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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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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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Functional Role of MrpA in the MrpABCDEFG Na+/H+ Antiporter Complex from the Archaeon Methanosarcina acetivorans. J Bacteriol 2016; 199:JB.00662-16. [PMID: 27799324 DOI: 10.1128/jb.00662-16] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2016] [Accepted: 10/18/2016] [Indexed: 11/20/2022] Open
Abstract
The multisubunit cation/proton antiporter 3 family, also called Mrp, is widely distributed in all three phylogenetic domains (Eukarya, Bacteria, and Archaea). Investigations have focused on Mrp complexes from the domain Bacteria to the exclusion of Archaea, with a consensus emerging that all seven subunits are required for Na+/H+ antiport activity. The MrpA subunit from the MrpABCDEFG Na+/H+ antiporter complex of the archaeon Methanosarcina acetivorans was produced in antiporter-deficient Escherichia coli strains EP432 and KNabc and biochemically characterized to determine the role of MrpA in the complex. Both strains containing MrpA grew in the presence of up to 500 mM NaCl and pH values up to 11.0 with no added NaCl. Everted vesicles from the strains containing MrpA were able to generate a NADH-dependent pH gradient (ΔpH), which was abated by the addition of monovalent cations. The apparent Km values for Na+ and Li+ were similar and ranged from 31 to 63 mM, whereas activity was too low to determine the apparent Km for K+ Optimum activity was obtained between pH 7.0 and 8.0. Homology molecular modeling identified two half-closed symmetry-related ion translocation channels that are linked, forming a continuous path from the cytoplasm to the periplasm, analogous to the NuoL subunit of complex I. Bioinformatics analyses revealed genes encoding homologs of MrpABCDEFG in metabolically diverse methane-producing species. Overall, the results advance the biochemical, evolutionary, and physiological understanding of Mrp complexes that extends to the domain Archaea IMPORTANCE: The work is the first reported characterization of an Mrp complex from the domain Archaea, specifically methanogens, for which Mrp is important for acetotrophic growth. The results show that the MrpA subunit is essential for antiport activity and, importantly, that not all seven subunits are required, which challenges current dogma for Mrp complexes from the domain Bacteria A mechanism is proposed in which an MrpAD subcomplex catalyzes Na+/H+ antiport independent of an MrpBCEFG subcomplex, although the activity of the former is modulated by the latter. Properties of MrpA strengthen proposals that the Mrp complex is of ancient origin and that subunits were recruited to evolve the ancestral complex I. Finally, bioinformatics analyses indicate that Mrp complexes function in diverse methanogenic pathways.
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Morino M, Ogoda S, Krulwich TA, Ito M. Differences in the phenotypic effects of mutations in homologous MrpA and MrpD subunits of the multi-subunit Mrp-type Na +/H + antiporter. Extremophiles 2016; 21:51-64. [PMID: 27709304 DOI: 10.1007/s00792-016-0877-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Accepted: 09/24/2016] [Indexed: 10/20/2022]
Abstract
Mrp antiporters are the sole antiporters in the Cation/Proton Antiporter 3 family of transporter databases because of their unusual structural complexity, 6-7 hydrophobic proteins that function as a hetero-oligomeric complex. The two largest and homologous subunits, MrpA and MrpD, are essential for antiport activity and have direct roles in ion transport. They also show striking homology with proton-conducting, membrane-embedded Nuo subunits of respiratory chain complex I of bacteria, e.g., Escherichia coli. MrpA has the closest homology to the complex I NuoL subunit and MrpD has the closest homology to the complex I NuoM and N subunits. Here, introduction of mutations in MrpD, in residues that are also present in MrpA, led to defects in antiport function and/or complex formation. No significant phenotypes were detected in strains with mutations in corresponding residues of MrpA, but site-directed changes in the C-terminal region of MrpA had profound effects, showing that the MrpA C-terminal region has indispensable roles in antiport function. The results are consistent with a divergence in adaptations that support the roles of MrpA and MrpD in secondary antiport, as compared to later adaptations supporting homologs in primary proton pumping by the respiratory chain complex I.
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Affiliation(s)
- Masato Morino
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA.,, 573-13 Kamitanui, Tarnaki-cho, Watarai-gun, Mie, 519-0417, Japan
| | - Shinichiro Ogoda
- Faculty of Life Sciences, Graduate School of Life Sciences, Toyo University, Oura-gun, Gunma, 374-0193, Japan
| | - Terry Ann Krulwich
- Department of Pharmacological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, 10029, USA
| | - Masahiro Ito
- Faculty of Life Sciences, Graduate School of Life Sciences, Toyo University, Oura-gun, Gunma, 374-0193, Japan. .,Bio-Nano Electronics Research Center, Toyo University, Kawagoe, Saitama, 350-0815, Japan.
