scholarly journals The 12.3 kDa subunit of complex I (respiratory-chain NADH dehydrogenase) from Neurospora crassa: cDNA cloning and chromosomal mapping of the gene

1993 ◽  
Vol 291 (3) ◽  
pp. 729-732 ◽  
Author(s):  
A Videira ◽  
J E Azevedo ◽  
S Werner ◽  
P Cabral
Keyword(s):  
Respiratory Chain ◽  
Complex I ◽  
Nadh Dehydrogenase ◽  
Single Gene ◽  
Complex Iii ◽  
Chromosomal Mapping ◽  
Helical Conformation ◽  
Significant Similarity ◽  
Hydrophobic Domain ◽  
Group I

The 12.3 kDa subunit of complex I (respiratory-chain NADH dehydrogenase) is a nuclear-coded protein of the hydrophobic fragment of the enzyme. We have isolated and sequenced a full-length cDNA clone coding for this polypeptide. The deduced protein is 104 amino acid residues long with a molecular mass of 12305 Da. This particular subunit of complex I lacks a cleavable mitochondrial targeting sequence. In agreement with its localization within complex I, we have found that this subunit behaves like an intrinsic membrane protein. Nevertheless, the deduced protein is rather hydrophilic, exhibiting no hydrophobic domain long enough to traverse a membrane in an alpha-helical conformation. The 12.3 kDa subunit shows a significant similarity to the hinge protein of complex III, suggesting that these two polypeptides may be involved in identical functions. This complex I subunit is coded for by a single gene. Applying restriction-fragment-length-polymorphism mapping, we located the gene on the right side of the centromere in linkage group I, linked to the lys-4 locus.

scholarly journals Physiological relevance, localization and substrate specificity of the alternative (type II) mitochondrial NADH dehydrogenases of Ogataea parapolymorpha

2021 ◽  
Author(s):  
Hannes Juergens ◽  
Álvaro Mielgo-Gómez ◽  
Albert Godoy-Hernández ◽  
Jolanda ter Horst ◽  
Janine M. Nijenhuis ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Respiratory Chain ◽  
Complex I ◽  
Nadh Dehydrogenase ◽  
Physiological Role ◽  
Proton Pumping ◽  
Type Ii ◽  
Respiratory Chains ◽  
Alternative Type ◽  
Nadh Dehydrogenases

AbstractMitochondria from Ogataea parapolymorpha harbor a branched electron-transport chain containing a proton-pumping Complex I NADH dehydrogenase and three alternative (type II) NADH dehydrogenases (NDH2s). To investigate the physiological role, localization and substrate specificity of these enzymes, growth of various NADH dehydrogenase mutants was quantitatively characterized in shake-flask and chemostat cultures, followed by oxygen-uptake experiments with isolated mitochondria. Furthermore, NAD(P)H:quinone oxidoreduction of the three NDH2s were individually assessed. Our findings show that the O. parapolymorpha respiratory chain contains an internal NADH-accepting NDH2 (Ndh2-1/OpNdi1), at least one external NAD(P)H-accepting enzyme and likely additional mechanisms for respiration-linked oxidation of cytosolic NADH. Metabolic regulation appears to prevent competition between OpNdi1 and Complex I for mitochondrial NADH. With the exception of OpNdi1, the respiratory chain of O. parapolymorpha exhibits metabolic redundancy and tolerates deletion of multiple NADH-dehydrogenase genes without compromising fully respiratory metabolism.ImportanceTo achieve high productivity and yields in microbial bioprocesses, efficient use of the energy substrate is essential. Organisms with branched respiratory chains can respire via the energy-efficient proton-pumping Complex I, or make use of alternative NADH dehydrogenases (NDH2s). The yeast Ogataea parapolymorpha contains three uncharacterized, putative NDH2s which were investigated in this work. We show that O. parapolymorpha contains at least one ‘internal’ NDH2, which provides an alternative to Complex I for mitochondrial NADH oxidation, albeit at a lower efficiency. The use of this NDH2 appeared to be limited to carbon excess conditions and the O. parapolymorpha respiratory chain tolerated multiple deletions without compromising respiratory metabolism, highlighting opportunities for metabolic (redox) engineering. By providing a more comprehensive understanding of the physiological role of NDH2s, including insights into their metabolic capacity, orientation and substrate specificity this study also extends our fundamental understanding of respiration in organisms with branched respiratory chains.

