Class-II dihydroorotate dehydrogenases from three phylogenetically distant fungi support anaerobic pyrimidine biosynthesis.

Background: In most fungi, quinone-dependent Class-II dihydroorotate dehydrogenases (DHODs) are essential for pyrimidine biosynthesis. Coupling of these Class-II DHODHs to mitochondrial respiration makes their in vivo activity dependent on oxygen availability. Saccharomyces cerevisiae and closely related yeast species harbor a cytosolic Class-I DHOD (Ura1) that uses fumarate as electron acceptor and thereby enables anaerobic pyrimidine synthesis.

Novel oleate hydratases and potential biotechnological applications.

Oleate hydratase catalyses the addition of water to the CC double bond of oleic acid to produce (R)-10-hydroxystearic acid. The enzyme requires an FAD cofactor that functions to optimise the active site structure. A wide range of unsaturated fatty acids can be hydrated at the C10 and in some cases the C13 position.

Purification and characterization of the tungsten enzyme aldehyde:ferredoxin oxidoreductase from the hyperthermophilic denitrifier Pyrobaculum aerophilum.

A tungsten-containing aldehyde:ferredoxin oxidoreductase (AOR) has been purified to homogeneity from Pyrobaculum aerophilum. The N-terminal sequence of the isolated enzyme matches a single open reading frame in the genome. Metal analysis and electron paramagnetic resonance (EPR) spectroscopy indicate that the P.

Redox characteristics of the tungsten DMSO reductase of Rhodobacter capsulatus.

The dimethylsulfoxide reductase (DMSOR) from Rhodobacter capsulatus is known to retain its three-dimensional structure and enzymatic activity upon substitution of molybdenum, the metal that occurs naturally at the active site, by tungsten. The redox properties of tungsten-substituted DMSOR (W-DMSOR) have been investigated by a dye-mediated reductive titration with the concentration of the W(V) state monitored by EPR spectroscopy. At pH 7.

Spectroscopic characterization and ligand-binding properties of chlorite dismutase from the chlorate respiring bacterial strain GR-1.

Chlorite dismutase (EC 1.13.11.

Resonance Raman characterization of the mononuclear iron active-site vibrations and putative electron transport pathways in Pyrococcus furiosus superoxide reductase.

The resonance Raman spectrum of oxidized wild-type P. furiosus SOR at pH 7.5 and 10.

Spectroscopic studies of Pyrococcus furiosus superoxide reductase: implications for active-site structures and the catalytic mechanism.

The combination of UV/visible/NIR absorption, CD and variable-temperature magnetic circular dichroism (VTMCD), EPR, and X-ray absorption (XAS) spectroscopies has been used to investigate the electronic and structural properties of the oxidized and reduced forms of Pyrococcus furiosus superoxide reductase (SOR) as a function of pH and exogenous ligand binding. XAS shows that the mononuclear ferric center in the oxidized enzyme is very susceptible to photoreduction in the X-ray beam. This observation facilitates interpretation of ground- and excited-state electronic properties and the EXAFS results for the oxidized enzyme in terms of the published X-ray crystallographic data (Yeh, A.