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Lothar Esser, Fei Zhou, Yihui Zhou, Yumei Xiao, Wai-Kwan Tang, Chang-An Yu, Zhaohai Qin, Di Xia
The Complex III or cytochrome bc1 (cyt bc1) complex constitutes an integral part of the respiratory chain of most aerobic organisms and of the photosynthetic apparatus of anoxygenic purple bacteria. The function of cyt bc1 is to couple the reaction of electron transfer (ET) from ubiquinol to cytochrome c to proton pumping across the membrane. Mechanistically, the ET reaction requires docking of its Rieske iron-sulfur protein (ISP) subunit to the quinol oxidation (QP) site of the complex. Formation of an H-bond between the ISP and the bound substrate was proposed to mediate the docking...
October 7, 2016: Journal of Biological Chemistry
Xue-Jiao Chang, Chao-Qun Zheng, Yu-Wei Wang, Chuang Meng, Xiao-Lu Xie, Hai-Peng Liu
Gradually increasing atmospheric CO2 partial pressure (pCO2) has caused an imbalance in carbonate chemistry and resulted in decreased seawater pH in marine ecosystems, termed seawater acidification. Anthropogenic seawater acidification is postulated to affect the physiology of many marine calcifying organisms. To understand the possible effects of seawater acidification on the proteomic responses of a marine crustacean brine shrimp (Artemia sinica) three groups of cysts were hatched and further raised in seawater at different pH levels (8...
October 7, 2016: Fish & Shellfish Immunology
Rich Boden, Lee P Hutt, Marcel Huntemann, Alicia Clum, Manoj Pillay, Krishnaveni Palaniappan, Neha Varghese, Natalia Mikhailova, Dimitrios Stamatis, Tatiparthi Reddy, Chew Yee Ngan, Chris Daum, Nicole Shapiro, Victor Markowitz, Natalia Ivanova, Tanja Woyke, Nikos Kyrpides
Thermithiobacillus tepidarius DSM 3134(T) was originally isolated (1983) from the waters of a sulfidic spring entering the Roman Baths (Temple of Sulis-Minerva) at Bath, United Kingdom and is an obligate chemolithoautotroph growing at the expense of reduced sulfur species. This strain has a genome size of 2,958,498 bp. Here we report the genome sequence, annotation and characteristics. The genome comprises 2,902 protein coding and 66 RNA coding genes. Genes responsible for the transaldolase variant of the Calvin-Benson-Bassham cycle were identified along with a biosynthetic horseshoe in lieu of Krebs' cycle sensu stricto...
2016: Standards in Genomic Sciences
Chang Sun, Alexander T Taguchi, Josh V Vermaas, Nathan J Beal, Patrick J O'Malley, Emad Tajkhorshid, Robert B Gennis, Sergei A Dikanov
The respiratory cytochrome bo3 ubiquinol oxidase from Escherichia coli has a high-affinity ubiquinone binding site that stabilizes the one-electron reduced ubisemiquinone (SQH), which is a transient intermediate during the electron-mediated reduction of O2 to water. It is known that SQH is stabilized by two strong hydrogen bonds from R71 and D75 to ubiquinone carbonyl oxygen O1 and weak hydrogen bonds from H98 and Q101 to O4. In this work, SQH was investigated with orientation-selective Q-band (∼34 GHz) pulsed (1)H electron-nuclear double resonance (ENDOR) spectroscopy on fully deuterated cytochrome (cyt) bo3 in a H2O solvent so that only exchangeable protons contribute to the observed ENDOR spectra...
October 11, 2016: Biochemistry
Huan Zhang, Lulu Shi, Xinlei Mao, Jinping Lin, Dongzhi Wei
Membrane-bound alcohol dehydrogenase (mADH) was overexpressed in Gluconobacter oxydans DSM 2003, and the effects on cell growth and glycolic acid production were investigated. The transcription levels of two terminal ubiquinol oxidases (bo3 and bd) in the respiratory chain of the engineered strain G. oxydans-adhABS were up-regulated by 13.4- and 3.8-fold, respectively, which effectively enhanced the oxygen uptake rate, resulting in higher resistance to acid. The cell biomass of G. oxydans-adhABS could increase by 26%-33% when cultivated in a 7L bioreactor...
