DOCSLIB.ORG

Dehydrogenase and Transhydrogenase Properties of the Soluble NADH Dehydrogenase of Bovine Heart Mitochondria

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Dehydrogenase and Transhydrogenase Properties of the Soluble NADH Dehydrogenase of Bovine Heart Mitochondria Proc. Natl. Acad. Sci. USA Vol. 74, No. 3, pp. 846-850, March 1977 Biochemistry Dehydrogenase and transhydrogenase properties of the soluble NADH dehydrogenase of bovine heart mitochondria (nicotinamide nucleotides/dehydrogenation/nonenergy-linked and energy-linked transhydrogenation) YOUSSEF HATEFI AND YVES M. GALANTE Department of Biochemistry, Scripps Clinic and Research Foundation, La Jolla, California 92037 Communicated by I. C. Gunsalus, November 17, 1976 ABSTRACT The soluble NADH dehydrogenase of low NADPH NADP, was shown in the present studies also to be molecular weight, isolated from complex I (NADH:ubiquinone energy-linked. oxidoreductase, EC 1.6.5.3) of the respiratory chain, has been shown to have NADPH dehydrogenase and NADPH - NAD METHODS AND MATERIALS transhydrogenase activities. Both activities are greatly increased in the presence of added guanidine*HCI and at pH values <6.5. Phosphorylating submitochondrial particles (9), complex I (10), The chromophores of the soluble enzyme (flavin and iron-sulfur and NADH dehydrogenase using either urea or 0.5 M NaCIO4 centers) are reduced by NADH and NADPH to the same extent. for complex I resolution (5) were prepared according to pub- The latter reduction is extremely slow, and is considerably lished methods. Sodium dodecyl sulfate/polyacrylamide gel stimulated in the presence of guanidineHCl. The soluble dehydrogenase has little or no NADH -_ NADP electrophoresis (11), protein determination (biuret), and de- and NADPH - NADP transhydrogenase activity. The former hydrogenase and transhydrogenase assays were carried out as reaction is known to be energy-linked in submitochondrial published (1). Other details are given with the results. Spec- particles; the latter was shown in the present studies also to be trophotometric studies were carried out with Cary 118 and energy-linked. Aminco-Chance dual wavelength/split beam spectropho- In view of the above and earlier results, possible mechanisms tometers. All nucleotides were obtained from P. L. Biochemi- for dehydrogenation and transhydrogenation (nonenergy-linked and energy-linked) involving reduced and oxidized NAD and cals. The sources of other chemicals were the same as detailed NADP are proposed. elsewhere (1). The mitochondrial electron transport system can oxidize RESULTS NADPH directly, i.e., without the intervention of NAD and the Effect of Guanidine on NADH Dehydrogenase. Table 1 transhydrogenase reaction (1, 2). Under optimal conditions, the summarizes the molecular and NADH dehydrogenase prop- rate of NADPH oxidation by submitochondrial particles is erties of complex I and the soluble NADH dehydrogenase iso- >250 nmol-min-1-mg-1 protein at 300, and under phosphor- lated from complex I. As compared to complex I, the soluble ylating conditions NADPH oxidation is coupled to ATP syn- dehydrogenase has a low dehydrogenase activity per mole of thesis with P/O of 2.4-2.9 (2, 3). Both NADPH dehydrogenase flavin and a higher Km for NADH. As seen in Fig. 1, addition and NADPH - NAD transhydrogenase activities fractionate of guanidine hydrochloride (up to about 150 mM) to the assay mainly into complex I (NADH:ubiquinone oxidoreductase, EC mixture increases the Vmax and lowers the KmNADH of the en- 1.6.5.3), the iron-sulfur centers of which have been shown in zyme, thus bringing these values closer to those of the complex recent electron paramagnetic resonance studies to be reduced I-bound dehydrogenase. Alkyl guanidines, including arginine to about the same extent by NADPH and the slowly oxidized and arginyl methyl ester, also activate the soluble dehydroge- NADH analog, reduced acetylpyridine adenine dinucleotide nase, but on a molar basis are less effective than guanidine-HCl (AcPyrADH) (4). (12). Guanido groups of enzyme