1
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Sirohiwal A, Gamiz-Hernandez AP, Kaila VRI. Mechanistic Principles of Hydrogen Evolution in the Membrane-Bound Hydrogenase. J Am Chem Soc 2024; 146:18019-18031. [PMID: 38888987 DOI: 10.1021/jacs.4c04476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/20/2024]
Abstract
The membrane-bound hydrogenase (Mbh) from Pyrococcus furiosus is an archaeal member of the Complex I superfamily. It catalyzes the reduction of protons to H2 gas powered by a [NiFe] active site and transduces the free energy into proton pumping and Na+/H+ exchange across the membrane. Despite recent structural advances, the mechanistic principles of H2 catalysis and ion transport in Mbh remain elusive. Here, we probe how the redox chemistry drives the reduction of the proton to H2 and how the catalysis couples to conformational dynamics in the membrane domain of Mbh. By combining large-scale quantum chemical density functional theory (DFT) and correlated ab initio wave function methods with atomistic molecular dynamics simulations, we show that the proton transfer reactions required for the catalysis are gated by electric field effects that direct the protons by water-mediated reactions from Glu21L toward the [NiFe] site, or alternatively along the nearby His75L pathway that also becomes energetically feasible in certain reaction steps. These local proton-coupled electron transfer (PCET) reactions induce conformational changes around the active site that provide a key coupling element via conserved loop structures to the ion transport activity. We find that H2 forms in a heterolytic proton reduction step, with spin crossovers tuning the energetics along key reaction steps. On a general level, our work showcases the role of electric fields in enzyme catalysis and how these effects are employed by the [NiFe] active site of Mbh to drive PCET reactions and ion transport.
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Affiliation(s)
- Abhishek Sirohiwal
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
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2
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Hackmann TJ. The vast landscape of carbohydrate fermentation in prokaryotes. FEMS Microbiol Rev 2024; 48:fuae016. [PMID: 38821505 PMCID: PMC11187502 DOI: 10.1093/femsre/fuae016] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2024] [Revised: 05/23/2024] [Accepted: 05/29/2024] [Indexed: 06/02/2024] Open
Abstract
Fermentation is a type of metabolism carried out by organisms in environments without oxygen. Despite being studied for over 185 years, the diversity and complexity of this metabolism are just now becoming clear. Our review starts with the definition of fermentation, which has evolved over the years and which we help further refine. We then examine the range of organisms that carry out fermentation and their traits. Over one-fourth of all prokaryotes are fermentative, use more than 40 substrates, and release more than 50 metabolic end products. These insights come from studies analyzing records of thousands of organisms. Next, our review examines the complexity of fermentation at the biochemical level. We map out pathways of glucose fermentation in unprecedented detail, covering over 120 biochemical reactions. We also review recent studies coupling genomics and enzymology to reveal new pathways and enzymes. Our review concludes with practical applications for agriculture, human health, and industry. All these areas depend on fermentation and could be improved through manipulating fermentative microbes and enzymes. We discuss potential approaches for manipulation, including genetic engineering, electrofermentation, probiotics, and enzyme inhibitors. We hope our review underscores the importance of fermentation research and stimulates the next 185 years of study.
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Affiliation(s)
- Timothy J Hackmann
- Department of Animal Science, University of California, Davis, CA 95616, United States
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3
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Djurabekova A, Lasham J, Zdorevskyi O, Zickermann V, Sharma V. Long-range electron proton coupling in respiratory complex I - insights from molecular simulations of the quinone chamber and antiporter-like subunits. Biochem J 2024; 481:499-514. [PMID: 38572757 DOI: 10.1042/bcj20240009] [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: 01/11/2024] [Revised: 03/11/2024] [Accepted: 03/14/2024] [Indexed: 04/05/2024]
Abstract
Respiratory complex I is a redox-driven proton pump. Several high-resolution structures of complex I have been determined providing important information about the putative proton transfer paths and conformational transitions that may occur during catalysis. However, how redox energy is coupled to the pumping of protons remains unclear. In this article, we review biochemical, structural and molecular simulation data on complex I and discuss several coupling models, including the key unresolved mechanistic questions. Focusing both on the quinone-reductase domain as well as the proton-pumping membrane-bound domain of complex I, we discuss a molecular mechanism of proton pumping that satisfies most experimental and theoretical constraints. We suggest that protonation reactions play an important role not only in catalysis, but also in the physiologically-relevant active/deactive transition of complex I.
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Affiliation(s)
| | - Jonathan Lasham
- Department of Physics, University of Helsinki, Helsinki, Finland
| | | | - Volker Zickermann
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt am Main, Germany
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Helsinki, Finland
- HiLIFE Institute of Biotechnology, University of Helsinki, Helsinki, Finland
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4
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Yang JI, Jung HC, Oh HM, Choi BG, Lee HS, Kang SG. NADP + or CO 2 reduction by frhAGB-encoded hydrogenase through interaction with formate dehydrogenase 3 in the hyperthermophilic archaeon Thermococcus onnurineus NA1. Appl Environ Microbiol 2023; 89:e0147423. [PMID: 37966269 PMCID: PMC10734459 DOI: 10.1128/aem.01474-23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2023] [Accepted: 09/23/2023] [Indexed: 11/16/2023] Open
Abstract
IMPORTANCE The strategy using structural homology with the help of structure prediction by AlphaFold was very successful in finding potential targets for the frhAGB-encoded hydrogenase of Thermococcus onnurineus NA1. The finding that the hydrogenase can interact with FdhB to reduce the cofactor NAD(P)+ is significant in that the enzyme can function to supply reducing equivalents, just as F420-reducing hydrogenases in methanogens use coenzyme F420 as an electron carrier. Additionally, it was identified that T. onnurineus NA1 could produce formate from H2 and CO2 by the concerted action of frhAGB-encoded hydrogenase and formate dehydrogenase Fdh3.
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Affiliation(s)
- Ji-in Yang
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
| | - Hae-Chang Jung
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
| | | | - Bo Gyoung Choi
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
| | - Hyun Sook Lee
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
| | - Sung Gyun Kang
- Marine Biotechnology Research Center, Korea Institute of Ocean Science & Technology, Busan, South Korea
- Department of Applied Ocean Science, University of Science and Technology, Daejeon, South Korea
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5
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Zhang X, Xie F, Ma S, Ma C, Jiang X, Yi Y, Song Y, Liu M, Zhao P, Ma X. Mitochondria: one of the vital hubs for molecular hydrogen's biological functions. Front Cell Dev Biol 2023; 11:1283820. [PMID: 38020926 PMCID: PMC10662307 DOI: 10.3389/fcell.2023.1283820] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2023] [Accepted: 10/23/2023] [Indexed: 12/01/2023] Open
Abstract
As a novel antioxidant, a growing body of studies has documented the diverse biological effects of molecular hydrogen (H2) in a wide range of organisms, spanning animals, plants, and microorganisms. Although several possible mechanisms have been proposed, they cannot fully explain the extensive biological effects of H2. Mitochondria, known for ATP production, also play crucial roles in diverse cellular functions, including Ca2+ signaling, regulation of reactive oxygen species (ROS) generation, apoptosis, proliferation, and lipid transport, while their dysfunction is implicated in a broad spectrum of diseases, including cardiovascular disorders, neurodegenerative conditions, metabolic disorders, and cancer. This review aims to 1) summarize the experimental evidence on the impact of H2 on mitochondrial function; 2) provide an overview of the mitochondrial pathways underlying the biological effects of H2, and 3) discuss H2 metabolism in eukaryotic organisms and its relationship with mitochondria. Moreover, based on previous findings, this review proposes that H2 may regulate mitochondrial quality control through diverse pathways in response to varying degrees of mitochondrial damage. By combining the existing research evidence with an evolutionary perspective, this review emphasizes the potential hydrogenase activity in mitochondria of higher plants and animals. Finally, this review also addresses potential issues in the current mechanistic study and offers insights into future research directions, aiming to provide a reference for future studies on the mechanisms underlying the action of H2.
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Affiliation(s)
- Xiaoyue Zhang
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Fei Xie
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Shiwen Ma
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Chen Ma
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Xue Jiang
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Yang Yi
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Yifei Song
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Mengyu Liu
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Pengxiang Zhao
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
| | - Xuemei Ma
- Faculty of Environment and Life, Beijing University of Technology, Beijing, China
- Beijing Molecular Hydrogen Research Center, Beijing, China
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6
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Grba DN, Chung I, Bridges HR, Agip ANA, Hirst J. Investigation of hydrated channels and proton pathways in a high-resolution cryo-EM structure of mammalian complex I. SCIENCE ADVANCES 2023; 9:eadi1359. [PMID: 37531432 PMCID: PMC10396290 DOI: 10.1126/sciadv.adi1359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/03/2023] [Indexed: 08/04/2023]
Abstract
Respiratory complex I, a key enzyme in mammalian metabolism, captures the energy released by reduction of ubiquinone by NADH to drive protons across the inner mitochondrial membrane, generating the proton-motive force for ATP synthesis. Despite remarkable advances in structural knowledge of this complicated membrane-bound enzyme, its mechanism of catalysis remains controversial. In particular, how ubiquinone reduction is coupled to proton pumping and the pathways and mechanisms of proton translocation are contested. We present a 2.4-Å resolution cryo-EM structure of complex I from mouse heart mitochondria in the closed, active (ready-to-go) resting state, with 2945 water molecules modeled. By analyzing the networks of charged and polar residues and water molecules present, we evaluate candidate pathways for proton transfer through the enzyme, for the chemical protons for ubiquinone reduction, and for the protons transported across the membrane. Last, we compare our data to the predictions of extant mechanistic models, and identify key questions to answer in future work to test them.
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7
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Vailionis JL, Zhao W, Zhang K, Rodionov DA, Lipscomb GL, Tanwee TNN, O'Quinn HC, Bing RG, Kelly RM, Adams MWW, Zhang Y. Optimizing Strategies for Bio-Based Ethanol Production Using Genome-Scale Metabolic Modeling of the Hyperthermophilic Archaeon, Pyrococcus furiosus. Appl Environ Microbiol 2023; 89:e0056323. [PMID: 37289085 PMCID: PMC10304669 DOI: 10.1128/aem.00563-23] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 05/13/2023] [Indexed: 06/09/2023] Open
Abstract
A genome-scale metabolic model, encompassing a total of 623 genes, 727 reactions, and 865 metabolites, was developed for Pyrococcus furiosus, an archaeon that grows optimally at 100°C by carbohydrate and peptide fermentation. The model uses subsystem-based genome annotation, along with extensive manual curation of 237 gene-reaction associations including those involved in central carbon metabolism, amino acid metabolism, and energy metabolism. The redox and energy balance of P. furiosus was investigated through random sampling of flux distributions in the model during growth on disaccharides. The core energy balance of the model was shown to depend on high acetate production and the coupling of a sodium-dependent ATP synthase and membrane-bound hydrogenase, which generates a sodium gradient in a ferredoxin-dependent manner, aligning with existing understanding of P. furiosus metabolism. The model was utilized to inform genetic engineering designs that favor the production of ethanol over acetate by implementing an NADPH and CO-dependent energy economy. The P. furiosus model is a powerful tool for understanding the relationship between generation of end products and redox/energy balance at a systems-level that will aid in the design of optimal engineering strategies for production of bio-based chemicals and fuels. IMPORTANCE The bio-based production of organic chemicals provides a sustainable alternative to fossil-based production in the face of today's climate challenges. In this work, we present a genome-scale metabolic reconstruction of Pyrococcus furiosus, a well-established platform organism that has been engineered to produce a variety of chemicals and fuels. The metabolic model was used to design optimal engineering strategies to produce ethanol. The redox and energy balance of P. furiosus was examined in detail, which provided useful insights that will guide future engineering designs.
