829 results match your criteria supercomplex observed


Homozygous missense mutation in UQCRC2 associated with severe encephalomyopathy, mitochondrial complex III assembly defect and activation of mitochondrial protein quality control.

Biochim Biophys Acta Mol Basis Dis 2021 Apr 15:166147. Epub 2021 Apr 15.

Department of Paediatrics and Inherited Metabolic Disorders, First Faculty of Medicine, Charles University and General University Hospital, Prague, Czech Republic. Electronic address:

The mitochondrial respiratory chain (MRC) complex III (CIII) associates with complexes I and IV (CI and CIV) into supercomplexes. We identified a novel homozygous missense mutation (c.665G>C; p. Read More

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The role of RST1 and RIPR proteins in plant RNA quality control systems.

Plant Mol Biol 2021 Apr 17. Epub 2021 Apr 17.

Biological Research Centre, Institute of Plant Biology, ELKH, Temesvári krt 62, 6726, Szeged, Hungary.

To keep mRNA homeostasis, the RNA degradation, quality control and silencing systems should act in balance in plants. Degradation of normal mRNA starts with deadenylation, then deadenylated transcripts are degraded by the SKI-exosome 3'-5' and/or XRN4 5'-3' exonucleases. RNA quality control systems identify and decay different aberrant transcripts. Read More

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Loss of LUC7L2 and U1 snRNP subunits shifts energy metabolism from glycolysis to OXPHOS.

Mol Cell 2021 Apr 10. Epub 2021 Apr 10.

Department of Molecular Biology and Howard Hughes Medical Institute, Massachusetts General Hospital, Boston, MA 02114, USA; Department of Systems Biology, Harvard Medical School, Boston, MA 02115, USA; Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA. Electronic address:

Oxidative phosphorylation (OXPHOS) and glycolysis are the two major pathways for ATP production. The reliance on each varies across tissues and cell states, and can influence susceptibility to disease. At present, the full set of molecular mechanisms governing the relative expression and balance of these two pathways is unknown. Read More

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A membrane arm of mitochondrial complex I sufficient to promote respirasome formation.

Cell Rep 2021 Apr;35(2):108963

Key Laboratory of Laboratory Medicine, Ministry of Education, Zhejiang Provincial Key Laboratory of Medical Genetics, Department of Cell Biology and Medical Genetics, College of Laboratory Medicine and Life sciences, Wenzhou Medical University, Wenzhou 325000, China; Department of Laboratory Medicine, Zhejiang Provincial People's Hospital, Affiliated People's Hospital of Hangzhou Medical College, Hangzhou 310000, China. Electronic address:

The assembly pathways of mitochondrial respirasome (supercomplex I+III+IV) are not fully understood. Here, we show that an early sub-complex I assembly, rather than holo-complex I, is sufficient to initiate mitochondrial respirasome assembly. We find that a distal part of the membrane arm of complex I (P-a module) is a scaffold for the incorporation of complexes III and IV to form a respirasome subcomplex. Read More

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Cryo-EM structure and kinetics reveal electron transfer by 2D diffusion of cytochrome in the yeast III-IV respiratory supercomplex.

Proc Natl Acad Sci U S A 2021 Mar;118(11)

Department of Biochemistry and Biophysics, The Arrhenius Laboratories for Natural Sciences, Stockholm University, SE-106 91 Stockholm, Sweden;

Energy conversion in aerobic organisms involves an electron current from low-potential donors, such as NADH and succinate, to dioxygen through the membrane-bound respiratory chain. Electron transfer is coupled to transmembrane proton transport, which maintains the electrochemical proton gradient used to produce ATP and drive other cellular processes. Electrons are transferred from respiratory complexes III to IV (CIII and CIV) by water-soluble cytochrome (cyt. Read More

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Molecular and Supramolecular Structure of the Mitochondrial Oxidative Phosphorylation System: Implications for Pathology.

Life (Basel) 2021 Mar 15;11(3). Epub 2021 Mar 15.

Department of Biomedical and Neuromotor Sciences, Alma Mater Studiorum University of Bologna, 40138 Bologna, Italy.

Under aerobic conditions, mitochondrial oxidative phosphorylation (OXPHOS) converts the energy released by nutrient oxidation into ATP, the currency of living organisms. The whole biochemical machinery is hosted by the inner mitochondrial membrane (mtIM) where the protonmotive force built by respiratory complexes, dynamically assembled as super-complexes, allows the FF-ATP synthase to make ATP from ADP + Pi. Recently mitochondria emerged not only as cell powerhouses, but also as signaling hubs by way of reactive oxygen species (ROS) production. Read More

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Direct Evidence for Excitation Energy Transfer Limitations Imposed by Low-Energy Chlorophylls in Photosystem I-Light Harvesting Complex I of Land Plants.

