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 PMCID: PMC11228991 DOI: 10.1021/jacs.4c04476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2024] [Revised: 05/22/2024] [Accepted: 05/23/2024] [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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Rigobello L, Lugli F, Caporali L, Bartocci A, Fadanni J, Zerbetto F, Iommarini L, Carelli V, Ghelli AM, Musiani F. A computational study to assess the pathogenicity of single or combinations of missense variants on respiratory complex I. Int J Biol Macromol 2024; 273:133086. [PMID: 38871105 DOI: 10.1016/j.ijbiomac.2024.133086] [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: 03/21/2024] [Revised: 06/07/2024] [Accepted: 06/09/2024] [Indexed: 06/15/2024]
Abstract
Variants found in the respiratory complex I (CI) subunit genes encoded by mitochondrial DNA can cause severe genetic diseases. However, it is difficult to establish a priori whether a single or a combination of CI variants may impact oxidative phosphorylation. Here we propose a computational approach based on coarse-grained molecular dynamics simulations aimed at investigating new CI variants. One of the primary CI variants associated with the Leber hereditary optic neuropathy (m.14484T>C/MT-ND6) was used as a test case and was investigated alone or in combination with two additional rare CI variants whose role remains uncertain. We found that the primary variant positioned in the E-channel region, which is fundamental for CI function, stiffens the enzyme dynamics. Moreover, a new mechanism for the transition between π- and α-conformation in the helix carrying the primary variant is proposed. This may have implications for the E-channel opening/closing mechanism. Finally, our findings show that one of the rare variants, located next to the primary one, further worsens the stiffening, while the other rare variant does not affect CI function. This approach may be extended to other variants candidate to exert a pathogenic impact on CI dynamics, or to investigate the interaction of multiple variants.
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Affiliation(s)
- Laura Rigobello
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy
| | - Francesca Lugli
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy.
| | - Leonardo Caporali
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna I-40124, Italy
| | - Alessio Bartocci
- Department of Physics, University of Trento, Trento I-38123, Italy; INFN-TIFPA, Trento Institute for Fundamental Physics and Applications, Trento I-38123, Italy
| | - Jacopo Fadanni
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy
| | - Francesco Zerbetto
- Department of Chemistry "Giacomo Ciamician", University of Bologna, Bologna I-40126, Italy
| | - Luisa Iommarini
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy
| | - Valerio Carelli
- IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna I-40124, Italy; Department of Biomedical and Neuromotor Sciences, University of Bologna, Bologna I-40123, Italy
| | - Anna Maria Ghelli
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy; IRCCS Istituto delle Scienze Neurologiche di Bologna, Programma di Neurogenetica, Bologna I-40124, Italy
| | - Francesco Musiani
- Department of Pharmacy and Biotechnology, University of Bologna, Bologna I-40127, Italy.
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3
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Pirnia A, Maqdisi R, Mittal S, Sener M, Singharoy A. Perspective on Integrative Simulations of Bioenergetic Domains. J Phys Chem B 2024; 128:3302-3319. [PMID: 38562105 DOI: 10.1021/acs.jpcb.3c07335] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Bioenergetic processes in cells, such as photosynthesis or respiration, integrate many time and length scales, which makes the simulation of energy conversion with a mere single level of theory impossible. Just like the myriad of experimental techniques required to examine each level of organization, an array of overlapping computational techniques is necessary to model energy conversion. Here, a perspective is presented on recent efforts for modeling bioenergetic phenomena with a focus on molecular dynamics simulations and its variants as a primary method. An overview of the various classical, quantum mechanical, enhanced sampling, coarse-grained, Brownian dynamics, and Monte Carlo methods is presented. Example applications discussed include multiscale simulations of membrane-wide electron transport, rate kinetics of ATP turnover from electrochemical gradients, and finally, integrative modeling of the chromatophore, a photosynthetic pseudo-organelle.
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Affiliation(s)
- Adam Pirnia
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Ranel Maqdisi
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
| | - Sumit Mittal
- VIT Bhopal University, Sehore 466114, Madhya Pradesh, India
| | - Melih Sener
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
- Beckman Institute, University of Illinois at Urbana-Champaign, Urbana, Illinois 61801, United States
| | - Abhishek Singharoy
- School of Molecular Sciences, Arizona State University, Tempe, Arizona 85287-1004, United States
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4
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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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5
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Shin YC, Latorre-Muro P, Djurabekova A, Zdorevskyi O, Bennett CF, Burger N, Song K, Xu C, Sharma V, Liao M, Puigserver P. Structural basis of respiratory complexes adaptation to cold temperatures. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.01.16.575914. [PMID: 38293190 PMCID: PMC10827213 DOI: 10.1101/2024.01.16.575914] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
In response to cold, mammals activate brown fat for respiratory-dependent thermogenesis reliant on the electron transport chain (1, 2). Yet, the structural basis of respiratory complex adaptation to cold remains elusive. Herein we combined thermoregulatory physiology and cryo-EM to study endogenous respiratory supercomplexes exposed to different temperatures. A cold-induced conformation of CI:III 2 (termed type 2) was identified with a ∼25° rotation of CIII 2 around its inter-dimer axis, shortening inter-complex Q exchange space, and exhibiting different catalytic states which favor electron transfer. Large-scale supercomplex simulations in lipid membrane reveal how unique lipid-protein arrangements stabilize type 2 complexes to enhance catalytic activity. Together, our cryo-EM studies, multiscale simulations and biochemical analyses unveil the mechanisms and dynamics of respiratory adaptation at the structural and energetic level.
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6
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Haxhija J, Guischard F, Koslowski T. A trick of the tail: computing the entropic contribution to the energetics of quinone-protein unbindung. Phys Chem Chem Phys 2023; 25:27498-27505. [PMID: 37800323 DOI: 10.1039/d3cp03466f] [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: 10/07/2023]
Abstract
We estimate the entropic contributions to the free energy of quinone unbinding in bacterial and mitochondrial respiratory chains using molecular dynamics (MD) and Monte Carlo (MC) computer simulations. For a varying length of the isoprenoid side chain, MD simulations in lipid bilayers and in unpolar solvents are used to assess the dihedral angle distributions along the chain. These form the basis of a MC estimate of the number of molecular structures that do not exhibit steric self-overlap and that are confined to the bilayer. We obtain an entropy drive of TΔS = 1.4 kcal mol-1 for each isoprene unit, which in sum is comparable to the redox potential differences involved in respiratory chain electron transfer. We postulate an entropy-driven zipper for quinone unbinding and discuss it in the context of the bioenergetics and the structure of complex I, and we indicate possible consequences of our findings for MD-based free energy computations.
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Affiliation(s)
- Jetmir Haxhija
- Institut für Physikalische Chemie, Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
| | - Felix Guischard
- Institut für Physikalische Chemie, Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
| | - Thorsten Koslowski
- Institut für Physikalische Chemie, Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
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7
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Kim H, Saura P, Pöverlein MC, Gamiz-Hernandez AP, Kaila VRI. Quinone Catalysis Modulates Proton Transfer Reactions in the Membrane Domain of Respiratory Complex I. J Am Chem Soc 2023; 145:17075-17086. [PMID: 37490414 PMCID: PMC10416309 DOI: 10.1021/jacs.3c03086] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Indexed: 07/27/2023]
Abstract
Complex I is a redox-driven proton pump that drives electron transport chains and powers oxidative phosphorylation across all domains of life. Yet, despite recently resolved structures from multiple organisms, it still remains unclear how the redox reactions in Complex I trigger proton pumping up to 200 Å away from the active site. Here, we show that the proton-coupled electron transfer reactions during quinone reduction drive long-range conformational changes of conserved loops and trans-membrane (TM) helices in the membrane domain of Complex I from Yarrowia lipolytica. We find that the conformational switching triggers a π → α transition in a TM helix (TM3ND6) and establishes a proton pathway between the quinone chamber and the antiporter-like subunits, responsible for proton pumping. Our large-scale (>20 μs) atomistic molecular dynamics (MD) simulations in combination with quantum/classical (QM/MM) free energy calculations show that the helix transition controls the barrier for proton transfer reactions by wetting transitions and electrostatic effects. The conformational switching is enabled by re-arrangements of ion pairs that propagate from the quinone binding site to the membrane domain via an extended network of conserved residues. We find that these redox-driven changes create a conserved coupling network within the Complex I superfamily, with point mutations leading to drastic activity changes and mitochondrial disorders. On a general level, our findings illustrate how catalysis controls large-scale protein conformational changes and enables ion transport across biological membranes.
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Affiliation(s)
- Hyunho Kim
- Department of Biochemistry and Biophysics, Stockholm University, Stockholm 10691, Sweden
| | - Patricia Saura
- 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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8
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Ikunishi R, Otani R, Masuya T, Shinzawa-Itoh K, Shiba T, Murai M, Miyoshi H. Respiratory complex I in mitochondrial membrane catalyzes oversized ubiquinones. J Biol Chem 2023; 299:105001. [PMID: 37394006 PMCID: PMC10416054 DOI: 10.1016/j.jbc.2023.105001] [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: 05/08/2023] [Revised: 06/20/2023] [Accepted: 06/23/2023] [Indexed: 07/04/2023] Open
Abstract
NADH-ubiquinone (UQ) oxidoreductase (complex I) couples electron transfer from NADH to UQ with proton translocation in its membrane part. The UQ reduction step is key to triggering proton translocation. Structural studies have identified a long, narrow, tunnel-like cavity within complex I, through which UQ may access a deep reaction site. To elucidate the physiological relevance of this UQ-accessing tunnel, we previously investigated whether a series of oversized UQs (OS-UQs), whose tail moiety is too large to enter and transit the narrow tunnel, can be catalytically reduced by complex I using the native enzyme in bovine heart submitochondrial particles (SMPs) and the isolated enzyme reconstituted into liposomes. Nevertheless, the physiological relevance remained unclear because some amphiphilic OS-UQs were reduced in SMPs but not in proteoliposomes, and investigation of extremely hydrophobic OS-UQs was not possible in SMPs. To uniformly assess the electron transfer activities of all OS-UQs with the native complex I, here we present a new assay system using SMPs, which were fused with liposomes incorporating OS-UQ and supplemented with a parasitic quinol oxidase to recycle reduced OS-UQ. In this system, all OS-UQs tested were reduced by the native enzyme, and the reduction was coupled with proton translocation. This finding does not support the canonical tunnel model. We propose that the UQ reaction cavity is flexibly open in the native enzyme to allow OS-UQs to access the reaction site, but their access is obstructed in the isolated enzyme as the cavity is altered by detergent-solubilizing from the mitochondrial membrane.
