51
|
Hidalgo R, Ash PA, Healy AJ, Vincent KA. Infrared Spectroscopy During Electrocatalytic Turnover Reveals the Ni-L Active Site State During H2Oxidation by a NiFe Hydrogenase. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201502338] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
|
52
|
Oteri F, Ciaccafava A, de Poulpiquet A, Baaden M, Lojou E, Sacquin-Mora S. The weak, fluctuating, dipole moment of membrane-bound hydrogenase from Aquifex aeolicus accounts for its adaptability to charged electrodes. Phys Chem Chem Phys 2015; 16:11318-22. [PMID: 24789038 DOI: 10.1039/c4cp00510d] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
[NiFe] hydrogenases from Aquifex aeolicus (AaHase) and Desulfovibrio fructosovorans (DfHase) have been mainly studied to characterize physiological electron transfer processes, or to develop biotechnological devices such as biofuel cells. In this context, it remains difficult to control the orientation of AaHases on electrodes to achieve a fast interfacial electron transfer. Here, we study the electrostatic properties of these two proteins based on microsecond-long molecular dynamics simulations that we compare to voltammetry experiments. Our calculations show weak values and large fluctuations of the dipole direction in AaHase compared to DfHase, enabling the AaHase to absorb on both negatively and positively charged electrodes, with an orientation distribution that induces a spread in electron transfer rates. Moreover, we discuss the role of the transmembrane helix of AaHase and show that it does not substantially impact the general features of the dipole moment.
Collapse
Affiliation(s)
- Francesco Oteri
- Laboratoire de Biochimie Théorique, UPR 9080 CNRS Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France.
| | | | | | | | | | | |
Collapse
|
53
|
[NiFe]-hydrogenase maturation in vitro: analysis of the roles of the HybG and HypD accessory proteins1. Biochem J 2015; 464:169-77. [PMID: 25184670 DOI: 10.1042/bj20140485] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
[NiFe]-hydrogenases (Hyd) bind a nickel-iron-based cofactor. The Fe ion of the cofactor is bound by two cyanide ligands and a single carbon monoxide ligand. Minimally six accessory proteins (HypA-HypF) are necessary for NiFe(CN)2CO cofactor biosynthesis in Escherichia coli. It has been shown that the anaerobically purified HypC-HypD-HypE scaffold complex carries the Fe(CN)2CO moiety of this cofactor. In the present study, we have purified the HybG-HypDE complex and used it to successfully reconstitute in vitro active Hyd from E. coli. HybG is a homologue of HypC that is specifically required for the maturation of Hyd-2 and also functions in the maturation of Hyd-1 of E. coli. Maturation of active Hyd-1 and Hyd-2 could be demonstrated in extracts derived from HybG- and HypD-deficient E. coli strains by adding anaerobically purified HybG-HypDE complex. In vitro maturation was dependent on ATP, carbamoylphosphate, nickel and reducing conditions. Hydrogenase maturation was prevented when the purified HybG-HypDE complex used in the maturation assay lacked a bound Fe(CN)2CO moiety. These findings demonstrate that it is possible to isolate incompletely processed intermediates on the maturation pathway and to use these to activate apo-forms of [NiFe]-hydrogenase large subunits.
Collapse
|
54
|
Structural differences of oxidized iron–sulfur and nickel–iron cofactors in O 2 -tolerant and O 2 -sensitive hydrogenases studied by X-ray absorption spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOENERGETICS 2015; 1847:162-170. [DOI: 10.1016/j.bbabio.2014.06.011] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2014] [Revised: 06/06/2014] [Accepted: 06/16/2014] [Indexed: 11/23/2022]
|
55
|
Xu L, Armstrong FA. Pushing the limits for enzyme-based membrane-less hydrogen fuel cells – achieving useful power and stability. RSC Adv 2015. [DOI: 10.1039/c4ra13565b] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The festive Hydrogen House, powered by a hydrogen–air mixture using an enzyme fuel cell.