November 10, 2016: Journal of Biotechnology
A Kamali Sangani, A A Masoudi, R Vaez Torshizi
The objectives of the current study were to investigate the activity of the electron transport chain (ETC) complexes, adenosine triphosphate (ATP), and reactive oxygen species (ROS) in the sperm mitochondria of 2 Iranian slow- and fast-growing chickens, namely native and Aryan strains. In this study, semen of 133 roosters was analyzed by computer-assisted sperm analysis (CASA). The roosters were categorized by sperm progressivity, as a low or high sperm motility phenotype. Mitochondrial complex I (NADH ubiquinone oxidoreductase), II (succinate dehydrogenase), III (ubiquinol cytochrome C reductase), IV (cytochrome C oxidase) activity, ATP, and ROS production in sperm were assayed...
September 2, 2016: Poultry Science
Francesco Francia, Marco Malferrari, Pascal Lanciano, Stefan Steimle, Fevzi Daldal, Giovanni Venturoli
The ubiquinol:cytochrome (cyt) c oxidoreductase (or cyt bc1) is an important membrane protein complex in photosynthetic and respiratory energy transduction. In bacteria such as Rhodobacter capsulatus it is constituted of three subunits: the iron-sulfur protein, cyt b and cyt c1, which form two catalytic domains, the Qo (hydroquinone (QH2) oxidation) and Qi (quinone (Q) reduction) sites. At the Qo site, the pathways of bifurcated electron transfers emanating from QH2 oxidation are known, but the associated proton release routes are not well defined...
August 18, 2016: Biochimica et Biophysica Acta
Yan-Hui Sun, Xiao-Yuan Zhang, Wei-Qun Xie, Guang-Jian Liu, Xi-Xin He, Ya-Li Huang, Guang-Xian Zhang, Jian Wang, Zao-Yuan Kuang, Ren Zhang
ETHNOPHARMACOLOGICAL RELEVANCE: Sophora flavescens Aiton (Radix Sophorae Flavescentis, Kushen) is used in traditional Chinese medicine to treat chronic hepatitis B (CHB), and has the ability to clear heat and dampness from the body. Oxymatrine is one of the major bioactive compounds extracted from Sophora flavescens Aiton and constitutes more than 90% of the oxymatrine injection commonly used for CHB treatment in clinics in China. AIM OF THE STUDY: We aim to analyze the protein binding target of oxymatrine in treating CHB by screening a T7 phage display cDNA library of human CHB and examine the biochemistry of protein-ligand binding between oxymatrine and its ligands...
August 3, 2016: Journal of Ethnopharmacology
Camilla Rydström Lundin, Christoph von Ballmoos, Martin Ott, Pia Ädelroth, Peter Brzezinski
The respiratory supercomplex factors (Rcf) 1 and 2 mediate supramolecular interactions between mitochondrial complexes III (ubiquinol-cytochrome c reductase; cyt. bc1) and IV (cytochrome c oxidase; CytcO). In addition, removal of these polypeptides results in decreased activity of CytcO, but not of cyt. bc1 In the present study, we have investigated the kinetics of ligand binding, the single-turnover reaction of CytcO with O2, and the linked cyt. bc1-CytcO quinol oxidation-oxygen-reduction activities in mitochondria in which Rcf1 or Rcf2 were removed genetically (strains rcf1Δ and rcf2Δ, respectively)...