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Zhu S, Canales A, Bedair M, Vik SB. Loss of Complex I activity in the Escherichia coli enzyme results from truncating the C-terminus of subunit K, but not from cross-linking it to subunits N or L. J Bioenerg Biomembr 2016; 48:325-33. [PMID: 26931547 DOI: 10.1007/s10863-016-9655-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Accepted: 02/25/2016] [Indexed: 12/16/2022]
Abstract
Complex I is a multi-subunit enzyme of the respiratory chain with seven core subunits in its membrane arm (A, H, J, K, L, M, and N). In the enzyme from Escherichia coli the C-terminal ten amino acids of subunit K lie along the lateral helix of subunit L, and contribute to a junction of subunits K, L and N on the cytoplasmic surface. Using double cysteine mutagenesis, the cross-linking of subunit K (R99C) to either subunit L (K581C) or subunit N (T292C) was attempted. A partial yield of cross-linked product had no effect on the activity of the enzyme, or on proton translocation, suggesting that the C-terminus of subunit K has no dynamic role in function. To further elucidate the role of subunit K genetic deletions were constructed at the C-terminus. Upon the serial deletion of the last 4 residues of the C-terminus of subunit K, various results were obtained. Deletion of one amino acid had little effect on the activity of Complex I, but deletions of 2 or more amino acids led to total loss of enzyme activity and diminished levels of subunits L, M, and N in preparations of membrane vesicles. Together these results suggest that while the C-terminus of subunit K has no dynamic role in energy transduction by Complex I, it is vital for the correct assembly of the enzyme.
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Affiliation(s)
- Shaotong Zhu
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, 75275-0376, USA.,Department of Neuroscience, University of Texas Southwestern Medical Center, Dallas, TX, 75390, USA
| | - Alejandra Canales
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, 75275-0376, USA.,Department of Biochemistry, University of Wisconsin, Madison, WI, 53706, USA
| | - Mai Bedair
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, 75275-0376, USA.,University of Texas Southwestern Medical School, Dallas, TX, 75390, USA
| | - Steven B Vik
- Department of Biological Sciences, Southern Methodist University, Dallas, TX, 75275-0376, USA.
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Schut GJ, Zadvornyy O, Wu CH, Peters JW, Boyd ES, Adams MWW. The role of geochemistry and energetics in the evolution of modern respiratory complexes from a proton-reducing ancestor. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2016; 1857:958-70. [PMID: 26808919 DOI: 10.1016/j.bbabio.2016.01.010] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/03/2015] [Revised: 12/26/2015] [Accepted: 01/18/2016] [Indexed: 11/29/2022]
Abstract
Complex I or NADH quinone oxidoreductase (NUO) is an integral component of modern day respiratory chains and has a close evolutionary relationship with energy-conserving [NiFe]-hydrogenases of anaerobic microorganisms. Specifically, in all of biology, the quinone-binding subunit of Complex I, NuoD, is most closely related to the proton-reducing, H2-evolving [NiFe]-containing catalytic subunit, MbhL, of membrane-bound hydrogenase (MBH), to the methanophenzine-reducing subunit of a methanogenic respiratory complex (FPO) and to the catalytic subunit of an archaeal respiratory complex (MBX) involved in reducing elemental sulfur (S°). These complexes also pump ions and have at least 10 homologous subunits in common. As electron donors, MBH and MBX use ferredoxin (Fd), FPO uses either Fd or cofactor F420, and NUO uses either Fd or NADH. In this review, we examine the evolutionary trajectory of these oxidoreductases from a proton-reducing ancestral respiratory complex (ARC). We hypothesize that the diversification of ARC to MBH, MBX, FPO and eventually NUO was driven by the larger energy yields associated with coupling Fd oxidation to the reduction of oxidants with increasing electrochemical potential, including protons, S° and membrane soluble organic compounds such as phenazines and quinone derivatives. Importantly, throughout Earth's history, the availability of these oxidants increased as the redox state of the atmosphere and oceans became progressively more oxidized as a result of the origin and ecological expansion of oxygenic photosynthesis. ARC-derived complexes are therefore remarkably stable respiratory systems with little diversity in core structure but whose general function appears to have co-evolved with the redox state of the biosphere. This article is part of a Special Issue entitled Respiratory Complex I, edited by Volker Zickermann and Ulrich Brandt.
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Affiliation(s)
- Gerrit J Schut
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, United States
| | - Oleg Zadvornyy
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, United States
| | - Chang-Hao Wu
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, United States
| | - John W Peters
- Department of Chemistry and Biochemistry, Montana State University, Bozeman, MT 59717, United States
| | - Eric S Boyd
- Department of Microbiology and Immunology, Montana State University, Bozeman, MT 59717, United States
| | - Michael W W Adams
- Department of Biochemistry & Molecular Biology, University of Georgia, Athens, GA 30602, United States.
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