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Affiliation(s)
- Ryo Ikunishi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Ryohei Otani
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takahiro Masuya
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kyoko Shinzawa-Itoh
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Hyogo, Japan
| | - Tomoo Shiba
- Department of Applied Biology, Graduate School of Science and Technology, Kyoto Institute of Technology, Kyoto, Japan
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
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9
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Tunnel dynamics of quinone derivatives and its coupling to protein conformational rearrangements in respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA. BIOENERGETICS 2023; 1864:148951. [PMID: 36509126 DOI: 10.1016/j.bbabio.2022.148951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 11/30/2022] [Accepted: 12/02/2022] [Indexed: 12/13/2022]
Abstract
Respiratory complex I in mitochondria and bacteria catalyzes the transfer of electrons from NADH to quinone (Q). The free energy available from the reaction is used to pump protons and to establish a membrane proton electrochemical gradient, which drives ATP synthesis. Even though several high-resolution structures of complex I have been resolved, how Q reduction is linked with proton pumping, remains unknown. Here, microsecond long molecular dynamics (MD) simulations were performed on Yarrowia lipolytica complex I structures where Q molecules have been resolved in the ~30 Å long Q tunnel. MD simulations of several different redox/protonation states of Q reveal the coupling between the Q dynamics and the restructuring of conserved loops and ion pairs. Oxidized quinone stabilizes towards the N2 FeS cluster, a binding mode not previously described in Yarrowia lipolytica complex I structures. On the other hand, reduced (and protonated) species tend to diffuse towards the Q binding sites closer to the tunnel entrance. Mechanistic and physiological relevance of these results are discussed.
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10
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Sazanov LA. From the 'black box' to 'domino effect' mechanism: what have we learned from the structures of respiratory complex I. Biochem J 2023; 480:319-333. [PMID: 36920092 DOI: 10.1042/bcj20210285] [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: 12/04/2022] [Revised: 01/20/2023] [Accepted: 01/23/2023] [Indexed: 03/16/2023]
Abstract
My group and myself have studied respiratory complex I for almost 30 years, starting in 1994 when it was known as a L-shaped giant 'black box' of bioenergetics. First breakthrough was the X-ray structure of the peripheral arm, followed by structures of the membrane arm and finally the entire complex from Thermus thermophilus. The developments in cryo-EM technology allowed us to solve the first complete structure of the twice larger, ∼1 MDa mammalian enzyme in 2016. However, the mechanism coupling, over large distances, the transfer of two electrons to pumping of four protons across the membrane remained an enigma. Recently we have solved high-resolution structures of mammalian and bacterial complex I under a range of redox conditions, including catalytic turnover. This allowed us to propose a robust and universal mechanism for complex I and related protein families. Redox reactions initially drive conformational changes around the quinone cavity and a long-distance transfer of substrate protons. These set up a stage for a series of electrostatically driven proton transfers along the membrane arm ('domino effect'), eventually resulting in proton expulsion from the distal antiporter-like subunit. The mechanism radically differs from previous suggestions, however, it naturally explains all the unusual structural features of complex I. In this review I discuss the state of knowledge on complex I, including the current most controversial issues.
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Affiliation(s)
- Leonid A Sazanov
- Institute of Science and Technology Austria, Am Campus 1, Klosterneuburg 3400, Austria
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11
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Wikström M, Djurabekova A, Sharma V. On the role of ubiquinone in the proton translocation mechanism of respiratory complex I. FEBS Lett 2023; 597:224-236. [PMID: 36180980 DOI: 10.1002/1873-3468.14506] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/23/2022] [Accepted: 09/23/2022] [Indexed: 01/26/2023]
Abstract
Complex I converts oxidoreduction energy into a proton electrochemical gradient across the inner mitochondrial or bacterial cell membrane. This gradient is the primary source of energy for aerobic synthesis of ATP. Oxidation of reduced nicotinamide adenine dinucleotide (NADH) by ubiquinone (Q) yields NAD+ and ubiquinol (QH2 ), which is tightly coupled to translocation of four protons from the negatively to the positively charged side of the membrane. Electrons from NADH oxidation reach the iron-sulfur centre N2 positioned near the bottom of a tunnel that extends circa 30 Å from the membrane domain into the hydrophilic domain of the complex. The tunnel is occupied by ubiquinone, which can take a distal position near the N2 centre or proximal positions closer to the membrane. Here, we review important structural, kinetic and thermodynamic properties of ubiquinone that define its role in complex I function. We suggest that this function exceeds that of a mere substrate or electron acceptor and propose that ubiquinone may be the redox element of complex I coupling electron transfer to proton translocation.
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Affiliation(s)
- Mårten Wikström
- HiLIFE Institute of Biotechnology, University of Helsinki, Finland
| | | | - Vivek Sharma
- HiLIFE Institute of Biotechnology, University of Helsinki, Finland.,Department of Physics, University of Helsinki, Finland
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12
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Binding of Natural Inhibitors to Respiratory Complex I. Pharmaceuticals (Basel) 2022; 15:ph15091088. [PMID: 36145309 PMCID: PMC9503403 DOI: 10.3390/ph15091088] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2022] [Revised: 08/23/2022] [Accepted: 08/24/2022] [Indexed: 11/26/2022] Open
Abstract
NADH:ubiquinone oxidoreductase (respiratory complex I) is a redox-driven proton pump with a central role in mitochondrial oxidative phosphorylation. The ubiquinone reduction site of complex I is located in the matrix arm of this large protein complex and connected to the membrane via a tunnel. A variety of chemically diverse compounds are known to inhibit ubiquinone reduction by complex I. Rotenone, piericidin A, and annonaceous acetogenins are representatives of complex I inhibitors from biological sources. The structure of complex I is determined at high resolution, and inhibitor binding sites are described in detail. In this review, we summarize the state of knowledge of how natural inhibitors bind in the Q reduction site and the Q access pathway and how their inhibitory mechanisms compare with that of a synthetic anti-cancer agent.
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13
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Respiratory complex I with charge symmetry in the membrane arm pumps protons. Proc Natl Acad Sci U S A 2022; 119:e2123090119. [PMID: 35759670 PMCID: PMC9271201 DOI: 10.1073/pnas.2123090119] [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: 11/18/2022] Open
Abstract
Respiratory complex I is a central enzyme of cellular energy metabolism coupling quinone reduction with proton translocation. Its mechanism, especially concerning proton translocation, remains enigmatic. Three homologous subunits that contain a conserved pattern of charged and polar amino acid residues catalyze proton translocation. Strikingly, the central subunit NuoM contains a conserved glutamate residue at a position where conserved lysine residues are found in the other two subunits, resulting in a charge asymmetry discussed to be essential for proton translocation. We found that the respective glutamate to lysine mutation in Escherichia coli complex I lowers the amount of protons translocated per electron transferred by one-quarter. These data clarify the discussion about possible mechanisms of proton translocation by complex I. Energy-converting NADH:ubiquinone oxidoreductase, respiratory complex I, is essential for cellular energy metabolism coupling NADH oxidation to proton translocation. The mechanism of proton translocation by complex I is still under debate. Its membrane arm contains an unusual central axis of polar and charged amino acid residues connecting the quinone binding site with the antiporter-type subunits NuoL, NuoM, and NuoN, proposed to catalyze proton translocation. Quinone chemistry probably causes conformational changes and electrostatic interactions that are propagated through these subunits by a conserved pattern of predominantly lysine, histidine, and glutamate residues. These conserved residues are thought to transfer protons along and across the membrane arm. The distinct charge distribution in the membrane arm is a prerequisite for proton translocation. Remarkably, the central subunit NuoM contains a conserved glutamate residue in a position that is taken by a lysine residue in the two other antiporter-type subunits. It was proposed that this charge asymmetry is essential for proton translocation, as it should enable NuoM to operate asynchronously with NuoL and NuoN. Accordingly, we exchanged the conserved glutamate in NuoM for a lysine residue, introducing charge symmetry in the membrane arm. The stably assembled variant pumps protons across the membrane, but with a diminished H+/e− stoichiometry of 1.5. Thus, charge asymmetry is not essential for proton translocation by complex I, casting doubts on the suggestion of an asynchronous operation of NuoL, NuoM, and NuoN. Furthermore, our data emphasize the importance of a balanced charge distribution in the protein for directional proton transfer.
