1
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Grba DN, Wright JJ, Yin Z, Fisher W, Hirst J. Molecular mechanism of the ischemia-induced regulatory switch in mammalian complex I. Science 2024; 384:1247-1253. [PMID: 38870289 DOI: 10.1126/science.ado2075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2024] [Accepted: 05/01/2024] [Indexed: 06/15/2024]
Abstract
Respiratory complex I is an efficient driver for oxidative phosphorylation in mammalian mitochondria, but its uncontrolled catalysis under challenging conditions leads to oxidative stress and cellular damage. Ischemic conditions switch complex I from rapid, reversible catalysis into a dormant state that protects upon reoxygenation, but the molecular basis for the switch is unknown. We combined precise biochemical definition of complex I catalysis with high-resolution cryo-electron microscopy structures in the phospholipid bilayer of coupled vesicles to reveal the mechanism of the transition into the dormant state, modulated by membrane interactions. By implementing a versatile membrane system to unite structure and function, attributing catalytic and regulatory properties to specific structural states, we define how a conformational switch in complex I controls its physiological roles.
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Affiliation(s)
| | | | | | | | - Judy Hirst
- Medical Research Council Mitochondrial Biology Unit, University of Cambridge, Keith Peters Building, Cambridge Biomedical Campus, Hills Road, Cambridge CB2 0XY, UK
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2
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Zheng W, Chai P, Zhu J, Zhang K. High-resolution in situ structures of mammalian respiratory supercomplexes. Nature 2024:10.1038/s41586-024-07488-9. [PMID: 38811722 DOI: 10.1038/s41586-024-07488-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2023] [Accepted: 04/30/2024] [Indexed: 05/31/2024]
Abstract
Mitochondria play a pivotal part in ATP energy production through oxidative phosphorylation, which occurs within the inner membrane through a series of respiratory complexes1-4. Despite extensive in vitro structural studies, determining the atomic details of their molecular mechanisms in physiological states remains a major challenge, primarily because of loss of the native environment during purification. Here we directly image porcine mitochondria using an in situ cryo-electron microscopy approach. This enables us to determine the structures of various high-order assemblies of respiratory supercomplexes in their native states. We identify four main supercomplex organizations: I1III2IV1, I1III2IV2, I2III2IV2 and I2III4IV2, which potentially expand into higher-order arrays on the inner membranes. These diverse supercomplexes are largely formed by 'protein-lipids-protein' interactions, which in turn have a substantial impact on the local geometry of the surrounding membranes. Our in situ structures also capture numerous reactive intermediates within these respiratory supercomplexes, shedding light on the dynamic processes of the ubiquinone/ubiquinol exchange mechanism in complex I and the Q-cycle in complex III. Structural comparison of supercomplexes from mitochondria treated under different conditions indicates a possible correlation between conformational states of complexes I and III, probably in response to environmental changes. By preserving the native membrane environment, our approach enables structural studies of mitochondrial respiratory supercomplexes in reaction at high resolution across multiple scales, from atomic-level details to the broader subcellular context.
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Affiliation(s)
- Wan Zheng
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Pengxin Chai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA
| | - Jiapeng Zhu
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, China.
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, USA.
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3
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Wang M, Wang Q, Wang X, Wang D, Yin X, Qiao Y, Ma M, Du Y, Wang B. Exploring the potential of Paris polyphylla var. yunnanensis pollen manipulation in modifying seed dormancy. FRONTIERS IN PLANT SCIENCE 2024; 15:1389357. [PMID: 38841278 PMCID: PMC11152045 DOI: 10.3389/fpls.2024.1389357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2024] [Accepted: 04/16/2024] [Indexed: 06/07/2024]
Abstract
Paris polyphylla var. yunnanensis, a well-known Chinese medicinal herb, shows a unique physiological trait characterized by the cyclic opening and closing of its anthers after pollen maturation. The aim of this study was to explore the implications of this phenomenon on breeding. RNA sequencing coupled with methylation sequencing was used to scrutinize and compare gene expression profiles and methylation alterations in pollen and seeds during anther opening and closing, along with cold exposure. Genes enriched within Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were examined to identify gene clusters susceptible to temperature-related methylation changes in both pollen and seeds. Four pollen treatment models, namely, normal control, "pollen protected from low temperatures," "pollen from just-opened anther," and "pollen from close-blocked anther," were used to produce corresponding seeds via artificial pollination. Subsequently, qRT-PCR was used to validate modifications in the expression patterns of marker genes in pollinated seeds under diverse treatment scenarios. Genes exhibiting significant differences in expression between anthers and normal tissues, along with gene regions linked to methylation variations