Collapse
Affiliation(s)
- Lang Xu
- Inorganic Chemistry Laboratory
- Department of Chemistry
- University of Oxford
- Oxford OX1 3QR
- UK
| | - Fraser A. Armstrong
- Inorganic Chemistry Laboratory
- Department of Chemistry
- University of Oxford
- Oxford OX1 3QR
- UK
| |
Collapse
|
56
|
Gan L, Jennings D, Laureanti J, Jones AK. Biomimetic Complexes for Production of Dihydrogen and Reduction of CO2. TOP ORGANOMETAL CHEM 2015. [DOI: 10.1007/3418_2015_146] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
|
57
|
Volbeda A, Martin L, Barbier E, Gutiérrez-Sanz O, De Lacey AL, Liebgott PP, Dementin S, Rousset M, Fontecilla-Camps JC. Crystallographic studies of [NiFe]-hydrogenase mutants: towards consensus structures for the elusive unready oxidized states. J Biol Inorg Chem 2015; 20:11-22. [PMID: 25315838 DOI: 10.1007/s00775-014-1203-9] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Accepted: 10/01/2014] [Indexed: 01/12/2023]
Abstract
Catalytically inactive oxidized O2-sensitive [NiFe]-hydrogenases are characterized by a mixture of the paramagnetic Ni-A and Ni-B states. Upon O2 exposure, enzymes in a partially reduced state preferentially form the unready Ni-A state. Because partial O2 reduction should generate a peroxide intermediate, this species was previously assigned to the elongated Ni-Fe bridging electron density observed for preparations of [NiFe]-hydrogenases known to contain the Ni-A state. However, this proposition has been challenged based on the stability of this state to UV light exposure and the possibility of generating it anaerobically under either chemical or electrochemical oxidizing conditions. Consequently, we have considered alternative structures for the Ni-A species including oxidation of thiolate ligands to either sulfenate or sulfenic acid. Here, we report both new and revised [NiFe]-hydrogenases structures and conclude, taking into account corresponding characterizations by Fourier transform infrared spectroscopy (FTIR), that the Ni-A species contains oxidized cysteine and bridging hydroxide ligands instead of the peroxide ligand we proposed earlier. Our analysis was rendered difficult by the typical formation of mixtures of unready oxidized states that, furthermore, can be reduced by X-ray induced photoelectrons. The present study could be carried out thanks to the use of Desulfovibrio fructosovorans [NiFe]-hydrogenase mutants with special properties. In addition to the Ni-A state, crystallographic results are also reported for two diamagnetic unready states, allowing the proposal of a revised oxidized inactive Ni-SU model and a new structure characterized by a persulfide ion that is assigned to an Ni-'Sox' species.
Collapse
Affiliation(s)
- Anne Volbeda
- University Grenoble Alpes, IBS, 38044, Grenoble, France. .,CEA, IBS, 38044, Grenoble, France. .,CNRS, IBS, 38044, Grenoble, France.
| | - Lydie Martin
- University Grenoble Alpes, IBS, 38044, Grenoble, France.,CEA, IBS, 38044, Grenoble, France.,CNRS, IBS, 38044, Grenoble, France
| | - Elodie Barbier
- University Grenoble Alpes, IBS, 38044, Grenoble, France.,CEA, IBS, 38044, Grenoble, France.,CNRS, IBS, 38044, Grenoble, France.,CEA, MINATEC, 38044, Grenoble, France
| | | | | | - Pierre-Pol Liebgott
- Aix-Marseille Université, CNRS, IMM, 13402, Marseille, France.,Aix-Marseille Université, CNRS/INSU, MIO, 13288, Marseille, France
| | | | - Marc Rousset
- Aix-Marseille Université, CNRS, IMM, 13402, Marseille, France.,Consulate General of France, 205 N Michigan Ave, Chicago, IL, 60601, USA
| | - Juan C Fontecilla-Camps
- University Grenoble Alpes, IBS, 38044, Grenoble, France.,CEA, IBS, 38044, Grenoble, France.,CNRS, IBS, 38044, Grenoble, France
| |
Collapse
|
58
|
Dance I. What is the trigger mechanism for the reversal of electron flow in oxygen-tolerant [NiFe] hydrogenases? Chem Sci 2014; 6:1433-1443. [PMID: 29560232 PMCID: PMC5811149 DOI: 10.1039/c4sc03223c] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/08/2014] [Indexed: 11/21/2022] Open
Abstract
A new mechanistic model is developed for the sequence of events by which oxygen-tolerant [NiFe] hydrogenase enzymes respond to O2.