Abstract 296: Early Mitochondrial Gene Regulation in Pediatric Cardiac Arrest

Circulation ◽  
2018 ◽  
Vol 138 (Suppl_2) ◽  
Author(s):  
Marco M Hefti ◽  
Kumaran Senthil ◽  
Michael Karlsson ◽  
Johannes Ehinger ◽  
Constantine D Mavroudis ◽  
...  
Keyword(s):  
Cardiac Arrest ◽  
Differential Expression ◽  
Respiratory Chain ◽  
Complex I ◽  
Mitochondrial Fission ◽  
Differential Expression Analysis ◽  
Complex Iii ◽  
Swine Model ◽  
Multiple Components ◽  
Dynamin 2

Introduction: Cerebral mitochondrial dysfunction is thought to play a role in the post-cardiac arrest syndrome, propagating secondary morbidity and mortality after return of spontaneous circulation (ROSC). Hypothesis: Based on our previous studies showing a persistent decrease in oxidative phosphorylation (particularly Complex I) and increased mitochondrial fission in a swine model of in-hospital cardiac arrest, we hypothesized that nuclear and mitochondrial genes related to respiratory function would be downregulated and genes promoting mitochondrial fission would be upregulated four hours post-ROSC. Methods: One-month old piglets were subjected to sham anesthesia (n=5) or asphyxial cardiac arrest (n=6; 7 minutes of asphyxia followed by induction of ventricular fibrillation) and treated with 10-20 minutes of AHA guideline-based CPR followed by four hours of standardized post-arrest management and humane euthanasia. RNA was extracted from flash-frozen sections of cerebral cortex using a QIAsymphony robot and sequenced on an Illumina HiSeq. Reads were aligned to the reference (SusScrofa11.1 and NC_012095) using STAR and quantified using subreads. Normalization and differential expression analysis were performed using DESeq2 with RNA quality, intra-arrest and post-ROSC physiologic variables as covariates. All p values were adjusted for multiple comparisons (Benjamini-Hochberg) with a significance cutoff of 0.05. Results: Compared to sham, cardiac arrest animals demonstrated reduced expression of multiple components of the respiratory chain, including NDUFA5 (2.4-fold, p<0.001) and NDUFC1 (2.0-fold, p=0.02), key components of Complex I. Components of Complex III (UQCRB, UQCRH) and Complex IV (COX1, COX7C, COX7A2, COX7B) were also downregulated. Dynamin-2 (DNM2), which increases mitochondrial fission, was upregulated (2.3-fold, p=0.005). There was also differential expression of inner membrane solute channel expression (SLC44A1, SLC25A48 and SLC25A16). Conclusions: Multiple components of the mitochondrial respiratory chain are downregulated 4 hours post-ROSC in the brain, including key components of Complex I with concurrent upregulation of the mitochondrial fission protein dynamin-2.

scholarly journals Mitochondrial Complex I Core Protein Regulates cAMP Signaling via Phosphodiesterase Pde2 and NAD Homeostasis in Candida albicans

2020 ◽  
Vol 11 ◽  
Author(s):  
Xiaodong She ◽  
Lulu Zhang ◽  
Jingwen Peng ◽  
Jingyun Zhang ◽  
Hongbin Li ◽  
...  
Keyword(s):  
Candida Albicans ◽  
Complex I ◽  
Core Protein ◽  
Single Gene ◽  
Metabolic Potential ◽  
Group I ◽  
Ergosterol Synthesis ◽  
Group Ii ◽  
Pka Pathway ◽  
The Impact