attributed to low-temperature-treated pollen and seeds, were identified through transcriptomic analysis. Convergence was observed in three signaling pathways: oxidative phosphorylation (ko00190), plant hormone signal transduction (Ko04075), and zeatin biosynthesis (ko00908). Notably, gene clusters prone to temperature-induced methylation changes, such as NADH-ubiquinone oxidoreductase chain 5, plasma membrane ATPase 4, cytochrome c oxidase subunit 2, cis-zeatin O-glucosyltransferase, ABSCISIC ACID-INSENSITIVE 5-like protein 4, and indole-3-acetic acid-amido synthetase (IAAS), were identified. Evaluation using various pollen pollination models revealed altered expression patterns of five dormancy-regulating marker genes: IAAS, sucrose synthase (SUS), gibberellin 2-oxidase (GA2ox), ABA INSENSITIVE 2 (ABI2), and auxin-repressed protein (ARP), in seeds pollinated with pollen from close-blocked anthers, cold-protected pollen, and pollen from freshly opened anthers. The close-blocked anther treatment led to significantly upregulated expression of IAAS, SUS, GA2ox, and ABI2, whereas ARP expression decreased markedly, indicating a propensity toward prolonged seed dormancy. Conversely, in the low-temperature-protected anther model, SUS, ARP, GA2ox, and IAAS exhibited reduced expression levels, whereas the expression of ABI2 was upregulated, overall facilitating seed germination.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Bin Wang
- School of Agriculture and Life Sciences, Kunming University, Kunming, Yunnan, China
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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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Zheng W, Chai P, Zhu J, Zhang K. High-resolution In-situ Structures of Mammalian Mitochondrial Respiratory Supercomplexes in Reaction within Native Mitochondria. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.04.02.587796. [PMID: 38617346 PMCID: PMC11014577 DOI: 10.1101/2024.04.02.587796] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/16/2024]
Abstract
Mitochondria play a pivotal role in ATP energy production through oxidative phosphorylation, which occurs within the inner membrane via a series of respiratory complexes. Despite extensive in-vitro structural studies, revealing the atomic details of their molecular mechanisms in physiological states remains a major challenge, primarily because of the loss of the native environment during purification. Here, we directly image porcine mitochondria using an in-situ cryo-electron microscopy approach. This enables us to determine the structures of various high-order assemblies of respiratory supercomplexes in their native states, achieving up to 1.8-Å local resolution. We identify four major supercomplex organizations: I1III2IV1, I1III2IV2, I2III2IV2, and I2III4IV2, which can potentially expand into higher-order arrays on the inner membranes. The formation of these diverse supercomplexes is largely contributed by 'protein-lipids-protein' interactions, which in turn dramatically impact the local geometry of the surrounding membranes. Our in-situ structures also capture numerous reactive intermediates within these respiratory supercomplexes, shedding light on the dynamic processes of the ubiquinone/ubiquinol exchange mechanism in complex I and the Q-cycle in complex III. By comparing supercomplex structures from mitochondria treated under distinct conditions, we elucidate how conformational changes and ligand binding states interplay between complexes I and III in response to environmental redox alterations. Our approach, by preserving the native membrane environment, enables structural studies of mitochondrial respiratory supercomplexes in reaction at high resolution across multiple scales, spanning from atomic-level details to the broader subcellular context.
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Affiliation(s)
- Wan Zheng
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06511, USA
| | - Pengxin Chai
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06511, USA
| | - Jiapeng Zhu
- School of Medicine & Holistic Integrative Medicine, Nanjing University of Chinese Medicine, Nanjing, 210023, China
| | - Kai Zhang
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT, 06511, USA
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6
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Laube E, Schiller J, Zickermann V, Vonck J. Using cryo-EM to understand the assembly pathway of respiratory complex I. Acta Crystallogr D Struct Biol 2024; 80:159-173. [PMID: 38372588 PMCID: PMC10910544 DOI: 10.1107/s205979832400086x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2023] [Accepted: 01/23/2024] [Indexed: 02/20/2024] Open
Abstract
Complex I (proton-pumping NADH:ubiquinone oxidoreductase) is the first component of the mitochondrial respiratory chain. In recent years, high-resolution cryo-EM studies of complex I from various species have greatly enhanced the understanding of the structure and function of this important membrane-protein complex. Less well studied is the structural basis of complex I biogenesis. The assembly of this complex of more than 40 subunits, encoded by nuclear or mitochondrial DNA, is an intricate process that requires at least 20 different assembly factors in humans. These are proteins that are transiently associated with building blocks of the complex and are involved in the assembly process, but are not part of mature complex I. Although the assembly pathways have been studied extensively, there is limited information on the structure and molecular function of the assembly factors. Here, the insights that have been gained into the assembly process using cryo-EM are reviewed.