August 2, 2016: Proceedings of the National Academy of Sciences of the United States of America
James Keane, Lotti Tajouri, Bon Gray
BACKGROUND: The purpose of this study was to investigate the mitochondrial effects exerted by physiological and supra-physiological concentrations of recombinant human growth hormone (rhGH) and recombinant insulin-like growth factor-1 (rIGF-1) under conditions of substrate saturation in peripheral blood mononuclear cells (PBMCs). METHODS: PBMCs from healthy male subjects were treated with either rhGH, at concentrations of 0.5, 5 and 50 μg/L, or rIGF-1 at concentrations of 100, 300 and 500 μg/L for 4 h...
2016: Nutrition & Metabolism
A S Thakur, G P Littaru, I Funahashi, U S Painkara, N S Dange, P Chauhan
In neuroendocrine system the increase in oxidative status is produced by a glucocorticoid-dependent and transcriptional increase in pro-oxidative drive, with concurrent inhibition of the antioxidant defense system, ultimately leading to increased neuronal cell death. Functional hypothalamic disturbances and neuroendocirne aberrations have both short and long term consequences for reproductive health. Understandably, an impaired or diminished hypothalamic-pituitary-ovarian axis leads to anovulation and hypoestrogenism...
July 2016: Indian Journal of Clinical Biochemistry: IJCB
Feng Gao, Qicai Liu, Guoping Li, Feng Dong, Minglian Qiu, Xiaoting Lv, Sheng Zhang, Zheng Guo
Ubiquinol cytochrome c reductase hinge (UQCRH) is a novel protein that localizes in the mitochondrial membrane and induces mitochondrial reactive oxygen species (ROS) generation. It had a high expression rate of 87.10% (108/124) in lung adenocarcinoma. Moreover, serum UQCRH level in patients with lung adenocarcinoma was significantly increased compared with that of pneumonia patients (p < 0.0001) and normal control subjects (p < 0.0001). Receiver operating characteristic curve analysis using an optimal cut-off value of 162...
June 2016: Open Biology
Kazuo Mukai, Kanae Nagai, Yoshifumi Egawa, Aya Ouchi, Shin-Ichi Nagaoka
Detailed kinetic studies have been performed for reactions of aroxyl (ArO(•)) and α-tocopheroxyl (α-Toc(•)) radicals with five catecholamines (CAs) (dopamine (DA), norepinephrine (NE), epinephrine (EN), and 5- and 6-hydroxydopamine (5- and 6-OHDA)) and two catechins (epicatechin (EC) and epigallocatechin gallate (EGCG)) to clarify the free-radical-scavenging activity of CAs. Second-order rate constants (ks and kr) for reactions of ArO(•) and α-Toc(•) radicals with the above antioxidants were measured in 2-propanol/water (5:1, v/v) solution at 25...
July 28, 2016: Journal of Physical Chemistry. B
Mario Contin, Pablo Bonelli, Silvia Lucangioli, Ana Cukierman, Valeria Tripodi
Molecularly imprinted polymer nanoparticles (MIPNPs) with the ability to recognize coenzyme Q10 (CoQ10) were synthesised in order to be employed as sorbent in a dispersive micro-solid phase extraction (DMSPE) for the determination of CoQ10 in a liver extract. CoQ10 is a redox-active, lipophilic substance integrated in the mitochondrial respiratory chain which acts as an electron carrier, shuttling electrons from complex I (NADH-ubiquinone oxidoreductase) and II (succinate-ubiquinone oxidoreductase) to complex III (ubiquinol-cytochrome c reductase), for the production of cellular energy...
July 22, 2016: Journal of Chromatography. A
Alexey V Lokhmatikov, Natalia Voskoboynikova, Dmitry A Cherepanov, Maxim V Skulachev, Heinz-Jürgen Steinhoff, Vladimir P Skulachev, Armen Y Mulkidjanian
Molecules of mitochondrial cardiolipin (CL) get selectively oxidized upon oxidative stress, which triggers the intrinsic apoptotic pathway. In a chemical model most closely resembling the mitochondrial membrane-liposomes of pure bovine heart CL-we compared ubiquinol-10, ubiquinol-6, and alpha-tocopherol, the most widespread naturally occurring antioxidants, with man-made, quinol-based amphiphilic antioxidants. Lipid peroxidation was induced by addition of an azo initiator in the absence and presence of diverse antioxidants, respectively...