The cyclic adenosine 3′,5′-monophosphate (cAMP)/protein kinase A (PKA) pathway of Candida albicans responds to nutrient availability to coordinate a series of cellular processes for its replication and survival. The elevation of cAMP for PKA signaling must be both transitory and tightly regulated. Otherwise, any abnormal cAMP/PKA pathway would disrupt metabolic potential and ergosterol synthesis and promote a stress response. One possible mechanism for controlling cAMP levels is direct induction of the phosphodiesterase PDE2 gene by cAMP itself. Our earlier studies have shown that most single-gene-deletion mutants of the mitochondrial electron transport chain (ETC) complex I (CI) are hypersensitive to fluconazole. To understand the fluconazole hypersensitivity observed in these mutants, we focused upon the cAMP/PKA-mediated ergosterol synthesis in CI mutants. Two groups of the ETC mutants were used in this study. Group I includes CI mutants. Group II is composed of CIII and CIV mutants; group II mutants are known to have greater respiratory loss. All mutants are not identical in cAMP/PKA-mediated ergosterol response. We found that ergosterol levels are decreased by 47.3% in the ndh51Δ (CI core subunit mutant) and by 23.5% in goa1Δ (CI regulator mutant). Both mutants exhibited a greater reduction of cAMP and excessive trehalose production compared with other mutants. Despite the normal cAMP level, ergosterol content decreased by 33.0% in the CIII mutant qce1Δ as well, thereby displaying a cAMP/PKA-independent ergosterol response. While the two CI mutants have some unique cAMP/PKA-mediated ergosterol responses, we found that the degree of cAMP reduction correlates linearly with a decrease in total nicotinamide adenine dinucleotide (NAD) levels in all mutants, particularly in the seven CI mutants. A mechanism study demonstrates that overactive PDE2 and cPDE activity must be the cause of the suppressive cAMP-mediated ergosterol response in the ndh51Δ and goa1Δ. While the purpose of this study is to understand the impact of ETC proteins on pathogenesis-associated cellular events, our results reveal the importance of Ndh51p in the regulation of the cAMP/PKA pathway through Pde2p inhibition in normal physiological environments. As a direct link between Ndh51p and Pde2p remains elusive, we suggest that Ndh51p participates in NAD homeostasis that might regulate Pde2p activity for the optimal cAMP pathway state.

scholarly journals Global ischaemia induces a biphasic response of the mitochondrial respiratory chain. Anoxic pre-perfusion protects against ischaemic damage

1992 ◽  
Vol 281 (3) ◽  
pp. 709-715 ◽  
Author(s):  
K Veitch ◽  
A Hombroeckx ◽  
D Caucheteux ◽  
H Pouleur ◽  
L Hue
Keyword(s):  
Respiratory Chain ◽  
Complex I ◽  
Nadh Oxidase ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Biphasic Response ◽  
Ischaemic Damage ◽  
Global Ischaemia ◽  
Complex I Activity ◽  
Mitochondrial Respiratory

Studies of Langendorff-perfused rat hearts have revealed a biphasic response of the mitochondrial respiratory chain to global ischaemia. The initial effect is a 30-40% increase in the rate of glutamate/malate oxidation after 10 min of ischaemia, owing to an increase in the capacity for NADH oxidation. This effect is followed by a progressive decrease in these oxidative activities as the ischaemia is prolonged, apparently owing to damage to Complex I at a site subsequent to the NADH dehydrogenase component. This damage is exacerbated by reperfusion, which causes a further decrease in Complex I activity and also decreases the activities of the other complexes, most notably of Complex III. Perfusion for up to 1 h with anoxic buffer produced only the increase in NADH oxidase activity, and neither anoxia alone, nor anoxia and reperfusion, caused loss of Complex I activity. Perfusing for 3-10 min with anoxic buffer before 1 h of global ischaemia had a significant protective effect against the ischaemia-induced damage to Complex I.

scholarly journals Maintenance of complex I and its super-complexes by NDUF-11 is essential for mitochondrial structure, function and health

2021 ◽  
Author(s):  
Amber Knapp-Wilson ◽  
Gonçalo C. Pereira ◽  
Emma Buzzard ◽  
Holly C. Ford ◽  
Andrew Richardson ◽  
...  
Keyword(s):  
Complex I ◽  
Nadh Dehydrogenase ◽  
Development Stage ◽  
Complex Iii ◽  
Mitochondrial Morphology ◽  
C Elegans ◽  
Monomeric Complex ◽  
L2 Development ◽  
Conserved Core ◽  
Knockout Allele

Mitochondrial super-complexes form around a conserved core of monomeric complex I and dimeric complex III; wherein subunit NDUFA11, of the former, is conspicuously situated at the interface. We identified B0491.5 (NDUF-11) as the C. elegans homologue, of which animals homozygous for a CRISPR-Cas9 generated knockout allele arrested at the L2 development stage. Reducing (but not eliminating) expression by RNAi allowed development to adulthood, enabling characterisation of the consequences: destabilisation of complex I and its super-complexes, and perturbation of respiratory function. The loss of NADH-dehydrogenase activity is compensated by enhanced complex II activity, with the potential for detrimental ROS-production. Electron cryo-tomography highlight aberrant cristae morphology and inter-membrane-space widening and cristae-junctions. The requirement of NDUF-11 for balanced respiration, mitochondrial morphology and development presumably arises due to its involvement in complex I/ super-complex maintenance. This highlights the importance of respiratory complex integrity for health and the potential of its perturbation for mitochondrial disease.

