Detection of conformational changes in Complex III of the respiratory chain by a maleimido spin label

1979 ◽  
Vol 11 (3-4) ◽  
pp. 79-95 ◽  
Author(s):  
Uttam DasGupta ◽  
David C. Wharton ◽  
John S. Rieske
Keyword(s):  
Respiratory Chain ◽  
Conformational Changes ◽  
Spin Label ◽  
Complex Iii

scholarly journals NAD + repletion produces no therapeutic effect in mice with respiratory chain complex III deficiency and chronic energy deprivation

2018 ◽  
Vol 32 (11) ◽  
pp. 5913-5926 ◽  
Author(s):  
Janne Purhonen ◽  
Jayasimman Rajendran ◽  
Saara Tegelberg ◽  
Olli-Pekka Smolander ◽  
Eija Pirinen ◽  
...  
Keyword(s):  
Therapeutic Effect ◽  
Respiratory Chain ◽  
Chain Complex ◽  
Complex Iii ◽  
Respiratory Chain Complex ◽  
Energy Deprivation

scholarly journals Specific requirements of nonbilayer phospholipids in mitochondrial respiratory chain function and formation

2016 ◽  
Vol 27 (14) ◽  
pp. 2161-2171 ◽  
Author(s):  
Charli D. Baker ◽  
Writoban Basu Ball ◽  
Erin N. Pryce ◽  
Vishal M. Gohil
Keyword(s):  
Respiratory Chain ◽  
Mitochondrial Membrane ◽  
Phospholipid Composition ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Specific Requirement ◽  
Transport Pathway ◽  
Contact Sites ◽  
Yeast Mutants ◽  
Mitochondrial Respiratory

Mitochondrial membrane phospholipid composition affects mitochondrial function by influencing the assembly of the mitochondrial respiratory chain (MRC) complexes into supercomplexes. For example, the loss of cardiolipin (CL), a signature non–bilayer-forming phospholipid of mitochondria, results in disruption of MRC supercomplexes. However, the functions of the most abundant mitochondrial phospholipids, bilayer-forming phosphatidylcholine (PC) and non–bilayer-forming phosphatidylethanolamine (PE), are not clearly defined. Using yeast mutants of PE and PC biosynthetic pathways, we show a specific requirement for mitochondrial PE in MRC complex III and IV activities but not for their formation, whereas loss of PC does not affect MRC function or formation. Unlike CL, mitochondrial PE or PC is not required for MRC supercomplex formation, emphasizing the specific requirement of CL in supercomplex assembly. Of interest, PE biosynthesized in the endoplasmic reticulum (ER) can functionally substitute for the lack of mitochondrial PE biosynthesis, suggesting the existence of PE transport pathway from ER to mitochondria. To understand the mechanism of PE transport, we disrupted ER–mitochondrial contact sites formed by the ERMES complex and found that, although not essential for PE transport, ERMES facilitates the efficient rescue of mitochondrial PE deficiency. Our work highlights specific roles of non–bilayer-forming phospholipids in MRC function and formation.

The interaction of ligands with chemically modified phosphorylase b

1976 ◽  
Vol 54 (5) ◽  
pp. 494-499
Author(s):  
D. Brooks ◽  
S. J. W. Busby ◽  
J. R. Griffiths ◽  
G. K. Radda ◽  
O. Avramovic-Zikic
Keyword(s):  
Conformational Changes ◽  
Spin Label ◽  
Native Enzyme ◽  
Carboxyl Groups ◽  
Chemically Modified ◽  
Allosteric Effector ◽  
Spin Resonance ◽  
Label Probe ◽  
Glycine Ethyl Ester ◽  
Modified Enzyme

Phosphorylase b which had been inactivated with 5-diazo-1H-tetrazole was specifically labelled with 4-iodoacetamidosalicylic acid (a fluorescent probe) or with N-(1-oxyl-2,2,6,6,-tetramethyl-4-piperidinyl)iodoacetamide (a spin label probe) so that the binding of ligands and accompanying conformational changes could be determined by fluorescence or electron spin resonance changes, respectively. The allosteric effector, AMP, causes conformational changes similar to those caused in the native enzyme. The affinity of binding of phosphate or AMP to the inhibited protein is the same as for the unmodified protein. The heterotropic interactions between glucose-1-phosphate or glycogen and AMP are much less in the inactivated enzyme than in unmodified phosphorylase. Using a light scattering assay, it is shown that the modified enzyme binds to glycogen less strongly than the native protein.Phosphorylase b which had been inactivated by carbodiimide in the presence of glycine ethyl ester, resulting in the modification of one or more carboxyl groups, was labelled with the spin label probe described above. The modified enzyme has an affinity for AMP similar to that of the native enzyme. AMP binding to the modified enzyme is tightened by glycogen, weakened by glucose-6-phosphate and is unaffected by glucose- 1-phosphate.The actions of 5-diazo-1H-tetrazole and carbodiimide on phosphorylase are discussed in the light of the above observations.