J Phys Chem B 2021 04 31;125(14):3566-3573. Epub 2021 Mar 31.

Istituto di Fotonica e Nanotecnologie del Consiglio Nazionale delle Ricerche, Dipartimento di Fisica, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milano, Italy.

The overall efficiency of photosynthetic energy conversion depends both on photochemical and excitation energy transfer processes from extended light-harvesting antenna networks. Understanding the trade-offs between increase in the antenna cross section and bandwidth and photochemical conversion efficiency is of central importance both from a biological perspective and for the design of biomimetic artificial photosynthetic complexes. Here, we employ two-dimensional electronic spectroscopy to spectrally resolve the excitation energy transfer dynamics and directly correlate them with the initial site of excitation in photosystem I-light harvesting complex I (PSI-LHCI) supercomplex of land plants, which has both a large antenna dimension and a wide optical bandwidth extending to energies lower than the peak of the reaction center chlorophylls. Read More

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Structure of plant photosystem I-light harvesting complex I supercomplex at 2.4 Å resolution.

J Integr Plant Biol 2021 Mar 31. Epub 2021 Mar 31.

Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.

Photosystem I (PSI) is one of the two photosystems in photosynthesis, and performs a series of electron transfer reactions leading to the reduction of ferredoxin. In higher plants, PSI is surrounded by four light-harvesting complex I (LHCI) subunits, which harvest and transfer energy efficiently to the PSI core. The crystal structure of PSI-LHCI supercomplex has been analyzed up to 2. Read More

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Growth-phase dependent morphological alteration in higher plant thylakoid is accompanied by changes in both photodamage and repair rates.

Physiol Plant 2021 Mar 30. Epub 2021 Mar 30.

Department of Chemistry, Graduate School of Science, Kyoto University, Kyoto, Japan.

Thylakoid membranes of young leaves consist of grana and stroma lamellae (stroma-grana [SG] structure). The SG thylakoid is gradually converted into isolated grana (IG), almost lacking the stroma lamellae during growth. This morphological alteration was found to cause a reduction in maximum photosynthetic rate and an enhancement of photoinhibition in photosystem II (PSII). Read More

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CST in maintaining genome stability: Beyond telomeres.

DNA Repair (Amst) 2021 Jun 22;102:103104. Epub 2021 Mar 22.

Department of Cancer Biology, Cardinal Bernardin Cancer Center, Loyola University Chicago Stritch School of Medicine, Maywood, IL, 60153, United States. Electronic address:

The human CST (CTC1-STN1-TEN1) complex is an RPA-like single-stranded DNA binding protein complex. While its telomeric functions have been well investigated, numerous studies have revealed that hCST also plays important roles in maintaining genome stability beyond telomeres. Here, we review and discuss recent discoveries on CST in various global genome maintenance pathways, including findings on the CST supercomplex structure, its functions in unperturbed DNA replication, stalled replication, double-strand break repair, and the ATR-CHK1 activation pathway. Read More

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Oil biodesulfurization: A review of applied analytical techniques.

J Chromatogr B Analyt Technol Biomed Life Sci 2021 May 24;1171:122602. Epub 2021 Feb 24.

Department of Chemistry, University of Cyprus, P.O. Box 20537, 1678 Nicosia, Cyprus. Electronic address:

The wide use of fossil fuels and their associated environmental concerns, highlighted the importance of affordable and clean energy (goal 7), as adopted by the Sustainable Development Goals of the United Nations for 2030. For years now, the detection of sulfur components in liquid fuels is performed mainly for environmental and health purposes in compliance with the respective legislations. Towards this, the aerobic and anaerobic biodesulfurization (BDS) process, which entails the use of microorganisms to limit the sulfur concentration is followed. Read More

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A CRISPR-Cas9-integrase complex generates precise DNA fragments for genome integration.

Nucleic Acids Res 2021 04;49(6):3546-3556

Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, CA 94720, USA.

CRISPR-Cas9 is an RNA-guided DNA endonuclease involved in bacterial adaptive immunity and widely repurposed for genome editing in human cells, animals and plants. In bacteria, RNA molecules that guide Cas9's activity derive from foreign DNA fragments that are captured and integrated into the host CRISPR genomic locus by the Cas1-Cas2 CRISPR integrase. How cells generate the specific lengths of DNA required for integrase capture is a central unanswered question of type II-A CRISPR-based adaptive immunity. Read More

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Building Better Barrels - β-barrel Biogenesis and Insertion in Bacteria and Mitochondria.