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14
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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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15
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Uno S, Masuya T, Zdorevskyi O, Ikunishi R, Shinzawa-Itoh K, Lasham J, Sharma V, Murai M, Miyoshi H. Diverse reaction behaviors of artificial ubiquinones in mitochondrial respiratory complex I. J Biol Chem 2022; 298:102075. [PMID: 35643318 PMCID: PMC9243180 DOI: 10.1016/j.jbc.2022.102075] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2022] [Revised: 05/23/2022] [Accepted: 05/23/2022] [Indexed: 11/24/2022] Open
Abstract
The ubiquinone (UQ) reduction step catalyzed by NADH-UQ oxidoreductase (mitochondrial respiratory complex I) is key to triggering proton translocation across the inner mitochondrial membrane. Structural studies have identified a long, narrow, UQ-accessing tunnel within the enzyme. We previously demonstrated that synthetic oversized UQs, which are unlikely to transit this narrow tunnel, are catalytically reduced by native complex I embedded in submitochondrial particles but not by the isolated enzyme. To explain this contradiction, we hypothesized that access of oversized UQs to the reaction site is obstructed in the isolated enzyme because their access route is altered following detergent solubilization from the inner mitochondrial membrane. In the present study, we investigated this using two pairs of photoreactive UQs (pUQm-1/pUQp-1 and pUQm-2/pUQp-2), with each pair having the same chemical properties except for a ∼1.0 Å difference in side-chain widths. Despite this subtle difference, reduction of the wider pUQs by the isolated complex was significantly slower than of the narrower pUQs, but both were similarly reduced by the native enzyme. In addition, photoaffinity-labeling experiments using the four [125I]pUQs demonstrated that their side chains predominantly label the ND1 subunit with both enzymes but at different regions around the tunnel. Finally, we show that the suppressive effects of different types of inhibitors on the labeling significantly changed depending on [125I]pUQs used, indicating that [125I]pUQs and these inhibitors do not necessarily share a common binding cavity. Altogether, we conclude that the reaction behaviors of pUQs cannot be simply explained by the canonical UQ tunnel model.
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Affiliation(s)
- Shinpei Uno
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Takahiro Masuya
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | | | - Ryo Ikunishi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Kyoko Shinzawa-Itoh
- Department of Life Science, Graduate School of Life Science, University of Hyogo, Hyogo, Japan
| | - Jonathan Lasham
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Helsinki, Finland
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan.
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16
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Cryo-EM structures define ubiquinone-10 binding to mitochondrial complex I and conformational transitions accompanying Q-site occupancy. Nat Commun 2022; 13:2758. [PMID: 35589726 PMCID: PMC9120487 DOI: 10.1038/s41467-022-30506-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 16.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 05/04/2022] [Indexed: 02/03/2023] Open
Abstract
Mitochondrial complex I is a central metabolic enzyme that uses the reducing potential of NADH to reduce ubiquinone-10 (Q10) and drive four protons across the inner mitochondrial membrane, powering oxidative phosphorylation. Although many complex I structures are now available, the mechanisms of Q10 reduction and energy transduction remain controversial. Here, we reconstitute mammalian complex I into phospholipid nanodiscs with exogenous Q10. Using cryo-EM, we reveal a Q10 molecule occupying the full length of the Q-binding site in the 'active' (ready-to-go) resting state together with a matching substrate-free structure, and apply molecular dynamics simulations to propose how the charge states of key residues influence the Q10 binding pose. By comparing ligand-bound and ligand-free forms of the 'deactive' resting state (that require reactivating to catalyse), we begin to define how substrate binding restructures the deactive Q-binding site, providing insights into its physiological and mechanistic relevance.
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17
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Djurabekova A, Galemou Yoga E, Nyman A, Pirttikoski A, Zickermann V, Haapanen O, Sharma V. Docking and molecular simulations reveal a quinone binding site on the surface of respiratory complex I. FEBS Lett 2022; 596:1133-1146. [PMID: 35363885 DOI: 10.1002/1873-3468.14346] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/11/2022] [Accepted: 03/24/2022] [Indexed: 11/07/2022]
Abstract
The first component of the mitochondrial electron transport chain is respiratory complex I. Several high-resolution structures of complex I from different species have been resolved. However, despite these significant achievements, the mechanism of redox-coupled proton pumping remains elusive. Here, we combined atomistic docking, molecular dynamics simulations and site-directed mutagenesis on respiratory complex I from Yarrowia lipolytica to identify a quinone (Q) binding site on its surface near the horizontal amphipathic helices of ND1 and NDUFS7 subunits. The surface-bound Q makes stable interactions with conserved charged and polar residues, including the highly conserved Arg72 from the NDUFS7 subunit. The binding and dynamics of a Q molecule at the surface-binding site raises interesting possibilities about the mechanism of complex I, which are discussed.
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Affiliation(s)
| | - Etienne Galemou Yoga
- 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
| | - Aino Nyman
- Department of Physics, University of 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
| | - Outi Haapanen
- Department of Physics, University of Helsinki, Finland
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Finland.,HiLIFE Institute of Biotechnology, University of Helsinki, Finland
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18
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Deng J, Cui Q. Electronic Polarization Is Essential for the Stabilization and Dynamics of Buried Ion Pairs in Staphylococcal Nuclease Mutants. J Am Chem Soc 2022; 144:4594-4610. [PMID: 35239338 PMCID: PMC9616648 DOI: 10.1021/jacs.2c00312] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Buried charged residues play important roles in the modulation of protein stabilities and conformational dynamics and make crucial contributions to protein functions. Considering the generally nonpolar nature of protein interior, a key question concerns the contribution of electronic polarization to the stabilization and properties of buried charges. We answer this question by conducting free energy simulations using the latest polarizable CHARMM force field based on Drude oscillators for a series of Staphylococcal nuclease mutants that involve a buried Glu-Lys pair in different titration states and orientations. While a nonpolarizable model suggests that the ionized form of the buried Glu-Lys pair is more than 40 kcal/mol less stable than the charge-neutral form, the two titration states are comparable in stability when electronic polarization is included explicitly, a result better reconcilable with available experimental data. Analysis of free energy components suggests that additional stabilization of the ionized Glu-Lys pair has contributions from both the enhanced salt-bridge strength and stronger interaction between the ion-pair and surrounding protein residues and penetrated water. Despite the stronger direct interaction between Glu and Lys, the ion-pair exhibits considerably larger and faster structural fluctuations when polarization is included, due to compensation of interactions in the cavity. Collectively, observations from this work provide compelling evidence that electronic polarization is essential to the stability, hydration, dynamics, and therefore function of buried charges in proteins. Therefore, our study advocates for the explicit consideration of electronic polarization for mechanistic and engineering studies that implicate buried charged residues, such as enzymes and ion transporters.
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Affiliation(s)
- Jiahua Deng
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Qiang Cui
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States.,Department of Physics, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States.,Department of Biomedical Engineering, Boston University, 44 Cummington Mall, Boston, Massachusetts 02215, United States
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19
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Hoeser F, Weiß M, Friedrich T. The clinically relevant triple mutation in the mtND1 gene inactivates Escherichia coli complex I. FEBS Lett 2022; 596:1124-1132. [PMID: 35234296 DOI: 10.1002/1873-3468.14325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Revised: 02/16/2022] [Accepted: 02/21/2022] [Indexed: 11/07/2022]
Abstract
NADH:ubiquinone oxidoreductase (respiratory complex I) plays a major role in cellular energy metabolism. Complex I deficiencies are the most common cause of mitochondrial dysfunction. Patients suffering from a variety of neurodegenerative diseases carry numerous mutations in the mitochondrially encoded subunits of the complex. The biochemical consequences of these mutations are largely unknown because these genes are difficult to access experimentally. Here, we use Escherichia coli as a model system to characterize the effect of a 7 bp inversion in mtND1 (m.3902-3908inv7) that results in a triple mutation. The triple mutant grew poorly but contained a normal amount of the stably assembled variant. The variant showed no enzymatic activity, which might contribute to the deleterious effect of the mutation in humans.
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Affiliation(s)
- Franziska Hoeser
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Maximilian Weiß
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstr. 21, 79104, Freiburg, Germany
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20
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Grba DN, Blaza JN, Bridges HR, Agip ANA, Yin Z, Murai M, Miyoshi H, Hirst J. Cryo-electron microscopy reveals how acetogenins inhibit mitochondrial respiratory complex I. J Biol Chem 2022; 298:101602. [PMID: 35063503 PMCID: PMC8861642 DOI: 10.1016/j.jbc.2022.101602] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2021] [Revised: 01/10/2022] [Accepted: 01/11/2022] [Indexed: 12/22/2022] Open
Abstract
Mitochondrial complex I (NADH:ubiquinone oxidoreductase), a crucial enzyme in energy metabolism, captures the redox potential energy from NADH oxidation/ubiquinone reduction to create the proton motive force used to drive ATP synthesis in oxidative phosphorylation. High-resolution single-particle electron cryo-EM analyses have provided detailed structural knowledge of the catalytic machinery of complex I, but not of the molecular principles of its energy transduction mechanism. Although ubiquinone is considered to bind in a long channel at the interface of the membrane-embedded and hydrophilic domains, with channel residues likely involved in coupling substrate reduction to proton translocation, no structures with the channel fully occupied have yet been described. Here, we report the structure (determined by cryo-EM) of mouse complex I with a tight-binding natural product acetogenin inhibitor, which resembles the native substrate, bound along the full length of the expected ubiquinone-binding channel. Our structure reveals the mode of acetogenin binding and the molecular basis for structure-activity relationships within the acetogenin family. It also shows that acetogenins are such potent inhibitors because they are highly hydrophobic molecules that contain two specific hydrophilic moieties spaced to lock into two hydrophilic regions of the otherwise hydrophobic channel. The central hydrophilic section of the channel does not favor binding of the isoprenoid chain when the native substrate is fully bound but stabilizes the ubiquinone/ubiquinol headgroup as it transits to/from the active site. Therefore, the amphipathic nature of the channel supports both tight binding of the amphipathic inhibitor and rapid exchange of the ubiquinone/ubiquinol substrate and product.