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Affiliation(s)
- Jason L. Vailionis
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| | - Weishu Zhao
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| | - Ke Zhang
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, Rhode Island, USA
| | - Dmitry A. Rodionov
- Sanford-Burnham-Prebys Medical Discovery Institute, La Jolla, California, USA
| | - Gina L. Lipscomb
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Tania N. N. Tanwee
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Hailey C. O'Quinn
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Ryan G. Bing
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Robert M. Kelly
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina, USA
| | - Michael W. W. Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Ying Zhang
- Department of Cell and Molecular Biology, College of the Environment and Life Sciences, University of Rhode Island, Kingston, Rhode Island, USA
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8
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Glass JB, Elbon CE, Williams LD. Something old, something new, something borrowed, something blue: the anaerobic microbial ancestry of aerobic respiration. Trends Microbiol 2023; 31:135-141. [PMID: 36058785 DOI: 10.1016/j.tim.2022.08.006] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 08/07/2022] [Accepted: 08/09/2022] [Indexed: 01/27/2023]
Abstract
Aerobic respiration evolved by bricolage, with modules cobbled together as microbial biochemistry coevolved with Earth's geochemistry. The mitochondrial electron transport chain represents a patchwork of respiratory modules inherited from microbial methanogenesis, iron oxidation, anoxygenic photosynthesis, and denitrification pathways, and preserves a biochemical record of Earth's redox environment over its four-billion-year history. Imprints of the anoxic early Earth are recognizable in Complex I's numerous iron-sulfur cofactors and vestigial binding sites for ferredoxin, nickel-iron, and molybdopterin, whereas the more recent advent of oxygen as a terminal electron acceptor necessitated use of heme and copper cofactors by Complex IV. Bricolage of respiratory complexes resulted in supercomplexes for improved electron transfer efficiency in some bacteria and archaea, and in many eukaryotes. Accessory subunits evolved to wrap mitochondrial supercomplexes for improved assembly and stability. Environmental microbes with 'fossil' proteins that are similar to ancestral forms of the respiratory complexes deserve further scrutiny and may reveal new insights on the evolution of aerobic respiration.
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Affiliation(s)
- Jennifer B Glass
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA.
| | - Claire E Elbon
- School of Earth and Atmospheric Sciences, Georgia Institute of Technology, Atlanta, GA, USA
| | - Loren Dean Williams
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, GA, USA
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9
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Burnap RL. Cyanobacterial Bioenergetics in Relation to Cellular Growth and Productivity. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2023; 183:25-64. [PMID: 36764956 DOI: 10.1007/10_2022_215] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
Cyanobacteria, the evolutionary originators of oxygenic photosynthesis, have the capability to convert CO2, water, and minerals into biomass using solar energy. This process is driven by intricate bioenergetic mechanisms that consist of interconnected photosynthetic and respiratory electron transport chains coupled. Over the last few decades, advances in physiochemical analysis, molecular genetics, and structural analysis have enabled us to gain a more comprehensive understanding of cyanobacterial bioenergetics. This includes the molecular understanding of the primary energy conversion mechanisms as well as photoprotective and other dissipative mechanisms that prevent photodamage when the rates of photosynthetic output, primarily in the form of ATP and NADPH, exceed the rates that cellular assimilatory processes consume these photosynthetic outputs. Despite this progress, there is still much to learn about the systems integration and the regulatory circuits that control expression levels for optimal cellular abundance and activity of the photosynthetic complexes and the cellular components that convert their products into biomass. With an improved understanding of these regulatory principles and mechanisms, it should be possible to optimally modify cyanobacteria for enhanced biotechnological purposes.
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Affiliation(s)
- Robert L Burnap
- Department of Microbiology and Molecular Genetics, Oklahoma State University, Stillwater, OK, USA.
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10
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Manoj KM, Gideon DA, Parashar A, Nirusimhan V, Annadurai P, Jacob VD, Manekkathodi A. Validating the predictions of murburn model for oxygenic photosynthesis: Analyses of ligand-binding to protein complexes and cross-system comparisons. J Biomol Struct Dyn 2022; 40:11024-11056. [PMID: 34328391 DOI: 10.1080/07391102.2021.1953607] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
In this second half of our treatise on oxygenic photosynthesis, we provide support for the murburn model of the light reaction of photosynthesis and ratify key predictions made in the first part. Molecular docking and visualization of various ligands of quinones/quinols (and their derivatives) with PS II/Cytochrome b6f complexes did not support chartered 2e-transport role of quinols. A broad variety of herbicides did not show any affinity/binding-based rationales for inhibition of photosynthesis. We substantiate the proposal that disubstituted phenolics (perceived as protonophores/uncouplers or affinity-based inhibitors in the classical purview) serve as interfacial modulators of diffusible reactive (oxygen) species or DR(O)S. The DRS-based murburn model is evidenced by the identification of multiple ADP-binding sites on the extra-membraneous projection of protein complexes and structure/distribution of the photo/redox catalysts. With a panoramic comparison of the redox metabolic machinery across diverse organellar/cellular systems, we highlight the ubiquitous one-electron murburn facets (cofactors of porphyrin, flavin, FeS, other metal centers and photo/redox active pigments) that enable a facile harnessing of the utility of DRS. In the summative analyses, it is demonstrated that the murburn model of light reaction explains the structures of membrane supercomplexes recently observed in thylakoids and also accounts for several photodynamic experimental observations and evolutionary considerations. In toto, the work provides a new orientation and impetus to photosynthesis research. Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Kelath Murali Manoj
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Daniel Andrew Gideon
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Abhinav Parashar
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vijay Nirusimhan
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Pushparaj Annadurai
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Vivian David Jacob
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
| | - Afsal Manekkathodi
- RedOx Lab, Department of Life Sciences, Satyamjayatu: The Science & Ethics Foundation, Palakkad District, Kerala, India
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11
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Proteome-wide 3D structure prediction provides insights into the ancestral metabolism of ancient archaea and bacteria. Nat Commun 2022; 13:7861. [PMID: 36543797 PMCID: PMC9772386 DOI: 10.1038/s41467-022-35523-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Accepted: 12/07/2022] [Indexed: 12/24/2022] Open
Abstract
Ancestral metabolism has remained controversial due to a lack of evidence beyond sequence-based reconstructions. Although prebiotic chemists have provided hints that metabolism might originate from non-enzymatic protometabolic pathways, gaps between ancestral reconstruction and prebiotic processes mean there is much that is still unknown. Here, we apply proteome-wide 3D structure predictions and comparisons to investigate ancestorial metabolism of ancient bacteria and archaea, to provide information beyond sequence as a bridge to the prebiotic processes. We compare representative bacterial and archaeal strains, which reveal surprisingly similar physiological and metabolic characteristics via microbiological and biophysical experiments. Pairwise comparison of protein structures identify the conserved metabolic modules in bacteria and archaea, despite interference from overly variable sequences. The conserved modules (for example, middle of glycolysis, partial TCA, proton/sulfur respiration, building block biosynthesis) constitute the basic functions that possibly existed in the archaeal-bacterial common ancestor, which are remarkably consistent with the experimentally confirmed protometabolic pathways. These structure-based findings provide a new perspective to reconstructing the ancestral metabolism and understanding its origin, which suggests high-throughput protein 3D structure prediction is a promising approach, deserving broader application in future ancestral exploration.
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12
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Lee Y, Haapanen O, Altmeyer A, Kühlbrandt W, Sharma V, Zickermann V. Ion transfer mechanisms in Mrp-type antiporters from high resolution cryoEM and molecular dynamics simulations. Nat Commun 2022; 13:6091. [PMID: 36241630 PMCID: PMC9568556 DOI: 10.1038/s41467-022-33640-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Accepted: 09/23/2022] [Indexed: 12/24/2022] Open
Abstract
Multiple resistance and pH adaptation (Mrp) cation/proton antiporters are essential for growth of a variety of halophilic and alkaliphilic bacteria under stress conditions. Mrp-type antiporters are closely related to the membrane domain of respiratory complex I. We determined the structure of the Mrp antiporter from Bacillus pseudofirmus by electron cryo-microscopy at 2.2 Å resolution. The structure resolves more than 99% of the sidechains of the seven membrane subunits MrpA to MrpG plus 360 water molecules, including ~70 in putative ion translocation pathways. Molecular dynamics simulations based on the high-resolution structure revealed details of the antiport mechanism. We find that switching the position of a histidine residue between three hydrated pathways in the MrpA subunit is critical for proton transfer that drives gated trans-membrane sodium translocation. Several lines of evidence indicate that the same histidine-switch mechanism operates in respiratory complex I.
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Affiliation(s)
- Yongchan Lee
- grid.419494.50000 0001 1018 9466Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany ,grid.268441.d0000 0001 1033 6139Present Address: Graduate School of Medical Life Science, Yokohama City University, 230-0045 Kanagawa, Japan
| | - Outi Haapanen
- grid.7737.40000 0004 0410 2071Department of Physics, University of Helsinki, 00014 Helsinki, Finland
| | - Anton Altmeyer
- grid.7839.50000 0004 1936 9721Institute of Biochemistry II, University Hospital, Goethe University, 60590 Frankfurt am Main, Germany ,grid.7839.50000 0004 1936 9721Centre for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- grid.419494.50000 0001 1018 9466Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Vivek Sharma
- grid.7737.40000 0004 0410 2071Department of Physics, University of Helsinki, 00014 Helsinki, Finland ,grid.7737.40000 0004 0410 2071HiLIFE Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Volker Zickermann
- grid.7839.50000 0004 1936 9721Institute of Biochemistry II, University Hospital, Goethe University, 60590 Frankfurt am Main, Germany ,grid.7839.50000 0004 1936 9721Centre for Biomolecular Magnetic Resonance, Institute of Biophysical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
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13
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Zhang X, Huang Y, Liu Y, Xu W, Pan J, Zheng X, Du H, Zhang C, Lu Z, Zou D, Liu Z, Cai M, Xiong J, Zhu Y, Dong Z, Jiang H, Dong H, Jiang J, Luo Z, Huang L, Li M. An Ancient Respiratory System in the Widespread Sedimentary Archaea Thermoprofundales. Mol Biol Evol 2022; 39:6742362. [PMID: 36181435 PMCID: PMC9585477 DOI: 10.1093/molbev/msac213] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Thermoprofundales, formerly Marine Benthic Group D (MBG-D), is a ubiquitous archaeal lineage found in sedimentary environments worldwide. However, its taxonomic classification, metabolic pathways, and evolutionary history are largely unexplored because of its uncultivability and limited number of sequenced genomes. In this study, phylogenomic analysis and average amino acid identity values of a collection of 146 Thermoprofundales genomes revealed five Thermoprofundales subgroups (A-E) with distinct habitat preferences. Most of the microorganisms from Subgroups B and D were thermophiles inhabiting hydrothermal vents and hot spring sediments, whereas those from Subgroup E were adapted to surface environments where sunlight is available. H2 production may be featured in Thermoprofundales as evidenced by a gene cluster encoding the ancient membrane-bound hydrogenase (MBH) complex. Interestingly, a unique structure separating the MBH gene cluster into two modular units was observed exclusively in the genomes of Subgroup E, which included a peripheral arm encoding the [NiFe] hydrogenase domain and a membrane arm encoding the Na+/H+ antiporter domain. These two modular structures were confirmed to function independently by detecting the H2-evolving activity in vitro and salt tolerance to 0.2 M NaCl in vivo, respectively. The peripheral arm of Subgroup E resembles the proposed common ancestral respiratory complex of modern respiratory systems, which plays a key role in the early evolution of life. In addition, molecular dating analysis revealed that Thermoprofundales is an early emerging archaeal lineage among the extant MBH-containing microorganisms, indicating new insights into the evolution of this ubiquitous archaea lineage.