arginyl residues have been Resolution of complex I with chaotropic agents yields a sol- demonstrated to be involved, apparently as substrate binding uble NADH dehydrogenase with a molecular weight of sites, in nicotinamide nucleotide and adenine nucleotide linked 70,000-80,000 (5, 6). The enzyme contains 1 mol of FMN, 4 enzymes (13-16), including the NADPH - NAD transhy- g-atoms of nonheme iron, and 4 mol of labile sulfide per mol, drogenase activity of the respiratory chain (2). The ability of and catalyzes the oxidation of NADH by quinoid structures guanidine.HCl and alkyl guanidines to restore the kinetic (menadione, ubiquinones, 2,6-dichloroindophenol, methylene characteristics of respiratory chain-linked dehydrogenase to blue), ferric compounds (ferricyanide, cytochromes c), and the soluble enzyme suggests that the soluble dehydrogenase NAD (for a recent review of complex I and the soluble NADH contains fewer (e.g., by loss of a polypeptide) or less favorably dehydrogenase, see ref. 7). positioned arginyl residues for substrate binding as compared The present studies show that the soluble NADH dehydro- to its membrane-bound counterpart. genase* also catalyzes NADPH dehydrogenation and NADPH NADPH Dehydrogenase Activity of the Soluble NADH NAD transhydrogenation. Little or no transhydrogenase Dehydrogenase. As seen in Fig. 2, the soluble dehydrogenase activity from NADH - NADP and NADPH NADP could has undetectable NADPH dehydrogenase activity at pH > 6.5. be demonstrated with the soluble dehydrogenase. The former Indeed, under the assay conditions applied to complex I, little reaction is known to be energy-linked in submitochondrial NADPH dehydrogenase and NADPH NAD transhydro- particles (8). The latter reaction, i.e., transhydrogenation from genase activity was found in any of the chaotrope-resolved fractions of complex I. However, as seen in Fig. 2, addition of Abbreviations: AcPyrAD, acetylpyridine adenine dinucleotide; ETPH, 75 mM guanidine-HCl allowed measurement of substantial phosphorylating submitochondrial particles. NADPH dehydrogenase activity, which greatly increased as * The designation "NADH dehydrogenase" has been applied by others was At this was to preparations comparable to complex I (for review, see ref. 7). In the assay pH lowered. pH 5.0, activity 13.1 gmol the present studies, this term is applied only to the soluble, low- of NADPH oxidized-min-l'mg-I protein. (For comparison the molecular-weight enzyme specified. in the preceding paragraph. NADH dehydrogenase activities of the enzyme in the absence 846 Downloaded by guest on September 29, 2021 Biochemistry: Hatefi and Galante Proc. Nati. Acad. Sci. USA 74 (1977) 847 Table 1. Molecular and enzymatic properties of complex I and the soluble, low-molecular-weight NADH dehydrogenase Dehydro- Parameter Complex I genase 0) cm E E g of protein/mol of flavin 7 x 105 7-8 x 104 C Flavin: Fe:S* 1:16-18:16-18 1:4:4 I Turnover numbert 5 x 105 2.9 x 104 I 00] KmNADH (MM) -45 - 80 z z * S, acid-labile sulfide. t Mol of NADH oxidized by potassium ferricyanide/mol of flavin per E E min. and presence of 75 mM guanidine are also shown.) Fig. 3 shows a similar effect of guanidine on the reduction of the enzyme prosthetic groups [FMN and iron-sulfur center(s)] by NADPH. At pH 6.0, the reduction of oxidized enzyme by NADPH from pH trace I to trace 6 of Fig. 3 took 25 min at 220, allowing multiple FIG. 2. NADH and NADPH dehydrogenase activities of NADH tracings of the intermediate stages of reduction to be made (Fig. dehydrogenase as a function of pH. Conditions: 100 mM K acetate 3 and inset, dashed traces). In the presence of 50 mM guanidine, for pH 5 and 5.5, 100 mM K phosphate for pH 6-8.5,150MM NADH, however, NADPH reduced the soluble dehydrogenase from 300 MM NADPH, and 0.2 mM 2-methylnaphthoquinone (K3) as trace I to trace 6 in less than 1 min. As seen in Fig. 2, guanidine electron acceptor at 380. The NADH dehydrogenase used was a stimulation of NADPH dehydrogenase activity, especially at 42-51% ammonium sulfate fraction of a complex I supernatant