scholarly journals Specific features and assembly of the plant mitochondrial complex I revealed by cryo-EM

2020 ◽  
Author(s):  
Heddy Soufari ◽  
Camila Parrot ◽  
Lauriane Kuhn ◽  
Florent Waltz ◽  
Yaser Hashem
Keyword(s):  
Carbonic Anhydrase ◽  
Complex I ◽  
Mitochondrial Respiratory Chain ◽  
Eukaryotic Cells ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Entry Site ◽  
Lipid Complex ◽  
Additional Domain

AbstractMitochondria are the powerhouses of eukaryotic cells and the site of essential metabolic reactions. Their main purpose is to maintain the high ATP/ADP ratio that is required to fuel the countless biochemical reactions taking place in eukaryotic cells1. This high ATP/ADP ratio is maintained through oxidative phosphorylation (OXPHOS). Complex I or NADH:ubiquinone oxidoreductase is the main entry site for electrons into the mitochondrial respiratory chain and constitutes the largest of the respiratory complexes2. Its structure and composition varies across eukaryotes species. However, high resolution structures are available only for one group of eukaryotes, opisthokonts3–6. In plants, only biochemical studies were carried out, already hinting the peculiar composition of complex I in the green lineage. Here, we report several cryo-electron microscopy structures of the plant mitochondrial complex I at near-atomic resolution. We describe the structure and composition of the plant complex I including the plant-specific additional domain composed by carbonic anhydrase proteins. We show that the carbonic anhydrase is an heterotrimeric complex with only one conserved active site. This domain is crucial for the overall stability of complex I as well as a peculiar lipid complex composed cardiolipin and phosphatidylinositols. Moreover we also describe the structure of one of the plant-specific complex I assembly intermediate, lacking the whole PD module, in presence of the maturation factor GLDH. GLDH prevents the binding of the plant specific P1 protein, responsible for the linkage of the PP to the PD module. Finally, as the carbonic anhydrase domain is likely to be associated with complex I from numerous other known eukaryotes, we propose that our structure unveils an ancestral-like organization of mitochondrial complex I.

scholarly journals Specific features and assembly of the plant mitochondrial complex I revealed by cryo-EM

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Heddy Soufari ◽  
Camila Parrot ◽  
Lauriane Kuhn ◽  
Florent Waltz ◽  
Yaser Hashem
Keyword(s):  
Carbonic Anhydrase ◽  
Complex I ◽  
Mitochondrial Respiratory Chain ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Entry Site ◽  
Lipid Complex ◽  
Maturation Factor ◽  
Specific Complex

Abstract Mitochondria are the powerhouses of eukaryotic cells and the site of essential metabolic reactions. Complex I or NADH:ubiquinone oxidoreductase is the main entry site for electrons into the mitochondrial respiratory chain and constitutes the largest of the respiratory complexes. Its structure and composition vary across eukaryote species. However, high resolution structures are available only for one group of eukaryotes, opisthokonts. In plants, only biochemical studies were carried out, already hinting at the peculiar composition of complex I in the green lineage. Here, we report several cryo-electron microscopy structures of the plant mitochondrial complex I. We describe the structure and composition of the plant respiratory complex I, including the ancestral mitochondrial domain composed of the carbonic anhydrase. We show that the carbonic anhydrase is a heterotrimeric complex with only one conserved active site. This domain is crucial for the overall stability of complex I as well as a peculiar lipid complex composed of cardiolipin and phosphatidylinositols. Moreover, we also describe the structure of one of the plant-specific complex I assembly intermediates, lacking the whole PD module, in presence of the maturation factor GLDH. GLDH prevents the binding of the plant specific P1 protein, responsible for the linkage of the PP to the PD module.

scholarly journals Paracoccus denitrificans: a genetically tractable model system for studying respiratory complex I