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Affiliation(s)
- Xinxu Zhang
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Yuhan Huang
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Yang Liu
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Wei Xu
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, Fujian, China
| | - Jie Pan
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Xiaowei Zheng
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Huan Du
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Cuijing Zhang
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Zhongyi Lu
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Dayu Zou
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Zongbao Liu
- Archaeal Biology Center, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China,Shenzhen Key Laboratory of Marine Microbiome Engineering, Institute for Advanced Study, Shenzhen University, Shenzhen, Guangdong, China
| | - Mingwei Cai
- Institute of Chemical Biology, Shenzhen Bay Laboratory, Shenzhen, Guangdong, China
| | - Jinbo Xiong
- State Key Laboratory for Managing Biotic and Chemical Threats to the Quality and Safety of Agro-products, Ningbo University, Ningbo, Zhejiang, China
| | - Yaxin Zhu
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Zhiyang Dong
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Hongchen Jiang
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Wuhan, Hubei, China
| | - Hailiang Dong
- State Key Laboratory of Biogeology and Environmental Geology, China University of Geosciences, Beijing, China
| | - Juquan Jiang
- Department of Microbiology and Biotechnology, College of Life Sciences, Northeast Agricultural University, Harbin, Heilongjiang, China
| | - Zhuhua Luo
- Key Laboratory of Marine Biogenetic Resources, Third Institute of Oceanography, Ministry of Natural Resources, Xiamen, Fujian, China
| | - Li Huang
- State Key Laboratory of Microbial Resources, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
| | - Meng Li
- Corresponding author: E-mail:
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14
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Steinhilper R, Höff G, Heider J, Murphy BJ. Structure of the membrane-bound formate hydrogenlyase complex from Escherichia coli. Nat Commun 2022; 13:5395. [PMID: 36104349 PMCID: PMC9474812 DOI: 10.1038/s41467-022-32831-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2022] [Accepted: 08/08/2022] [Indexed: 01/30/2023] Open
Abstract
The prototypical hydrogen-producing enzyme, the membrane-bound formate hydrogenlyase (FHL) complex from Escherichia coli, links formate oxidation at a molybdopterin-containing formate dehydrogenase to proton reduction at a [NiFe] hydrogenase. It is of intense interest due to its ability to efficiently produce H2 during fermentation, its reversibility, allowing H2-dependent CO2 reduction, and its evolutionary link to respiratory complex I. FHL has been studied for over a century, but its atomic structure remains unknown. Here we report cryo-EM structures of FHL in its aerobically and anaerobically isolated forms at resolutions reaching 2.6 Å. This includes well-resolved density for conserved loops linking the soluble and membrane arms believed to be essential in coupling enzymatic turnover to ion translocation across the membrane in the complex I superfamily. We evaluate possible structural determinants of the bias toward hydrogen production over its oxidation and describe an unpredicted metal-binding site near the interface of FdhF and HycF subunits that may play a role in redox-dependent regulation of FdhF interaction with the complex. New cryo-EM structures of the formate hydrogenlyase complex from the model bacterium E. coli clarify how electrons and protons move through the complex and are combined to make H2 gas. The complex shows important similarities and differences to related bioenergetic complexes across the tree of life.
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15
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Méheust R, Castelle CJ, Jaffe AL, Banfield JF. Conserved and lineage-specific hypothetical proteins may have played a central role in the rise and diversification of major archaeal groups. BMC Biol 2022; 20:154. [PMID: 35790962 PMCID: PMC9258230 DOI: 10.1186/s12915-022-01348-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 06/09/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Archaea play fundamental roles in the environment, for example by methane production and consumption, ammonia oxidation, protein degradation, carbon compound turnover, and sulfur compound transformations. Recent genomic analyses have profoundly reshaped our understanding of the distribution and functionalities of Archaea and their roles in eukaryotic evolution. RESULTS Here, 1179 representative genomes were selected from 3197 archaeal genomes. The representative genomes clustered based on the content of 10,866 newly defined archaeal protein families (that will serve as a community resource) recapitulates archaeal phylogeny. We identified the co-occurring proteins that distinguish the major lineages. Those with metabolic roles were consistent with experimental data. However, two families specific to Asgard were determined to be new eukaryotic signature proteins. Overall, the blocks of lineage-specific families are dominated by proteins that lack functional predictions. CONCLUSIONS Given that these hypothetical proteins are near ubiquitous within major archaeal groups, we propose that they were important in the origin of most of the major archaeal lineages. Interestingly, although there were clearly phylum-specific co-occurring proteins, no such blocks of protein families were shared across superphyla, suggesting a burst-like origin of new lineages early in archaeal evolution.
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Affiliation(s)
- Raphaël Méheust
- Department of Earth and Planetary Science, University of California, Berkeley, CA, USA. .,Innovative Genomics Institute, University of California, Berkeley, CA, USA. .,LABGeM, Génomique Métabolique, Genoscope, Institut François Jacob, CEA, Evry, France.
| | - Cindy J Castelle
- Department of Earth and Planetary Science, University of California, Berkeley, CA, USA.,Chan Zuckerberg Biohub, San Francisco, CA, USA
| | - Alexander L Jaffe
- Department of Plant and Microbial Biology, University of California, Berkeley, CA, USA
| | - Jillian F Banfield
- Department of Earth and Planetary Science, University of California, Berkeley, CA, USA. .,Innovative Genomics Institute, University of California, Berkeley, CA, USA. .,Chan Zuckerberg Biohub, San Francisco, CA, USA. .,Department of Environmental Science, Policy, and Management, University of California, Berkeley, CA, USA.
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16
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Katsyv A, Müller V. A purified energy-converting hydrogenase from Thermoanaerobacter kivui demonstrates coupled H +-translocation and reduction in vitro. J Biol Chem 2022; 298:102216. [PMID: 35779632 PMCID: PMC9356269 DOI: 10.1016/j.jbc.2022.102216] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Revised: 06/22/2022] [Accepted: 06/24/2022] [Indexed: 12/04/2022] Open
Abstract
Energy-converting hydrogenases (Ech) are ancient, membrane-bound enzymes that use reduced ferredoxin (Fd) as an electron donor to reduce protons to molecular H2. Experiments with whole cells, membranes and vesicle-fractions suggest that proton reduction is coupled to proton translocation across the cytoplasmatic membrane, but this has never been demonstrated with a purified enzyme. To this end, we produced a His-tagged Ech complex in the thermophilic and anaerobic bacterium Thermoanaerobacter kivui. The enzyme could be purified by affinity chromatography from solubilized membranes with full retention of its eight subunits, as well as full retention of physiological activities, i.e., H2-dependent Fd reduction and Fd2--dependent H2 production. We found the purified enzyme contained 34.2 ± 12.2 mol of iron/mol of protein, in accordance with seven predicted [4Fe-4S]-clusters and one [Ni-Fe]-center. The pH and temperature optima were at 7 to 8 and 66 °C, respectively. Notably, we found that the enzymatic activity was inhibited by N,N′-dicyclohexylcarbodiimide, an agent known to bind ion-translocating glutamates or aspartates buried in the cytoplasmic membrane and thereby inhibiting ion transport. To demonstrate the function of the Ech complex in ion transport, we further established a procedure to incorporate the enzyme complex into liposomes in an active state. We show the enzyme did not require Na+ for activity and did not translocate 22Na+ into the proteoliposomal lumen. In contrast, Ech activity led to the generation of a pH gradient and membrane potential across the proteoliposomal membrane, demonstrating that the Ech complex of T. kivui is a H+-translocating, H+-reducing enzyme.
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Affiliation(s)
- Alexander Katsyv
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany
| | - Volker Müller
- Department of Molecular Microbiology & Bioenergetics, Institute of Molecular Biosciences, Johann Wolfgang Goethe University, Frankfurt am Main, Germany.
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17
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Kampjut D, Sazanov LA. Structure of respiratory complex I – An emerging blueprint for the mechanism. Curr Opin Struct Biol 2022; 74:102350. [PMID: 35316665 PMCID: PMC7613608 DOI: 10.1016/j.sbi.2022.102350] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Revised: 01/25/2022] [Accepted: 02/08/2022] [Indexed: 11/26/2022]
Abstract
Complex I is one of the major respiratory complexes, conserved from bacteria to mammals. It oxidises NADH, reduces quinone and pumps protons across the membrane, thus playing a central role in the oxidative energy metabolism. In this review we discuss our current state of understanding the structure of complex I from various species of mammals, plants, fungi, and bacteria, as well as of several complex I-related proteins. By comparing the structural evidence from these systems in different redox states and data from mutagenesis and molecular simulations, we formulate the mechanisms of electron transfer and proton pumping and explain how they are conformationally and electrostatically coupled. Finally, we discuss the structural basis of the deactivation phenomenon in mammalian complex I.
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18
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Williams TJ, Allen MA, Panwar P, Cavicchioli R. Into the darkness: The ecologies of novel 'microbial dark matter' phyla in an Antarctic lake. Environ Microbiol 2022; 24:2576-2603. [PMID: 35466505 PMCID: PMC9324843 DOI: 10.1111/1462-2920.16026] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/18/2022] [Accepted: 04/20/2022] [Indexed: 11/29/2022]
Abstract
Uncultivated microbial clades ("microbial dark matter") are inferred to play important, but uncharacterized roles in nutrient cycling. Using Antarctic lake (Ace Lake, Vestfold Hills) metagenomes, 12 metagenome-assembled genomes (MAGs; 88-100% complete) were generated for four "dark matter" phyla: six MAGs from Candidatus Auribacterota (= Aureabacteria, SURF-CP-2), inferred to be hydrogen- and sulfide-producing fermentative heterotrophs, with individual MAGs encoding bacterial microcompartments (BMCs), gas vesicles, and type IV pili; one MAG (100% complete) from Candidatus Hinthialibacterota (= OLB16), inferred to be a facultative anaerobe capable of dissimilatory nitrate reduction to ammonia, specialized for mineralization of complex organic matter (e.g., sulfated polysaccharides), and encoding BMCs, flagella, and Tad pili; three MAGs from Candidatus Electryoneota (= AABM5-125-24), previously reported to include facultative anaerobes capable of dissimilatory sulfate reduction, and here inferred to perform sulfite oxidation, reverse tricarboxylic acid cycle for autotrophy, and possess numerous proteolytic enzymes; two MAGs from Candidatus Lernaellota (= FEN-1099), inferred to be capable of formate oxidation, amino acid fermentation, and possess numerous enzymes for protein and polysaccharide degradation. The presence of 16S rRNA gene sequences in public metagenome datasets (88-100% identity) suggests these "dark matter" phyla contribute to sulfur cycling, degradation of complex organic matter, ammonification and/or chemolithoautrophic CO2 fixation in diverse global environments. This article is protected by copyright. All rights reserved.
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Affiliation(s)
- Timothy J Williams
- School of Biotechnology and Biomolecular Sciences UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Michelle A Allen
- School of Biotechnology and Biomolecular Sciences UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Pratibha Panwar
- School of Biotechnology and Biomolecular Sciences UNSW Sydney, Sydney, New South Wales, 2052, Australia
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences UNSW Sydney, Sydney, New South Wales, 2052, Australia
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19
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Modularity of membrane-bound charge-translocating protein complexes. Biochem Soc Trans 2021; 49:2669-2685. [PMID: 34854900 DOI: 10.1042/bst20210462] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2021] [Revised: 11/02/2021] [Accepted: 11/15/2021] [Indexed: 02/05/2023]
Abstract
Energy transduction is the conversion of one form of energy into another; this makes life possible as we know it. Organisms have developed different systems for acquiring energy and storing it in useable forms: the so-called energy currencies. A universal energy currency is the transmembrane difference of electrochemical potential (Δμ~). This results from the translocation of charges across a membrane, powered by exergonic reactions. Different reactions may be coupled to charge-translocation and, in the majority of cases, these reactions are catalyzed by modular enzymes that always include a transmembrane subunit. The modular arrangement of these enzymes allows for different catalytic and charge-translocating modules to be combined. Thus, a transmembrane charge-translocating module can be associated with different catalytic subunits to form an energy-transducing complex. Likewise, the same catalytic subunit may be combined with a different membrane charge-translocating module. In this work, we analyze the modular arrangement of energy-transducing membrane complexes and discuss their different combinations, focusing on the charge-translocating module.