re- solved with 0.5 M NaCl04. (0 --- 0,0 --- 0) NADH - K3; ( pH >6.0, is much greater than stimulation of NADH dehy- A-A) NADPH - K3; (0, A) 75 mM Gdn-HCl. drogenase activity, and at pH <5.5 the enzyme has considerable NADPH dehydrogenase activity in the absence of added gua- nidine. hydride ion donor is NADH or NADPH. Fig. 4 shows the effect Transhydrogenase Activities of the Soluble NADH De- of pH on the NADPH AcPyrAD transhydrogenase activity hydrogenase. Table 2 summarizes the dehydrogenase and of the soluble enzyme in the absence and presence of 75 mM transhydrogenase activities of a typical preparation of the en- guanidine. As in the case of NADPH dehydrogenase activity zyme at two pH values in the absence and presence of 75 mM shown in Fig. 2, the enzyme has negligible NADPH -- NAD guanidine-HCI. Dehydrogenase and transhydrogenase activities transhydrogenase activity at pH >6.5, but it is substantially were measured using, respectively, ferricyanide and the 3- stimulated by lowering of pH and/or addition of guanidine- acetylpyridine analogs of the oxidized nucleotides as acceptors. HCL. It is seen that at the appropriate pH values (8 for NADH, 5.5 for NADPH), the dehydrogenase exhibits both NADH o Ac- PyrAD and NADPH -- AcPyrAD transhydrogenase activities, which are again stimulated in the presence of 75 mM guani- dine-HCI. It may also be noted that when the NADP analog is the acceptor, there is little or no transhydrogenase activity in the absence or presence of guanidine, regardless of whether the II, Ie .02~~ =00 0.06~ ~ ~ == 0Mm 20 -r x I E z E 400 450 500 Wavelength, nm FIG. 3. Reduction of NADH dehydrogenase chromophores by NADPH in the absence and presence of 50 mM guanidine-HCl. The enzyme at a concentration of 0.5 mg of protein per ml was dissolved in 0.1 M potassium phosphate at pH 6.0, and placed in a stoppered cuvette. The cuvette was evacuated and filled with argon five times.
Load more

Recommended publications
  • A Web Tool for Hydrogenase Classification and Analysis Dan Søndergaard1, Christian N
    www.nature.com/scientificreports OPEN HydDB: A web tool for hydrogenase classification and analysis Dan Søndergaard1, Christian N. S. Pedersen1 & Chris Greening2,3 H2 metabolism is proposed to be the most ancient and diverse mechanism of energy-conservation. The Received: 24 June 2016 metalloenzymes mediating this metabolism, hydrogenases, are encoded by over 60 microbial phyla Accepted: 09 September 2016 and are present in all major ecosystems. We developed a classification system and web tool, HydDB, Published: 27 September 2016 for the structural and functional analysis of these enzymes. We show that hydrogenase function can be predicted by primary sequence alone using an expanded classification scheme (comprising 29 [NiFe], 8 [FeFe], and 1 [Fe] hydrogenase classes) that defines 11 new classes with distinct biological functions. Using this scheme, we built a web tool that rapidly and reliably classifies hydrogenase primary sequences using a combination of k-nearest neighbors’ algorithms and CDD referencing. Demonstrating its capacity, the tool reliably predicted hydrogenase content and function in 12 newly-sequenced bacteria, archaea, and eukaryotes. HydDB provides the capacity to browse the amino acid sequences of 3248 annotated hydrogenase catalytic subunits and also contains a detailed repository of physiological, biochemical, and structural information about the 38 hydrogenase classes defined here. The database and classifier are freely and publicly available at http://services.birc.au.dk/hyddb/ Microorganisms conserve energy by metabolizing H2. Oxidation of this high-energy fuel yields electrons that can be used for respiration and carbon-fixation. This diffusible gas is also produced in diverse fermentation and 1 anaerobic respiratory processes . H2 metabolism contributes to the growth and survival of microorganisms across the three domains of life, including chemotrophs and phototrophs, lithotrophs and heterotrophs, aerobes and 1,2 anaerobes, mesophiles and extremophiles alike .