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Owen D. Jarman ◽  
Olivier Biner ◽  
John J. Wright ◽  
Judy Hirst
Keyword(s):  
Complex I ◽  
Paracoccus Denitrificans ◽  
Model System ◽  
Proton Pumping ◽  
Model Systems ◽  
Metabolic Enzyme ◽  
Nadh:Ubiquinone Oxidoreductase ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Inner Mitochondrial Membrane

AbstractMitochondrial complex I (NADH:ubiquinone oxidoreductase) is a crucial metabolic enzyme that couples the free energy released from NADH oxidation and ubiquinone reduction to the translocation of four protons across the inner mitochondrial membrane, creating the proton motive force for ATP synthesis. The mechanism by which the energy is captured, and the mechanism and pathways of proton pumping, remain elusive despite recent advances in structural knowledge. Progress has been limited by a lack of model systems able to combine functional and structural analyses with targeted mutagenic interrogation throughout the entire complex. Here, we develop and present the α-proteobacterium Paracoccus denitrificans as a suitable bacterial model system for mitochondrial complex I. First, we develop a robust purification protocol to isolate highly active complex I by introducing a His6-tag on the Nqo5 subunit. Then, we optimize the reconstitution of the enzyme into liposomes, demonstrating its proton pumping activity. Finally, we develop a strain of P. denitrificans that is amenable to complex I mutagenesis and create a catalytically inactive variant of the enzyme. Our model provides new opportunities to disentangle the mechanism of complex I by combining mutagenesis in every subunit with established interrogative biophysical measurements on both the soluble and membrane bound enzymes.

scholarly journals The carbonic anhydrase domain of plant mitochondrial complex I

2016 ◽  
Vol 157 (3) ◽  
pp. 289-296 ◽  
Author(s):  
Steffanie Fromm ◽  
Jennifer Senkler ◽  
Eduardo Zabaleta ◽  
Christoph Peterhänsel ◽  
Hans-Peter Braun
Keyword(s):  
Carbonic Anhydrase ◽  
Complex I ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex

scholarly journals Dopamine-derived Dopaminochrome Promotes H2O2Release at Mitochondrial Complex I

2005 ◽  
Vol 280 (16) ◽  
pp. 15587-15594 ◽  
Author(s):  
Franco Zoccarato ◽  
Paola Toscano ◽  
Adolfo Alexandre
Keyword(s):  
Complex I ◽  
Mitochondrial Respiratory Chain ◽  
Brain Mitochondria ◽  
Oxidation Products ◽  
Mitochondrial Complex I ◽  
Redox Cycle ◽  
Mitochondrial Complex ◽  
Low Concentrations ◽  
Symptoms And Signs ◽  
Primary Action

Inhibitors of Complex I of the mitochondrial respiratory chain, such as rotenone, promote Parkinson disease-like symptoms and signs of oxidative stress. Dopamine (DA) oxidation products may be implicated in such a process. We show here that theo-quinone dopaminochrome (DACHR), a relatively stable DA oxidation product, promotes concentration (0.1–0.2 μm)- and respiration-dependent generation of H2O2at Complex I in brain mitochondria, with further stimulation by low concentrations of rotenone (5–30 nm). The rotenone effect required that contaminating Ca2+(8–10 μm) was not removed. DACHR apparently extracts an electron from the constitutively autoxidizable site in Complex I, producing a semiquinone, which then transfers an electron to O2, generating\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{O}_{2}^{{\bar{{\cdot}}}}\) \end{document}and then H2O2. Mitochondrial removal of H2O2monoamine, formed by either oxidase activity or DACHR, was performed largely by glutathione peroxidase and glutathione reductase, which were negatively regulated by low intramitochondrial Ca2+levels. Thus, the H2O2formed accumulated in the medium if contaminating Ca2+was present; in the absence of Ca2+, H2O2was completely removed if it originated from monoamine oxidase, but was less completely removed if it originated from DACHR. We propose that the primary action of rotenone is to promote extracellular\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{O}_{2}^{{\bar{{\cdot}}}}\) \end{document}release via activation of NADPH oxidase in the microglia. In turn,\batchmode \documentclass[fleqn,10pt,legalpaper]{article} \usepackage{amssymb} \usepackage{amsfonts} \usepackage{amsmath} \pagestyle{empty} \begin{document} \(\mathrm{O}_{2}^{{\bar{{\cdot}}}}\) \end{document}oxidizes DA to DACHR extracellularly. (The reaction is favored by the lack of GSH, which would otherwise preferably produce GSH adducts of dopaminoquinone.) Once formed, DACHR (which is resistant to GSH) enters neurons to activate the rotenone-stimulated redox cycle described.