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Affiliation(s)
- Daniel N Grba
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - James N Blaza
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Hannah R Bridges
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Ahmed-Noor A Agip
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Zhan Yin
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto, Japan
| | - Judy Hirst
- MRC Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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21
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Gu J, Liu T, Guo R, Zhang L, Yang M. The coupling mechanism of mammalian mitochondrial complex I. Nat Struct Mol Biol 2022; 29:172-182. [PMID: 35145322 DOI: 10.1038/s41594-022-00722-w] [Citation(s) in RCA: 43] [Impact Index Per Article: 21.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 01/06/2022] [Indexed: 01/03/2023]
Abstract
Mammalian respiratory complex I (CI) is a 45-subunit, redox-driven proton pump that generates an electrochemical gradient across the mitochondrial inner membrane to power ATP synthesis in mitochondria. In the present study, we report cryo-electron microscopy structures of CI from Sus scrofa in six treatment conditions at a resolution of 2.4-3.5 Å, in which CI structures of each condition can be classified into two biochemical classes (active or deactive), with a notably higher proportion of active CI particles. These structures illuminate how hydrophobic ubiquinone-10 (Q10) with its long isoprenoid tail is bound and reduced in a narrow Q chamber comprising four different Q10-binding sites. Structural comparisons of active CI structures from our decylubiquinone-NADH and rotenone-NADH datasets reveal that Q10 reduction at site 1 is not coupled to proton pumping in the membrane arm, which might instead be coupled to Q10 oxidation at site 2. Our data overturn the widely accepted previous proposal about the coupling mechanism of CI.
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Affiliation(s)
- Jinke Gu
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China.,Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Shenzhen University Health Science Center, Shenzhen, China
| | - Tianya Liu
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Runyu Guo
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Laixing Zhang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China
| | - Maojun Yang
- Ministry of Education Key Laboratory of Protein Science, Beijing Advanced Innovation Center for Structural Biology, Beijing Frontier Research Center for Biological Structure, School of Life Sciences, Tsinghua University, Tsinghua-Peking Center for Life Sciences, Beijing, China. .,SUSTech Cryo-EM Facility Center, Southern University of Science & Technology, Shenzhen, China.
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22
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Kaila VRI. Resolving Chemical Dynamics in Biological Energy Conversion: Long-Range Proton-Coupled Electron Transfer in Respiratory Complex I. Acc Chem Res 2021; 54:4462-4473. [PMID: 34894649 PMCID: PMC8697550 DOI: 10.1021/acs.accounts.1c00524] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
![]()
Biological energy conversion is catalyzed by membrane-bound proteins
that transduce chemical or light energy into energy forms that power
endergonic processes in the cell. At a molecular level, these catalytic
processes involve elementary electron-, proton-, charge-, and energy-transfer
reactions that take place in the intricate molecular machineries of
cell respiration and photosynthesis. Recent developments in structural
biology, particularly cryo-electron microscopy (cryoEM), have resolved
the molecular architecture of several energy transducing proteins,
but detailed mechanistic principles of their charge transfer reactions
still remain poorly understood and a major challenge for modern biochemical
research. To this end, multiscale molecular simulations provide a
powerful approach to probe mechanistic principles on a broad range
of time scales (femtoseconds to milliseconds) and spatial resolutions
(101–106 atoms), although technical challenges
also require balancing between the computational accuracy, cost, and
approximations introduced within the model. Here we discuss how the
combination of atomistic (aMD) and hybrid quantum/classical molecular
dynamics (QM/MM MD) simulations with free energy (FE) sampling methods
can be used to probe mechanistic principles of enzymes responsible
for biological energy conversion. We present mechanistic explorations
of long-range proton-coupled electron transfer (PCET) dynamics in
the highly intricate respiratory chain enzyme Complex I, which functions
as a redox-driven proton pump in bacterial and mitochondrial respiratory
chains by catalyzing a 300 Å fully reversible PCET process. This
process is initiated by a hydride (H–) transfer
between NADH and FMN, followed by long-range (>100 Å) electron
transfer along a wire of 8 FeS centers leading to a quinone biding
site. The reduction of the quinone to quinol initiates dissociation
of the latter to a second membrane-bound binding site, and triggers
proton pumping across the membrane domain of complex I, in subunits
up to 200 Å away from the active site. Our simulations across
different size and time scales suggest that transient charge transfer
reactions lead to changes in the internal hydration state of key regions,
local electric fields, and the conformation of conserved ion pairs,
which in turn modulate the dynamics of functional steps along the
reaction cycle. Similar functional principles, which operate on much
shorter length scales, are also found in some unrelated proteins,
suggesting that enzymes may employ conserved principles in the catalysis
of biological energy transduction processes.
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Affiliation(s)
- Ville R. I. Kaila
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
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23
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Quinone binding in respiratory complex I: Going through the eye of a needle. The squeeze-in mechanism of passing the narrow entrance of the quinone site. Photochem Photobiol Sci 2021; 21:1-12. [PMID: 34813075 PMCID: PMC8799541 DOI: 10.1007/s43630-021-00113-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Accepted: 10/04/2021] [Indexed: 02/02/2023]
Abstract
At the joint between the membrane and hydrophilic arms of the enzyme, the structure of the respiratory complex I reveals a tunnel-like Q-chamber for ubiquinone binding and reduction. The narrow entrance of the quinone chamber located in ND1 subunit forms a bottleneck (eye of a needle) which in all resolved structures was shown to be too small for a bulky quinone to pass through, and it was suggested that a conformational change is required to open the channel. The closed bottleneck appears to be a well-established feature of all structures reported so-far, both for the so-called open and closed states of the enzyme, with no indication of a stable open state of the bottleneck. We propose a squeeze-in mechanism of the bottleneck passage, where dynamic thermal conformational fluctuations allow quinone to get in and out. Here, using molecular dynamics simulations of the bacterial enzyme, we have identified collective conformational changes that open the quinone chamber bottleneck. The model predicts a significant reduction—due to a need for a rare opening of the bottleneck—of the effective bi-molecular rate constant, in line with the available kinetic data. We discuss possible reasons for such a tight control of the quinone passage into the binding chamber and mechanistic consequences for the quinone two-electron reduction.
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24
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Parey K, Lasham J, Mills DJ, Djurabekova A, Haapanen O, Yoga EG, Xie H, Kühlbrandt W, Sharma V, Vonck J, Zickermann V. High-resolution structure and dynamics of mitochondrial complex I-Insights into the proton pumping mechanism. SCIENCE ADVANCES 2021; 7:eabj3221. [PMID: 34767441 PMCID: PMC8589321 DOI: 10.1126/sciadv.abj3221] [Citation(s) in RCA: 53] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/05/2021] [Accepted: 09/24/2021] [Indexed: 05/23/2023]
Abstract
Mitochondrial NADH:ubiquinone oxidoreductase (complex I) is a 1-MDa membrane protein complex with a central role in energy metabolism. Redox-driven proton translocation by complex I contributes substantially to the proton motive force that drives ATP synthase. Several structures of complex I from bacteria and mitochondria have been determined, but its catalytic mechanism has remained controversial. We here present the cryo-EM structure of complex I from Yarrowia lipolytica at 2.1-Å resolution, which reveals the positions of more than 1600 protein-bound water molecules, of which ~100 are located in putative proton translocation pathways. Another structure of the same complex under steady-state activity conditions at 3.4-Å resolution indicates conformational transitions that we associate with proton injection into the central hydrophilic axis. By combining high-resolution structural data with site-directed mutagenesis and large-scale molecular dynamic simulations, we define details of the proton translocation pathways and offer insights into the redox-coupled proton pumping mechanism of complex I.
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Affiliation(s)
- Kristian Parey
- Institute of Biochemistry II, University Hospital, Goethe University, 60590 Frankfurt am Main, Germany
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
| | - Jonathan Lasham
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland
| | - Deryck J. Mills
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Amina Djurabekova
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland
| | - Outi Haapanen
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland
| | - Etienne Galemou Yoga
- Institute of Biochemistry II, University Hospital, Goethe University, 60590 Frankfurt am Main, Germany
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
| | - Hao Xie
- Department of Molecular Membrane Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Werner Kühlbrandt
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Vivek Sharma
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland
- HiLIFE Institute of Biotechnology, University of Helsinki, 00014 Helsinki, Finland
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Volker Zickermann
- Institute of Biochemistry II, University Hospital, Goethe University, 60590 Frankfurt am Main, Germany
- Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, 60438 Frankfurt am Main, Germany
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25
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Róg T, Girych M, Bunker A. Mechanistic Understanding from Molecular Dynamics in Pharmaceutical Research 2: Lipid Membrane in Drug Design. Pharmaceuticals (Basel) 2021; 14:1062. [PMID: 34681286 PMCID: PMC8537670 DOI: 10.3390/ph14101062] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 11/17/2022] Open
Abstract
We review the use of molecular dynamics (MD) simulation as a drug design tool in the context of the role that the lipid membrane can play in drug action, i.e., the interaction between candidate drug molecules and lipid membranes. In the standard "lock and key" paradigm, only the interaction between the drug and a specific active site of a specific protein is considered; the environment in which the drug acts is, from a biophysical perspective, far more complex than this. The possible mechanisms though which a drug can be designed to tinker with physiological processes are significantly broader than merely fitting to a single active site of a single protein. In this paper, we focus on the role of the lipid membrane, arguably the most important element outside the proteins themselves, as a case study. We discuss work that has been carried out, using MD simulation, concerning the transfection of drugs through membranes that act as biological barriers in the path of the drugs, the behavior of drug molecules within membranes, how their collective behavior can affect the structure and properties of the membrane and, finally, the role lipid membranes, to which the vast majority of drug target proteins are associated, can play in mediating the interaction between drug and target protein. This review paper is the second in a two-part series covering MD simulation as a tool in pharmaceutical research; both are designed as pedagogical review papers aimed at both pharmaceutical scientists interested in exploring how the tool of MD simulation can be applied to their research and computational scientists interested in exploring the possibility of a pharmaceutical context for their research.