2016: Oxidative Medicine and Cellular Longevity
Sinan Al-Attar, Yuanjie Yu, Martijn Pinkse, Jo Hoeser, Thorsten Friedrich, Dirk Bald, Simon de Vries
Cytochrome bd is a prokaryotic terminal oxidase that catalyses the electrogenic reduction of oxygen to water using ubiquinol as electron donor. Cytochrome bd is a tri-haem integral membrane enzyme carrying a low-spin haem b558, and two high-spin haems: b595 and d. Here we show that besides its oxidase activity, cytochrome bd from Escherichia coli is a genuine quinol peroxidase (QPO) that reduces hydrogen peroxide to water. The highly active and pure enzyme preparation used in this study did not display the catalase activity recently reported for E...
2016: Scientific Reports
Milla-Riikka Hautakangas, Reetta Hinttala, Heikki Rantala, Pentti Nieminen, Johanna Uusimaa, Ilmo E Hassinen
Due to the relative rarity of mitochondrial diseases, generating reference ranges is problematic in evaluation of respiratory chain activities particularly in pediatric cases. We determined the sample distribution of respiratory chain enzyme activities in skeletal muscle biopsies collected from pediatric patients suspected of neuromuscular disorders. Activities of NADH-ubiquinone reductase, NADH-cytochrome c reductase, succinate-cytochrome c reductase; ubiquinol-cytochrome c reductase and cytochrome c oxidase activities have log-normal distributions even when confirmed mitochondrial diseases were ruled out...
July 2016: Mitochondrion
Rafał Pietras, Marcin Sarewicz, Artur Osyczka
The two-electron ubiquinol oxidation or ubiquinone reduction typically involves semiquinone (SQ) intermediates. Natural engineering of ubiquinone binding sites of bioenergetic enzymes secures that SQ is sufficiently stabilized, so that it does not leave the site to membranous environment before full oxidation/reduction is completed. The ubiquinol oxidation Qo site of cytochrome bc1 (mitochondrial complex III, cytochrome b6f in plants) has been considered an exception with catalytic reactions assumed to involve highly unstable SQ or not to involve any SQ intermediate...
May 2016: Journal of the Royal Society, Interface
Alvaro Sarmiento, Javier Diaz-Castro, Mario Pulido-Moran, Jorge Moreno-Fernandez, Naroa Kajarabille, Ignacio Chirosa, Isabel M Guisado, Luis Javier Chirosa, Rafael Guisado, Julio J Ochoa
Studies about Coenzyme Q10 (CoQ10 ) supplementation on strenuous exercise are scarce, especially those related with oxidative stress associated with physical activity and virtually nonexistent with the reduced form, Ubiquinol. The objective of this study was to determine, for the first time, whether a short-term supplementation with Ubiquinol can prevent oxidative stress associated to strenuous exercise. The participants (n = 100 healthy and well trained, but not on an elite level) were classified in two groups: Ubiquinol (experimental group), and placebo group (control)...
May 19, 2016: BioFactors
Wei-Si Liu, Yi-Dong Liu, Qiang Fu, Wei-Juan Zhang, Le Xu, Yuan Chang, Jie-Jie Xu
Ubiquinol-cytochrome c reductase hinge protein (UQCRH), as a connecter between cytochrome c1 with cytochrome c in complex III of respiratory chain, is top-ranked hypermethylated gene in clear cell renal cell carcinoma (ccRCC). This study aims to evaluate the impact of UQCRH on recurrence and survival of 424 ccRCC patients enrolled retrospectively from a single institution after surgical resection using immunohistochemistry method. UQCRH was specifically downregulated in ccRCC, compared with papillary and chromophobe RCC...
2016: American Journal of Cancer Research
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