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20
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Mühlbauer ME, Gamiz-Hernandez AP, Kaila VRI. Functional Dynamics of an Ancient Membrane-Bound Hydrogenase. J Am Chem Soc 2021; 143:20873-20883. [PMID: 34846879 PMCID: PMC8679088 DOI: 10.1021/jacs.1c09356] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
![]()
The membrane-bound
hydrogenase (Mbh) is a redox-driven Na+/H+ transporter
that employs the energy from hydrogen
gas (H2) production to catalyze proton pumping and Na+/H+ exchange across cytoplasmic membranes of archaea.
Despite a recently resolved structure of this ancient energy-transducing
enzyme [Yu et al. Cell2018, 173, 1636–1649], the molecular principles of its
redox-driven ion-transport mechanism remain puzzling and of major
interest for understanding bioenergetic principles of early cells.
Here we use atomistic molecular dynamics (MD) simulations in combination
with data clustering methods and quantum chemical calculations to
probe principles underlying proton reduction as well as proton and
sodium transport in Mbh from the hyperthermophilic archaeon Pyrococcus furiosus. We identify putative Na+ binding sites and proton pathways leading across the membrane
and to the NiFe-active center as well as conformational changes that
regulate ion uptake. We suggest that Na+ binding and protonation
changes at a putative ion-binding site couple to proton transfer across
the antiporter-like MbhH subunit by modulating the conformational
state of a conserved ion pair at the subunit interface. Our findings
illustrate conserved coupling principles within the complex I superfamily
and provide functional insight into archaeal energy transduction mechanisms.
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Affiliation(s)
- Max E Mühlbauer
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.,Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.,Department of Chemistry, Technical University of Munich, Lichtenbergstraße 4, 85748 Garching, Germany
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21
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Williams TJ, Allen MA, Berengut JF, Cavicchioli R. Shedding Light on Microbial "Dark Matter": Insights Into Novel Cloacimonadota and Omnitrophota From an Antarctic Lake. Front Microbiol 2021; 12:741077. [PMID: 34707591 PMCID: PMC8542988 DOI: 10.3389/fmicb.2021.741077] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 09/13/2021] [Indexed: 11/13/2022] Open
Abstract
The potential metabolism and ecological roles of many microbial taxa remain unknown because insufficient genomic data are available to assess their functional potential. Two such microbial "dark matter" taxa are the Candidatus bacterial phyla Cloacimonadota and Omnitrophota, both of which have been identified in global anoxic environments, including (but not limited to) organic-carbon-rich lakes. Using 24 metagenome-assembled genomes (MAGs) obtained from an Antarctic lake (Ace Lake, Vestfold Hills), novel lineages and novel metabolic traits were identified for both phyla. The Cloacimonadota MAGs exhibited a capacity for carbon fixation using the reverse tricarboxylic acid cycle driven by oxidation of hydrogen and sulfur. Certain Cloacimonadota MAGs encoded proteins that possess dockerin and cohesin domains, which is consistent with the assembly of extracellular cellulosome-like structures that are used for degradation of polypeptides and polysaccharides. The Omnitrophota MAGs represented phylogenetically diverse taxa that were predicted to possess a strong biosynthetic capacity for amino acids, nucleosides, fatty acids, and essential cofactors. All of the Omnitrophota were inferred to be obligate fermentative heterotrophs that utilize a relatively narrow range of organic compounds, have an incomplete tricarboxylic acid cycle, and possess a single hydrogenase gene important for achieving redox balance in the cell. We reason that both Cloacimonadota and Omnitrophota form metabolic interactions with hydrogen-consuming partners (methanogens and Desulfobacterota, respectively) and, therefore, occupy specific niches in Ace Lake.
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Affiliation(s)
- Timothy J Williams
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Michelle A Allen
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
| | - Jonathan F Berengut
- EMBL Australia Node for Single Molecule Science, School of Medical Sciences, UNSW Sydney, Kensington, NSW, Australia
| | - Ricardo Cavicchioli
- School of Biotechnology and Biomolecular Sciences, UNSW Sydney, Sydney, NSW, Australia
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22
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Haja DK, Adams MWW. pH Homeostasis and Sodium Ion Pumping by Multiple Resistance and pH Antiporters in Pyrococcus furiosus. Front Microbiol 2021; 12:712104. [PMID: 34484150 PMCID: PMC8415708 DOI: 10.3389/fmicb.2021.712104] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2021] [Accepted: 07/23/2021] [Indexed: 11/13/2022] Open
Abstract
Multiple Resistance and pH (Mrp) antiporters are seven-subunit complexes that couple transport of ions across the membrane in response to a proton motive force (PMF) and have various physiological roles, including sodium ion sensing and pH homeostasis. The hyperthermophilic archaeon Pyrococcus furiosus contains three copies of Mrp encoding genes in its genome. Two are found as integral components of two respiratory complexes, membrane bound hydrogenase (MBH) and the membrane bound sulfane sulfur reductase (MBS) that couple redox activity to sodium translocation, while the third copy is a stand-alone Mrp. Sequence alignments show that this Mrp does not contain an energy-input (PMF) module but contains all other predicted functional Mrp domains. The P. furiosus Mrp deletion strain exhibits no significant changes in optimal pH or sodium ion concentration for growth but is more sensitive to medium acidification during growth. Cell suspension hydrogen gas production assays using the deletion strain show that this Mrp uses sodium as the coupling ion. Mrp likely maintains cytoplasmic pH by exchanging protons inside the cell for extracellular sodium ions. Deletion of the MBH sodium-translocating module demonstrates that hydrogen gas production is uncoupled from ion pumping and provides insights into the evolution of this Mrp-containing respiratory complex.
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Affiliation(s)
- Dominik K Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, United States
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23
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Kolata P, Efremov RG. Structure of Escherichia coli respiratory complex I reconstituted into lipid nanodiscs reveals an uncoupled conformation. eLife 2021; 10:e68710. [PMID: 34308841 PMCID: PMC8357420 DOI: 10.7554/elife.68710] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2021] [Accepted: 07/23/2021] [Indexed: 01/22/2023] Open
Abstract
Respiratory complex I is a multi-subunit membrane protein complex that reversibly couples NADH oxidation and ubiquinone reduction with proton translocation against transmembrane potential. Complex I from Escherichia coli is among the best functionally characterized complexes, but its structure remains unknown, hindering further studies to understand the enzyme coupling mechanism. Here, we describe the single particle cryo-electron microscopy (cryo-EM) structure of the entire catalytically active E. coli complex I reconstituted into lipid nanodiscs. The structure of this mesophilic bacterial complex I displays highly dynamic connection between the peripheral and membrane domains. The peripheral domain assembly is stabilized by unique terminal extensions and an insertion loop. The membrane domain structure reveals novel dynamic features. Unusual conformation of the conserved interface between the peripheral and membrane domains suggests an uncoupled conformation of the complex. Considering constraints imposed by the structural data, we suggest a new simple hypothetical coupling mechanism for the molecular machine.
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Affiliation(s)
- Piotr Kolata
- Center for Structural Biology, Vlaams Instituut voor BiotechnologieBrusselsBelgium
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit BrusselBrusselsBelgium
| | - Rouslan G Efremov
- Center for Structural Biology, Vlaams Instituut voor BiotechnologieBrusselsBelgium
- Structural Biology Brussels, Department of Bioengineering Sciences, Vrije Universiteit BrusselBrusselsBelgium
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24
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Zhu G, Zeng H, Zhang S, Juli J, Tai L, Zhang D, Pang X, Zhang Y, Lam SM, Zhu Y, Peng G, Michel H, Sun F. The Unusual Homodimer of a Heme‐Copper Terminal Oxidase Allows Itself to Utilize Two Electron Donors. Angew Chem Int Ed Engl 2021. [DOI: 10.1002/ange.202016785] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Guoliang Zhu
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- College of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Hui Zeng
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Straβe 3 60438 Frankfurt am Main Germany
| | - Shuangbo Zhang
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- College of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Jana Juli
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Straβe 3 60438 Frankfurt am Main Germany
| | - Linhua Tai
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- College of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Danyang Zhang
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- College of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Xiaoyun Pang
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
| | - Yan Zhang
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
| | - Sin Man Lam
- LipidALL Technologies Company Limited Changzhou 213022 Jiangsu Province China
- State Key Laboratory of Molecular Developmental Biology Institute of Genetics and Developmental Biology Chinese Academy of Sciences No.1 West Beichen Road, Chaoyang District Beijing 100101 China
| | - Yun Zhu
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- College of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China
| | - Guohong Peng
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Straβe 3 60438 Frankfurt am Main Germany
| | - Hartmut Michel
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Straβe 3 60438 Frankfurt am Main Germany
| | - Fei Sun
- National Key Laboratory of Biomacromolecules CAS Center for Excellence in Biomacromolecules Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- College of Life Sciences University of Chinese Academy of Sciences Beijing 100049 China
- Center for Biological Imaging Institute of Biophysics Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
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25
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Zhu G, Zeng H, Zhang S, Juli J, Tai L, Zhang D, Pang X, Zhang Y, Lam SM, Zhu Y, Peng G, Michel H, Sun F. The Unusual Homodimer of a Heme-Copper Terminal Oxidase Allows Itself to Utilize Two Electron Donors. Angew Chem Int Ed Engl 2021; 60:13323-13330. [PMID: 33665933 PMCID: PMC8251803 DOI: 10.1002/anie.202016785] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Indexed: 02/03/2023]
Abstract
The heme-copper oxidase superfamily comprises cytochrome c and ubiquinol oxidases. These enzymes catalyze the transfer of electrons from different electron donors onto molecular oxygen. A B-family cytochrome c oxidase from the hyperthermophilic bacterium Aquifex aeolicus was discovered previously to be able to use both cytochrome c and naphthoquinol as electron donors. Its molecular mechanism as well as the evolutionary significance are yet unknown. Here we solved its 3.4 Å resolution electron cryo-microscopic structure and discovered a novel dimeric structure mediated by subunit I (CoxA2) that would be essential for naphthoquinol binding and oxidation. The unique structural features in both proton and oxygen pathways suggest an evolutionary adaptation of this oxidase to its hyperthermophilic environment. Our results add a new conceptual understanding of structural variation of cytochrome c oxidases in different species.
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Affiliation(s)
- Guoliang Zhu
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Hui Zeng
- Department of Molecular Membrane BiologyMax Planck Institute of BiophysicsMax-von Laue-Straβe 360438Frankfurt am MainGermany
| | - Shuangbo Zhang
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Jana Juli
- Department of Molecular Membrane BiologyMax Planck Institute of BiophysicsMax-von Laue-Straβe 360438Frankfurt am MainGermany
| | - Linhua Tai
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Danyang Zhang
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Xiaoyun Pang
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
| | - Yan Zhang
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
| | - Sin Man Lam
- LipidALL Technologies Company LimitedChangzhou213022Jiangsu ProvinceChina
- State Key Laboratory of Molecular Developmental BiologyInstitute of Genetics and Developmental BiologyChinese Academy of SciencesNo.1 West Beichen Road, Chaoyang DistrictBeijing100101China
| | - Yun Zhu
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijing100049China
| | - Guohong Peng
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
- Department of Molecular Membrane BiologyMax Planck Institute of BiophysicsMax-von Laue-Straβe 360438Frankfurt am MainGermany
| | - Hartmut Michel
- Department of Molecular Membrane BiologyMax Planck Institute of BiophysicsMax-von Laue-Straβe 360438Frankfurt am MainGermany
| | - Fei Sun
- National Key Laboratory of BiomacromoleculesCAS Center for Excellence in BiomacromoleculesInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
- College of Life SciencesUniversity of Chinese Academy of SciencesBeijing100049China
- Center for Biological ImagingInstitute of BiophysicsChinese Academy of Sciences15 Datun Road, Chaoyang DistrictBeijing100101China
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26
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Yu H, Schut GJ, Haja DK, Adams MWW, Li H. Evolution of complex I-like respiratory complexes. J Biol Chem 2021; 296:100740. [PMID: 33957129 PMCID: PMC8165549 DOI: 10.1016/j.jbc.2021.100740] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2021] [Revised: 04/28/2021] [Accepted: 04/30/2021] [Indexed: 11/06/2022] Open
Abstract
The modern-day respiratory complex I shares a common ancestor with the membrane-bound hydrogenase (MBH) and membrane-bound sulfane sulfur reductase (MBS). MBH and MBS use protons and sulfur as their respective electron sinks, which helped to conserve energy during early life in the Proterozoic era when the Earth's atmosphere was low in oxygen. MBH and MBS likely evolved from an integration of an ancestral, membrane-embedded, multiple resistance and pH antiporter and a soluble redox-active module encompassing a [NiFe] hydrogenase. In this review, we discuss how the structures of MBH, MBS, multiple resistance and pH, photosynthetic NADH dehydrogenase-like complex type-1, and complex I, which have been determined recently, thanks to the advent of high-resolution cryo-EM, have significantly improved our understanding of the catalytic reaction mechanisms and the evolutionary relationships of the respiratory complexes.
