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Showing 1 to 18 of 18 for “"[NiFe]-hydrogenase"”.
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Ultrafast dynamics of [NiFe] hydrogenase models
Submission published under a 24 month embargo labeled 'U of I Access', the embargo will last until 2027-05-01
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Investigation of Escherichia coli [NiFe]-Hydrogenase Maturation
[NiFe]-hydrogenases catalyze the reversible oxidation of hydrogen gas at a bimetallic active site and are important enzymes in bacteria and archaea for anaerobic growth and pathogenesis. The maturation of [NiFe]-hydrogenase requires at least seven dedicated accessory proteins to assemble and insert …
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Modeling The Active Site Of [NiFe]-Hydrogenase
The hydrogenases are metalloenzymes that act to catalytically interconvert dihydrogen with protons and electrons. Although there are three classes of hydrogenases that are known, the focus of this research will be on the first hydrogenase to be evolved, the [NiFe]-hydrogenase, which contains a …
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Incorporation of cyanide ligands into models of [FeFe]- and [NiFe]-hydrogenase
… in Nature by a class of metalloenzymes called hydrogenases. Hydrogenase enzymes catalyze the reduction of protons into H2 or oxidized H2 into protons. The catalytic rates and overpotentials of hydrogenase enzymes are comparable to Pt catalysts. The most prevalent hydrogenase enzymes are …
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Hydrogen production from model complexes of the [FeFe]- and [NiFe]-hydrogenase active sites
… direction toward this goal, as enzymes called hydrogenases evolved several billion years ago to utilize molecular hydrogen as a fuel. The [FeFe]-hydrogenases predominately function to produce hydrogen from protons and electrons, while the [NiFe]-hydrogenases function to oxidize hydrogen. The …
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Investigating [NiFe]-hydrogenases in γ-Proteobacteria
… family involved in hydrogen metabolism are Hydrogenases. These enzymes catalyse the reversible conversion of molecular hydrogen to protons and electrons (H2 ↔ 2H+ + 2e-). These enzymes have the potential to be utilised for biotechnological applications such as hydrogen fuel cells, but they …
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Exploring the microbe-mediated soil H² sink : a lab-based study of the physiology and related H² consumption of isolates from the Harvard Forest LTER
… PCB7) containing a low-threshold, high-affinity NiFe-hydrogenase functional at ambient H² levels (approx. 530 ppb) made it possible to identify a model organism to characterize microbial H²-uptake behavior. In the present research, several strains of Streptomyces containing the high-affinity …
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An Organometallic Approach to Iron Triazacyclononane Coordination Complexes
The active site of NiFe hydrogenase features a bis(thiolate) bridged nickel-iron site, where the iron is bound to two carbonyls and a cyanide. The reaction of the square planar Ni(N2S2), where (N2S2)2- = -SCH2CH2N(Me)CH2CH 2N(Me)CH2CH2S- and (Me 3TACN)FeCl2 gives [Ni(N2S2)FeCl(Me3TACN)](BPh 4), a …
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Vibrational spectroscopic studies on [NiFe] hydrogenases: insights into structure and function
… is orchestrated by metalloenzymes known as hydrogenases, which operate with remarkable catalytic rates using exclusively nickel and/or iron metals. The discovery of hydrogenases has been a breakthrough towards novel catalytic strategies to replace noble metals like platinum. Additionally, …
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Hydrogen Production From Model Complexes of the [iron-Iron]- and [nickel-Iron]-Hydrogenase Active Sites
Unlike the [FeFe]-hydrogenases, model complexes for the [NiFe]-hydrogenases were unknown prior to the crystal structure in 1996. However, most synthetic efforts focused on structural models for the active site, and neglected the catalytically imperative hydride ligand. Thus, we sought a nickel-iron …
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Biohydrogen as a Fuel: Understanding and Engineering Hydrogenase Enzymes for Biotechnological Applications
… for microbial H2 evolution are called hydrogenases. The model organism Escherichia coli produces H2 during mixed acid fermentation by the action of it native hydrogenases. However, the natural level of H2 produced is too low to meet current industrial demand for H2 or any future uses as …
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A combined approach of electronic structure calculations and spectroscopy for elucidating reaction mechanisms in organic and bioinorganic systems
… harvesting. The mechanisms by which [FeFe] and [NiFe] hydrogenase enzymes catalyse the reversible reduction of protons to dihydrogen are of intrinsic interest in the context of a developing hydrogen technology for energy transduction. Gas phase DFT calculations are used to simulate and assign …
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Model-Based Experimental Investigation of Hydrogenase-Like Electrocatalytic Inactivation and Activation Mechanisms
… a complex redox system, a recently observed hydrogenase-like reaction. Subtle kinetic and mechanistic information is extracted from the voltammetric behaviour and quantitative mechanistic insights obtained. In Chapter 5, an alternative chronoamperometric voltammetry is introduced to explore …
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Structure-function relationships of metalloenzymes
Anhand der Modellsysteme [NiFe] Hydrogenase und Superoxid Reduktase wurden Struktur-Funktionsbeziehungen von Metalloenzymen, die die Umwandlung kleiner Moleküle katalysieren, mittels theoretischer und spektroskopischer Methoden analysiert. Der erste Teil dieser Arbeit ist der Charakterisierung …
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Reactions at coordinated ligands: redox-active ligands and coordination of Lewis acids
… however, this theme has not been applied to hydrogenase models. Cyanide is an essential component of the [FeFe]- and [NiFe]-hydrogenase active sites, both enzymes feature two cyanide ligands, however, models using cyanides ligands are plagued by undesirable side reactions such as …
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Metabolic and molecular responses to interspecies hydrogen transfer between Ruminococcus albus and Wolinella succinogenes
… bacterium with two known hydrogen-producing hydrogenase complexes, HydABC and HydA2, as well as a putative hydrogen-sensing protein, HydS. HydABC is the only chromosomal hydrogenase, while HydA2 and HydS form a transcriptional unit on its plasmid pRumal01. The electron-bifurcating ferredoxin- …
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Coordination chemistry of unusual oxidation states of nickel and palladium relevant to homogeneous catalysis
… mimic of the redox-active Ni center of [NiFe] hydrogenase. The small-molecule model was shown to switch between NiI and NiIII via a C-H activation process, mimicking the enzyme’s key redox states. It was also an active electrocatalyst for proton reduction. Further modifications of the …
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Small molecule mimics of hydrogenase enzymes: synthesis, protonation, and electrocatalysis
In nature, H2 is processed by enzymes called hydrogenases, which catalyze the reduction of protons to dihydrogen, as well as the reverse reaction. The active sites of the two most prevalent hydrogenases contain NiFe or FeFe cores, bound to thiolates, cyanide, and carbon monoxide ligands. These …