J Mol Biol 2021 Feb 24:166894. Epub 2021 Feb 24.

Laboratory of Molecular Biology, National Institute of Diabetes & Digestive & Kidney Diseases, National Institutes of Health, 9000 Rockville Pike, Bethesda, MD 20892, USA. Electronic address:

β-barrel proteins are folded and inserted into outer membranes by multi-subunit protein complexes that are conserved across different types of outer membranes. In Gram-negative bacteria this complex is the barrel-assembly machinery (BAM), in mitochondria it is the sorting and assembly machinery (SAM) complex, and in chloroplasts it is the outer envelope protein Oep80. Mitochondrial β-barrel precursor proteins are translocated from the cytoplasm to the intermembrane space by the translocase of the outer membrane (TOM) complex, and stabilized by molecular chaperones before interaction with the assembly machinery. Read More

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February 2021

Structure of photosystem I-LHCI-LHCII from the green alga Chlamydomonas reinhardtii in State 2.

Nat Commun 2021 02 17;12(1):1100. Epub 2021 Feb 17.

Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, China.

Photosystem I (PSI) and II (PSII) balance their light energy distribution absorbed by their light-harvesting complexes (LHCs) through state transition to maintain the maximum photosynthetic performance and to avoid photodamage. In state 2, a part of LHCII moves to PSI, forming a PSI-LHCI-LHCII supercomplex. The green alga Chlamydomonas reinhardtii exhibits state transition to a far larger extent than higher plants. Read More

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February 2021

Antenna arrangement and energy-transfer pathways of PSI-LHCI from the moss Physcomitrella patens.

Cell Discov 2021 Feb 16;7(1):10. Epub 2021 Feb 16.

Photosynthesis Research Center, Key Laboratory of Photobiology, Institute of Botany, Chinese Academy of Sciences, Beijing, 100093, China.

Plants harvest light energy utilized for photosynthesis by light-harvesting complex I and II (LHCI and LHCII) surrounding photosystem I and II (PSI and PSII), respectively. During the evolution of green plants, moss is at an evolutionarily intermediate position from aquatic photosynthetic organisms to land plants, being the first photosynthetic organisms that landed. Here, we report the structure of the PSI-LHCI supercomplex from the moss Physcomitrella patens (Pp) at 3. Read More

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February 2021

Loss of COX4I1 Leads to Combined Respiratory Chain Deficiency and Impaired Mitochondrial Protein Synthesis.

Cells 2021 Feb 10;10(2). Epub 2021 Feb 10.

Laboratory of Bioenergetics, Institute of Physiology, Czech Academy of Sciences, 142 00 Prague, Czech Republic.

The oxidative phosphorylation (OXPHOS) system localized in the inner mitochondrial membrane secures production of the majority of ATP in mammalian organisms. Individual OXPHOS complexes form supramolecular assemblies termed supercomplexes. The complexes are linked not only by their function but also by interdependency of individual complex biogenesis or maintenance. Read More

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February 2021

How Can We Predict Accurate Electrochromic Shifts for Biochromophores? A Case Study on the Photosynthetic Reaction Center.

J Chem Theory Comput 2021 Mar 10;17(3):1858-1873. Epub 2021 Feb 10.

Max-Planck-Institut für Kohlenforschung, Kaiser-Wilhelm-Platz 1, 45470 Mülheim an der Ruhr, Germany.

Protein-embedded chromophores are responsible for light harvesting, excitation energy transfer, and charge separation in photosynthesis. A critical part of the photosynthetic apparatus are reaction centers (RCs), which comprise groups of (bacterio)chlorophyll and (bacterio)pheophytin molecules that transform the excitation energy derived from light absorption into charge separation. The lowest excitation energies of individual pigments (site energies) are key for understanding photosynthetic systems, and form a prime target for quantum chemistry. Read More

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Ordered Clusters of the Complete Oxidative Phosphorylation System in Cardiac Mitochondria.

Int J Mol Sci 2021 Feb 2;22(3). Epub 2021 Feb 2.

Moscow Institute of Physics and Technology, 141701 Dolgoprudny, Russia.

The existence of a complete oxidative phosphorylation system (OXPHOS) supercomplex including both electron transport system and ATP synthases has long been assumed based on functional evidence. However, no structural confirmation of the docking between ATP synthase and proton pumps has been obtained. In this study, cryo-electron tomography was used to reveal the supramolecular architecture of the rat heart mitochondria cristae during ATP synthesis. Read More

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February 2021

The Chloroplast -Splicing RNA-Protein Supercomplex from the Green Alga .