    [Show full text]
  • Progressive Encephalopathy and Central Hypoventilation Related to Homozygosity of NDUFV1 Nuclear Gene, a Rare Mitochondrial Disease
    Avens Publishing Group Inviting Innovations Open Access Case Report J Pediatr Child Care August 2019 Volume:5, Issue:1 © All rights are reserved by AL-Buali MJ, et al. AvensJournal Publishing of Group Inviting Innovations Progressive Encephalopathy Pediatrics & and Central Hypoventilation Child Care AL-Buali MJ*, Al Ramadhan S, Al Buali H, Al-Faraj J and Related to Homozygosity of Al Mohanna M Pediatric Department , Maternity Children Hospital , Saudi Arabia *Address for Correspondence: NDUFV1 Nuclear Gene, a Rare Al-buali MJ, Pediatric Consultant and Consultant of Medical Genetics, Deputy Chairman of Medical Genetic Unite, Pediatrics Department , Maternity Children Hospital, Al-hassa, Hofuf city, Mitochondrial Disease Saudi Arabia; E-mail: [email protected] Submission: 15 July 2019 Accepted: 5 August 2019 Keywords: Progressive encephalopathy; Central hypoventilation; Published: 9 August 2019 Nuclear mitochondrial disease; NDUFV1 gene Copyright: © 2019 AL-Buali MJ, et al. This is an open access article distributed under the Creative Commons Attribution License, which Abstract permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Background: Mitochondrial diseases are a group of disorders caused by dysfunctional organelles that generate energy for our body. Mitochondria small double-membrane organelles found in of the most common groups of genetic diseases with a minimum every cell of the human body except red blood cells. Mitochondrial diseases are sometimes caused by mutations in the mitochondrial DNA prevalence of greater than 1 in 5000 in adults. Mitochondrial diseases that affect mitochondrial function. Other mitochondrial diseases are can be present at birth but can be manifested also at any age [2].
    [Show full text]
  • Supplementary Table S4. FGA Co-Expressed Gene List in LUAD
    Supplementary Table S4. FGA co-expressed gene list in LUAD tumors Symbol R Locus Description FGG 0.919 4q28 fibrinogen gamma chain FGL1 0.635 8p22 fibrinogen-like 1 SLC7A2 0.536 8p22 solute carrier family 7 (cationic amino acid transporter, y+ system), member 2 DUSP4 0.521 8p12-p11 dual specificity phosphatase 4 HAL 0.51 12q22-q24.1histidine ammonia-lyase PDE4D 0.499 5q12 phosphodiesterase 4D, cAMP-specific FURIN 0.497 15q26.1 furin (paired basic amino acid cleaving enzyme) CPS1 0.49 2q35 carbamoyl-phosphate synthase 1, mitochondrial TESC 0.478 12q24.22 tescalcin INHA 0.465 2q35 inhibin, alpha S100P 0.461 4p16 S100 calcium binding protein P VPS37A 0.447 8p22 vacuolar protein sorting 37 homolog A (S. cerevisiae) SLC16A14 0.447 2q36.3 solute carrier family 16, member 14 PPARGC1A 0.443 4p15.1 peroxisome proliferator-activated receptor gamma, coactivator 1 alpha SIK1 0.435 21q22.3 salt-inducible kinase 1 IRS2 0.434 13q34 insulin receptor substrate 2 RND1 0.433 12q12 Rho family GTPase 1 HGD 0.433 3q13.33 homogentisate 1,2-dioxygenase PTP4A1 0.432 6q12 protein tyrosine phosphatase type IVA, member 1 C8orf4 0.428 8p11.2 chromosome 8 open reading frame 4 DDC 0.427 7p12.2 dopa decarboxylase (aromatic L-amino acid decarboxylase) TACC2 0.427 10q26 transforming, acidic coiled-coil containing protein 2 MUC13 0.422 3q21.2 mucin 13, cell surface associated C5 0.412 9q33-q34 complement component 5 NR4A2 0.412 2q22-q23 nuclear receptor subfamily 4, group A, member 2 EYS 0.411 6q12 eyes shut homolog (Drosophila) GPX2 0.406 14q24.1 glutathione peroxidase