The [NiFe] hydrogenases use an electron transfer relay of three FeS clusters – proximal, medial and distal – to release the electrons from the principal reaction, H2 → 2H+ + 2e–, that occurs at the Ni–Fe catalytic site. This site is normally inactivated by O2, but the subclass of O2-tolerant [NiFe] hydrogenases are able to counter this inactivation through the agency of an unusual and unprecedented proximal cluster, with composition [Fe4S3(Scys)6], that is able to transfer two electrons back to the Ni–Fe site and effect crucial reduction of O2-derived species and thereby reactivate the Ni–Fe site. This proximal cluster gates both the direction and the number of electrons flowing through it, and can reverse the normal flow during O2 attack. The unusual structures and redox potentials of the proximal cluster are known: a structural change in the proximal cluster causes changes in its electron-transfer potentials. Using protein structure analysis and density functional simulations, this paper identifies a closed protonic system comprising the proximal cluster, some contiguous residues, and a proton reservoir, and proposes that it is activated by O2-induced conformational change at the Ni–Fe site. This change is linked to a key histidine residue which then causes protonation of the proximal cluster, and migration of this proton to a key μ3-S atom. The resulting SH group causes the required structural change at the proximal cluster, modifying its redox potentials, and leads to the reversed electron flow back to the Ni–Fe site. This cycle is reversible, and the protons involved are independent of those used or produced in reactions at the active site. Existing experimental support for this model is cited, and new testing experiments are suggested.
Collapse
Affiliation(s)
- Ian Dance
- School of Chemistry , University of New South Wales , Sydney 2052 , Australia .
| |
Collapse
|
59
|
Oteri F, Baaden M, Lojou E, Sacquin-Mora S. Multiscale Simulations Give Insight into the Hydrogen In and Out Pathways of [NiFe]-Hydrogenases from Aquifex aeolicus and Desulfovibrio fructosovorans. J Phys Chem B 2014; 118:13800-11. [DOI: 10.1021/jp5089965] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Affiliation(s)
- Francesco Oteri
- Laboratoire
de Biochimie Théorique, CNRS UPR9080, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Marc Baaden
- Laboratoire
de Biochimie Théorique, CNRS UPR9080, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| | - Elisabeth Lojou
- Bioénergétique
et Ingénierie des Protéines, Institut de Microbiologie
de la Méditerranée, CNRS, Aix Marseille University, 31 Chemin Joseph Aiguier, 13402 Marseille Cedex, France
| | - Sophie Sacquin-Mora
- Laboratoire
de Biochimie Théorique, CNRS UPR9080, Institut de Biologie Physico-Chimique, 13 rue Pierre et Marie Curie, 75005 Paris, France
| |
Collapse
|
60
|
So K, Kitazumi Y, Shirai O, Kurita K, Nishihara H, Higuchi Y, Kano K. Kinetic Analysis of Inactivation and Enzyme Reaction of Oxygen-Tolerant [NiFe]-Hydrogenase at Direct Electron-Transfer Bioanode. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2014. [DOI: 10.1246/bcsj.20140223] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Affiliation(s)
- Keisei So
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
| | - Yuki Kitazumi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
| | - Osamu Shirai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Kouhei Kurita
- Department of Bioresource Science, Collage of Agriculture, Ibaraki University
| | - Hirofumi Nishihara
- Department of Bioresource Science, Collage of Agriculture, Ibaraki University
| | - Yoshiki Higuchi
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
- Department of Life Science, Graduate School of Life Science, University of Hyogo
| | - Kenji Kano
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| |
Collapse
|
61
|
So K, Kitazumi Y, Shirai O, Kurita K, Nishihara H, Higuchi Y, Kano K. Gas-diffusion and Direct-electron-transfer-type Bioanode for Hydrogen Oxidation with Oxygen-tolerant [NiFe]-hydrogenase as an Electrocatalyst. CHEM LETT 2014. [DOI: 10.1246/cl.140622] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Affiliation(s)