Mitochondrial function in flying honeybees (Apis mellifera): respiratory chain enzymes and electron flow from complex III to oxygen

2000 ◽  
Vol 203 (5) ◽  
pp. 905-911 ◽  
Author(s):  
R.K. Suarez ◽  
J.F. Staples ◽  
J.R. Lighton ◽  
O. Mathieu-Costello
Keyword(s):  
Surface Area ◽  
Muscle Mass ◽  
Respiratory Chain ◽  
Mitochondrial Function ◽  
Electron Flow ◽  
Complex Iii ◽  
High Mass ◽  
Metabolic Rates ◽  
Turnover Rates ◽  
Respiratory Enzymes

The biochemical bases for the high mass-specific metabolic rates of flying insects remain poorly understood. To gain insights into mitochondrial function during flight, metabolic rates of individual flying honeybees were measured using respirometry, and their thoracic muscles were fixed for electron microscopy. Mitochondrial volume densities and cristae surface densities, combined with biochemical data concerning cytochrome content per unit mass, were used to estimate respiratory chain enzyme densities per unit cristae surface area. Despite the high content of respiratory enzymes per unit muscle mass, these are accommodated by abundant mitochondria and high cristae surface densities such that enzyme densities per unit cristae surface area are similar to those found in mammalian muscle and liver. These results support the idea that a unit area of mitochondrial inner membrane constitutes an invariant structural unit. Rates of O(2) consumption per unit cristae surface area are much higher than those estimated in mammals as a consequence of higher enzyme turnover rates (electron transfer rates per enzyme molecule) during flight. Cytochrome c oxidase, in particular, operates close to its maximum catalytic capacity (k(cat)). Thus, high flux rates are achieved via (i) high respiratory enzyme content per unit muscle mass and (ii) the operation of these enzymes at high fractional velocities.

Succinimidyl oleate, established inhibitor of CD36/FAT translocase inhibits complex III of mitochondrial respiratory chain

2010 ◽  
Vol 391 (3) ◽  
pp. 1348-1351 ◽  
Author(s):  
Zdeněk Drahota ◽  
Marek Vrbacký ◽  
Hana Nůsková ◽  
Ludmila Kazdová ◽  
Václav Zídek ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Mitochondrial Respiratory Chain ◽  
Complex Iii ◽  
Mitochondrial Respiratory

scholarly journals Mutations in CYC1, Encoding Cytochrome c1 Subunit of Respiratory Chain Complex III, Cause Insulin-Responsive Hyperglycemia

2013 ◽  
Vol 93 (2) ◽  
pp. 384-389 ◽  
Author(s):  
Pauline Gaignard ◽  
Minal Menezes ◽  
Manuel Schiff ◽  
Aurélien Bayot ◽  
Malgorzata Rak ◽  
...  
Keyword(s):  
Respiratory Chain ◽  
Chain Complex ◽  
Complex Iii ◽  
Respiratory Chain Complex ◽  
Cytochrome C1

A Spin-label Study on Calcium-induced Conformational Changes of Troponin Components*

1974 ◽  
Vol 75 (1) ◽  
pp. 211-213 ◽  
Author(s):  
Setsuro EBASHI ◽  
Shun-ichi OHNISHI ◽  
Shin-ichi ABE ◽  
Koscak MARUYAMA
Keyword(s):  
Conformational Changes ◽  
Spin Label ◽  
Label Study

scholarly journals Enhanced hepatic respiratory capacity and altered lipid metabolism support metabolic homeostasis during short-term hypoxic stress

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Katie A. O’Brien ◽  
Ben D. McNally ◽  
Alice P. Sowton ◽  
Antonio Murgia ◽  
James Armitage ◽  
...  
Keyword(s):  
Lipid Metabolism ◽  
Respiratory Chain ◽  
Complex Iii ◽  
Whole Body ◽  
Hypoxic Exposure ◽  
Metabolic Homeostasis ◽  
Short Term ◽  
Respiratory Capacity ◽  
Alcoholic Fatty Liver ◽  
Hepatic Diseases

Abstract Background Tissue hypoxia is a key feature of several endemic hepatic diseases, including alcoholic and non-alcoholic fatty liver disease, and organ failure. Hypoxia imposes a severe metabolic challenge on the liver, potentially disrupting its capacity to carry out essential functions including fuel storage and the integration of lipid metabolism at the whole-body level. Mitochondrial respiratory function is understood to be critical in mediating the hepatic hypoxic response, yet the time-dependent nature of this response and the role of the respiratory chain in this remain unclear. Results Here, we report that hepatic respiratory capacity is enhanced following short-term exposure to hypoxia (2 days, 10% O2) and is associated with increased abundance of the respiratory chain supercomplex III2+IV and increased cardiolipin levels. Suppression of this enhanced respiratory capacity, achieved via mild inhibition of mitochondrial complex III, disrupted metabolic homeostasis. Hypoxic exposure for 2 days led to accumulation of plasma and hepatic long chain acyl-carnitines. This was observed alongside depletion of hepatic triacylglycerol species with total chain lengths of 39-53 carbons, containing palmitic, palmitoleic, stearic, and oleic acids, which are associated with de novo lipogenesis. The changes to hepatic respiratory capacity and lipid metabolism following 2 days hypoxic exposure were transient, becoming resolved after 14 days in line with systemic acclimation to hypoxia and elevated circulating haemoglobin concentrations. Conclusions The liver maintains metabolic homeostasis in response to shorter term hypoxic exposure through transient enhancement of respiratory chain capacity and alterations to lipid metabolism. These findings may have implications in understanding and treating hepatic pathologies associated with hypoxia.

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.

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