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Affiliation(s)
- Eike Laube
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
| | - Jonathan Schiller
- 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
| | - 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
| | - Janet Vonck
- Department of Structural Biology, Max Planck Institute of Biophysics, 60438 Frankfurt am Main, Germany
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7
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He Z, Wu M, Tian H, Wang L, Hu Y, Han F, Zhou J, Wang Y, Zhou L. Euglena's atypical respiratory chain adapts to the discoidal cristae and flexible metabolism. Nat Commun 2024; 15:1628. [PMID: 38388527 PMCID: PMC10884005 DOI: 10.1038/s41467-024-46018-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 02/09/2024] [Indexed: 02/24/2024] Open
Abstract
Euglena gracilis, a model organism of the eukaryotic supergroup Discoba harbouring also clinically important parasitic species, possesses diverse metabolic strategies and an atypical electron transport chain. While structures of the electron transport chain complexes and supercomplexes of most other eukaryotic clades have been reported, no similar structure is currently available for Discoba, limiting the understandings of its core metabolism and leaving a gap in the evolutionary tree of eukaryotic bioenergetics. Here, we report high-resolution cryo-EM structures of Euglena's respirasome I + III2 + IV and supercomplex III2 + IV2. A previously unreported fatty acid synthesis domain locates on the tip of complex I's peripheral arm, providing a clear picture of its atypical subunit composition identified previously. Individual complexes are re-arranged in the respirasome to adapt to the non-uniform membrane curvature of the discoidal cristae. Furthermore, Euglena's conformationally rigid complex I is deactivated by restricting ubiquinone's access to its substrate tunnel. Our findings provide structural insights for therapeutic developments against euglenozoan parasite infections.
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Affiliation(s)
- Zhaoxiang He
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Mengchen Wu
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Hongtao Tian
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Liangdong Wang
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China
| | - Yiqi Hu
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Fangzhu Han
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China
| | - Jiancang Zhou
- Department of Critical Care Medicine, Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310016, China.
| | - Yong Wang
- College of Life Sciences, Zhejiang University, Hangzhou, 310058, China.
- The Provincial International Science and Technology Cooperation Base on Engineering Biology, International Campus of Zhejiang University, Haining, 314400, China.
| | - Long Zhou
- Department of Biophysics and Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, 310058, China.
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8
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Nesterov SV, Plokhikh KS, Chesnokov YM, Mustafin DA, Goleva TN, Rogov AG, Vasilov RG, Yaguzhinsky LS. Safari with an Electron Gun: Visualization of Protein and Membrane Interactions in Mitochondria in Natural Environment. BIOCHEMISTRY. BIOKHIMIIA 2024; 89:257-268. [PMID: 38622094 DOI: 10.1134/s0006297924020068] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/24/2023] [Revised: 02/06/2024] [Accepted: 02/07/2024] [Indexed: 04/17/2024]
Abstract
This paper presents new structural data about mitochondria using correlative light and electron microscopy (CLEM) and cryo-electron tomography. These state-of-the-art structural biology methods allow studying biological objects at nanometer scales under natural conditions. Non-invasiveness of these methods makes them comparable to observing animals in their natural environment on a safari. The paper highlights two areas of research that can only be accomplished using these methods. The study visualized location of the Aβ42 amyloid aggregates in relation to mitochondria to test a hypothesis of development of mitochondrial dysfunction in Alzheimer's disease. The results showed that the Aβ42 aggregates do not interact with mitochondria, although some of them are closely located. Therefore, the study demonstrated that mitochondrial dysfunction is not directly associated with the effects of aggregates on mitochondrial structure. Other processes should be considered as sources of mitochondrial dysfunction. Second unique area presented in this work is high-resolution visualization of the mitochondrial membranes and proteins in them. Analysis of the cryo-ET data reveals toroidal holes in the lamellar structures of cardiac mitochondrial cristae, where ATP synthases are located. The study proposes a new mechanism for sorting and clustering protein complexes in the membrane based on topology. According to this suggestion, position of the OXPHOS system proteins in the membrane is determined by its curvature. High-resolution tomography expands and complements existing ideas about the structural and functional organization of mitochondria. This makes it possible to study the previously inaccessible structural interactions of proteins with each other and with membranes in vivo.
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Affiliation(s)
- Semen V Nesterov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia.
| | | | - Yuriy M Chesnokov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Denis A Mustafin
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Tatyana N Goleva
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Anton G Rogov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Raif G Vasilov
- National Research Center "Kurchatov Institute", Moscow, 123182, Russia
| | - Lev S Yaguzhinsky
- Belozersky Research Institute for Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, 119992, Russia
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9
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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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10
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Braun HP, Klusch N. Promotion of oxidative phosphorylation by complex I-anchored carbonic anhydrases? TRENDS IN PLANT SCIENCE 2024; 29:64-71. [PMID: 37599162 DOI: 10.1016/j.tplants.2023.07.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 07/12/2023] [Accepted: 07/19/2023] [Indexed: 08/22/2023]
Abstract
The mitochondrial NADH-dehydrogenase complex of the respiratory chain, known as complex I, includes a carbonic anhydrase (CA) module attached to its membrane arm on the matrix side in protozoans, algae, and plants. Its physiological role is so far unclear. Recent electron cryo-microscopy (cryo-EM) structures show that the CA module may directly provide protons for translocation across the inner mitochondrial membrane at complex I. CAs can have a central role in adjusting the proton concentration in the mitochondrial matrix. We suggest that CA anchoring in complex I represents the original configuration to secure oxidative phosphorylation (OXPHOS) in the context of early endosymbiosis. After development of 'modern mitochondria' with pronounced cristae structures, this anchoring became dispensable, but has been retained in protozoans, algae, and plants.