    [Show full text]
  • Hydrogenases of Methanogens
    ANRV413-BI79-18 ARI 27 April 2010 21:0 Hydrogenases from Methanogenic Archaea, Nickel, a Novel Cofactor, and H2 Storage Rudolf K. Thauer, Anne-Kristin Kaster, Meike Goenrich, Michael Schick, Takeshi Hiromoto, and Seigo Shima Max Planck Institute for Terrestrial Microbiology, D-35043 Marburg, Germany; email: [email protected] Annu. Rev. Biochem. 2010. 79:507–36 Key Words First published online as a Review in Advance on H2 activation, energy-converting hydrogenase, complex I of the March 17, 2010 respiratory chain, chemiosmotic coupling, electron bifurcation, The Annual Review of Biochemistry is online at reversed electron transfer biochem.annualreviews.org This article’s doi: Abstract 10.1146/annurev.biochem.030508.152103 Most methanogenic archaea reduce CO2 with H2 to CH4. For the Copyright c 2010 by Annual Reviews. activation of H2, they use different [NiFe]-hydrogenases, namely All rights reserved energy-converting [NiFe]-hydrogenases, heterodisulfide reductase- 0066-4154/10/0707-0507$20.00 associated [NiFe]-hydrogenase or methanophenazine-reducing by University of Texas - Austin on 06/10/13. For personal use only. [NiFe]-hydrogenase, and F420-reducing [NiFe]-hydrogenase. The energy-converting [NiFe]-hydrogenases are phylogenetically related Annu. Rev. Biochem. 2010.79:507-536. Downloaded from www.annualreviews.org to complex I of the respiratory chain. Under conditions of nickel limitation, some methanogens synthesize a nickel-independent [Fe]- hydrogenase (instead of F420-reducing [NiFe]-hydrogenase) and by that reduce their nickel requirement. The [Fe]-hydrogenase harbors a unique iron-guanylylpyridinol cofactor (FeGP cofactor), in which a low-spin iron is ligated by two CO, one C(O)CH2-, one S-CH2-, and a sp2-hybridized pyridinol nitrogen.
    [Show full text]
  • A Web Tool for Hydrogenase Classification and Analysis
    bioRxiv preprint doi: https://doi.org/10.1101/061994; this version posted September 16, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 1 HydDB: A web tool for hydrogenase 2 classification and analysis 3 Dan Søndergaarda, Christian N. S. Pedersena, Chris Greeningb, c* 4 5 a Aarhus University, Bioinformatics Research Centre, C.F. Møllers Allé 8, Aarhus 6 DK-8000, Denmark 7 b The Commonwealth Scientific and Industrial Research Organisation, Land and 8 Water Flagship, Clunies Ross Street, Acton, ACT 2060, Australia 9 c Monash University, School of Biological Sciences, Clayton, VIC 2800, Australia 10 11 Correspondence: 12 Dr Chris Greening ([email protected]), Monash University, School of 13 Biological Sciences, Clayton, VIC 2800, Australia 14 Dan Søndergaard ([email protected]), Aarhus University, Bioinformatics Research 15 Centre, C.F. Møllers Allé 8, Aarhus DK-8000, Denmark 1 bioRxiv preprint doi: https://doi.org/10.1101/061994; this version posted September 16, 2016. The copyright holder for this preprint (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is made available under aCC-BY-NC-ND 4.0 International license. 16 Abstract 17 H2 metabolism is proposed to be the most ancient and diverse mechanism of 18 energy-conservation. The metalloenzymes mediating this metabolism, 19 hydrogenases, are encoded by over 60 microbial phyla and are present in all major 20 ecosystems.