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Affiliation(s)
- Tomasz Róg
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland;
| | - Mykhailo Girych
- Department of Physics, University of Helsinki, 00014 Helsinki, Finland;
| | - Alex Bunker
- Drug Research Program, Division of Pharmaceutical Biosciences, Faculty of Pharmacy, University of Helsinki, 00014 Helsinki, Finland;
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26
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Schimpf J, Oppermann S, Gerasimova T, Santos Seica AF, Hellwig P, Grishkovskaya I, Wohlwend D, Haselbach D, Friedrich T. Structure of the peripheral arm of a minimalistic respiratory complex I. Structure 2021; 30:80-94.e4. [PMID: 34562374 DOI: 10.1016/j.str.2021.09.005] [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: 03/04/2021] [Revised: 07/09/2021] [Accepted: 09/08/2021] [Indexed: 10/20/2022]
Abstract
Respiratory complex I drives proton translocation across energy-transducing membranes by NADH oxidation coupled with (ubi)quinone reduction. In humans, its dysfunction is associated with neurodegenerative diseases. The Escherichia coli complex represents the structural minimal form of an energy-converting NADH:ubiquinone oxidoreductase. Here, we report the structure of the peripheral arm of the E. coli complex I consisting of six subunits, the FMN cofactor, and nine iron-sulfur clusters at 2.7 Å resolution obtained by cryo electron microscopy. While the cofactors are in equivalent positions as in the complex from other species, individual subunits are adapted to the absence of supernumerary proteins to guarantee structural stability. The catalytically important subunits NuoC and D are fused resulting in a specific architecture of functional importance. Striking features of the E. coli complex are scrutinized by mutagenesis and biochemical characterization of the variants. Moreover, the arrangement of the subunits sheds light on the unknown assembly of the complex.
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Affiliation(s)
- Johannes Schimpf
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Sabrina Oppermann
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Tatjana Gerasimova
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany; Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CMC, Université de Strasbourg CNRS, 4 Rue Blaise Pascal, 67081 Strasbourg, France
| | - Ana Filipa Santos Seica
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CMC, Université de Strasbourg CNRS, 4 Rue Blaise Pascal, 67081 Strasbourg, France
| | - Petra Hellwig
- Laboratoire de Bioélectrochimie et Spectroscopie, UMR 7140, CMC, Université de Strasbourg CNRS, 4 Rue Blaise Pascal, 67081 Strasbourg, France; University of Strasbourg, Institute for Advanced Studies (USIAS), 5 Allée du Général Rouvillois, 67083 Strasbourg, France
| | - Irina Grishkovskaya
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Daniel Wohlwend
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - David Haselbach
- Research Institute of Molecular Pathology (IMP), Campus-Vienna-Biocenter 1, 1030 Vienna, Austria
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany.
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27
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Abstract
The electron transport chain of mitochondria is initiated by the respiratory complex I that converts chemical energy into a proton motive force to power synthesis of adenosine triphosphate. On a chemical level, complex I catalyzes elementary electron and proton transfer processes that couple across large molecular distances of >300 Å. However, under low oxygen concentrations, the respiratory chain operates in reverse mode and produces harmful reactive oxygen species. To avoid cell damage, the mitochondrial complex I transitions into a deactive state that inhibits turnover by molecular principles that remain elusive. By combining large-scale molecular simulations with cryo-electron microscopy data, we show here that complex I deactivation blocks the communication between proton pumping and redox modules by conformational and hydration changes. Cellular respiration is powered by membrane-bound redox enzymes that convert chemical energy into an electrochemical proton gradient and drive the energy metabolism. By combining large-scale classical and quantum mechanical simulations with cryo-electron microscopy data, we resolve here molecular details of conformational changes linked to proton pumping in the mammalian complex I. Our data suggest that complex I deactivation blocks water-mediated proton transfer between a membrane-bound quinone site and proton-pumping modules, decoupling the energy-transduction machinery. We identify a putative gating region at the interface between membrane domain subunits ND1 and ND3/ND4L/ND6 that modulates the proton transfer by conformational changes in transmembrane helices and bulky residues. The region is perturbed by mutations linked to human mitochondrial disorders and is suggested to also undergo conformational changes during catalysis of simpler complex I variants that lack the “active”-to-“deactive” transition. Our findings suggest that conformational changes in transmembrane helices modulate the proton transfer dynamics by wetting/dewetting transitions and provide important functional insight into the mammalian respiratory complex I.
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28
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Biochemical consequences of two clinically relevant ND-gene mutations in Escherichia coli respiratory complex I. Sci Rep 2021; 11:12641. [PMID: 34135385 PMCID: PMC8209014 DOI: 10.1038/s41598-021-91631-3] [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] [Received: 02/01/2021] [Accepted: 05/28/2021] [Indexed: 11/28/2022] Open
Abstract
NADH:ubiquinone oxidoreductase (respiratory complex I) plays a major role in energy metabolism by coupling electron transfer from NADH to quinone with proton translocation across the membrane. Complex I deficiencies were found to be the most common source of human mitochondrial dysfunction that manifest in a wide variety of neurodegenerative diseases. Seven subunits of human complex I are encoded by mitochondrial DNA (mtDNA) that carry an unexpectedly large number of mutations discovered in mitochondria from patients’ tissues. However, whether or how these genetic aberrations affect complex I at a molecular level is unknown. Here, we used Escherichia coli as a model system to biochemically characterize two mutations that were found in mtDNA of patients. The V253AMT-ND5 mutation completely disturbed the assembly of complex I, while the mutation D199GMT-ND1 led to the assembly of a stable complex capable to catalyze redox-driven proton translocation. However, the latter mutation perturbs quinone reduction leading to a diminished activity. D199MT-ND1 is part of a cluster of charged amino acid residues that are suggested to be important for efficient coupling of quinone reduction and proton translocation. A mechanism considering the role of D199MT-ND1 for energy conservation in complex I is discussed.
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29
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Nuber F, Mérono L, Oppermann S, Schimpf J, Wohlwend D, Friedrich T. A Quinol Anion as Catalytic Intermediate Coupling Proton Translocation With Electron Transfer in E. coli Respiratory Complex I. Front Chem 2021; 9:672969. [PMID: 34026733 PMCID: PMC8138167 DOI: 10.3389/fchem.2021.672969] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Accepted: 04/09/2021] [Indexed: 11/18/2022] Open
Abstract
Energy-converting NADH:ubiquinone oxidoreductase, respiratory complex I, plays a major role in cellular energy metabolism. It couples NADH oxidation and quinone reduction with the translocation of protons across the membrane, thus contributing to the protonmotive force. Complex I has an overall L-shaped structure with a peripheral arm catalyzing electron transfer and a membrane arm engaged in proton translocation. Although both reactions are arranged spatially separated, they are tightly coupled by a mechanism that is not fully understood. Using redox-difference UV-vis spectroscopy, an unknown redox component was identified in Escherichia coli complex I as reported earlier. A comparison of its spectrum with those obtained for different quinone species indicates features of a quinol anion. The re-oxidation kinetics of the quinol anion intermediate is significantly slower in the D213GH variant that was previously shown to operate with disturbed quinone chemistry. Addition of the quinone-site inhibitor piericidin A led to strongly decreased absorption peaks in the difference spectrum. A hypothesis for a mechanism of proton-coupled electron transfer with the quinol anion as catalytically important intermediate in complex I is discussed.
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Affiliation(s)
- Franziska Nuber
- Institut für Biochemie, Albert-Ludwigs-Universität, Freiburg, Germany
| | - Luca Mérono
- Institut für Biochemie, Albert-Ludwigs-Universität, Freiburg, Germany
| | - Sabrina Oppermann
- Institut für Biochemie, Albert-Ludwigs-Universität, Freiburg, Germany
| | - Johannes Schimpf
- Institut für Biochemie, Albert-Ludwigs-Universität, Freiburg, Germany
| | - Daniel Wohlwend
- Institut für Biochemie, Albert-Ludwigs-Universität, Freiburg, Germany
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30
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Galemou Yoga E, Schiller J, Zickermann V. Ubiquinone Binding and Reduction by Complex I-Open Questions and Mechanistic Implications. Front Chem 2021; 9:672851. [PMID: 33996767 PMCID: PMC8119997 DOI: 10.3389/fchem.2021.672851] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2021] [Accepted: 04/06/2021] [Indexed: 11/13/2022] Open
Abstract
NADH: ubiquinone oxidoreductase (complex I) is the first enzyme complex of the respiratory chain. Complex I is a redox-driven proton pump that contributes to the proton motive force that drives ATP synthase. The structure of complex I has been analyzed by x-ray crystallography and electron cryo-microscopy and is now well-described. The ubiquinone (Q) reduction site of complex I is buried in the peripheral arm and a tunnel-like structure is thought to provide access for the hydrophobic substrate from the membrane. Several intermediate binding positions for Q in the tunnel were identified in molecular simulations. Structural data showed the binding of native Q molecules and short chain analogs and inhibitors in the access pathway and in the Q reduction site, respectively. We here review the current knowledge on the interaction of complex I with Q and discuss recent hypothetical models for the coupling mechanism.