- Keisei So
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
| | - Yuki Kitazumi
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
| | - Osamu Shirai
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| | - Kouhei Kurita
- Department of Bioresource Science, College of Agriculture, Ibaraki University
| | - Hirofumi Nishihara
- Department of Bioresource Science, College of Agriculture, Ibaraki University
| | - Yoshiki Higuchi
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
- Department of Life Science, Graduate School of Life Science, University of Hyogo
| | - Kenji Kano
- Division of Applied Life Sciences, Graduate School of Agriculture, Kyoto University
- Core Research for Evolutional Science and Technology (CREST), Japan Science and Technology Agency (JST)
| |
Collapse
|
62
|
A redox hydrogel protects hydrogenase from high-potential deactivation and oxygen damage. Nat Chem 2014; 6:822-7. [PMID: 25143219 DOI: 10.1038/nchem.2022] [Citation(s) in RCA: 144] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 06/30/2014] [Indexed: 11/08/2022]
Abstract
Hydrogenases are nature's efficient catalysts for both the generation of energy via oxidation of molecular hydrogen and the production of hydrogen via the reduction of protons. However, their O2 sensitivity and deactivation at high potential limit their applications in practical devices, such as fuel cells. Here, we show that the integration of an O2-sensitive hydrogenase into a specifically designed viologen-based redox polymer protects the enzyme from O2 damage and high-potential deactivation. Electron transfer between the polymer-bound viologen moieties controls the potential applied to the active site of the hydrogenase and thus insulates the enzyme from excessive oxidative stress. Under catalytic turnover, electrons provided from the hydrogen oxidation reaction induce viologen-catalysed O2 reduction at the polymer surface, thus providing self-activated protection from O2. The advantages of this tandem protection are demonstrated using a single-compartment biofuel cell based on an O2-sensitive hydrogenase and H2/O2 mixed feed under anode-limiting conditions.
Collapse
|
63
|
Cammack R, Balk J. Iron-sulfur Clusters. BINDING, TRANSPORT AND STORAGE OF METAL IONS IN BIOLOGICAL CELLS 2014. [DOI: 10.1039/9781849739979-00333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Iron-sulfur clusters are universally distributed groups occurring in iron-sulfur proteins. They have a wide range of cellular functions which reflect the chemistry of the clusters. Some clusters are involved in electron transport and energy transduction in photosynthesis and respiration. Others can bind substrates and participate in enzyme catalysis. Regulatory functions have also been documented for clusters that respond to oxygen partial pressure and iron availability. Finally, there are some for which no function has been defined; they may act as stabilizing structures, for example, in enzymes involved in nucleic acid metabolism. The clusters are constructed intracellularly and inserted into proteins, which can then be transported to intracellular targets, in some cases, across membranes. Three different types of iron-sulfur cluster assembly machinery have evolved in prokaryotes: NIF, ISC and SUF. Each system involves a scaffold protein on which the cluster is constructed (encoded by genes nifU, iscU, sufU or sufB) and a cysteine desulfurase (encoded by nifS, iscS or sufS) which provides the sulfide sulfur. In eukaryotic cells, clusters are formed in the mitochondria for the many iron-sulfur proteins in this organelle. The mitochondrial biosynthesis pathway is linked to the cytoplasmic iron-sulfur assembly system (CIA) for the maturation of cytoplasmic and nuclear iron-sulfur proteins. In plant cells, a SUF-type system is used for cluster assembly in the plastids. Many accessory proteins are involved in cluster transfer before insertion into the appropriate sites in Fe-S proteins.