    [Show full text]
  • [Nife]-Hydrogenase Ingmar Bürstela,B, Elisabeth Siebertb, Stefan Frielingsdorfa,B, Ingo Zebgerb, Bärbel Friedricha, and Oliver Lenza,B,1
    CO synthesized from the central one-carbon pool as source for the iron carbonyl in O2-tolerant [NiFe]-hydrogenase Ingmar Bürstela,b, Elisabeth Siebertb, Stefan Frielingsdorfa,b, Ingo Zebgerb, Bärbel Friedricha, and Oliver Lenza,b,1 aDepartment of Biology, Microbiology, Humboldt-Universität zu Berlin, 10115 Berlin, Germany; and bDepartment of Chemistry, Biophysical Chemistry, Technische Universität Berlin, 10623 Berlin, Germany Edited by Harry B. Gray, California Institute of Technology, Pasadena, CA, and approved November 8, 2016 (received for review September 1, 2016) Hydrogenases are nature’s key catalysts involved in both microbial of the HypD and HypC proteins acts as scaffold for the assembly of consumption and production of molecular hydrogen. H2 exhibits a the Fe(CN)2(CO) entity of the active site (7, 8). The HypF and − strongly bonded, almost inert electron pair and requires transition HypE proteins deliver the CN ligands, which are synthesized metals for activation. Consequently, all hydrogenases are metal- from carbamoyl phosphate (9). Incorporation of the nickel is fa- loenzymes that contain at least one iron atom in the catalytic center. cilitated by the HypB and HypA proteins (10). However, source For appropriate interaction with H2, the iron moiety demands for a and synthesis of the active site CO ligand remained elusive. sophisticated coordination environment that cannot be provided Maturation studies on the O2-tolerant, energy-generating just by standard amino acids. This dilemma has been overcome by [NiFe]-hydrogenases in the facultative H2-oxidizing bacterium the introduction of unprecedented chemistry—that is, by ligating Ralstonia eutropha H16 indicate that at least two different meta- the iron with carbon monoxide (CO) and cyanide (or equivalent) bolic sources exist for CO ligand synthesis (11).
    [Show full text]
  • Characterization of Electron Transport in Turnip Microsomes
    CHARACTERIZATION OF ELECTRON TRANSPORT IN TURNIP MICROSOMES By J. M. RUNGIE* and J.T. WISKICH* [Manuscript received 2 July 1971] Ab8tract Electron transport activities in the turnip microsome fraction were char­ acterized. Cytochrome c, 2,6-dichlorophenolindophenol (DCPIP), ferricyanide (FeCN), and neotetrazolium were reduced in the presence of NADH and NADPH, NADPH supporting a rate usually less than 10% that with NADH. Cytochrome ba was present and implicated in cytochrome c reduction. However, cytochrome P-450 was not detected. The effects of treatment of the microsomes with Triton X-I00, trypsin, and Naja naja venom on the reductase activities were studied. The treatments resulted in loss of NADH-cytochrome c reductase activity but had variable effects on the NADH-DCPIP and -FeCN reductase activities. The effects on the NADPH dehydro­ genase activities were also variable, but usually NADPH-cytochrome c reductase was inhibited while NADPH-DCPIP and -FeCN reductases were stimulated. Fractionation of the microsomes by differential centrifuging and centrifuging through sucrose gradients in the presence of ions yielded a fraction rich in NADH dehydrogenases, NADPH-cytochrome c reductase, and cytochrome b3 • There was a broader distribution of the other NADPH dehydrogenase activities. The results indicated the presence of two distinct electron transport chains on the turnip microsomal membranes, one specific for NADH and the other for NADPH. However, the activity of the latter may be partially due to soluble fraction contamination. I. INTRODUCTION Characterization of microsomal electron transport systems has concentrated on fractions isolated from animal tissue (Dallner 1963; Siekevitz 1963). It is now well established that there are two distinct electron transport schemes on the microsomal membranes.