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Affiliation(s)
- Hans-Peter Braun
- Institute of Plant Genetics, Leibniz Universität Hannover, Herrenhäuser Str. 2, 30419 Hannover, Germany.
| | - Niklas Klusch
- Department of Structural Biology, Max-Planck-Institute of Biophysics, Max-von-Laue-Straße 3, 60438 Frankfurt, Germany.
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11
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Nagaraj PH. Determining Macromolecular Structures Using Cryo-Electron Microscopy. Methods Mol Biol 2024; 2787:315-332. [PMID: 38656500 DOI: 10.1007/978-1-0716-3778-4_22] [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: 04/26/2024]
Abstract
Structural insights into macromolecular and protein complexes provide key clues about the molecular basis of the function. Cryogenic electron microscopy (cryo-EM) has emerged as a powerful structural biology method for studying protein and macromolecular structures at high resolution in both native and near-native states. Despite the ability to get detailed structural insights into the processes underlying protein function using cryo-EM, there has been hesitancy amongst plant biologists to apply the method for biomolecular interaction studies. This is largely evident from the relatively fewer structural depositions of proteins and protein complexes from plant origin in electron microscopy databank. Even though the progress has been slow, cryo-EM has significantly contributed to our understanding of the molecular biology processes underlying photosynthesis, energy transfer in plants, besides viruses infecting plants. This chapter introduces sample preparation for both negative-staining electron microscopy (NSEM) and cryo-EM for plant proteins and macromolecular complexes and data analysis using single particle analysis for beginners.
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Affiliation(s)
- Pradeep Hiriyur Nagaraj
- Institute of Molecular Biotechnology, Department of Biotechnology, University of Natural Resources and Life Sciences (BOKU), Vienna, Austria.
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12
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Kohler A, Barrientos A, Fontanesi F, Ott M. The functional significance of mitochondrial respiratory chain supercomplexes. EMBO Rep 2023; 24:e57092. [PMID: 37828827 PMCID: PMC10626428 DOI: 10.15252/embr.202357092] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2023] [Revised: 07/10/2023] [Accepted: 09/14/2023] [Indexed: 10/14/2023] Open
Abstract
The mitochondrial respiratory chain (MRC) is a key energy transducer in eukaryotic cells. Four respiratory chain complexes cooperate in the transfer of electrons derived from various metabolic pathways to molecular oxygen, thereby establishing an electrochemical gradient over the inner mitochondrial membrane that powers ATP synthesis. This electron transport relies on mobile electron carries that functionally connect the complexes. While the individual complexes can operate independently, they are in situ organized into large assemblies termed respiratory supercomplexes. Recent structural and functional studies have provided some answers to the question of whether the supercomplex organization confers an advantage for cellular energy conversion. However, the jury is still out, regarding the universality of these claims. In this review, we discuss the current knowledge on the functional significance of MRC supercomplexes, highlight experimental limitations, and suggest potential new strategies to overcome these obstacles.
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Affiliation(s)
- Andreas Kohler
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
- Institute of Molecular BiosciencesUniversity of GrazGrazAustria
| | - Antoni Barrientos
- Department of Neurology, Miller School of MedicineUniversity of MiamiMiamiFLUSA
- Department of Biochemistry and Molecular Biology, Miller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Flavia Fontanesi
- Department of Biochemistry and Molecular Biology, Miller School of MedicineUniversity of MiamiMiamiFLUSA
| | - Martin Ott
- Department of Biochemistry and BiophysicsStockholm UniversityStockholmSweden
- Department of Medical Biochemistry and Cell BiologyUniversity of GothenburgGothenburgSweden
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13
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Ukolova IV, Borovskii GB. OXPHOS Organization and Activity in Mitochondria of Plants with Different Life Strategies. Int J Mol Sci 2023; 24:15229. [PMID: 37894910 PMCID: PMC10607765 DOI: 10.3390/ijms242015229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2023] [Revised: 10/07/2023] [Accepted: 10/12/2023] [Indexed: 10/29/2023] Open
Abstract
The study of the supramolecular organization of the mitochondrial oxidative phosphorylation system (OXPHOS) in various eukaryotes has led to the accumulation of a considerable amount of data on the composition, stoichiometry, and architecture of its constituent superstructures. However, the link between the features of system arrangement and the biological characteristics of the studied organisms has been poorly explored. Here, we report a comparative investigation into supramolecular and functional OXPHOS organization in the mitochondria of etiolated shoots of winter wheat (Triticum aestivum L.), maize (Zea mays L.), and pea (Pisum sativum L.). Investigations based on BN-PAGE, in-gel activity assays, and densitometric analysis revealed both similarities and specific OXPHOS features apparently related to the life strategies of each species. Frost-resistant winter wheat was distinguished by highly stable basic I1III2IVa/b respirasomes and V2 dimers, highly active complex I, and labile complex IV, which were probably essential for effective OXPHOS adaptation during hypothermia. Maize, a C4 plant, had the highly stable dimers IV2 and V2, less active complex I, and active alternative NAD(P)H dehydrogenases. The latter fact could contribute to successful chloroplast-mitochondrial cooperation, which is essential for highly efficient photosynthesis in this species. The pea OXPHOS contained detergent-resistant high-molecular respirasomes I1-2III2IVn, highly active complexes IV and V, and stable succinate dehydrogenase, suggesting an active energy metabolism in organelles of this plant. The results and conclusions are in good agreement with the literature data on the respiratory activity of mitochondria from these species and are summarized in a proposed scheme of organization of OXPHOS fragments.