Collapse
Affiliation(s)
- Richard Cammack
- King's College London, Department of Biochemistry, 150 Stamford Street London SE1 9NH UK
| | - Janneke Balk
- John Innes Centre and University of East Anglia Norwich Research Park, Colney Lane Norwich NR4 7UH UK
| |
Collapse
|
64
|
Radu V, Frielingsdorf S, Evans SD, Lenz O, Jeuken LJC. Enhanced oxygen-tolerance of the full heterotrimeric membrane-bound [NiFe]-hydrogenase of Ralstonia eutropha. J Am Chem Soc 2014; 136:8512-5. [PMID: 24866391 PMCID: PMC4073834 DOI: 10.1021/ja503138p] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Hydrogenases are oxygen-sensitive enzymes that catalyze the conversion between protons and hydrogen. Water-soluble subcomplexes of membrane-bound [NiFe]-hydrogenases (MBH) have been extensively studied for applications in hydrogen-oxygen fuel cells as they are relatively tolerant to oxygen, although even these catalysts are still inactivated in oxidative conditions. Here, the full heterotrimeric MBH of Ralstonia eutropha, including the membrane-integral cytochrome b subunit, was investigated electrochemically using electrodes modified with planar tethered bilayer lipid membranes (tBLM). Cyclic voltammetry and chronoamperometry experiments show that MBH, in equilibrium with the quinone pool in the tBLM, does not anaerobically inactivate under oxidative redox conditions. In aerobic environments, the MBH is reversibly inactivated by O2, but reactivation was found to be fast even under oxidative redox conditions. This enhanced resistance to inactivation is ascribed to the oligomeric state of MBH in the lipid membrane.
Collapse
Affiliation(s)
- Valentin Radu
- School of Biomedical Sciences, the Astbury Centre for Structural Molecular Biology, and School of Physics & Astronomy, University of Leeds , Leeds LS2 9JT, United Kingdom
| | | | | | | | | |
Collapse
|
65
|
Abstract
An oxygen-tolerant respiratory [NiFe]-hydrogenase is proven to be a four-electron hydrogen/oxygen oxidoreductase, catalyzing the reaction 2 H2 + O2 = 2 H2O, equivalent to hydrogen combustion, over a sustained period without inactivating. At least 86% of the H2O produced by Escherichia coli hydrogenase-1 exposed to a mixture of 90% H2 and 10% O2 is accounted for by a direct four-electron pathway, whereas up to 14% arises from slower side reactions proceeding via superoxide and hydrogen peroxide. The direct pathway is assigned to O2 reduction at the [NiFe] active site, whereas the side reactions are an unavoidable consequence of the presence of low-potential relay centers that release electrons derived from H2 oxidation. The oxidase activity is too slow to be useful in removing O2 from the bacterial periplasm; instead, the four-electron reduction of molecular oxygen to harmless water ensures that the active site survives to catalyze sustained hydrogen oxidation.
Collapse
|
66
|
Affiliation(s)
- Wolfgang Lubitz
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Hideaki Ogata
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Olaf Rüdiger
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| | - Edward Reijerse
- Max Planck Institute for Chemical Energy Conversion, Stiftstr. 34-36, 45470 Mülheim an der Ruhr, Germany
| |
Collapse
|
67
|
Poulpiquet AD, Marques-Knopf H, Wernert V, Giudici-Orticoni MT, Gadiou R, Lojou E. Carbon nanofiber mesoporous films: efficient platforms for bio-hydrogen oxidation in biofuel cells. Phys Chem Chem Phys 2014; 16:1366-78. [DOI: 10.1039/c3cp54631d] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
|
68
|
|
69
|
Sakai T, Mersch D, Reisner E. Photocatalytic hydrogen evolution with a hydrogenase in a mediator-free system under high levels of oxygen. Angew Chem Int Ed Engl 2013; 52:12313-6. [PMID: 24115736 PMCID: PMC4138992 DOI: 10.1002/anie.201306214] [Citation(s) in RCA: 115] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Indexed: 12/03/2022]
Abstract
Take a breath: An oxygen-tolerant hydrogenase can be employed with a dye in a photocatalytic scheme for the generation of H2 . The homogeneous system does not require a redox mediator and visible-light irradiation yields high amounts of H2 even in the presence of air.