Cells 2021 Feb 1;10(2). Epub 2021 Feb 1.

Allgemeine und Molekulare Botanik, Faculty for Biology and Biotechnology, Ruhr-Universität Bochum, Universitätsstraße 150, 44780 Bochum, Germany.

In eukaryotes, RNA -splicing is a significant RNA modification process for the end-to-end ligation of exons from separately transcribed primary transcripts to generate mature mRNA. So far, three different categories of RNA -splicing have been found in organisms within a diverse range. Here, we review -splicing of discontinuous group II introns, which occurs in chloroplasts and mitochondria of lower eukaryotes and plants. Read More

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February 2021

Atomic structures of respiratory complex III, complex IV, and supercomplex III-IV from vascular plants.

Elife 2021 Jan 19;10. Epub 2021 Jan 19.

Department of Molecular and Cellular Biology, University of California Davis, Davis, United States.

Mitochondrial complex III (CIII) and complex IV (CIV), which can associate into a higher-order supercomplex (SC III+IV), play key roles in respiration. However, structures of these plant complexes remain unknown. We present atomic models of CIII, CIV, and SC III+IV from determined by single-particle cryoEM. Read More

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January 2021

The two roles of complex III in plants.

Authors:
Hans-Peter Braun

Elife 2021 Jan 19;10. Epub 2021 Jan 19.

Institut für Pflanzengenetik, Leibniz Universität Hannover, Hannover, Germany.

Atomic structures of mitochondrial enzyme complexes in plants are shedding light on their multiple functions. Read More

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January 2021

Co-purification of nitrate reductase 1 with components of the cytochrome bcc-aa oxidase supercomplex from spores of Streptomyces coelicolor A3(2).

FEBS Open Bio 2021 Mar 14;11(3):652-669. Epub 2021 Feb 14.

Institute of Microbiology, Martin-Luther University Halle-Wittenberg, Halle (Saale), Germany.

In order to reduce nitrate in vivo, the spore-specific respiratory nitrate reductase, Nar1, of Streptomyces coelicolor relies on an active cytochrome bcc-aa oxidase supercomplex (bcc-aa supercomplex). This suggests that membrane-associated Nar1, comprising NarG1, NarH1, and NarI1 subunits, might not act as a classical menaquinol oxidase but could either receive electrons from the bcc-aa supercomplex, or require the supercomplex to stabilize the reductase in the membrane to allow it to function. To address the biochemical basis for this dependence on the bcc-aa supercomplex, we purified two different Strep-tagged variants of Nar1 and enriched the native enzyme complex from spore extracts using different chromatographic and electrophoretic procedures. Read More

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β-carotene oxygenase 2 deficiency-triggered mitochondrial oxidative stress promotes low-grade inflammation and metabolic dysfunction.

Free Radic Biol Med 2021 Feb 13;164:271-284. Epub 2021 Jan 13.

Department of Nutritional Sciences, Oklahoma State University, Stillwater, OK, 74078, USA. Electronic address:

Low-grade inflammation is a critical pathological factor contributing to the development of metabolic disorders. β-carotene oxygenase 2 (BCO2) was initially identified as an enzyme catalyzing carotenoids in the inner mitochondrial membrane. Mutations in BCO2 are associated with inflammation and metabolic disorders in humans, yet the underlying mechanisms remain unknown. Read More

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February 2021

Mitochondrial Structure and Bioenergetics in Normal and Disease Conditions.

Int J Mol Sci 2021 Jan 8;22(2). Epub 2021 Jan 8.

Mitochondrial Biology Unit, The MRC and University of Cambridge, Cambridge CB2 0XY, UK.

Mitochondria are ubiquitous intracellular organelles found in almost all eukaryotes and involved in various aspects of cellular life, with a primary role in energy production. The interest in this organelle has grown stronger with the discovery of their link to various pathologies, including cancer, aging and neurodegenerative diseases. Indeed, dysfunctional mitochondria cannot provide the required energy to tissues with a high-energy demand, such as heart, brain and muscles, leading to a large spectrum of clinical phenotypes. Read More

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January 2021

Mutations in SARS-CoV-2 nsp7 and nsp8 proteins and their predicted impact on replication/transcription complex structure.

J Med Virol 2021 Jan 12. Epub 2021 Jan 12.