scholarly journals Mechanistic insight from the crystal structure of mitochondrial complex I

Science ◽  
2015 ◽  
Vol 347 (6217) ◽  
pp. 44-49 ◽  
Author(s):  
Volker Zickermann ◽  
Christophe Wirth ◽  
Hamid Nasiri ◽  
Karin Siegmund ◽  
Harald Schwalbe ◽  
...  
Keyword(s):  
Complex I ◽  
Protein Complexes ◽  
Active Form ◽  
Mitochondrial Respiratory Chain ◽  
Structural Rearrangement ◽  
Proton Pumping ◽  
Mitochondrial Complex I ◽  
Mitochondrial Complex ◽  
Degenerative Disorders ◽  
Pumping Units

Proton-pumping complex I of the mitochondrial respiratory chain is among the largest and most complicated membrane protein complexes. The enzyme contributes substantially to oxidative energy conversion in eukaryotic cells. Its malfunctions are implicated in many hereditary and degenerative disorders. We report the x-ray structure of mitochondrial complex I at a resolution of 3.6 to 3.9 angstroms, describing in detail the central subunits that execute the bioenergetic function. A continuous axis of basic and acidic residues running centrally through the membrane arm connects the ubiquinone reduction site in the hydrophilic arm to four putative proton-pumping units. The binding position for a substrate analogous inhibitor and blockage of the predicted ubiquinone binding site provide a model for the “deactive” form of the enzyme. The proposed transition into the active form is based on a concerted structural rearrangement at the ubiquinone reduction site, providing support for a two-state stabilization-change mechanism of proton pumping.

scholarly journals Complex I assembly into supercomplexes determines differential mitochondrial ROS production in neurons and astrocytes

2016 ◽  
Vol 113 (46) ◽  
pp. 13063-13068 ◽  
Author(s):  
Irene Lopez-Fabuel ◽  
Juliette Le Douce ◽  
Angela Logan ◽  
Andrew M. James ◽  
Gilles Bonvento ◽  
...  
Keyword(s):  
Reactive Oxygen Species ◽  
Complex I ◽  
Structural Organization ◽  
Mitochondrial Respiratory Chain ◽  
Mitochondrial Complex I ◽  
Ros Production ◽  
Oxygen Species ◽  
Mitochondrial Complex ◽  
Mitochondrial Ros ◽  
Complex I Assembly

Neurons depend on oxidative phosphorylation for energy generation, whereas astrocytes do not, a distinctive feature that is essential for neurotransmission and neuronal survival. However, any link between these metabolic differences and the structural organization of the mitochondrial respiratory chain is unknown. Here, we investigated this issue and found that, in neurons, mitochondrial complex I is predominantly assembled into supercomplexes, whereas in astrocytes the abundance of free complex I is higher. The presence of free complex I in astrocytes correlates with the severalfold higher reactive oxygen species (ROS) production by astrocytes compared with neurons. Using a complexomics approach, we found that the complex I subunit NDUFS1 was more abundant in neurons than in astrocytes. Interestingly, NDUFS1 knockdown in neurons decreased the association of complex I into supercomplexes, leading to impaired oxygen consumption and increased mitochondrial ROS. Conversely, overexpression of NDUFS1 in astrocytes promoted complex I incorporation into supercomplexes, decreasing ROS. Thus, complex I assembly into supercomplexes regulates ROS production and may contribute to the bioenergetic differences between neurons and astrocytes.

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