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Research has been conducted on the benzoyl-CoA reductase from the anaerobic bacterium Thauera aromatica. The Birch-like mechanism in enzymatic aromatic ring reduction has been investigated and the results support the hypothesis of the Birch-like mechanism presence in benzoyl-CoA reductase catalysis.

Research has been conducted on the benzoyl-CoA reductase (BCR) catalyzing the ATP-driven two electron transport from a reduced ferrodoxin to the aromatic benzoyl-CoA ring. A mechanism that involves radical species and low potential electrons has been investigated.

Research has been conducted on the reduced ferrodoxin in Thauera aromatica. The use of cyclic voltammetry and multifrequency electronic paramagnetic properties (EPR) in investigating electromagnetic and EPR spectroscopic properties of T. aromatica ferrodoxin clusters is described.

The crystal structure of the obligately anaerobic bacteria Desulfococcus multivorans ([GDH.sub.Des]) with and without glutaconyl-coenzyme A is determined in order to understand the distinct catalytic behavior of two glutaryl-coenzyme A dehydrogenase (GDH) types on an atomic basis. The structural changes have prevented decarboxylation by strengthening the C4-C5 bond of glutaconyl-coenzyme A, by reducing the leaving group potential of C[O.sub.2] and by increasing the distance between the C4 atom and the adjacent glutamic acid.

Study shows that benzoyl-coenzymeA reductase (BCR) reaction stereoselectivity yields the trans-dienoyl-CoA product. The unexpected exhanges at C-2 and C-6 provide evidence for the proposed Birch reduction mechanism.

The catalytic cycle of Benzoyl-CoA reductase [BCR], the binding affinities and stoichiometries of all substrates and other effects on reduction kinetics using stopped-flow UV/vis spectroscopy, freeze-quench EPR spectroscopy and equilibrium dialysis is studied. The results show that nucleotide-dependent conformational changes take care of the catalytic cycle of BCR.

The Birch reduction of aromatic rings to cyclohexadiene compounds is widely used in chemical synthesis and requires solvated electrons, the most potent reductants known in organic chemistry. Benzoyl-coenzyme A (CoA) reductases (BCR) are key enzymes in the anaerobic bacterial degradation of aromatic compounds and catalyze an analogous reaction under physiological conditions. Class I BCRs are FeS enzymes and couple the reductive dearomatization of benzoyl-CoA to cyclohexa-1,5-diene-1-carboxyl-CoA (dienoyl-CoA) to a stoichiometric ATP hydrolysis. Here, we report on a tungsten-containing class II BCR from Geobacter metallireducens that catalyzed the fully reversible, ATP-independent dearomatization of benzoyl-CoA to dienoyl-CoA. BCR additionally catalyzed the disproportionation of dienoyl-CoA to benzoyl-CoA/monoenoyl-CoA and the four- and six-electron reduction of benzoyl-CoA in the presence of a reduced low-potential bridged 2,2′-bipyridyl redox dye. Reversible redox titration experiments in the presence of this redox dye revealed a midpoint potential of E0′= -622 mV for the benzoyl-CoA/dienoyl-CoA couple, which is far below the values of other known reversible substrate/product redox couples in enzymology. This work demonstrates the efficiency of reversible metalloenzyme catalysis, which in chemical synthesis can only be achieved under essentially irreversible conditions. [ABSTRACT FROM AUTHOR]