Collapse
Affiliation(s)
- Tsubasa Sakai
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge CB2 1EW (UK)
| | - Dirk Mersch
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge CB2 1EW (UK)
| | - Erwin Reisner
- Department of Chemistry, University of CambridgeLensfield Road, Cambridge CB2 1EW (UK)
| |
Collapse
|
70
|
Sakai T, Mersch D, Reisner E. Photocatalytic Hydrogen Evolution with a Hydrogenase in a Mediator-Free System under High Levels of Oxygen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201306214] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
71
|
Bowman L, Palmer T, Sargent F. A regulatory domain controls the transport activity of a twin-arginine signal peptide. FEBS Lett 2013; 587:3365-70. [PMID: 24036452 DOI: 10.1016/j.febslet.2013.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2013] [Revised: 09/02/2013] [Accepted: 09/03/2013] [Indexed: 11/25/2022]
Abstract
The twin-arginine translocation (Tat) pathway is used by bacteria for the transmembrane transport of folded proteins. Proteins are targeted to the Tat translocase by signal peptides that have common tripartite structures consisting of polar n-regions, hydrophobic h-regions, and polar c-regions. In this work, the signal peptide of [NiFe] hydrogenase-1 from Escherichia coli has been studied. The hydrogenase-1 signal peptide contains an extended n-region that has a conserved primary structure. Genetic and biochemical approaches reveal that the signal peptide n-region is essential for hydrogenase assembly and acts as a regulatory domain controlling transport activity of the signal peptide.
Collapse
Affiliation(s)
- Lisa Bowman
- College of Life Sciences, University of Dundee, Dundee DD1 5EH, Scotland, UK
| | | | | |
Collapse
|
72
|
Pelmenschikov V, Kaupp M. Redox-Dependent Structural Transformations of the [4Fe-3S] Proximal Cluster in O2-Tolerant Membrane-Bound [NiFe]-Hydrogenase: A DFT Study. J Am Chem Soc 2013; 135:11809-23. [DOI: 10.1021/ja402159u] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Vladimir Pelmenschikov
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie, Sekr. C7, Strasse
des 17. Juni 135, 10623 Berlin, Germany
| | - Martin Kaupp
- Technische Universität Berlin, Institut für Chemie, Theoretische Chemie, Sekr. C7, Strasse
des 17. Juni 135, 10623 Berlin, Germany
| |
Collapse
|
73
|
Lauterbach L, Lenz O, Vincent KA. H₂-driven cofactor regeneration with NAD(P)⁺-reducing hydrogenases. FEBS J 2013; 280:3058-68. [PMID: 23497170 DOI: 10.1111/febs.12245] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2013] [Revised: 03/05/2013] [Accepted: 03/08/2013] [Indexed: 12/15/2022]
Abstract
A large number of industrially relevant enzymes depend upon nicotinamide cofactors, which are too expensive to be added in stoichiometric amounts. Existing NAD(P)H-recycling systems suffer from low activity, or the generation of side products. H₂-driven cofactor regeneration has the advantage of 100% atom efficiency and the use of H₂ as a cheap reducing agent, in a world where sustainable energy carriers are increasingly attractive. The state of development of H₂-driven cofactor-recycling systems and examples of their integration with enzyme reactions are summarized in this article. The O₂-tolerant NAD⁺-reducing hydrogenase from Ralstonia eutropha is a particularly attractive candidate for this approach, and we therefore discuss its catalytic properties that are relevant for technical applications.
Collapse
|