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Affiliation(s)
- Irina V. Ukolova
- Laboratory of Physiological Genetics, Siberian Institute of Plant Physiology and Biochemistry, Siberian Branch of the Russian Academy of Sciences, 664033 Irkutsk, Russia;
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14
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Brischigliaro M, Cabrera-Orefice A, Arnold S, Viscomi C, Zeviani M, Fernández-Vizarra E. Structural rather than catalytic role for mitochondrial respiratory chain supercomplexes. eLife 2023; 12:RP88084. [PMID: 37823874 PMCID: PMC10569793 DOI: 10.7554/elife.88084] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/13/2023] Open
Abstract
Mammalian mitochondrial respiratory chain (MRC) complexes are able to associate into quaternary structures named supercomplexes (SCs), which normally coexist with non-bound individual complexes. The functional significance of SCs has not been fully clarified and the debate has been centered on whether or not they confer catalytic advantages compared with the non-bound individual complexes. Mitochondrial respiratory chain organization does not seem to be conserved in all organisms. In fact, and differently from mammalian species, mitochondria from Drosophila melanogaster tissues are characterized by low amounts of SCs, despite the high metabolic demands and MRC activity shown by these mitochondria. Here, we show that attenuating the biogenesis of individual respiratory chain complexes was accompanied by increased formation of stable SCs, which are missing in Drosophila melanogaster in physiological conditions. This phenomenon was not accompanied by an increase in mitochondrial respiratory activity. Therefore, we conclude that SC formation is necessary to stabilize the complexes in suboptimal biogenesis conditions, but not for the enhancement of respiratory chain catalysis.
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Affiliation(s)
- Michele Brischigliaro
- Department of Biomedical Sciences, University of PadovaPadovaItaly
- Veneto Institute of Molecular MedicinePaduaItaly
| | - Alfredo Cabrera-Orefice
- Radboud Institute for Molecular Life Sciences, Radboud University Medical CenterNijmegenNetherlands
| | - Susanne Arnold
- Radboud Institute for Molecular Life Sciences, Radboud University Medical CenterNijmegenNetherlands
- Cologne Excellence Cluster on Cellular Stress Responses in Aging-Associated Diseases (CECAD), University of CologneCologneGermany
| | - Carlo Viscomi
- Department of Biomedical Sciences, University of PadovaPadovaItaly
- Veneto Institute of Molecular MedicinePaduaItaly
| | - Massimo Zeviani
- Department of Neurosciences, University of PadovaPadovaItaly
| | - Erika Fernández-Vizarra
- Department of Biomedical Sciences, University of PadovaPadovaItaly
- Veneto Institute of Molecular MedicinePaduaItaly
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15
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Amthor JS. ATP yield of plant respiration: potential, actual and unknown. ANNALS OF BOTANY 2023; 132:133-162. [PMID: 37409716 PMCID: PMC10550282 DOI: 10.1093/aob/mcad075] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2023] [Accepted: 07/04/2023] [Indexed: 07/07/2023]
Abstract
BACKGROUND AND AIMS The ATP yield of plant respiration (ATP/hexose unit respired) quantitatively links active heterotrophic processes with substrate consumption. Despite its importance, plant respiratory ATP yield is uncertain. The aim here was to integrate current knowledge of cellular mechanisms with inferences required to fill knowledge gaps to generate a contemporary estimate of respiratory ATP yield and identify important unknowns. METHOD A numerical balance sheet model combining respiratory carbon metabolism and electron transport pathways with uses of the resulting transmembrane electrochemical proton gradient was created and parameterized for healthy, non-photosynthesizing plant cells catabolizing sucrose or starch to produce cytosolic ATP. KEY RESULTS Mechanistically, the number of c subunits in the mitochondrial ATP synthase Fo sector c-ring, which is unquantified in plants, affects ATP yield. A value of 10 was (justifiably) used in the model, in which case respiration of sucrose potentially yields about 27.5 ATP/hexose (0.5 ATP/hexose more from starch). Actual ATP yield often will be smaller than its potential due to bypasses of energy-conserving reactions in the respiratory chain, even in unstressed plants. Notably, all else being optimal, if 25 % of respiratory O2 uptake is via the alternative oxidase - a typically observed fraction - ATP yield falls 15 % below its potential. CONCLUSIONS Plant respiratory ATP yield is smaller than often assumed (certainly less than older textbook values of 36-38 ATP/hexose) leading to underestimation of active-process substrate requirements. This hinders understanding of ecological/evolutionary trade-offs between competing active processes and assessments of crop growth gains possible through bioengineering of processes that consume ATP. Determining the plant mitochondrial ATP synthase c-ring size, the degree of any minimally required (useful) bypasses of energy-conserving reactions in the respiratory chain, and the magnitude of any 'leaks' in the inner mitochondrial membrane are key research needs.
