Oxygen-tolerant hydrogenases in hydrogen-based technologies

Friedrich, Bärbel; Fritsch, Johannes; Lenz, Oliver

doi:10.1016/j.copbio.2011.01.006

Cited by 105 publications

(86 citation statements)

References 53 publications

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“…The binding energies for these peaks were as follows: 69. 6 Morphological Characterization. Figure 4 shows FE-TEM images for the MWNT-PVPMe before and after adsorption of H 2 ase, together with those of the MWNTs asreceived and MWNT-BenBr.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Pd(II)-Directed Encapsulation of Hydrogenase within the Layer-by-Layer Multilayers of Carbon Nanotube Polyelectrolyte Used as a Heterogeneous Catalyst for Oxidation of Hydrogen

et al. 2015

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A metal-directed assembling approach has been developed to encapsulate hydrogenase (H2ase) within a layer-by-layer (LBL) multilayer of carbon nanotube polyelectrolyte (MWNT-PVPMe), which showed efficient biocatalytic oxidation of H2 gas. The MWNT-PVPMe was prepared via a diazonium process and addition reactions with poly(4-vinylpyridine) (PVP) and methyl iodide (MeI). The covalently attached polymers and organic substituents in the polyelectrolyte comprised 60-70% of the total weight. The polyelectrolyte was then used as a substrate for H2ase binding to produce MWNT-PVPMe@H2ase bionanocomposites. X-ray photoelectron spectra revealed that the bionanocomposites included the elements of Br, S, C, N, O, I, Fe, and Ni, which confirmed that they were composed of MWNT-PVPMe and H2ase. Field emission transmission electron microscope images revealed that the H2ase was adsorbed on the surface of MWNT-PVPMe with the domains ranging from 20 to 40 nm. Further, with the use of the bionanocomposites as nanolinkers and Na2PdCl4 as connectors, the (Pd/MWNT-PVPMe@H2ase)n multilayers were constructed on the quartz and gold substrate surfaces by the Pd(II)-directed LBL assembling technique. Finally, the as-prepared LBL multilayers were used as heterogeneous catalysts for hydrogen oxidation with methyl viologen (MV(2+)) as an electron carrier. The dynamic processes for the reversible color change between blue-colored MV(+) and colorless MV(2+) (catalyzed by the LBL multilayers) were video recorded, which confirmed that the H2ase encapsulated within the present LBL multilayers was of much stronger stability and higher biocatalytic activity of H2 oxidation resulting in potential applications for the development of H2 biosensors and fuel cells.

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Section: ■ Results and Discussionmentioning

confidence: 99%

Pd(II)-Directed Encapsulation of Hydrogenase within the Layer-by-Layer Multilayers of Carbon Nanotube Polyelectrolyte Used as a Heterogeneous Catalyst for Oxidation of Hydrogen

et al. 2015

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“…11–13 However, H 2 ases are relatively fragile, costly proteins, and as such, are generally poorly suited for large-scale application. 14–16 Alternative methods for sustainable hydrogen generation are needed.…”

Section: Introductionmentioning

confidence: 99%

Experimental and DFT Investigations Reveal the Influence of the Outer Coordination Sphere on the Vibrational Spectra of Nickel-Substituted Rubredoxin, a Model Hydrogenase Enzyme

et al. 2017

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Nickel-substituted rubredoxin (NiRd) is a functional enzyme mimic of hydrogenase, highly active for electrocatalytic and solution-phase hydrogen generation. Spectroscopic methods can provide valuable insight into the catalytic mechanism, provided the appropriate technique is used. In this study, we have employed multi-wavelength resonance Raman spectroscopy coupled with DFT calculations on an extended active-site model of NiRd to probe the electronic and geometric structures of the resting state of this system. Excellent agreement between experiment and theory is observed, allowing normal mode assignments to be made on the basis of frequency and intensity analyses. Both metal-ligand and ligand-centered vibrational modes are enhanced in the resonance Raman spectra. The latter provide information about the hydrogen bonding network and structural distortions due to perturbations in the secondary coordination sphere. To reproduce the resonance enhancement patterns seen for high-frequency vibrational modes, the secondary coordination sphere must be included in the computational model. The structure and reduction potential of the NiIIIRd state have also been investigated both experimentally and computationally. This work begins to establish a foundation for computational resonance Raman spectroscopy to serve in a predictive fashion for investigating catalytic intermediates of NiRd.