    [Show full text]
  • Higher NDUFS8 Serum Levels Correlate with Better Insulin Sensitivity in Type 1 Diabetes
    Higher NDUFS8 Serum Levels Correlate with Better Insulin Sensitivity in Type 1 Diabetes Justyna Flotyńska ( [email protected] ) Poznan University of Medical Sciences, Department of Internal Medicine and Diabetology Daria Klause Poznan University of Medical Sciences, Department of Internal Medicine and Diabetology Michał Kulecki Poznan University of Medical Sciences, Department of Internal Medicine and Diabetology Aleksandra Cieluch Poznan University of Medical Sciences, Department of Internal Medicine and Diabetology Martyna Pakuła Poznan University of Medical Sciences, Department of Hypertensiology, Angiology and Internal Medicine Dorota Zozulińska-Ziółkiewicz Poznan University of Medical Sciences, Department of Internal Medicine and Diabetology Aleksandra Uruska Poznan University of Medical Sciences, Department of Internal Medicine and Diabetology Research Article Keywords: diabetes mellitus type 1, insulin resistance, e-GDR: estimated glucose disposal rate, NADH dehydrogenase iron-sulfur protein 8 Posted Date: May 11th, 2021 DOI: https://doi.org/10.21203/rs.3.rs-496330/v1 License: This work is licensed under a Creative Commons Attribution 4.0 International License. Read Full License Higher NDUFS8 serum levels correlate with better insulin sensitivity in Type 1 Diabetes. Authors: Justyna Flotyńska1*, Daria Klause1*, Michał Kulecki1, Aleksandra Cieluch1, Martyna Pakuła2, Dorota Zozulińska-Ziółkiewicz1, Aleksandra Uruska1 1Department of Internal Medicine and Diabetology, Poznan University of Medical Sciences, Raszeja Hospital,
    [Show full text]
  • Discovery of Industrially Relevant Oxidoreductases
    DISCOVERY OF INDUSTRIALLY RELEVANT OXIDOREDUCTASES Thesis Submitted for the Degree of Master of Science by Kezia Rajan, B.Sc. Supervised by Dr. Ciaran Fagan School of Biotechnology Dublin City University Ireland Dr. Andrew Dowd MBio Monaghan Ireland January 2020 Declaration I hereby certify that this material, which I now submit for assessment on the programme of study leading to the award of Master of Science, is entirely my own work, and that I have exercised reasonable care to ensure that the work is original, and does not to the best of my knowledge breach any law of copyright, and has not been taken from the work of others save and to the extent that such work has been cited and acknowledged within the text of my work. Signed: ID No.: 17212904 Kezia Rajan Date: 03rd January 2020 Acknowledgements I would like to thank the following: God, for sending me angels in the form of wonderful human beings over the last two years to help me with any- and everything related to my project. Dr. Ciaran Fagan and Dr. Andrew Dowd, for guiding me and always going out of their way to help me. Thank you for your patience, your advice, and thank you for constantly believing in me. I feel extremely privileged to have gotten an opportunity to work alongside both of you. Everything I’ve learnt and the passion for research that this project has sparked in me, I owe it all to you both. Although I know that words will never be enough to express my gratitude, I still want to say a huge thank you from the bottom of my heart.
    [Show full text]
  • Reconstitution of [Fe]-Hydrogenase Using Model Complexes
    View metadata, citation and similar papers at core.ac.uk brought to you by CORE provided by Infoscience - École polytechnique fédérale de Lausanne Reconstitution of [Fe]-hydrogenase using model complexes Seigo Shima1,2,*, Dafa Chen3, Tao Xu4, Matthew D. Wodrich4,5, Takashi Fujishiro1, Katherine M. Schultz4, Jörg Kahnt1, Kenichi Ataka6 & Xile Hu4,* 1Max Planck Institute for Terrestrial Microbiology, 35043 Marburg, Germany. 2PRESTO, Japan Science and Technology Agency (JST), 332-0012 Saitama, Japan. 3School of Chemical Engineering and Technology, Harbin Institute of Technology, 150001 Harbin, China. 4Laboratory of Inorganic Synthesis and Catalysis, Institute of Chemical Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. 5Laboratory for Computational Molecular Design, Institute of Chemical Science and Engineering, Ecole Polytechnique Fédérale de Lausanne (EPFL), 1015 Lausanne, Switzerland. 6Department of Physics, Freie Universität Berlin, 14195 Berlin, Germany. 1 Abstract. [Fe]-Hydrogenase catalyzes the reversible hydrogenation of a methenyl- tetrahydromethanopterin substrate, which is an intermediate step during methanogenesis from CO2 and H2. The active site contains an iron-guanylylpyridinol (FeGP) cofactor, in which Fe2+ is coordinated by two CO ligands, as well as an acyl carbon atom and a pyridinyl nitrogen atom from a 3,4,5,6-substituted 2-pyridinol ligand. However, the mechanism of H2 activation by [Fe]-hydrogenase is unclear. Here, we report reconstitution of [Fe]-hydrogenase from an apoenzyme using two FeGP cofactor mimics to create semi-synthetic enzymes. The small molecule mimics reproduce the ligand environment of the active site, but are inactive towards H2 binding and activation on their own. We show that reconstituting the enzyme using a mimic containing a 2-hydroxy pyridine group restores activity, whilst an analogous experiment with a 2-methoxy-pyridine complex was essentially inactive.