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Affiliation(s)
- J S Amthor
- Center for Ecosystem Science and Society and Department of Biological Sciences, Northern Arizona University, Flagstaff, AZ 86011, USA
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16
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Zhang Y, Hu Y, Wang Z, Lin X, Li Z, Ren Y, Zhao J. The translocase of the inner mitochondrial membrane 22-2 is required for mitochondrial membrane function during Arabidopsis seed development. JOURNAL OF EXPERIMENTAL BOTANY 2023; 74:4427-4448. [PMID: 37105529 DOI: 10.1093/jxb/erad141] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Accepted: 04/27/2023] [Indexed: 06/19/2023]
Abstract
The carrier translocase (also known as translocase of the inner membrane 22; TIM22 complex) is an important component of the mitochondrial protein import apparatus. However, the biological functions of AtTIM22-2 in Arabidopsis remain poorly defined. Here, we report studies on two tim22-2 mutants that exhibit defects in embryo and endosperm development, leading to seed abortion. AtTIM22-2, which was localized in mitochondria, was widely expressed in embryos and in various seedling organs. Loss of AtTIM22-2 function resulted in irregular mitochondrial cristae, decreased respiratory activity, and a lower membrane potential, together with changes in gene expression and enzyme activity related to reactive oxygen species (ROS) metabolism, leading to increased accumulation of ROS in the embryo. The levels of transcripts encoding mitochondrial protein import components were also altered in the tim22-2 mutants. Furthermore, mass spectrometry, bimolecular fluorescence complementation and co-immunoprecipitation assays revealed that AtTIM22-2 interacted with AtTIM23-2, AtB14.7 (a member of Arabidopsis OEP16 family encoded by At2G42210), and AT5G27395 (mitochondrial inner membrane translocase complex, subunit TIM44-related protein). Taken together, these results demonstrate that AtTIM22-2 is essential for maintaining mitochondrial membrane functions during seed development. These findings lay the foundations for a new model of the composition and functions of the TIM22 complex in higher plants.
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Affiliation(s)
- Yuqin Zhang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yuanyuan Hu
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zhiqin Wang
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Xiaodi Lin
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Zihui Li
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Yafang Ren
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
| | - Jie Zhao
- State Key Laboratory of Hybrid Rice, College of Life Sciences, Wuhan University, Wuhan 430072, China
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17
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Grba DN, Chung I, Bridges HR, Agip ANA, Hirst J. Investigation of hydrated channels and proton pathways in a high-resolution cryo-EM structure of mammalian complex I. SCIENCE ADVANCES 2023; 9:eadi1359. [PMID: 37531432 PMCID: PMC10396290 DOI: 10.1126/sciadv.adi1359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Accepted: 07/03/2023] [Indexed: 08/04/2023]
Abstract
Respiratory complex I, a key enzyme in mammalian metabolism, captures the energy released by reduction of ubiquinone by NADH to drive protons across the inner mitochondrial membrane, generating the proton-motive force for ATP synthesis. Despite remarkable advances in structural knowledge of this complicated membrane-bound enzyme, its mechanism of catalysis remains controversial. In particular, how ubiquinone reduction is coupled to proton pumping and the pathways and mechanisms of proton translocation are contested. We present a 2.4-Å resolution cryo-EM structure of complex I from mouse heart mitochondria in the closed, active (ready-to-go) resting state, with 2945 water molecules modeled. By analyzing the networks of charged and polar residues and water molecules present, we evaluate candidate pathways for proton transfer through the enzyme, for the chemical protons for ubiquinone reduction, and for the protons transported across the membrane. Last, we compare our data to the predictions of extant mechanistic models, and identify key questions to answer in future work to test them.
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18
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Ghifari AS, Saha S, Murcha MW. The biogenesis and regulation of the plant oxidative phosphorylation system. PLANT PHYSIOLOGY 2023; 192:728-747. [PMID: 36806687 DOI: 10.1093/plphys/kiad108] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Revised: 01/19/2023] [Accepted: 01/22/2023] [Indexed: 06/01/2023]
Abstract
Mitochondria are central organelles for respiration in plants. At the heart of this process is oxidative phosphorylation (OXPHOS) system, which generates ATP required for cellular energetic needs. OXPHOS complexes comprise of multiple subunits that originated from both mitochondrial and nuclear genome, which requires careful orchestration of expression, translation, import, and assembly. Constant exposure to reactive oxygen species due to redox activity also renders OXPHOS subunits to be more prone to oxidative damage, which requires coordination of disassembly and degradation. In this review, we highlight the composition, assembly, and activity of OXPHOS complexes in plants based on recent biochemical and structural studies. We also discuss how plants regulate the biogenesis and turnover of OXPHOS subunits and the importance of OXPHOS in overall plant respiration. Further studies in determining the regulation of biogenesis and activity of OXPHOS will advances the field, especially in understanding plant respiration and its role to plant growth and development.