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Affiliation(s)
- Hongjun Yu
- Department of Biochemistry and Molecular Biology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China.
| | - Gerrit J Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Domink K Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA.
| | - Huilin Li
- Department of Structural Biology, Van Andel Institute, Grand Rapids, Michigan, USA.
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27
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Abstract
Bacteria power their energy metabolism using membrane-bound respiratory enzymes that capture chemical energy and transduce it by pumping protons or Na+ ions across their cell membranes. Recent breakthroughs in molecular bioenergetics have elucidated the architecture and function of many bacterial respiratory enzymes, although key mechanistic principles remain debated. In this Review, we present an overview of the structure, function and bioenergetic principles of modular bacterial respiratory chains and discuss their differences from the eukaryotic counterparts. We also discuss bacterial supercomplexes, which provide central energy transduction systems in several bacteria, including important pathogens, and which could open up possible avenues for treatment of disease.
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28
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Vali SW, Haja DK, Brand RA, Adams MWW, Lindahl PA. The Pyrococcus furiosus ironome is dominated by [Fe 4S 4] 2+ clusters or thioferrate-like iron depending on the availability of elemental sulfur. J Biol Chem 2021; 296:100710. [PMID: 33930466 PMCID: PMC8219758 DOI: 10.1016/j.jbc.2021.100710] [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: 02/21/2021] [Revised: 04/12/2021] [Accepted: 04/22/2021] [Indexed: 11/28/2022] Open
Abstract
Pyrococcus furiosus is a hyperthermophilic anaerobic archaeon whose metabolism depends on whether elemental sulfur is (+S0) or is not (-S0) included in growth medium. Under +S0 conditions, expression of respiratory hydrogenase declines while respiratory membrane-bound sulfane reductase and the putative iron-storage protein IssA increase. Our objective was to investigate the iron content of WT and ΔIssA cells under these growth conditions using Mössbauer spectroscopy. WT-S0 cells contained ∼1 mM Fe, with ∼85% present as two spectroscopically distinct forms of S = 0 [Fe4S4]2+ clusters; the remainder was mainly high-spin FeII. WT+S0 cells contained 5 to 9 mM Fe, with 75 to 90% present as magnetically ordered thioferrate-like (TFL) iron nanoparticles. TFL iron was similar to chemically defined thioferrates; both consisted of FeIII ions coordinated by an S4 environment, and both exhibited strong coupling between particles causing high applied fields to have little spectral effect. At high temperatures with magnetic hyperfine interactions abolished, TFL iron exhibited two doublets overlapping those of [Fe4S4]2+ clusters in -S0 cells. This coincidence arose because of similar coordination environments of TFL iron and cluster iron. The TFL structure was more heterogeneous in the presence of IssA. Presented data suggest that IssA may coordinate insoluble iron sulfides as TFL iron, formed as a byproduct of anaerobic sulfur respiration under high iron conditions, which thereby reduces its toxicity to the cell. This was the first Mössbauer characterization of the ironome of an archaeon, and it illustrates differences relative to the iron content of better-studied bacteria such as Escherichia coli.
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Affiliation(s)
- Shaik Waseem Vali
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA
| | - Dominik K Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Richard A Brand
- Faculty of Physics, University of Duisburg-Essen, Duisburg, Germany; Institute of Nanotechnology, Karlsruhe Institute of Technology, Eggenstein-Leopoldshafen, Germany
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, Georgia, USA
| | - Paul A Lindahl
- Department of Biochemistry and Biophysics, Texas A&M University, College Station, Texas, USA; Department of Chemistry, Texas A&M University, College Station, Texas, USA.
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29
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Zuchan K, Baymann F, Baffert C, Brugna M, Nitschke W. The dyad of the Y-junction- and a flavin module unites diverse redox enzymes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148401. [PMID: 33684340 DOI: 10.1016/j.bbabio.2021.148401] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 08/27/2020] [Revised: 02/09/2021] [Accepted: 02/16/2021] [Indexed: 11/26/2022]
Abstract
The concomitant presence of two distinctive polypeptide modules, which we have chosen to denominate as the "Y-junction" and the "flavin" module, is observed in 3D structures of enzymes as functionally diverse as complex I, NAD(P)-dependent [NiFe]-hydrogenases and NAD(P)-dependent formate dehydrogenases. Amino acid sequence conservation furthermore suggests that both modules are also part of NAD(P)-dependent [FeFe]-hydrogenases for which no 3D structure model is available yet. The flavin module harbours the site of interaction with the substrate NAD(P) which exchanges two electrons with a strictly conserved flavin moiety. The Y-junction module typically contains four iron-sulphur centres arranged to form a Y-shaped electron transfer conduit and mediates electron transfer between the flavin module and the catalytic units of the respective enzymes. The Y-junction module represents an electron transfer hub with three potential electron entry/exit sites. The pattern of specific redox centres present both in the Y-junction and the flavin module is correlated to present knowledge of these enzymes' functional properties. We have searched publicly accessible genomes for gene clusters containing both the Y-junction and the flavin module to assemble a comprehensive picture of the diversity of enzymes harbouring this dyad of modules and to reconstruct their phylogenetic relationships. These analyses indicate the presence of the dyad already in the last universal common ancestor and the emergence of complex I's EFG-module out of a subgroup of NAD(P)- dependent formate dehydrogenases.
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Affiliation(s)
- Kilian Zuchan
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Frauke Baymann
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Carole Baffert
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
| | - Myriam Brugna
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France.
| | - Wolfgang Nitschke
- Aix Marseille Univ, CNRS, BIP, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex 09, France
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30
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Loh HQ, Hervé V, Brune A. Metabolic Potential for Reductive Acetogenesis and a Novel Energy-Converting [NiFe] Hydrogenase in Bathyarchaeia From Termite Guts - A Genome-Centric Analysis. Front Microbiol 2021; 11:635786. [PMID: 33613473 PMCID: PMC7886697 DOI: 10.3389/fmicb.2020.635786] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2020] [Accepted: 12/31/2020] [Indexed: 12/11/2022] Open
Abstract
Symbiotic digestion of lignocellulose in the hindgut of higher termites is mediated by a diverse assemblage of bacteria and archaea. During a large-scale metagenomic study, we reconstructed 15 metagenome-assembled genomes of Bathyarchaeia that represent two distinct lineages in subgroup 6 (formerly MCG-6) unique to termite guts. One lineage (TB2; Candidatus Termitimicrobium) encodes all enzymes required for reductive acetogenesis from CO2 via an archaeal variant of the Wood–Ljungdahl pathway, involving tetrahydromethanopterin as C1 carrier and an (ADP-forming) acetyl-CoA synthase. This includes a novel 11-subunit hydrogenase, which possesses the genomic architecture of the respiratory Fpo-complex of other archaea but whose catalytic subunit is phylogenetically related to and shares the conserved [NiFe] cofactor-binding motif with [NiFe] hydrogenases of subgroup 4 g. We propose that this novel Fpo-like hydrogenase provides part of the reduced ferredoxin required for CO2 reduction and is driven by the electrochemical membrane potential generated from the ATP conserved by substrate-level phosphorylation; the other part may require the oxidation of organic electron donors, which would make members of TB2 mixotrophic acetogens. Members of the other lineage (TB1; Candidatus Termiticorpusculum) are definitely organotrophic because they consistently lack hydrogenases and/or methylene-tetrahydromethanopterin reductase, a key enzyme of the archaeal Wood–Ljungdahl pathway. Both lineages have the genomic capacity to reduce ferredoxin by oxidizing amino acids and might conduct methylotrophic acetogenesis using unidentified methylated compound(s). Our results indicate that Bathyarchaeia of subgroup 6 contribute to acetate formation in the guts of higher termites and substantiate the genomic evidence for reductive acetogenesis from organic substrates, possibly including methylated compounds, in other uncultured representatives of the phylum.
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Affiliation(s)
- Hui Qi Loh
- Research Group Insect Microbiology and Symbiosis, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Vincent Hervé
- Research Group Insect Microbiology and Symbiosis, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
| | - Andreas Brune
- Research Group Insect Microbiology and Symbiosis, Max Planck Institute for Terrestrial Microbiology, Marburg, Germany
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31
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Calisto F, Sousa FM, Sena FV, Refojo PN, Pereira MM. Mechanisms of Energy Transduction by Charge Translocating Membrane Proteins. Chem Rev 2021; 121:1804-1844. [PMID: 33398986 DOI: 10.1021/acs.chemrev.0c00830] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Life relies on the constant exchange of different forms of energy, i.e., on energy transduction. Therefore, organisms have evolved in a way to be able to harvest the energy made available by external sources (such as light or chemical compounds) and convert these into biological useable energy forms, such as the transmembrane difference of electrochemical potential (Δμ̃). Membrane proteins contribute to the establishment of Δμ̃ by coupling exergonic catalytic reactions to the translocation of charges (electrons/ions) across the membrane. Irrespectively of the energy source and consequent type of reaction, all charge-translocating proteins follow two molecular coupling mechanisms: direct- or indirect-coupling, depending on whether the translocated charge is involved in the driving reaction. In this review, we explore these two coupling mechanisms by thoroughly examining the different types of charge-translocating membrane proteins. For each protein, we analyze the respective reaction thermodynamics, electron transfer/catalytic processes, charge-translocating pathways, and ion/substrate stoichiometries.
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Affiliation(s)
- Filipa Calisto
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipe M Sousa
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Filipa V Sena
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
| | - Patricia N Refojo
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal
| | - Manuela M Pereira
- Instituto de Tecnologia Química e Biológica-António Xavier, Universidade Nova de Lisboa, Av. da República EAN, 2780-157, Oeiras, Portugal.,BioISI-Biosystems & Integrative Sciences Institute, University of Lisboa, Faculty of Sciences, Campo Grande, 1749-016 Lisboa, Portugal
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32
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Maldonado M, Guo F, Letts JA. Atomic structures of respiratory complex III 2, complex IV, and supercomplex III 2-IV from vascular plants. eLife 2021; 10:e62047. [PMID: 33463523 PMCID: PMC7815315 DOI: 10.7554/elife.62047] [Citation(s) in RCA: 116] [Impact Index Per Article: 38.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Accepted: 11/25/2020] [Indexed: 12/11/2022] Open
Abstract
Mitochondrial complex III (CIII2) and complex IV (CIV), which can associate into a higher-order supercomplex (SC III2+IV), play key roles in respiration. However, structures of these plant complexes remain unknown. We present atomic models of CIII2, CIV, and SC III2+IV from Vigna radiata determined by single-particle cryoEM. The structures reveal plant-specific differences in the MPP domain of CIII2 and define the subunit composition of CIV. Conformational heterogeneity analysis of CIII2 revealed long-range, coordinated movements across the complex, as well as the motion of CIII2's iron-sulfur head domain. The CIV structure suggests that, in plants, proton translocation does not occur via the H channel. The supercomplex interface differs significantly from that in yeast and bacteria in its interacting subunits, angle of approach and limited interactions in the mitochondrial matrix. These structures challenge long-standing assumptions about the plant complexes and generate new mechanistic hypotheses.