    [Show full text]
  • Perspectives
    PERSPECTIVES in a number of enzymes such as [FeFe]- hydrogenase, [FeNi]-hydrogenase, Natural inspirations for metal–ligand [Fe]-hydrogenase, lactate racemase and alcohol dehydrogenase. In this Perspective, cooperative catalysis we discuss these examples of biological cooperative catalysis and how, inspired by these naturally occurring systems, chemists Matthew D. Wodrich and Xile Hu have sought to create functional analogues. Abstract | In conventional homogeneous catalysis, supporting ligands act as We also speculate that cooperative catalysis spectators that do not interact directly with substrates. However, in metal–ligand may be at play in [NiFe]-carbon monoxide cooperative catalysis, ligands are involved in facilitating reaction pathways that dehydrogenase ([NiFe]-CODHase), which may inspire the design of synthetic CO2 would be less favourable were they to occur solely at the metal centre. This reduction catalysts making use of these catalysis paradigm has been known for some time, in part because it is at play motifs. Each section in the following in enzyme catalysis. For example, studies of hydrogenative and dehydrogenative discussion is devoted to an enzyme and its enzymes have revealed striking details of metal–ligand cooperative catalysis synthetic models. that involve functional groups proximal to metal active sites. In addition to [FeFe]- and [NiFe]-hydrogenase the more well-known [FeFe]-hydrogenase and [NiFe]-hydrogenase enzymes, Hydrogenases are enzymes that catalyse [Fe]-hydrogenase, lactate racemase and alcohol dehydrogenase each makes use (REF. 5) the production and utilization of H2 . of cooperative catalysis. This Perspective highlights these enzymatic examples of Three variants of hydrogenase enzymes exist metal–ligand cooperative catalysis and describes functional bioinspired which are named [FeFe]-, [NiFe]- and [Fe]-hydrogenase because their active molecular catalysts that also make use of these motifs.
    [Show full text]
  • Hydrogenase and Ferredoxin:NADP -Oxidoreductase (FNR)
    Photosynthetic electron partitioning between [FeFe]- hydrogenase and ferredoxin:NADPþ-oxidoreductase (FNR) enzymes in vitro Iftach Yacobya,1, Sergii Pochekailova, Hila Toporikb, Maria L. Ghirardic, Paul W. Kingc,1, and Shuguang Zhanga,1 aCenter for Biomedical Engineering NE47-379, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139-4307; cBiosciences Center, National Renewable Energy Laboratory, 1617 Cole Boulevard, Golden, CO 80401-3305; and bDepartment of Biochemistry and Molecular Biology, The George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv, 69978, Israel Edited by Alan R. Fersht, Medical Research Council Laboratory of Molecular Biology, Cambridge, United Kingdom, and approved April 28, 2011 (receivedfor review March 5, 2011) Photosynthetic water splitting, coupled to hydrogenase-catalyzed hydrogen production, is considered a promising clean, renewable source of energy. It is widely accepted that the oxygen sensitivity of hydrogen production, combined with competition between hydrogenases and NADPH-dependent carbon dioxide fixation are the main limitations for its commercialization. Here we provide evi- dence that, under the anaerobic conditions that support hydrogen production, there is a significant loss of photosynthetic electrons toward NADPH production in vitro. To elucidate the basis for com- petition, we bioengineered a ferredoxin-hydrogenase fusion and characterized hydrogen production kinetics in the presence of Fd, ferredoxin:NADPþ-oxidoreductase (FNR), and NADPþ. Replacing the hydrogenase with a ferredoxin-hydrogenase fusion switched the bias of electron transfer from FNR to hydrogenase and resulted in an increased rate of hydrogen photoproduction. These results suggest a new direction for improvement of biohydrogen produc- tion and a means to further resolve the mechanisms that control partitioning of photosynthetic electron transport.
    [Show full text]