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Affiliation(s)
- Abi S Ghifari
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia
| | - Saurabh Saha
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia
| | - Monika W Murcha
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Crawley, Perth, WA 6009, Australia
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19
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Han F, Hu Y, Wu M, He Z, Tian H, Zhou L. Structures of Tetrahymena thermophila respiratory megacomplexes on the tubular mitochondrial cristae. Nat Commun 2023; 14:2542. [PMID: 37248254 DOI: 10.1038/s41467-023-38158-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2022] [Accepted: 04/19/2023] [Indexed: 05/31/2023] Open
Abstract
Tetrahymena thermophila, a classic ciliate model organism, has been shown to possess tubular mitochondrial cristae and highly divergent electron transport chain involving four transmembrane protein complexes (I-IV). Here we report cryo-EM structures of its ~8 MDa megacomplex IV2 + (I + III2 + II)2, as well as a ~ 10.6 MDa megacomplex (IV2 + I + III2 + II)2 at lower resolution. In megacomplex IV2 + (I + III2 + II)2, each CIV2 protomer associates one copy of supercomplex I + III2 and one copy of CII, forming a half ring-shaped architecture that adapts to the membrane curvature of mitochondrial cristae. Megacomplex (IV2 + I + III2 + II)2 defines the relative position between neighbouring half rings and maintains the proximity between CIV2 and CIII2 cytochrome c binding sites. Our findings expand the current understanding of divergence in eukaryotic electron transport chain organization and how it is related to mitochondrial morphology.
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Affiliation(s)
- Fangzhu Han
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
- Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
| | - Yiqi Hu
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
- Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
| | - Mengchen Wu
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
- Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
| | - Zhaoxiang He
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
- Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
| | - Hongtao Tian
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
- Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China
| | - Long Zhou
- Department of Biophysics, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China.
- Department of Critical Care Medicine of Sir Run Run Shaw Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, 310058, China.
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20
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Abstract
We present a brief review of the mitochondrial respiratory chain with emphasis on complexes I, III and IV, which contribute to the generation of protonmotive force across the inner mitochondrial membrane, and drive the synthesis of ATP by the process called oxidative phosphorylation. The basic structural and functional details of these complexes are discussed. In addition, we briefly review the information on the so-called supercomplexes, aggregates of complexes I-IV, and summarize basic physiological aspects of cell respiration.
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Affiliation(s)
- Mårten Wikström
- HiLife Institute of Biotechnology, University of Helsinki, Biocenter, Viikinkaari, Helsinki, Finland.
| | - Cristina Pecorilla
- Department of Physics, University of Helsinki, Gustaf Hällströmin katu, Helsinki, Finland
| | - Vivek Sharma
- HiLife Institute of Biotechnology, University of Helsinki, Biocenter, Viikinkaari, Helsinki, Finland; Department of Physics, University of Helsinki, Gustaf Hällströmin katu, Helsinki, Finland
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21
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Iverson TM, Singh PK, Cecchini G. An evolving view of Complex II - non-canonical complexes, megacomplexes, respiration, signaling, and beyond. J Biol Chem 2023; 299:104761. [PMID: 37119852 DOI: 10.1016/j.jbc.2023.104761] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/20/2023] [Accepted: 04/22/2023] [Indexed: 05/01/2023] Open
Abstract
Mitochondrial Complex II is traditionally studied for its participation in two key respiratory processes: the electron transport chain and the Krebs cycle. There is now a rich body of literature explaining how Complex II contributes to respiration. However, more recent research shows that not all of the pathologies associated with altered Complex II activity clearly correlate with this respiratory role. Complex II activity has now been shown to be necessary for a range of biological processes peripherally-related to respiration, including metabolic control, inflammation, and cell fate. Integration of findings from multiple types of studies suggests that Complex II both participates in respiration and controls multiple succinate-dependent signal transduction pathways. Thus, the emerging view is that the true biological function of Complex II is well beyond respiration. This review uses a semi-chronological approach to highlight major paradigm shifts that occurred over time. Special emphasis is given to the more recently identified functions of Complex II and its subunits because these findings have infused new directions into an established field.
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Affiliation(s)
- T M Iverson
- Departments of Pharmacology, Vanderbilt University, Nashville, TN 37232; Departments of Biochemistry, Vanderbilt University, Nashville, TN 37232; Departments of Center for Structural Biology, Vanderbilt University, Nashville, TN 37232; Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN 37232.
| | - Prashant K Singh
- Departments of Pharmacology, Vanderbilt University, Nashville, TN 37232; Departments of Center for Structural Biology, Vanderbilt University, Nashville, TN 37232
| | - Gary Cecchini
- Molecular Biology Division, San Francisco VA Health Care System, San Francisco, CA 94121; Department of Biochemistry & Biophysics, University of California, San Francisco, CA 94158.