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Affiliation(s)
- Maria Maldonado
- Department of Molecular and Cellular Biology, University of California DavisDavisUnited States
| | - Fei Guo
- Department of Molecular and Cellular Biology, University of California DavisDavisUnited States
- BIOEM Facility, University of California DavisDavisUnited States
| | - James A Letts
- Department of Molecular and Cellular Biology, University of California DavisDavisUnited States
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33
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Kozlova MI, Bushmakin IM, Belyaeva JD, Shalaeva DN, Dibrova DV, Cherepanov DA, Mulkidjanian AY. Expansion of the "Sodium World" through Evolutionary Time and Taxonomic Space. BIOCHEMISTRY. BIOKHIMIIA 2020; 85:1518-1542. [PMID: 33705291 DOI: 10.1134/s0006297920120056] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
In 1986, Vladimir Skulachev and his colleagues coined the term "Sodium World" for the group of diverse organisms with sodium (Na)-based bioenergetics. Albeit only few such organisms had been discovered by that time, the authors insightfully noted that "the great taxonomic variety of organisms employing the Na-cycle points to the ubiquitous distribution of this novel type of membrane-linked energy transductions". Here we used tools of bioinformatics to follow expansion of the Sodium World through the evolutionary time and taxonomic space. We searched for those membrane protein families in prokaryotic genomes that correlate with the use of the Na-potential for ATP synthesis by different organisms. In addition to the known Na-translocators, we found a plethora of uncharacterized protein families; most of them show no homology with studied proteins. In addition, we traced the presence of Na-based energetics in many novel archaeal and bacterial clades, which were recently identified by metagenomic techniques. The data obtained support the view that the Na-based energetics preceded the proton-dependent energetics in evolution and prevailed during the first two billion years of the Earth history before the oxygenation of atmosphere. Hence, the full capacity of Na-based energetics in prokaryotes remains largely unexplored. The Sodium World expanded owing to the acquisition of new functions by Na-translocating systems. Specifically, most classes of G-protein-coupled receptors (GPCRs), which are targeted by almost half of the known drugs, appear to evolve from the Na-translocating microbial rhodopsins. Thereby the GPCRs of class A, with 700 representatives in human genome, retained the Na-binding site in the center of the transmembrane heptahelical bundle together with the capacity of Na-translocation. Mathematical modeling showed that the class A GPCRs could use the energy of transmembrane Na-potential for increasing both their sensitivity and selectivity. Thus, GPCRs, the largest protein family coded by human genome, stem from the Sodium World, which encourages exploration of other Na-dependent enzymes of eukaryotes.
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Affiliation(s)
- M I Kozlova
- School of Physics, Osnabrueck University, Osnabrueck, 49069, Germany. .,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
| | - I M Bushmakin
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia.
| | - J D Belyaeva
- School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia.
| | - D N Shalaeva
- School of Physics, Osnabrueck University, Osnabrueck, 49069, Germany.
| | - D V Dibrova
- Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.
| | - D A Cherepanov
- Semenov Institute of Chemical Physics, Russian Academy of Sciences, Moscow, 119991, Russia.
| | - A Y Mulkidjanian
- School of Physics, Osnabrueck University, Osnabrueck, 49069, Germany. .,Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia.,School of Bioengineering and Bioinformatics, Lomonosov Moscow State University, Moscow, 119992, Russia
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34
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Essential role of accessory subunit LYRM6 in the mechanism of mitochondrial complex I. Nat Commun 2020; 11:6008. [PMID: 33243981 PMCID: PMC7693276 DOI: 10.1038/s41467-020-19778-7] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Accepted: 10/29/2020] [Indexed: 01/18/2023] Open
Abstract
Respiratory complex I catalyzes electron transfer from NADH to ubiquinone (Q) coupled to vectorial proton translocation across the inner mitochondrial membrane. Despite recent progress in structure determination of this very large membrane protein complex, the coupling mechanism is a matter of ongoing debate and the function of accessory subunits surrounding the canonical core subunits is essentially unknown. Concerted rearrangements within a cluster of conserved loops of central subunits NDUFS2 (β1-β2S2 loop), ND1 (TMH5-6ND1 loop) and ND3 (TMH1-2ND3 loop) were suggested to be critical for its proton pumping mechanism. Here, we show that stabilization of the TMH1-2ND3 loop by accessory subunit LYRM6 (NDUFA6) is pivotal for energy conversion by mitochondrial complex I. We determined the high-resolution structure of inactive mutant F89ALYRM6 of eukaryotic complex I from the yeast Yarrowia lipolytica and found long-range structural changes affecting the entire loop cluster. In atomistic molecular dynamics simulations of the mutant, we observed conformational transitions in the loop cluster that disrupted a putative pathway for delivery of substrate protons required in Q redox chemistry. Our results elucidate in detail the essential role of accessory subunit LYRM6 for the function of eukaryotic complex I and offer clues on its redox-linked proton pumping mechanism. Respiratory complex I plays a key role in energy metabolism. Cryo-EM structure of a mutant accessory subunit LYRM6 from the yeast Yarrowia lipolytica and molecular dynamics simulations reveal conformational changes at the interface between LYRM6 and subunit ND3, propagated further into the complex. These findings offer insight into the mechanism of proton pumping by respiratory complex I.
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35
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Structure of the Dietzia Mrp complex reveals molecular mechanism of this giant bacterial sodium proton pump. Proc Natl Acad Sci U S A 2020; 117:31166-31176. [PMID: 33229520 PMCID: PMC7733839 DOI: 10.1073/pnas.2006276117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Multiple resistance and pH adaptation (Mrp) complexes are the most sophisticated known cation/proton exchangers and are essential for the survival of a vast variety of alkaliphilic and/or halophilic microorganisms. Moreover, this family of antiporters represents the ancestor of cation pumps in nearly all known redox-driven transporter complexes, including the complex I of the respiratory chain. For the Mrp complex, an experimental structure is lacking. We now report the structure of Mrp complex at 3.0-Å resolution solved using the single-particle cryo-EM method. The structure-inspired functional study of Mrp provides detailed information for further biophysical and biochemical investigation of the intriguingly pumping mechanism and physiological functions of this complex, as well as for exploring its potential as a therapeutic drug target. Multiple resistance and pH adaptation (Mrp) complexes are sophisticated cation/proton exchangers found in a vast variety of alkaliphilic and/or halophilic microorganisms, and are critical for their survival in highly challenging environments. This family of antiporters is likely to represent the ancestor of cation pumps found in many redox-driven transporter complexes, including the complex I of the respiratory chain. Here, we present the three-dimensional structure of the Mrp complex from a Dietzia sp. strain solved at 3.0-Å resolution using the single-particle cryoelectron microscopy method. Our structure-based mutagenesis and functional analyses suggest that the substrate translocation pathways for the driving substance protons and the substrate sodium ions are separated in two modules and that symmetry-restrained conformational change underlies the functional cycle of the transporter. Our findings shed light on mechanisms of redox-driven primary active transporters, and explain how driving substances of different electric charges may drive similar transport processes.
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36
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Yu H, Haja DK, Schut GJ, Wu CH, Meng X, Zhao G, Li H, Adams MWW. Structure of the respiratory MBS complex reveals iron-sulfur cluster catalyzed sulfane sulfur reduction in ancient life. Nat Commun 2020; 11:5953. [PMID: 33230146 PMCID: PMC7684303 DOI: 10.1038/s41467-020-19697-7] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2020] [Accepted: 10/19/2020] [Indexed: 11/17/2022] Open
Abstract
Modern day aerobic respiration in mitochondria involving complex I converts redox energy into chemical energy and likely evolved from a simple anaerobic system now represented by hydrogen gas-evolving hydrogenase (MBH) where protons are the terminal electron acceptor. Here we present the cryo-EM structure of an early ancestor in the evolution of complex I, the elemental sulfur (S0)-reducing reductase MBS. Three highly conserved protein loops linking cytoplasmic and membrane domains enable scalable energy conversion in all three complexes. MBS contains two proton pumps compared to one in MBH and likely conserves twice the energy. The structure also reveals evolutionary adaptations of MBH that enabled S0 reduction by MBS catalyzed by a site-differentiated iron-sulfur cluster without participation of protons or amino acid residues. This is the simplest mechanism proposed for reduction of inorganic or organic disulfides. It is of fundamental significance in the iron and sulfur-rich volcanic environments of early earth and possibly the origin of life. MBS provides a new perspective on the evolution of modern-day respiratory complexes and of catalysis by biological iron-sulfur clusters. The sulfur-reducing enzyme MBS and the hydrogen-gas evolving MBH are the evolutionary link between the ancestor Mrp antiporter and the mitochondrial respiratory complex I. Here, the authors characterise MBS from the hyperthermophilic archaeon Pyrococcus furiosus, solve its cryo-EM structure and discuss the structural evolution from Mrp to MBH and MBS and to the modern-day complex I.
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Affiliation(s)
- Hongjun Yu
- Structural Biology Program, Van Andel Institute, Grand Rapids, MI, USA.,Department of Biochemistry and Molecular Biology, School of Basic Medicine and Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Dominik K Haja
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Gerrit J Schut
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Chang-Hao Wu
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA
| | - Xing Meng
- Structural Biology Program, Van Andel Institute, Grand Rapids, MI, USA
| | - Gongpu Zhao
- Structural Biology Program, Van Andel Institute, Grand Rapids, MI, USA
| | - Huilin Li
- Structural Biology Program, Van Andel Institute, Grand Rapids, MI, USA.
| | - Michael W W Adams
- Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA, USA.
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37
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The Rnf complex is a Na + coupled respiratory enzyme in a fermenting bacterium, Thermotoga maritima. Commun Biol 2020; 3:431. [PMID: 32770029 PMCID: PMC7414866 DOI: 10.1038/s42003-020-01158-y] [Citation(s) in RCA: 37] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2020] [Accepted: 07/15/2020] [Indexed: 11/21/2022] Open
Abstract
rnf genes are widespread in bacteria and biochemical and genetic data are in line with the hypothesis that they encode a membrane-bound enzyme that oxidizes reduced ferredoxin and reduces NAD and vice versa, coupled to ion transport across the cytoplasmic membrane. The Rnf complex is of critical importance in many bacteria for energy conservation but also for reverse electron transport to drive ferredoxin reduction. However, the enzyme has never been purified and thus, ion transport could not be demonstrated yet. Here, we have purified the Rnf complex from the anaerobic, fermenting thermophilic bacterium Thermotoga maritima and show that is a primary Na+ pump. These studies provide the proof that the Rnf complex is indeed an ion (Na+) translocating, respiratory enzyme. Together with a Na+-F1FO ATP synthase it builds a simple, two-limb respiratory chain in T. maritima. The physiological role of electron transport phosphorylation in a fermenting bacterium is discussed. From a fermenting bacterium, Thermotoga maritima, Kuhns, Trifunovi ć et al. purify a complex that includes a respiratory enzyme, Rnf. They find that the Rnf complex requires Na+ for activity and that it catalyzes Na+ transport in liposomes. This study shows that the Rnf complex is indeed an ion translocating, respiratory enzyme.