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“…[1] Three FeS clusters aligned as a conductive wire drive electrons from the [NiFe] active site to the surface of the enzyme, where the redox partner (including the electrode) binds. Direct enzyme connection gave access to thermodynamic and kinetic data of enzymatic reactions through direct electron transfer (DET).…”

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confidence: 99%

Electrochemistry, AFM, and PM‐IRRA Spectroscopy of Immobilized Hydrogenase: Role of a Hydrophobic Helix in Enzyme Orientation for Efficient H₂ Oxidation

et al. 2011

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Nickel-iron hydrogenase ([NiFe] Hase) catalyzes hydrogen splitting into protons and electrons, and is a potential biocatalyst in fuel cells.[1] Three FeS clusters aligned as a conductive wire drive electrons from the [NiFe] active site to the surface of the enzyme, where the redox partner (including the electrode) binds. Direct enzyme connection gave access to thermodynamic and kinetic data of enzymatic reactions through direct electron transfer (DET). Mediated electron transfer (MET) allowed recreation of the physiological electron-transfer chain, and/or connection of unfavorably oriented enzymes. [2][3][4][5][6] Previous work demonstrated that DET or MET processes for H 2 oxidation by a soluble, O 2 -sensitive [NiFe] Hase from Desulfovibrio species could be controlled by electrostatic interaction. [7] The presence of an acidic patch of amino acids, coupled to a dipole moment pointing towards the distal FeS cluster (positioned at the surface of the enzyme), allowed orientation of the enzyme, which turned upside down as a function of the charge on the electrochemical interface.Recently, we reported on the electrochemistry of membrane-bound Aquifex aeolicus (Aa) [NiFe] Hase, which exhibits outstanding resistance to O 2 , CO, and heat. [8][9][10] Efficient immobilization of this Hase was achieved on graphite electrodes, in aqueous electrolytes and ionic liquids, by encapsulation in carbon nanotube networks, or connection to a redox polymer. [11,12] In contrast to the soluble, O 2 -sensitive [NiFe] Hase, no specific orientation could be obtained by electrostatic interaction for Aa Hase, and thus control of the electron-transfer process was not possible. A model structure accordingly put forward a very different environment of the distal FeS cluster, with no charged amino acid patch, in accordance with the membrane anchorage. [12] We analyze herein H 2 oxidation by Aa Hase immobilized on self-assembled monolayers (SAMs) on gold electrodes as a function of both the length and the nature of the thiol derivative (see SI 1 and SI 2 in the Supporting Information). For the first time, AFM and polarization modulation infrared reflection adsorption (PM-IRRA) studies are reported for understanding Aa Hase orientation and its consequences for electron-transfer process in H 2 oxidation.Positively charged 4-aminothiophenol (ArNH 2 ) and negatively charged 6-mercaptohexanoic acid (C 5 COOH) SAMs both yield DET and MET processes for H 2 oxidation (Figure 1 a and b), and neither process is favored over the other. A mixed process was similarly observed for H 2 oxidation at charged short-chain alkanethiols, which are known to be more disordered.[8] This strongly suggests that electroenzymatic H 2 oxidation is linked to multiple orientations of Hase on top of the charged SAMs, and not to Hase present inside possible SAM defects. The lipophilic methylene blue (MB) molecule

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Oxygen-tolerant hydrogenases in hydrogen-based technologies

Cited by 105 publications

References 53 publications

Pd(II)-Directed Encapsulation of Hydrogenase within the Layer-by-Layer Multilayers of Carbon Nanotube Polyelectrolyte Used as a Heterogeneous Catalyst for Oxidation of Hydrogen

Pd(II)-Directed Encapsulation of Hydrogenase within the Layer-by-Layer Multilayers of Carbon Nanotube Polyelectrolyte Used as a Heterogeneous Catalyst for Oxidation of Hydrogen

Experimental and DFT Investigations Reveal the Influence of the Outer Coordination Sphere on the Vibrational Spectra of Nickel-Substituted Rubredoxin, a Model Hydrogenase Enzyme

Electrochemistry, AFM, and PM‐IRRA Spectroscopy of Immobilized Hydrogenase: Role of a Hydrophobic Helix in Enzyme Orientation for Efficient H₂ Oxidation

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Oxygen-tolerant hydrogenases in hydrogen-based technologies

Cited by 105 publications

References 53 publications

Pd(II)-Directed Encapsulation of Hydrogenase within the Layer-by-Layer Multilayers of Carbon Nanotube Polyelectrolyte Used as a Heterogeneous Catalyst for Oxidation of Hydrogen

Pd(II)-Directed Encapsulation of Hydrogenase within the Layer-by-Layer Multilayers of Carbon Nanotube Polyelectrolyte Used as a Heterogeneous Catalyst for Oxidation of Hydrogen

Experimental and DFT Investigations Reveal the Influence of the Outer Coordination Sphere on the Vibrational Spectra of Nickel-Substituted Rubredoxin, a Model Hydrogenase Enzyme

Electrochemistry, AFM, and PM‐IRRA Spectroscopy of Immobilized Hydrogenase: Role of a Hydrophobic Helix in Enzyme Orientation for Efficient H2 Oxidation

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Electrochemistry, AFM, and PM‐IRRA Spectroscopy of Immobilized Hydrogenase: Role of a Hydrophobic Helix in Enzyme Orientation for Efficient H₂ Oxidation