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Affiliation(s)
- Etienne Galemou Yoga
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt, Germany.,Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Jonathan Schiller
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt, Germany.,Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany
| | - Volker Zickermann
- Institute of Biochemistry II, University Hospital, Goethe University, Frankfurt, Germany.,Centre for Biomolecular Magnetic Resonance, Institute for Biophysical Chemistry, Goethe University, Frankfurt, Germany
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31
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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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32
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Masuya T, Uno S, Murai M, Miyoshi H. Pinpoint Dual Chemical Cross-Linking Explores the Structural Dynamics of the Ubiquinone Reaction Site in Mitochondrial Complex I. Biochemistry 2021; 60:813-824. [PMID: 33650850 DOI: 10.1021/acs.biochem.0c00991] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The ubiquinone reduction step in NADH-ubiquinone oxidoreductase (complex I) is the key to triggering proton translocation in its membrane part. Although the existence of a long and narrow quinone-access channel has been identified, it remains debatable whether the channel model can account for binding of various ligands (ubiquinones and inhibitors) to the enzyme. We previously proposed that the matrix-side interfacial region of the 49 kDa, ND1, PSST, and 39 kDa subunits, which is covered by a loop connecting transmembrane helices (TMHs) 1 and 2 of ND3, may be the area for entry of some bulky ligands into the quinone reaction cavity. However, this proposition lacks direct evidence that the cavity is accessible from the putative matrix-side region, which allows ligands to pass. To address this, we examined whether Cys39 of ND3 and Asp160 of 49 kDa can be specifically cross-linked by bifunctional cross-linkers (tetrazine-maleimide hybrid, named TMBC). On the basis of the structural models of complex I, such dual cross-linking is unexpected because ND3 Cys39 and 49 kDa Asp160 are located on the TMH1-2 loop and deep inside the channel, respectively, and hence, they are physically separated by peptide chains forming the channel wall. However, three TMBCs with different spacer lengths did cross-link the two residues, resulting in the formation of new cross-linked ND3/49 kDa subunits. Chemical modification of either ND3 Cys39 or 49 kDa Asp160 blocked the dual cross-linking, ensuring the specificity of the cross-linking. Altogether, this study provides direct evidence that the quinone reaction cavity is indeed accessible from the proposed matrix-side region covered by the ND3 TMH1-2 loop.
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Affiliation(s)
- Takahiro Masuya
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Shinpei Uno
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
| | - Hideto Miyoshi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University, Kyoto 606-8502, Japan
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33
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Bennett JP, Onyango IG. Energy, Entropy and Quantum Tunneling of Protons and Electrons in Brain Mitochondria: Relation to Mitochondrial Impairment in Aging-Related Human Brain Diseases and Therapeutic Measures. Biomedicines 2021; 9:225. [PMID: 33671585 PMCID: PMC7927033 DOI: 10.3390/biomedicines9020225] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2021] [Revised: 02/18/2021] [Accepted: 02/18/2021] [Indexed: 11/16/2022] Open
Abstract
Adult human brains consume a disproportionate amount of energy substrates (2-3% of body weight; 20-25% of total glucose and oxygen). Adenosine triphosphate (ATP) is a universal energy currency in brains and is produced by oxidative phosphorylation (OXPHOS) using ATP synthase, a nano-rotor powered by the proton gradient generated from proton-coupled electron transfer (PCET) in the multi-complex electron transport chain (ETC). ETC catalysis rates are reduced in brains from humans with neurodegenerative diseases (NDDs). Declines of ETC function in NDDs may result from combinations of nitrative stress (NS)-oxidative stress (OS) damage; mitochondrial and/or nuclear genomic mutations of ETC/OXPHOS genes; epigenetic modifications of ETC/OXPHOS genes; or defects in importation or assembly of ETC/OXPHOS proteins or complexes, respectively; or alterations in mitochondrial dynamics (fusion, fission, mitophagy). Substantial free energy is gained by direct O2-mediated oxidation of NADH. Traditional ETC mechanisms require separation between O2 and electrons flowing from NADH/FADH2 through the ETC. Quantum tunneling of electrons and much larger protons may facilitate this separation. Neuronal death may be viewed as a local increase in entropy requiring constant energy input to avoid. The ATP requirement of the brain may partially be used for avoidance of local entropy increase. Mitochondrial therapeutics seeks to correct deficiencies in ETC and OXPHOS.
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Affiliation(s)
| | - Isaac G. Onyango
- International Clinical Research Center, St. Anne’s University Hospital, CZ-65691 Brno, Czech Republic;
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34
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Di Luca A, Kaila VRI. Molecular strain in the active/deactive-transition modulates domain coupling in respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2021; 1862:148382. [PMID: 33513365 DOI: 10.1016/j.bbabio.2021.148382] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Revised: 01/08/2021] [Accepted: 01/21/2021] [Indexed: 12/14/2022]
Abstract
Complex I functions as a primary redox-driven proton pump in aerobic respiratory chains, establishing a proton motive force that powers ATP synthesis and active transport. Recent cryo-electron microscopy (cryo-EM) experiments have resolved the mammalian complex I in the biomedically relevant active (A) and deactive (D) states (Zhu et al., 2016; Fiedorczuk et al., 2016; Agip et al., 2018 [1-3]) that could regulate enzyme turnover, but it still remains unclear how the conformational state and activity are linked. We show here how global motion along the A/D transition accumulates molecular strain at specific coupling regions important for both redox chemistry and proton pumping. Our data suggest that the A/D motion modulates force propagation pathways between the substrate-binding site and the proton pumping machinery that could alter electrostatic and conformational coupling across large distances. Our findings provide a molecular basis to understand how global protein dynamics can modulate the biological activity of large molecular complexes.
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Affiliation(s)
- Andrea Di Luca
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, 10691 Stockholm, Sweden.
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35
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Röpke M, Saura P, Riepl D, Pöverlein MC, Kaila VRI. Functional Water Wires Catalyze Long-Range Proton Pumping in the Mammalian Respiratory Complex I. J Am Chem Soc 2020; 142:21758-21766. [PMID: 33325238 PMCID: PMC7785131 DOI: 10.1021/jacs.0c09209] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
The respiratory complex I is a gigantic
(1 MDa) redox-driven proton
pump that reduces the ubiquinone pool and generates proton motive
force to power ATP synthesis in mitochondria. Despite resolved molecular
structures and biochemical characterization of the enzyme from multiple
organisms, its long-range (∼300 Å) proton-coupled electron
transfer (PCET) mechanism remains unsolved. We employ here microsecond
molecular dynamics simulations to probe the dynamics of the mammalian
complex I in combination with hybrid quantum/classical (QM/MM) free
energy calculations to explore how proton pumping reactions are triggered
within its 200 Å wide membrane domain. Our simulations predict
extensive hydration dynamics of the antiporter-like subunits in complex
I that enable lateral proton transfer reactions on a microsecond time
scale. We further show how the coupling between conserved ion pairs
and charged residues modulate the proton transfer dynamics, and how
transmembrane helices and gating residues control the hydration process.
Our findings suggest that the mammalian complex I pumps protons by
tightly linked conformational and electrostatic coupling principles.
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Affiliation(s)
- Michael Röpke
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748 Garching, Germany
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Daniel Riepl
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Maximilian C Pöverlein
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.,Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748 Garching, Germany
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36
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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: 25] [Impact Index Per Article: 6.3] [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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37
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Abstract
Respiratory complex I (NADH:ubiquinone oxidoreductase) captures the free energy from oxidising NADH and reducing ubiquinone to drive protons across the mitochondrial inner membrane and power oxidative phosphorylation. Recent cryo-EM analyses have produced near-complete models of the mammalian complex, but leave the molecular principles of its long-range energy coupling mechanism open to debate. Here, we describe the 3.0-Å resolution cryo-EM structure of complex I from mouse heart mitochondria with a substrate-like inhibitor, piericidin A, bound in the ubiquinone-binding active site. We combine our structural analyses with both functional and computational studies to demonstrate competitive inhibitor binding poses and provide evidence that two inhibitor molecules bind end-to-end in the long substrate binding channel. Our findings reveal information about the mechanisms of inhibition and substrate reduction that are central for understanding the principles of energy transduction in mammalian complex I. The respiratory complex I (NADH:ubiquinone oxidoreductase) is a large redox-driven proton pump that initiates respiration in mitochondria. Here, the authors present the 3.0 Å cryo-EM structure of complex I from mouse heart mitochondria with the ubiquinone-analogue inhibitor piericidin A bound in the active site and with kinetic measurements and MD simulations they further show that this inhibitor acts competitively against the native ubiquinone-10 substrate.
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38
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Melo MCR, Bernardi RC, de la Fuente-Nunez C, Luthey-Schulten Z. Generalized correlation-based dynamical network analysis: a new high-performance approach for identifying allosteric communications in molecular dynamics trajectories. J Chem Phys 2020; 153:134104. [DOI: 10.1063/5.0018980] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Affiliation(s)
- Marcelo C. R. Melo
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Penn Institute for Computational Science, and Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Rafael C. Bernardi
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
- Department of Physics, Auburn University, Auburn, Alabama 36849, USA
| | - Cesar de la Fuente-Nunez
- Machine Biology Group, Departments of Psychiatry and Microbiology, Institute for Biomedical Informatics, Institute for Translational Medicine and Therapeutics, Perelman School of Medicine, Penn Institute for Computational Science, and Department of Bioengineering, University of Pennsylvania, Philadelphia, Pennsylvania 19104, USA
| | - Zaida Luthey-Schulten
- Center for Biophysics and Computational Biology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
- Department of Chemistry, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
- Beckman Institute for Advanced Science and Technology, University of Illinois at Urbana-Champaign, Champaign, Illinois 61801, USA
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39
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Grba DN, Hirst J. Mitochondrial complex I structure reveals ordered water molecules for catalysis and proton translocation. Nat Struct Mol Biol 2020; 27:892-900. [PMID: 32747785 PMCID: PMC7612091 DOI: 10.1038/s41594-020-0473-x] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Accepted: 06/26/2020] [Indexed: 01/09/2023]
Abstract
Mitochondrial complex I powers ATP synthesis by oxidative phosphorylation, exploiting the energy from ubiquinone reduction by NADH to drive protons across the energy-transducing inner membrane. Recent cryo-EM analyses of mammalian and yeast complex I have revolutionized structural and mechanistic knowledge and defined structures in different functional states. Here, we describe a 2.7-Å-resolution structure of the 42-subunit complex I from the yeast Yarrowia lipolytica containing 275 structured water molecules. We identify a proton-relay pathway for ubiquinone reduction and water molecules that connect mechanistically crucial elements and constitute proton-translocation pathways through the membrane. By comparison with known structures, we deconvolute structural changes governing the mammalian 'deactive transition' (relevant to ischemia-reperfusion injury) and their effects on the ubiquinone-binding site and a connected cavity in ND1. Our structure thus provides important insights into catalysis by this enigmatic respiratory machine.