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38
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Steiner J, Sazanov L. Structure and mechanism of the Mrp complex, an ancient cation/proton antiporter. eLife 2020; 9:59407. [PMID: 32735215 PMCID: PMC7419157 DOI: 10.7554/elife.59407] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2020] [Accepted: 07/30/2020] [Indexed: 11/19/2022] Open
Abstract
Multiple resistance and pH adaptation (Mrp) antiporters are multi-subunit Na+ (or K+)/H+ exchangers representing an ancestor of many essential redox-driven proton pumps, such as respiratory complex I. The mechanism of coupling between ion or electron transfer and proton translocation in this large protein family is unknown. Here, we present the structure of the Mrp complex from Anoxybacillus flavithermus solved by cryo-EM at 3.0 Å resolution. It is a dimer of seven-subunit protomers with 50 trans-membrane helices each. Surface charge distribution within each monomer is remarkably asymmetric, revealing probable proton and sodium translocation pathways. On the basis of the structure we propose a mechanism where the coupling between sodium and proton translocation is facilitated by a series of electrostatic interactions between a cation and key charged residues. This mechanism is likely to be applicable to the entire family of redox proton pumps, where electron transfer to substrates replaces cation movements.
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Affiliation(s)
- Julia Steiner
- Institute of Science and Technology Austria, Klosterneuburg, Austria
| | - Leonid Sazanov
- Institute of Science and Technology Austria, Klosterneuburg, Austria
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Cui J, Sun T, Li S, Xie Y, Song X, Wang F, Chen L, Zhang W. Improved Salt Tolerance and Metabolomics Analysis of Synechococcus elongatus UTEX 2973 by Overexpressing Mrp Antiporters. Front Bioeng Biotechnol 2020; 8:500. [PMID: 32528943 PMCID: PMC7264159 DOI: 10.3389/fbioe.2020.00500] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2019] [Accepted: 04/29/2020] [Indexed: 11/20/2022] Open
Abstract
The fast-growing cyanobacterium Synechococcus elongatus UTEX 2973 (Syn2973) is a promising candidate for photosynthetic microbial factory. Seawater utilization is necessary for large-scale cultivation of Syn2973 in the future. However, Syn2973 is sensitive to salt stress, making it necessary to improve its salt tolerance. In this study, 21 exogenous putative transporters were individually overexpressed in Syn2973 to evaluate their effects on salt tolerance. The results showed the overexpression of three Mrp antiporters significantly improved the salt tolerance of Syn2973. Notably, overexpressing the Mrp antiporter from Synechococcus sp. PCC 7002 improved cell growth by 57.7% under 0.4 M NaCl condition. In addition, the metabolomics and biomass composition analyses revealed the possible mechanisms against salt stress in both Syn2973 and the genetically engineered strain. The study provides important engineering strategies to improve salt tolerance of Syn2973 and is valuable for understanding mechanisms of salt tolerance in cyanobacteria.
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Affiliation(s)
- Jinyu Cui
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Frontier Science Center for Synthetic Biology, Ministry of Education of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Tao Sun
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, China
| | - Shubin Li
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Frontier Science Center for Synthetic Biology, Ministry of Education of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Yaru Xie
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Frontier Science Center for Synthetic Biology, Ministry of Education of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Xinyu Song
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, China
| | - Fangzhong Wang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, China
| | - Lei Chen
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Frontier Science Center for Synthetic Biology, Ministry of Education of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China
| | - Weiwen Zhang
- Laboratory of Synthetic Microbiology, School of Chemical Engineering and Technology, Tianjin University, Tianjin, China.,Key Laboratory of Systems Bioengineering, Frontier Science Center for Synthetic Biology, Ministry of Education of China, Tianjin, China.,Collaborative Innovation Center of Chemical Science and Engineering, Tianjin, China.,Center for Biosafety Research and Strategy, Tianjin University, Tianjin, China
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40
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Modification of the glycolytic pathway in Pyrococcus furiosus and the implications for metabolic engineering. Extremophiles 2020; 24:511-518. [PMID: 32415359 DOI: 10.1007/s00792-020-01172-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2020] [Accepted: 04/16/2020] [Indexed: 10/24/2022]
Abstract
The key difference in the modified Embden-Meyerhof glycolytic pathway in hyperthermophilic Archaea, such as Pyrococcus furiosus, occurs at the conversion from glyceraldehyde-3-phosphate (GAP) to 3-phosphoglycerate (3-PG) where the typical intermediate 1,3-bisphosphoglycerate (1,3-BPG) is not present. The absence of the ATP-yielding step catalyzed by phosphoglycerate kinase (PGK) alters energy yield, redox energetics, and kinetics of carbohydrate metabolism. Either of the two enzymes, ferredoxin-dependent glyceraldehyde-3-phosphate ferredoxin oxidoreductase (GAPOR) or NADP+-dependent non-phosphorylating glyceraldehyde-3-phosphate dehydrogenase (GAPN), responsible for this "bypass" reaction, could be deleted individually without impacting viability, albeit with differences in native fermentation product profiles. Furthermore, P. furiosus was viable in the gluconeogenic direction (growth on pyruvate or peptides plus elemental sulfur) in a ΔgapnΔgapor strain. Ethanol was utilized as a proxy for potential heterologous products (e.g., isopropanol, butanol, fatty acids) that require reducing equivalents (e.g., NAD(P)H, reduced ferredoxin) generated from glycolysis. Insertion of a single gene encoding the thermostable NADPH-dependent primary alcohol dehydrogenase (adhA) (Tte_0696) from Caldanaerobacter subterraneus, resulted in a strain producing ethanol via the previously established aldehyde oxidoreductase (AOR) pathway. This strain demonstrated a high ratio of ethanol over acetate (> 8:1) at 80 °C and enabled ethanol production up to 85 °C, the highest temperature for bio-ethanol production reported to date.
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Skorupa P, Lindenstrauß U, Burschel S, Blumenscheit C, Friedrich T, Pinske C. The N-terminal domains of the paralogous HycE and NuoCD govern assembly of the respective formate hydrogenlyase and NADH dehydrogenase complexes. FEBS Open Bio 2020; 10:371-385. [PMID: 31925988 PMCID: PMC7050243 DOI: 10.1002/2211-5463.12787] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2019] [Revised: 12/17/2019] [Accepted: 01/08/2020] [Indexed: 11/23/2022] Open
Abstract
Formate hydrogenlyase (FHL) is the main hydrogen-producing enzyme complex in enterobacteria. It converts formate to CO2 and H2 via a formate dehydrogenase and a [NiFe]-hydrogenase. FHL and complex I are evolutionarily related and share a common core architecture. However, complex I catalyses the fundamentally different electron transfer from NADH to quinone and pumps protons. The catalytic FHL subunit, HycE, resembles NuoCD of Escherichia coli complex I; a fusion of NuoC and NuoD present in other organisms. The C-terminal domain of HycE harbours the [NiFe]-active site and is similar to other hydrogenases, while this domain in NuoCD is involved in quinone binding. The N-terminal domains of these proteins do not bind cofactors and are not involved in electron transfer. As these N-terminal domains are separate proteins in some organisms, we removed them in E. coli and observed that both FHL and complex I activities were essentially absent. This was due to either a disturbed assembly or to complex instability. Replacing the N-terminal domain of HycE with a 180 amino acid E. coli NuoC protein fusion did not restore activity, indicating that the domains have complex-specific functions. A FHL complex in which the N- and C-terminal domains of HycE were physically separated still retained most of its FHL activity, while the separation of NuoCD abolished complex I activity completely. Only the FHL complex tolerates physical separation of the HycE domains. Together, the findings strongly suggest that the N-terminal domains of these proteins are key determinants in complex assembly.
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Affiliation(s)
- Philipp Skorupa
- Institute of Biology/MicrobiologyMartin‐Luther University Halle‐WittenbergGermany
| | - Ute Lindenstrauß
- Institute of Biology/MicrobiologyMartin‐Luther University Halle‐WittenbergGermany
| | - Sabrina Burschel
- Institute of Biochemistry/Molecular BioenergeticsAlbert‐Ludwigs‐University FreiburgGermany
| | | | - Thorsten Friedrich
- Institute of Biochemistry/Molecular BioenergeticsAlbert‐Ludwigs‐University FreiburgGermany
| | - Constanze Pinske
- Institute of Biology/MicrobiologyMartin‐Luther University Halle‐WittenbergGermany
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42
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Orsi WD, Schink B, Buckel W, Martin WF. Physiological limits to life in anoxic subseafloor sediment. FEMS Microbiol Rev 2020; 44:219-231. [PMID: 32065239 PMCID: PMC7269680 DOI: 10.1093/femsre/fuaa004] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2019] [Accepted: 02/13/2020] [Indexed: 12/21/2022] Open
Abstract
In subseafloor sediment, microbial cell densities exponentially decrease with depth into the fermentation zone. Here, we address the classical question of 'why are cells dying faster than they are growing?' from the standpoint of physiology. The stoichiometries of fermentative ATP production and consumption in the fermentation zone place bounds on the conversion of old cell biomass into new. Most fermentable organic matter in deep subseafloor sediment is amino acids from dead cells because cells are mostly protein by weight. Conversion of carbon from fermented dead cell protein into methanogen protein via hydrogenotrophic and acetoclastic methanogenesis occurs at ratios of ∼200:1 and 100:1, respectively, while fermenters can reach conversion ratios approaching 6:1. Amino acid fermentations become thermodynamically more efficient at lower substrate and product concentrations, but the conversion of carbon from dead cell protein into fermenter protein is low because of the high energetic cost of translation. Low carbon conversion factors within subseafloor anaerobic feeding chains account for exponential declines in cellular biomass in the fermentation zone of anoxic sediments. Our analysis points to the existence of a life-death transition zone in which the last biologically catalyzed life processes are replaced with purely chemical reactions no longer coupled to life.
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Affiliation(s)
- William D Orsi
- Department of Earth and Environmental Sciences, Paleontology and Geobiology, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
- GeoBio-Center, Ludwig-Maximilians-Universität München, 80333 Munich, Germany
| | - Bernhard Schink
- Department of Biology, University of Konstanz, 78457 Constance, Germany
| | - Wolfgang Buckel
- Department of Biology, Philipps-Universität, 35032 Marburg, Germany
| | - William F Martin
- Institute for Molecular Evolution, Heinrich Heine Universität Düsseldorf, 40225 Düsseldorf, Germany
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43
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Benoit SL, Maier RJ, Sawers RG, Greening C. Molecular Hydrogen Metabolism: a Widespread Trait of Pathogenic Bacteria and Protists. Microbiol Mol Biol Rev 2020; 84:e00092-19. [PMID: 31996394 PMCID: PMC7167206 DOI: 10.1128/mmbr.00092-19] [Citation(s) in RCA: 51] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Pathogenic microorganisms use various mechanisms to conserve energy in host tissues and environmental reservoirs. One widespread but often overlooked means of energy conservation is through the consumption or production of molecular hydrogen (H2). Here, we comprehensively review the distribution, biochemistry, and physiology of H2 metabolism in pathogens. Over 200 pathogens and pathobionts carry genes for hydrogenases, the enzymes responsible for H2 oxidation and/or production. Furthermore, at least 46 of these species have been experimentally shown to consume or produce H2 Several major human pathogens use the large amounts of H2 produced by colonic microbiota as an energy source for aerobic or anaerobic respiration. This process has been shown to be critical for growth and virulence of the gastrointestinal bacteria Salmonella enterica serovar Typhimurium, Campylobacter jejuni, Campylobacter concisus, and Helicobacter pylori (including carcinogenic strains). H2 oxidation is generally a facultative trait controlled by central regulators in response to energy and oxidant availability. Other bacterial and protist pathogens produce H2 as a diffusible end product of fermentation processes. These include facultative anaerobes such as Escherichia coli, S Typhimurium, and Giardia intestinalis, which persist by fermentation when limited for respiratory electron acceptors, as well as obligate anaerobes, such as Clostridium perfringens, Clostridioides difficile, and Trichomonas vaginalis, that produce large amounts of H2 during growth. Overall, there is a rich literature on hydrogenases in growth, survival, and virulence in some pathogens. However, we lack a detailed understanding of H2 metabolism in most pathogens, especially obligately anaerobic bacteria, as well as a holistic understanding of gastrointestinal H2 transactions overall. Based on these findings, we also evaluate H2 metabolism as a possible target for drug development or other therapies.