scholarly journals The respiratory-chain NADH dehydrogenase (complex I) of mitochondria

1991 ◽  
Vol 197 (3) ◽  
pp. 563-576 ◽  
Author(s):  
Hanns WEISS ◽  
Thorsten FRIEDRICH ◽  
Gotz HOFHAUS ◽  
Dagmar PREIS
Keyword(s):  
Respiratory Chain ◽  
Complex I ◽  
Nadh Dehydrogenase ◽  
Dehydrogenase Complex

scholarly journals Effects of proteolytic digestion by chymotrypsin on the structure and catalytic properties of reduced nicotinamide–adenine dinucleotide–ubiquinone oxidoreductase from bovine heart mitochondria

1977 ◽  
Vol 165 (2) ◽  
pp. 295-301 ◽  
Author(s):  
Susan E. Crowder ◽  
C. Ian Ragan
Keyword(s):  
Complex I ◽  
Time Course ◽  
Nadh Dehydrogenase ◽  
Sodium Dodecyl ◽  
Complex Iii ◽  
Type Ii ◽  
Oxidoreductase Activity ◽  
Ubiquinone Oxidoreductase ◽  
Nadh Cytochrome ◽  
Reduced Nicotinamide Adenine Dinucleotide

1. Incubation of NADH–ubiquinone oxidoreductase (Complex I) with chymotrypsin caused loss of rotenone-sensitive ubiquinone-1 reduction and an increase in rotenone-insensitive ubiquinone reduction. 2. Within the same time-course, NADH–K3Fe(CN)6 oxidoreductase activity was unaffected. 3. Mixing of chymotrypsin-treated Complex I with Complex III did not give rise to NADH–cytochrome c oxidoreductase activity. 4. Gel electrophoresis in the presence of sodium dodecyl sulphate revealed selective degradation of several constituent polypeptides by chymotrypsin. 5. With higher chymotrypsin concentrations and longer incubation times, a decrease in NADH–K3Fe(CN)6 oxidoreductase was observed. The kinetics of this decrease correlated with solubilization of the low-molecular-weight type-II NADH dehydrogenase (subunit mol.wts. 53000 and 27000) and with degradation of a polypeptide of mol.wt. 30000. 6. Phospholipid-depleted Complex I was more rapidly degraded by chymotrypsin. Specifically, a subunit of mol.wt. 75000, resistant to chymotrypsin in untreated Complex I, was degraded in phospholipid-depleted Complex I. In addition, the 30000-mol.wt. polypeptide was also more rapidly digested, correlating with an increased rate of transformation to type II NADH dehydrogenase.

scholarly journals Conserved in situ arrangement of complex I and III2 in mitochondrial respiratory chain supercomplexes of mammals, yeast, and plants

2018 ◽  
Vol 115 (12) ◽  
pp. 3024-3029 ◽  
Author(s):  
Karen M. Davies ◽  
Thorsten B. Blum ◽  
Werner Kühlbrandt
Keyword(s):  
Respiratory Chain ◽  
Complex I ◽  
Principal Component ◽  
Complex Iii ◽  
Asparagus Officinalis ◽  
Mutual Arrangement ◽  
Inner Mitochondrial Membrane ◽  
Respiratory Chain Complexes ◽  
Complex Iv

We used electron cryo-tomography and subtomogram averaging to investigate the structure of complex I and its supramolecular assemblies in the inner mitochondrial membrane of mammals, fungi, and plants. Tomographic volumes containing complex I were averaged at ∼4 nm resolution. Principal component analysis indicated that ∼60% of complex I formed a supercomplex with dimeric complex III, while ∼40% were not associated with other respiratory chain complexes. The mutual arrangement of complex I and III2 was essentially conserved in all supercomplexes investigated. In addition, up to two copies of monomeric complex IV were associated with the complex I1III2 assembly in bovine heart and the yeast Yarrowia lipolytica, but their positions varied. No complex IV was detected in the respiratory supercomplex of the plant Asparagus officinalis. Instead, an ∼4.5-nm globular protein density was observed on the matrix side of the complex I membrane arm, which we assign to γ-carbonic anhydrase. Our results demonstrate that respiratory chain supercomplexes in situ have a conserved core of complex I and III2, but otherwise their stoichiometry and structure varies. The conserved features of supercomplex assemblies indicate an important role in respiratory electron transfer.

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