
| | - Katarzyna Kuczkowska
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Aas, Norway.
| | - Eirin Huseby
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Aas, Norway.
| | - Morten Jacobsen
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Aas, Norway; Ostfold Hospital Trust, 1603 Fredrikstad, Norway.
| | - Tor Lea
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Aas, Norway.
| | - Charlotte Ramstad Kleiveland
- Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, 1430 Aas, Norway; Ostfold Hospital Trust, 1603 Fredrikstad, Norway.
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Khmelenina VN, Rozova ON, But SY, Mustakhimov II, Reshetnikov AS, Beschastnyi AP, Trotsenko YA. Biosynthesis of secondary metabolites in methanotrophs: Biochemical and genetic aspects (Review). APPL BIOCHEM MICRO+ 2015. [DOI: 10.1134/s0003683815020088] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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9
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Welte C, Deppenmeier U. Bioenergetics and anaerobic respiratory chains of aceticlastic methanogens. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2013; 1837:1130-47. [PMID: 24333786 DOI: 10.1016/j.bbabio.2013.12.002] [Citation(s) in RCA: 151] [Impact Index Per Article: 13.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/28/2013] [Revised: 12/02/2013] [Accepted: 12/05/2013] [Indexed: 12/16/2022]
Abstract
Methane-forming archaea are strictly anaerobic microbes and are essential for global carbon fluxes since they perform the terminal step in breakdown of organic matter in the absence of oxygen. Major part of methane produced in nature derives from the methyl group of acetate. Only members of the genera Methanosarcina and Methanosaeta are able to use this substrate for methane formation and growth. Since the free energy change coupled to methanogenesis from acetate is only -36kJ/mol CH4, aceticlastic methanogens developed efficient energy-conserving systems to handle this thermodynamic limitation. The membrane bound electron transport system of aceticlastic methanogens is a complex branched respiratory chain that can accept electrons from hydrogen, reduced coenzyme F420 or reduced ferredoxin. The terminal electron acceptor of this anaerobic respiration is a mixed disulfide composed of coenzyme M and coenzyme B. Reduced ferredoxin has an important function under aceticlastic growth conditions and novel and well-established membrane complexes oxidizing ferredoxin will be discussed in depth. Membrane bound electron transport is connected to energy conservation by proton or sodium ion translocating enzymes (F420H2 dehydrogenase, Rnf complex, Ech hydrogenase, methanophenazine-reducing hydrogenase and heterodisulfide reductase). The resulting electrochemical ion gradient constitutes the driving force for adenosine triphosphate synthesis. Methanogenesis, electron transport, and the structure of key enzymes are discussed in this review leading to a concept of how aceticlastic methanogens make a living. This article is part of a Special Issue entitled: 18th European Bioenergetic Conference.
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Affiliation(s)
- Cornelia Welte
- Institute of Microbiology and Biotechnology, University of Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany; Department of Microbiology, IWWR, Radboud University Nijmegen, Heyendaalseweg 135, 6525 AJ Nijmegen, The Netherlands.
| | - Uwe Deppenmeier
- Institute of Microbiology and Biotechnology, University of Bonn, Meckenheimer Allee 168, 53115 Bonn, Germany.
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Rozova ON, Khmelenina VN, Trotsenko YA. Characterization of recombinant PPi-dependent 6-phosphofructokinases from Methylosinus trichosporium OB3b and Methylobacterium nodulans ORS 2060. BIOCHEMISTRY (MOSCOW) 2013; 77:288-95. [PMID: 22803946 DOI: 10.1134/s0006297912030078] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The properties of the purified recombinant PPi-dependent 6-phosphofructokinases (PPi-PFKs) from the methanotroph Methylosinus trichosporium OB3b and rhizospheric phytosymbiont Methylobacterium nodulans ORS 2060 were determined. The dependence of activities of PPi-PFK-His(6)-tag from Ms. trichosporium OB3b (6 × 45 kDa) and PPi-PFK from Mb. nodulans ORS 2060 (4 × 43 kDa) on the concentrations of substrates of forward and reverse reactions conformed to Michaelis-Menten kinetics. Besides fructose-6-phosphate, the enzymes also phosphorylated sedoheptulose-7-phosphate. ADP or AMP (1 mM each) inhibited activity of the Ms. trichosporium PPi-PFK but did not affect the activity of the Mb. nodulans enzyme. Preference of PPi-PFKs to fructose-1,6-bisphosphate implied a predominant function of the enzymes in hexose phosphate synthesis in these bacteria. PPi-PFKs from the methylotrophs have low similarity of translated amino acid sequences (17% identity) and belong to different phylogenetic subgroups of type II 6-phosphofructokinases. The relationship of PPi-PFKs with microaerophilic character of Ms. trichosporium OB3b and adaptation of Mb. nodulans ORS 2060 to anaerobic phase of phytosymbiosis are discussed.
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Affiliation(s)
- O N Rozova
- Skryabin Institute of Biochemistry and Physiology of Microorganisms, Russian Academy of Sciences, Pushchino, Moscow Region, 142290, Russia
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11
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Acetate activation in Methanosaeta thermophila: characterization of the key enzymes pyrophosphatase and acetyl-CoA synthetase. ARCHAEA-AN INTERNATIONAL MICROBIOLOGICAL JOURNAL 2012; 2012:315153. [PMID: 22927778 PMCID: PMC3426162 DOI: 10.1155/2012/315153] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/16/2012] [Accepted: 06/30/2012] [Indexed: 11/17/2022]
Abstract
The thermophilic methanogen Methanosaeta thermophila uses acetate as sole substrate for methanogenesis. It was proposed that the acetate activation reaction that is needed to feed acetate into the methanogenic pathway requires the hydrolysis of two ATP, whereas the acetate activation reaction in Methanosarcina sp. is known to require only one ATP. As these organisms live at the thermodynamic limit that sustains life, the acetate activation reaction in Mt. thermophila seems too costly and was thus reevaluated. It was found that of the putative acetate activation enzymes one gene encoding an AMP-forming acetyl-CoA synthetase was highly expressed. The corresponding enzyme was purified and characterized in detail. It catalyzed the ATP-dependent formation of acetyl-CoA, AMP, and pyrophosphate (PPi)
and was only moderately inhibited by PPi. The breakdown of PPi
was performed by a soluble pyrophosphatase. This enzyme was also purified and characterized. The pyrophosphatase hydrolyzed the major part of PPi
(KM = 0.27 ± 0.05 mM) that was produced in the acetate activation reaction. Activity was not inhibited by nucleotides or PPi. However, it cannot be excluded that other PPi-dependent enzymes take advantage of the remaining PPi
and contribute to the energy balance of the cell.
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