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22
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Röhricht H, Przybyla-Toscano J, Forner J, Boussardon C, Keech O, Rouhier N, Meyer EH. Mitochondrial ferredoxin-like is essential for forming complex I-containing supercomplexes in Arabidopsis. PLANT PHYSIOLOGY 2023; 191:2170-2184. [PMID: 36695030 PMCID: PMC10069907 DOI: 10.1093/plphys/kiad040] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 01/11/2023] [Indexed: 06/02/2023]
Abstract
In eukaryotes, mitochondrial ATP is mainly produced by the oxidative phosphorylation (OXPHOS) system, which is composed of 5 multiprotein complexes (complexes I-V). Analyses of the OXPHOS system by native gel electrophoresis have revealed an organization of OXPHOS complexes into supercomplexes, but their roles and assembly pathways remain unclear. In this study, we characterized an atypical mitochondrial ferredoxin (mitochondrial ferredoxin-like, mFDX-like). This protein was previously found to be part of the bridge domain linking the matrix and membrane arms of the complex I. Phylogenetic analysis suggested that the Arabidopsis (Arabidopsis thaliana) mFDX-like evolved from classical mitochondrial ferredoxins (mFDXs) but lost one of the cysteines required for the coordination of the iron-sulfur (Fe-S) cluster, supposedly essential for the electron transfer function of FDXs. Accordingly, our biochemical study showed that AtmFDX-like does not bind an Fe-S cluster and is therefore unlikely to be involved in electron transfer reactions. To study the function of mFDX-like, we created deletion lines in Arabidopsis using a CRISPR/Cas9-based strategy. These lines did not show any abnormal phenotype under standard growth conditions. However, the characterization of the OXPHOS system demonstrated that mFDX-like is important for the assembly of complex I and essential for the formation of complex I-containing supercomplexes. We propose that mFDX-like and the bridge domain are required for the correct conformation of the membrane arm of complex I that is essential for the association of complex I with complex III2 to form supercomplexes.
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Affiliation(s)
| | - Jonathan Przybyla-Toscano
- Present address: Laboratoire Physiologie Cellulaire & Végétale, Institut de Recherche Interdisciplinaire de Grenoble, Université Grenoble Alpes, Institut National de Recherche pour l'Agriculture, l'Alimentation et l'Environnement, Commissariat à l’Energie Atomique et aux Energie Alternatives, Centre National de la Recherche Scientifique, F-38000 Grenoble, France
| | - Joachim Forner
- Department of Organelle Biology, Biotechnology and Molecular Ecophysiology, Max-Planck-Institute of Molecular Plant Physiology, D-14476 Potsdam-Golm, Germany
| | - Clément Boussardon
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, S-90187 Umeå, Sweden
| | - Olivier Keech
- Department of Plant Physiology, Umeå Plant Science Centre, Umeå University, S-90187 Umeå, Sweden
| | - Nicolas Rouhier
- Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE), Interactions Arbres-Microorganismes (IAM), Université de Lorraine, F-54000 Nancy, France
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23
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Møller IM. Super-complex supercomplex. NATURE PLANTS 2023; 9:5-6. [PMID: 36639556 DOI: 10.1038/s41477-022-01329-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Affiliation(s)
- Ian Max Møller
- Department of Molecular Biology and Genetics, Aarhus University, Slagelse, Denmark.
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24
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Maldonado M, Fan Z, Abe KM, Letts JA. Plant-specific features of respiratory supercomplex I + III 2 from Vigna radiata. NATURE PLANTS 2023; 9:157-168. [PMID: 36581760 PMCID: PMC9873571 DOI: 10.1038/s41477-022-01306-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Accepted: 11/08/2022] [Indexed: 05/07/2023]
Abstract
The last steps of cellular respiration-an essential metabolic process in plants-are carried out by mitochondrial oxidative phosphorylation. This process involves a chain of multi-subunit membrane protein complexes (complexes I-V) that form higher-order assemblies called supercomplexes. Although supercomplexes are the most physiologically relevant form of the oxidative phosphorylation complexes, their functions and structures remain mostly unknown. Here we present the cryogenic electron microscopy structure of the supercomplex I + III2 from Vigna radiata (mung bean). The structure contains the full subunit complement of complex I, including a newly assigned, plant-specific subunit. It also shows differences in the mitochondrial processing peptidase domain of complex III2 relative to a previously determined supercomplex with complex IV. The supercomplex interface, while reminiscent of that in other organisms, is plant specific, with a major interface involving complex III2's mitochondrial processing peptidase domain and no participation of complex I's bridge domain. The complex I structure suggests that the bridge domain sets the angle between the enzyme's two arms, limiting large-scale conformational changes. Moreover, complex I's catalytic loops and its response in active-to-deactive assays suggest that, in V. radiata, the resting complex adopts a non-canonical state and can sample deactive- or open-like conformations even in the presence of substrate. This study widens our understanding of the possible conformations and behaviour of complex I and supercomplex I + III2. Further studies of complex I and its supercomplexes in diverse organisms are needed to determine the universal and clade-specific mechanisms of respiration.
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Affiliation(s)
- M Maldonado
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
- Department of Plant Biology, University of California, Davis, CA, USA.
| | - Z Fan
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - K M Abe
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA
| | - J A Letts
- Department of Molecular and Cellular Biology, University of California, Davis, CA, USA.
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