Department of Chemical Engineering, Indian Institute of Technology Bombay, Mumbai, Maharashtra, India.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA-dependent RNA polymerase (RdRp) has been identified to be a mutation hot spot, with the P323L mutation being commonly observed in viral genomes isolated from North America. RdRp forms a complex with nonstructural proteins nsp7 and nsp8 to form the minimal replication/transcription machinery required for genome replication. As mutations in RdRp may affect formation of the RdRp-nsp7-nsp8 supercomplex, we analyzed viral genomes to identify mutations in nsp7 and nsp8 protein sequences. Read More

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January 2021

Confronting FCP structure with ultrafast spectroscopy data: evidence for structural variations.

Phys Chem Chem Phys 2021 Jan;23(2):806-821

Institute of Chemical Physics, Faculty of Physics, Vilnius University, Sauletekio 9-III, 10222 Vilnius, Lithuania. and Department of Molecular Compound Physics, Center for Physical Sciences and Technology, Sauletekio 3, 10257 Vilnius, Lithuania.

Diatoms are a major group of algae, responsible for a quarter of the global primary production on our planet. Their adaptation to marine environments is ensured by their light-harvesting antenna - the fucoxanthin-chlorophyll protein (FCP) complex, which absorbs strongly in the blue-green spectral region. Although these essential proteins have been the subject of many studies, for a long time their comprehensive description was not possible in the absence of structural data. Read More

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January 2021

A new function for the xanthophyll zeaxanthin: glueing chlorophyll biosynthesis to thylakoid protein assembly.

Authors:
Roberto Bassi

Biochem J 2021 01;478(1):61-62

Department of Biotechnology, University of Verona, Strada Le Grazie, 37134 Verona, Italy.

Xanthophylls are coloured isoprenoid metabolites synthesized in many organisms with a variety of functions from the attraction of animals for impollination to absorption of light energy for photosynthesis to photoprotection against photooxidative stress. The finding by Proctor and co-workers makes a new addition to the last type of functions by showing that zeaxanthin is instrumental in coordinating chlorophyll biosynthesis with the insertion of pigment-binding proteins into the photosynthetic membrane by glueing the protein components catalyzing these functions into a supercomplex and regulating its activity. Read More

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January 2021

Terminal Respiratory Oxidases: A Targetables Vulnerability of Mycobacterial Bioenergetics?

Front Cell Infect Microbiol 2020 23;10:589318. Epub 2020 Nov 23.

Molecular Mycobacteriology, Council of Scientific and Industrial Research, Institute of Microbial Technology, Chandigarh, India.

Recently, ATP synthase inhibitor Bedaquiline was approved for the treatment of multi-drug resistant tuberculosis emphasizing the importance of oxidative phosphorylation for the survival of mycobacteria. ATP synthesis is primarily dependent on the generation of proton motive force through the electron transport chain in mycobacteria. The mycobacterial electron transport chain utilizes two terminal oxidases for the reduction of oxygen, namely the supercomplex and the cytochrome oxidase. Read More

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November 2020

Differential RNA Editing and Intron Splicing in Soybean Mitochondria during Nodulation.

Int J Mol Sci 2020 Dec 9;21(24). Epub 2020 Dec 9.

School of Biological Sciences, University of Hong Kong, Pokfulam, Hong Kong, China.

Nitrogen fixation in soybean consumes a tremendous amount of energy, leading to substantial differences in energy metabolism and mitochondrial activities between nodules and uninoculated roots. While C-to-U RNA editing and intron splicing of mitochondrial transcripts are common in plant species, their roles in relation to nodule functions are still elusive. In this study, we performed RNA-seq to compare transcript profiles and RNA editing of mitochondrial genes in soybean nodules and roots. Read More

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December 2020

HIGD-Driven Regulation of Cytochrome Oxidase Biogenesis and Function.

Cells 2020 12 6;9(12). Epub 2020 Dec 6.

Department of Neurology, University of Miami Miller School of Medicine, Miami, FL 33136, USA.

The biogenesis and function of eukaryotic cytochrome oxidase or mitochondrial respiratory chain complex IV (CIV) undergo several levels of regulation to adapt to changing environmental conditions. Adaptation to hypoxia and oxidative stress involves CIV subunit isoform switch, changes in phosphorylation status, and modulation of CIV assembly and enzymatic activity by interacting factors. The latter include the Hypoxia Inducible Gene Domain (HIGD) family yeast respiratory supercomplex factors 1 and 2 (Rcf1 and Rcf2) and two mammalian homologs of Rcf1, the proteins HIGD1A and HIGD2A. Read More

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December 2020