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Affiliation(s)
- Daniel N Grba
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK
| | - Judy Hirst
- The Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Cambridge, UK.
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40
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Kampjut D, Sazanov LA. The coupling mechanism of mammalian respiratory complex I. Science 2020; 370:science.abc4209. [PMID: 32972993 DOI: 10.1126/science.abc4209] [Citation(s) in RCA: 129] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Accepted: 09/08/2020] [Indexed: 12/16/2022]
Abstract
Mitochondrial complex I couples NADH:ubiquinone oxidoreduction to proton pumping by an unknown mechanism. Here, we present cryo-electron microscopy structures of ovine complex I in five different conditions, including turnover, at resolutions up to 2.3 to 2.5 angstroms. Resolved water molecules allowed us to experimentally define the proton translocation pathways. Quinone binds at three positions along the quinone cavity, as does the inhibitor rotenone that also binds within subunit ND4. Dramatic conformational changes around the quinone cavity couple the redox reaction to proton translocation during open-to-closed state transitions of the enzyme. In the induced deactive state, the open conformation is arrested by the ND6 subunit. We propose a detailed molecular coupling mechanism of complex I, which is an unexpected combination of conformational changes and electrostatic interactions.
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Affiliation(s)
- Domen Kampjut
- IST Austria, Am Campus 1, 3400 Klosterneuburg, Austria
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41
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Melin F, Hellwig P. Redox Properties of the Membrane Proteins from the Respiratory Chain. Chem Rev 2020; 120:10244-10297. [DOI: 10.1021/acs.chemrev.0c00249] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Frederic Melin
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
| | - Petra Hellwig
- Chimie de la Matière Complexe UMR 7140, Laboratoire de Bioelectrochimie et Spectroscopie, CNRS-Université de Strasbourg, 1 rue Blaise Pascal, 67070 Strasbourg, France
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42
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Gutiérrez-Fernández J, Kaszuba K, Minhas GS, Baradaran R, Tambalo M, Gallagher DT, Sazanov LA. Key role of quinone in the mechanism of respiratory complex I. Nat Commun 2020; 11:4135. [PMID: 32811817 PMCID: PMC7434922 DOI: 10.1038/s41467-020-17957-0] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Accepted: 07/28/2020] [Indexed: 01/12/2023] Open
Abstract
Complex I is the first and the largest enzyme of respiratory chains in bacteria and mitochondria. The mechanism which couples spatially separated transfer of electrons to proton translocation in complex I is not known. Here we report five crystal structures of T. thermophilus enzyme in complex with NADH or quinone-like compounds. We also determined cryo-EM structures of major and minor native states of the complex, differing in the position of the peripheral arm. Crystal structures show that binding of quinone-like compounds (but not of NADH) leads to a related global conformational change, accompanied by local re-arrangements propagating from the quinone site to the nearest proton channel. Normal mode and molecular dynamics analyses indicate that these are likely to represent the first steps in the proton translocation mechanism. Our results suggest that quinone binding and chemistry play a key role in the coupling mechanism of complex I. Complex I (NADH:ubiquinone oxidoreductase) is the first enzyme of the respiratory chain in bacteria and mitochondria. Here, the authors present cryo-EM and crystal structures of T. thermophilus complex I in different conformational states and further analyse them by Normal Mode Analysis and molecular dynamics simulations and conclude that quinone redox reactions are important for the coupling mechanism of complex I.
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Affiliation(s)
| | - Karol Kaszuba
- Institute of Science and Technology Austria, Am Campus 1, A-3400, Klosterneuburg, Austria
| | - Gurdeep S Minhas
- Medical Research Council Mitochondrial Biology Unit, Keith Peters Building, Hills rd, Cambridge, CB2 0XY, UK.,Sosei Heptares, Steinmetz Building, Granta Park, Cambridge, CB21 6DG, UK
| | - Rozbeh Baradaran
- Medical Research Council Mitochondrial Biology Unit, Keith Peters Building, Hills rd, Cambridge, CB2 0XY, UK.,Science for Life Laboratory, Department of Biochemistry and Biophysics, Stockholm University, 17165, Solna, Sweden
| | - Margherita Tambalo
- Institute of Science and Technology Austria, Am Campus 1, A-3400, Klosterneuburg, Austria
| | - David T Gallagher
- Medical Research Council Mitochondrial Biology Unit, Keith Peters Building, Hills rd, Cambridge, CB2 0XY, UK
| | - Leonid A Sazanov
- Institute of Science and Technology Austria, Am Campus 1, A-3400, Klosterneuburg, Austria.
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43
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Haapanen O, Reidelbach M, Sharma V. Coupling of quinone dynamics to proton pumping in respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148287. [PMID: 32777307 DOI: 10.1016/j.bbabio.2020.148287] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/23/2020] [Revised: 07/09/2020] [Accepted: 08/03/2020] [Indexed: 12/12/2022]
Abstract
Respiratory complex I (NADH:quinone oxidoreductase) plays a central role in generating the proton electrochemical gradient in mitochondrial and bacterial membranes, which is needed to generate ATP. Several high-resolution structures of complex I have been determined, revealing its intricate architecture and complementing the biochemical and biophysical studies. However, the molecular mechanism of long-range coupling between ubiquinone (Q) reduction and proton pumping is not known. Computer simulations have been applied to decipher the dynamics of Q molecule in the ~30 Å long Q tunnel. In this short report, we discuss the binding and dynamics of Q at computationally predicted Q binding sites, many of which are supported by structural data on complex I. We suggest that the binding of Q at these sites is coupled to proton pumping by means of conformational rearrangements in the conserved loops of core subunits.
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Affiliation(s)
- Outi Haapanen
- Department of Physics, University of Helsinki, Finland
| | | | - Vivek Sharma
- Department of Physics, University of Helsinki, Finland; HiLIFE Institute of Biotechnology, University of Helsinki, Finland.
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44
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Mühlbauer ME, Saura P, Nuber F, Di Luca A, Friedrich T, Kaila VRI. Water-Gated Proton Transfer Dynamics in Respiratory Complex I. J Am Chem Soc 2020; 142:13718-13728. [PMID: 32643371 PMCID: PMC7659035 DOI: 10.1021/jacs.0c02789] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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The respiratory complex I transduces
redox energy into an electrochemical
proton gradient in aerobic respiratory chains, powering energy-requiring
processes in the cell. However, despite recently resolved molecular
structures, the mechanism of this gigantic enzyme remains poorly understood.
By combining large-scale quantum and classical simulations with site-directed
mutagenesis and biophysical experiments, we show here how the conformational
state of buried ion-pairs and water molecules control the protonation
dynamics in the membrane domain of complex I and establish evolutionary
conserved long-range coupling elements. We suggest that an electrostatic
wave propagates in forward and reverse directions across the 200 Å
long membrane domain during enzyme turnover, without significant dissipation
of energy. Our findings demonstrate molecular principles that enable
efficient long-range proton–electron coupling (PCET) and how
perturbation of this PCET machinery may lead to development of mitochondrial
disease.
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Affiliation(s)
- Max E Mühlbauer
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.,Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748 Garching, Germany
| | - Patricia Saura
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.,Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748 Garching, Germany
| | - Franziska Nuber
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Andrea Di Luca
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.,Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748 Garching, Germany
| | - Thorsten Friedrich
- Institut für Biochemie, Albert-Ludwigs-Universität Freiburg, Albertstrasse 21, 79104 Freiburg, Germany
| | - Ville R I Kaila
- Department of Biochemistry and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden.,Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748 Garching, Germany
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45
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Khaniya U, Gupta C, Cai X, Mao J, Kaur D, Zhang Y, Singharoy A, Gunner MR. Hydrogen bond network analysis reveals the pathway for the proton transfer in the E-channel of T. thermophilus Complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148240. [PMID: 32531220 DOI: 10.1016/j.bbabio.2020.148240] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 05/19/2020] [Accepted: 06/03/2020] [Indexed: 10/24/2022]
Abstract
Complex I, NADH-ubiquinone oxidoreductase, is the first enzyme in the mitochondrial and bacterial aerobic respiratory chain. It pumps four protons through four transiently open pathways from the high pH, negative, N-side of the membrane to the positive, P-side driven by the exergonic transfer of electrons from NADH to a quinone. Three protons transfer through subunits descended from antiporters, while the fourth, E-channel is unique. The path through the E-channel is determined by a network analysis of hydrogen bonded pathways obtained by Monte Carlo sampling of protonation states, polar hydrogen orientation and water occupancy. Input coordinates are derived from molecular dynamics trajectories comparing oxidized, reduced (dihydro) and no menaquinone-8 (MQ). A complex proton transfer path from the N- to the P-side is found consisting of six clusters of highly connected hydrogen-bonded residues. The network connectivity depends on the presence of quinone and its redox state, supporting a role for this cofactor in coupling electron and proton transfers. The N-side is more organized with MQ-bound complex I facilitating proton entry, while the P-side is more connected in the apo-protein, facilitating proton exit. Subunit Nqo8 forms the core of the E channel; Nqo4 provides the N-side entry, Nqo7 and then Nqo10 join the pathway in the middle, while Nqo11 contributes to the P-side exit.
