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This review regards the use of dynamic electrochemistry to study the mechanism of redox enzymes, with exclusive emphasis on the configuration where the protein is adsorbed onto an electrode and electron tranfer is direct. We still often come across the statement these days that redox enzymes are too large and too fragile to interact directly with a metallic(More)
The role of the high potential [3Fe-4S]1+,0 cluster of [NiFe] hydrogenase from Desulfovibrio species located halfway between the proximal and distal low potential [4Fe-4S]2+,1+ clusters has been investigated by using site-directed mutagenesis. Proline 238 of Desulfovibrio fructosovorans [NiFe] hydrogenase, which occupies the position of a potential ligand(More)
Hydrogenases, which catalyze H(2) to H(+) conversion as part of the bioenergetic metabolism of many microorganisms, are among the metalloenzymes for which a gas-substrate tunnel has been described by using crystallography and molecular dynamics. However, the correlation between protein structure and gas-diffusion kinetics is unexplored. Here, we introduce(More)
In NiFe hydrogenases, electrons are transferred from the active site to the redox partner via a chain of three Iron-Sulfur clusters, and the surface-exposed [4Fe4S] cluster has an unusual His(Cys)3 ligation. When this Histidine (H184 in Desulfovibrio fructosovorans) is changed into a cysteine or a glycine, a distal cubane is still assembled but the(More)
This work aims to highlight the relationship between primary productivity, sulphate reduction and organic carbon preservation in cyclic marine sediments from the Kimmeridge Clay Formation. A concomitant increase of the total sulphur content with the preserved organic content (TOC), shows the progressive supply of both metabolisable organic matter and(More)
We enrolled 30 infants (median age 3 months, range 1-12 months), hospitalized for bronchiolitis in a randomized double-blind trial, to examine the efficacy and safety of nebulized epinephrine compared to salbutamol. Once admitted, patients were treated with either nebulized 0.5 mg of an 0.1% epinephrine solution (0.5 mL in 3.5 mL normal saline (NS)) or 2.5(More)
Molybdoenzymes of the xanthine oxidase family contain two [2Fe-2S](1+,2+) clusters that are bound to the protein by very different cysteine motifs. In the X-ray crystal structure of Desulfovibrio gigas aldehyde oxidoreductase, the cluster ligated by a ferredoxin-type motif is close to the protein surface, whereas that ligated by an unusual cysteine motif is(More)
The membrane-bound hydrogenase (Hase I) of the hyperthermophilic bacterium Aquifex aeolicus belongs to an intriguing class of redox enzymes that show enhanced thermostability and oxygen tolerance. Protein film electrochemistry is employed here to portray the interaction of Hase I with molecular oxygen and obtain an overall picture of the catalytic activity.(More)
We investigated di-hydrogen transport between the solvent and the active site of FeFe hydrogenases. Substrate channels supposedly exist and serve various functions in certain redox enzymes which use or produce O2, H2, NO, CO, or N2, but the preferred paths have not always been unambiguously identified, and whether a continuous, permanent channel is an(More)
Time-of-flight secondary ion mass spectrometry (TOF-SIMS) analyses were performed on the first-row transition metal oxides from scandium to zinc in positive and negative detection modes. The nature of the numerous M(x)O(y)(+/-) ionic species generated by 15 keV Ga(+) primary ion bombardment allows the identification of a given metal-oxygen system. To(More)