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Affiliation(s)
- Stéphane L Benoit
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - Robert J Maier
- Department of Microbiology, University of Georgia, Athens, Georgia, USA
| | - R Gary Sawers
- Institute of Microbiology, Martin Luther University Halle-Wittenberg, Halle, Germany
| | - Chris Greening
- School of Biological Sciences, Monash University, Clayton, VIC, Australia
- Department of Microbiology, Monash Biomedicine Discovery Institute, Clayton, VIC, Australia
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44
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Parey K, Wirth C, Vonck J, Zickermann V. Respiratory complex I - structure, mechanism and evolution. Curr Opin Struct Biol 2020; 63:1-9. [PMID: 32058886 DOI: 10.1016/j.sbi.2020.01.004] [Citation(s) in RCA: 72] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2019] [Accepted: 01/10/2020] [Indexed: 02/07/2023]
Abstract
Respiratory complex I is an intricate multi-subunit membrane protein with a central function in aerobic energy metabolism. During the last years, structures of mitochondrial complex I and respiratory supercomplexes were determined by cryo-EM at increasing resolution. Structural and computational studies have shed light on the dynamics of proton translocation pathways, the interaction of complex I with lipids and the unusual access pathway of ubiquinone to the active site. Recent advances in understanding complex I function include characterization of specific conformational changes that are critical for proton pumping. Cryo-EM structures of the NADH dehydrogenase-like (NDH) complex of photosynthesis and a bacterial membrane bound hydrogenase (MBH) have provided a broader perspective on the complex I superfamily.
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Affiliation(s)
- Kristian Parey
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt am Main, Germany; Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany; Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt am Main, Germany
| | - Christophe Wirth
- Institute of Biochemistry and Molecular Biology, ZBMZ, Medical Faculty, Albert-Ludwigs-University Freiburg, Freiburg, Germany
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, Frankfurt am Main, Germany.
| | - Volker Zickermann
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt am Main, Germany; Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt am Main, Germany.
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45
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Nishikawa K, Ogata H, Higuchi Y. Structural Basis of the Function of [NiFe]-hydrogenases. CHEM LETT 2020. [DOI: 10.1246/cl.190814] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Koji Nishikawa
- Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
| | - Hideaki Ogata
- Institute of Low Temperature Science, Hokkaido University, Kita19Nishi8, Kita-ku, Sapporo, Hokkaido 060-0819, Japan
| | - Yoshiki Higuchi
- Graduate School of Life Science, University of Hyogo, 3-2-1 Koto, Kamigori-cho, Ako-gun, Hyogo 678-1297, Japan
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46
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Schuller JM, Saura P, Thiemann J, Schuller SK, Gamiz-Hernandez AP, Kurisu G, Nowaczyk MM, Kaila VRI. Redox-coupled proton pumping drives carbon concentration in the photosynthetic complex I. Nat Commun 2020; 11:494. [PMID: 31980611 PMCID: PMC6981117 DOI: 10.1038/s41467-020-14347-4] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2019] [Accepted: 12/22/2019] [Indexed: 11/25/2022] Open
Abstract
Photosynthetic organisms capture light energy to drive their energy metabolism, and employ the chemical reducing power to convert carbon dioxide (CO2) into organic molecules. Photorespiration, however, significantly reduces the photosynthetic yields. To survive under low CO2 concentrations, cyanobacteria evolved unique carbon-concentration mechanisms that enhance the efficiency of photosynthetic CO2 fixation, for which the molecular principles have remained unknown. We show here how modular adaptations enabled the cyanobacterial photosynthetic complex I to concentrate CO2 using a redox-driven proton-pumping machinery. Our cryo-electron microscopy structure at 3.2 Å resolution shows a catalytic carbonic anhydrase module that harbours a Zn2+ active site, with connectivity to proton-pumping subunits that are activated by electron transfer from photosystem I. Our findings illustrate molecular principles in the photosynthetic complex I machinery that enabled cyanobacteria to survive in drastically changing CO2 conditions.
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Affiliation(s)
- Jan M Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany.
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
- Center of Integrated Protein Science at the Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Jacqueline Thiemann
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780, Bochum, Germany
| | - Sandra K Schuller
- Department of Structural Cell Biology, Max Planck Institute of Biochemistry, 82152, Martinsried, Germany
| | - Ana P Gamiz-Hernandez
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden
- Center of Integrated Protein Science at the Department of Chemistry, Technical University of Munich, Garching, Germany
| | - Genji Kurisu
- Institute for Protein Research, Osaka University, Suita, Osaka, 565-0871, Japan
- Department of Macromolecular Science, Graduate School of Science, Osaka University, Toyonaka, 560-0043, Japan
| | - Marc M Nowaczyk
- Plant Biochemistry, Faculty of Biology and Biotechnology, Ruhr University Bochum, 44780, Bochum, Germany.
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91, Stockholm, Sweden.
- Center of Integrated Protein Science at the Department of Chemistry, Technical University of Munich, Garching, Germany.
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Respiratory complex I - Mechanistic insights and advances in structure determination. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148153. [PMID: 31935361 DOI: 10.1016/j.bbabio.2020.148153] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2019] [Revised: 12/16/2019] [Accepted: 01/08/2020] [Indexed: 12/17/2022]
Abstract
Complex I is the largest and most intricate redox-driven proton pump of the respiratory chain. The structure of bacterial and mitochondrial complex I has been determined by X-ray crystallography and cryo-EM at increasing resolution. The recent cryo-EM structures of the complex I-like NDH complex and membrane bound hydrogenase open a new and more comprehensive perspective on the complex I superfamily. Functional studies and molecular modeling approaches have greatly advanced our understanding of the catalytic cycle of complex I. However, the molecular mechanism by which energy is extracted from the redox reaction and utilized to drive proton translocation is unresolved and a matter of ongoing debate. Here, we review progress in structure determination and functional characterization of complex I and discuss current mechanistic models.
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Zhu G, Zeng H, Zhang S, Juli J, Pang X, Hoffmann J, Zhang Y, Morgner N, Zhu Y, Peng G, Michel H, Sun F. A 3.3 Å‐Resolution Structure of Hyperthermophilic Respiratory Complex III Reveals the Mechanism of Its Thermal Stability. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.201911554] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Guoliang Zhu
- National Laboratory of Biomacromolecules Institute of Biophysics (IBP) Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- University of Chinese Academy of Sciences Beijing 100101 China
| | - Hui Zeng
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Shuangbo Zhang
- National Laboratory of Biomacromolecules Institute of Biophysics (IBP) Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
| | - Jana Juli
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Strasse 3 60438 Frankfurt am Main Germany
| | | | - Jan Hoffmann
- Institute of Physical and Theoretical Chemistry Goethe University Max-von Laue-Strasse 7 60438 Frankfurt am Main Germany
| | - Yan Zhang
- National Laboratory of Biomacromolecules Institute of Biophysics (IBP) Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
| | - Nina Morgner
- Institute of Physical and Theoretical Chemistry Goethe University Max-von Laue-Strasse 7 60438 Frankfurt am Main Germany
| | - Yun Zhu
- National Laboratory of Biomacromolecules Institute of Biophysics (IBP) Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
| | - Guohong Peng
- National Laboratory of Biomacromolecules Institute of Biophysics (IBP) Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Hartmut Michel
- Department of Molecular Membrane Biology Max Planck Institute of Biophysics Max-von Laue-Strasse 3 60438 Frankfurt am Main Germany
| | - Fei Sun
- National Laboratory of Biomacromolecules Institute of Biophysics (IBP) Chinese Academy of Sciences 15 Datun Road, Chaoyang District Beijing 100101 China
- University of Chinese Academy of Sciences Beijing 100101 China
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Fukuyama Y, Inoue M, Omae K, Yoshida T, Sako Y. Anaerobic and hydrogenogenic carbon monoxide-oxidizing prokaryotes: Versatile microbial conversion of a toxic gas into an available energy. ADVANCES IN APPLIED MICROBIOLOGY 2020; 110:99-148. [PMID: 32386607 DOI: 10.1016/bs.aambs.2019.12.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Carbon monoxide (CO) is a gas that is toxic to various organisms including humans and even microbes; however, it has low redox potential, which can fuel certain microbes, namely, CO oxidizers. Hydrogenogenic CO oxidizers utilize an energy conservation system via a CO dehydrogenase/energy-converting hydrogenase complex to produce hydrogen gas, a zero emission fuel, by CO oxidation coupled with proton reduction. Biochemical and molecular biological studies using a few model organisms have revealed their enzymatic reactions and transcriptional response mechanisms using CO. Biotechnological studies for CO-dependent hydrogen production have also been carried out with these model organisms. In this chapter, we review recent advances in the studies of these microbes, which reveal their unique and versatile metabolic profiles and provides future perspectives on ecological roles and biotechnological applications. Over the past decade, the number of isolates has doubled (37 isolates in 5 phyla, 20 genera, and 32 species). Some of the recently isolated ones show broad specificity to electron acceptors. Moreover, accumulating genomic information predicts their unique physiologies and reveals their phylogenomic relationships with novel potential hydrogenogenic CO oxidizers. Combined with genomic database surveys, a molecular ecological study has unveiled the wide distribution and low abundance of these microbes. Finally, recent biotechnological applications of hydrogenogenic CO oxidizers have been achieved via diverse approaches (e.g., metabolic engineering and co-cultivation), and the identification of thermophilic facultative anaerobic CO oxidizers will promote industrial applications as oxygen-tolerant biocatalysts for efficient hydrogen production by genomic engineering.
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Affiliation(s)
- Yuto Fukuyama
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Masao Inoue
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kimiho Omae
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takashi Yoshida
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Yoshihiko Sako
- Laboratory of Marine Microbiology, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
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50
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Vasiliadou R, Dimov N, Szita N, Jordan SF, Lane N. Possible mechanisms of CO 2 reduction by H 2 via prebiotic vectorial electrochemistry. Interface Focus 2019; 9:20190073. [PMID: 31641439 PMCID: PMC6802132 DOI: 10.1098/rsfs.2019.0073] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/27/2019] [Indexed: 02/07/2023] Open
Abstract
Methanogens are putatively ancestral autotrophs that reduce CO2 with H2 to form biomass using a membrane-bound, proton-motive Fe(Ni)S protein called the energy-converting hydrogenase (Ech). At the origin of life, geologically sustained H+ gradients across inorganic barriers containing Fe(Ni)S minerals could theoretically have driven CO2 reduction by H2 through vectorial chemistry in a similar way to Ech. pH modulation of the redox potentials of H2, CO2 and Fe(Ni)S minerals could in principle enable an otherwise endergonic reaction. Here, we analyse whether vectorial electrochemistry can facilitate the reduction of CO2 by H2 under alkaline hydrothermal conditions using a microfluidic reactor. We present pilot data showing that steep pH gradients of approximately 5 pH units can be sustained over greater than 5 h across Fe(Ni)S barriers, with H+-flux across the barrier about two million-fold faster than OH--flux. This high flux produces a calculated 3-pH unit-gradient (equating to 180 mV) across single approximately 25-nm Fe(Ni)S nanocrystals, which is close to that required to reduce CO2. However, the poor solubility of H2 at atmospheric pressure limits CO2 reduction by H2, explaining why organic synthesis has so far proved elusive in our reactor. Higher H2 concentration will be needed in future to facilitate CO2 reduction through prebiotic vectorial electrochemistry.
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Affiliation(s)
- Rafaela Vasiliadou
- Centre for Life's Origin and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Nikolay Dimov
- School of Engineering and Computer Science, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
| | - Nicolas Szita
- Department of Biochemical Engineering, University College London, Bernard Katz Building, Gower Street, London WC1E 6BT, UK
| | - Sean F. Jordan
- Centre for Life's Origin and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
| | - Nick Lane
- Centre for Life's Origin and Evolution, Department of Genetics, Evolution and Environment, University College London, Darwin Building, Gower Street, London WC1E 6BT, UK
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