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Affiliation(s)
- Umesh Khaniya
- Department of Physics, City College of New York, New York 10031, USA; Department of Physics, The Graduate Center, City University of New York, New York 10016, USA
| | - Chitrak Gupta
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA; Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - Xiuhong Cai
- Department of Physics, City College of New York, New York 10031, USA; Department of Physics, The Graduate Center, City University of New York, New York 10016, USA
| | - Junjun Mao
- Department of Physics, City College of New York, New York 10031, USA
| | - Divya Kaur
- Department of Physics, City College of New York, New York 10031, USA; Department of Chemistry, The Graduate Center, City University of New York, New York 10016, USA
| | - Yingying Zhang
- Department of Physics, City College of New York, New York 10031, USA; Department of Physics, The Graduate Center, City University of New York, New York 10016, USA
| | - Abhishek Singharoy
- School of Molecular Sciences, Arizona State University, Tempe, AZ, USA; Biodesign Institute, Arizona State University, Tempe, AZ, USA
| | - M R Gunner
- Department of Physics, City College of New York, New York 10031, USA; Department of Physics, The Graduate Center, City University of New York, New York 10016, USA; Department of Chemistry, The Graduate Center, City University of New York, New York 10016, USA.
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46
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Murai M. Exploring the binding pocket of quinone/inhibitors in mitochondrial respiratory complex I by chemical biology approaches. Biosci Biotechnol Biochem 2020; 84:1322-1331. [PMID: 32264779 DOI: 10.1080/09168451.2020.1747974] [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] [Indexed: 02/08/2023]
Abstract
NADH-quinone oxidoreductase (respiratory complex I) is a key player in mitochondrial energy metabolism. The enzyme couples electron transfer from NADH to quinone with the translocation of protons across the membrane, providing a major proton-motive force that drives ATP synthesis. Recently, X-ray crystallography and cryo-electron microscopy provided further insights into the structure and functions of the enzyme. However, little is known about the mechanism of quinone reduction, which is a crucial step in the energy coupling process. A variety of complex I inhibitors targeting the quinone-binding site have been indispensable tools for mechanistic studies on the enzyme. Using biorationally designed inhibitor probes, the author has accumulated a large amount of experimental data characterizing the actions of complex I inhibitors. On the basis of comprehensive interpretations of the data, the author reviews the structural features of the binding pocket of quinone/inhibitors in bovine mitochondrial complex I. ABBREVIATIONS ATP: adenosine triphosphate; BODIPY: boron dipyrromethene; complex I: proton-translocating NADH-quinone oxidoreductase; DIBO: dibenzocyclooctyne; EM: electron microscopy; FeS: iron-sulfur; FMN: flavin adenine mononucleotide; LDT: ligand-directed tosylate; NADH: nicotinamide adenine dinucleotide; ROS: reactive oxygen species; SMP: submitochondrial particle; TAMRA: 6-carboxy-N,N,N',N'-tetramethylrhodamine; THF: tetrahydrofuran; TMH: transmembrane helix.
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Affiliation(s)
- Masatoshi Murai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University , Kyoto, Japan
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47
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Saura P, Röpke M, Gamiz-Hernandez AP, Kaila VRI. Quantum Chemical and QM/MM Models in Biochemistry. Methods Mol Biol 2020; 2022:75-104. [PMID: 31396900 DOI: 10.1007/978-1-4939-9608-7_4] [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] [Indexed: 02/25/2023]
Abstract
Quantum chemical (QC) calculations provide a basis for deriving a microscopic understanding of enzymes and photobiological systems. Here we describe how QC models can be used to explore the electronic structure, dynamics, and energetics of biomolecules. We introduce the hybrid quantum mechanics/classical mechanics (QM/MM) approach, where a quantum mechanically described system of interest is embedded in a classically described force field representation of the biochemical surroundings. We also discuss the QM cluster model approach, as well as embedding theories, that provide complementary methodologies to model quantum mechanical effects in biomolecules. The chapter also provides some practical guides for building quantum biochemical models using the quinone reduction catalysis in respiratory complex I and a model reaction in solution as examples.
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Affiliation(s)
- Patricia Saura
- Department Chemie, Technische Universität München, Garching, Germany
| | - Michael Röpke
- Department Chemie, Technische Universität München, Garching, Germany
| | | | - Ville R I Kaila
- Department Chemie, Technische Universität München, Garching, Germany.
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48
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Djurabekova A, Haapanen O, Sharma V. Proton motive function of the terminal antiporter-like subunit in respiratory complex I. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2020; 1861:148185. [PMID: 32171794 DOI: 10.1016/j.bbabio.2020.148185] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2019] [Revised: 01/15/2020] [Accepted: 03/09/2020] [Indexed: 12/20/2022]
Abstract
In the aerobic respiratory chains of many organisms, complex I functions as the first electron input. By reducing ubiquinone (Q) to ubiquinol, it catalyzes the translocation of protons across the membrane as far as ~200 Å from the site of redox reactions. Despite significant amount of structural and biochemical data, the details of redox coupled proton pumping in complex I are poorly understood. In particular, the proton transfer pathways are extremely difficult to characterize with the current structural and biochemical techniques. Here, we applied multiscale computational approaches to identify the proton transfer paths in the terminal antiporter-like subunit of complex I. Data from combined classical and quantum chemical simulations reveal for the first time structural elements that are exclusive to the subunit, and enables the enzyme to achieve coupling between the spatially separated Q redox reactions and proton pumping. By studying long time scale protonation and hydration dependent conformational dynamics of key amino acid residues, we provide novel insights into the proton pumping mechanism of complex I.
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Affiliation(s)
| | - Outi Haapanen
- Department of Physics, University of Helsinki, Helsinki, Finland
| | - Vivek Sharma
- Department of Physics, University of Helsinki, Helsinki, Finland; Institute of Biotechnology, University of Helsinki, Helsinki, Finland.
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49
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Mader SL, Lopez A, Lawatscheck J, Luo Q, Rutz DA, Gamiz-Hernandez AP, Sattler M, Buchner J, Kaila VRI. Conformational dynamics modulate the catalytic activity of the molecular chaperone Hsp90. Nat Commun 2020; 11:1410. [PMID: 32179743 PMCID: PMC7075974 DOI: 10.1038/s41467-020-15050-0] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2018] [Accepted: 02/16/2020] [Indexed: 12/31/2022] Open
Abstract
The heat shock protein 90 (Hsp90) is a molecular chaperone that employs the free energy of ATP hydrolysis to control the folding and activation of several client proteins in the eukaryotic cell. To elucidate how the local ATPase reaction in the active site couples to the global conformational dynamics of Hsp90, we integrate here large-scale molecular simulations with biophysical experiments. We show that the conformational switching of conserved ion pairs between the N-terminal domain, harbouring the active site, and the middle domain strongly modulates the catalytic barrier of the ATP-hydrolysis reaction by electrostatic forces. Our combined findings provide a mechanistic model for the coupling between catalysis and protein dynamics in Hsp90, and show how long-range coupling effects can modulate enzymatic activity. The chaperone Hsp90 uses the free energy from ATP hydrolysis to control the folding of client proteins in eukaryotic cells. Here the authors provide mechanistic insights into how its catalytic activity is coupled to conformational changes by combining large-scale molecular simulations with NMR, FRET and SAXS experiments.
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Affiliation(s)
- Sophie L Mader
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany
| | - Abraham Lopez
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg, 85764, Germany
| | - Jannis Lawatscheck
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany
| | - Qi Luo
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany.,Soft Matter Research Center and Department of Chemistry, Zhejiang University, Hangzhou, 310027, China
| | - Daniel A Rutz
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany
| | - Ana P Gamiz-Hernandez
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany.,Department of Biochemistry and Biophysics, Stockholm University, SE-10691, Stockholm, Sweden
| | - Michael Sattler
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany.,Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, Neuherberg, 85764, Germany
| | - Johannes Buchner
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany
| | - Ville R I Kaila
- Center for Integrated Protein Science Munich at the Department of Chemistry, Technical University of Munich, Lichtenbergstrasse 4, D85748, Garching, Germany. .,Department of Biochemistry and Biophysics, Stockholm University, SE-10691, Stockholm, Sweden.
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50
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Reis AAO, Sayegh RSR, Marana SR, Arantes GM. Combining Free Energy Simulations and NMR Chemical-Shift Perturbation To Identify Transient Cation-π Contacts in Proteins. J Chem Inf Model 2020; 60:890-897. [PMID: 31738549 DOI: 10.1021/acs.jcim.9b00859] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Flexible protein regions containing cationic and aromatic side-chains exposed to solvent may form transient cation-π interactions with structural and functional roles. To evaluate their stability and identify important intramolecular cation-π contacts, a combination of free energy profiles estimated from umbrella sampling with molecular dynamics simulations and chemical shift perturbations (CSP) obtained from nuclear magnetic resonance (NMR) experiments is applied here to the complete catalytic domain of human phosphatase Cdc25B. This protein is a good model system for transient cation-π interactions as it contains only one Trp residue (W550) in the disordered C-terminal segment and a total of 17 Arg residues, many exposed to solvent. Eight putative Arg-Trp pairs were simulated here. Only R482 and R544 show bound profiles corresponding to important transient cation-π interactions, while the others have dissociative or almost flat profiles. These results are corroborated by CSP analysis of three Cdc25B point mutants (W550A, R482A, and R544A) disrupting cation-π contacts. The proposed validation of statistically representative molecular simulations by NMR spectroscopy could be applied to identify transient contacts of proteins in general but carefully, as NMR chemical shifts are sensitive to changes in both molecular contacts and conformational distributions.
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Affiliation(s)
- André A O Reis
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , São Paulo , Brazil
| | - Raphael S R Sayegh
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , São Paulo , Brazil
| | - Sandro R Marana
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , São Paulo , Brazil
| | - Guilherme M Arantes
- Department of Biochemistry, Instituto de Química , Universidade de São Paulo , Av. Prof. Lineu Prestes 748 , 05508-900 São Paulo , São Paulo , Brazil
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