Identification and characterization of oxalate oxidoreductase, a novel thiamine pyrophosphate-dependent 2-oxoacid oxidoreductase that enables anaerobic growth on oxalate. (1/11)

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Mutational analysis of residues in the regulatory CBS domains of Moorella thermoacetica pyrophosphatase corresponding to disease-related residues of human proteins. (2/11)

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Evidence that ferredoxin interfaces with an internal redox shuttle in Acetyl-CoA synthase during reductive activation and catalysis. (3/11)

Acetyl-CoA synthase (ACS), a subunit of the bifunctional CO dehydrogenase/acetyl-CoA synthase (CODH/ACS) complex of Moorella thermoacetica requires reductive activation in order to catalyze acetyl-CoA synthesis and related partial reactions, including the CO/[1-(14)C]-acetyl-CoA exchange reaction. We show that the M. thermoacetica ferredoxin(II) (Fd-II), which harbors two [4Fe-4S] clusters and is an electron acceptor for CODH, serves as a redox activator of ACS. The level of activation depends on the oxidation states of both ACS and Fd-II, which strongly suggests that Fd-II acts as a reducing agent. By the use of controlled potential enzymology, the midpoint reduction potential for the catalytic one-electron redox-active species in the CO/acetyl-CoA exchange reaction is -511 mV, which is similar to the midpoint reduction potential that was earlier measured for other reactions involving ACS. Incubation of ACS with Fd-II and CO leads to the formation of the NiFeC species, which also supports the role of Fd-II as a reductant for ACS. In addition to being a reductant, Fd-II can accept electrons from acetylated ACS, as observed by the increased intensity of the EPR spectrum of reduced Fd-II, indicating that there is a stored electron within an "electron shuttle" in the acetyl-Ni(II) form of ACS. This "shuttle" is proposed to serve as a redox mediator during activation and at different steps of the ACS catalytic cycle.  (+info)

Electrosynthesis of organic compounds from carbon dioxide is catalyzed by a diversity of acetogenic microorganisms. (4/11)

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Moorella humiferrea sp. nov., a thermophilic, anaerobic bacterium capable of growth via electron shuttling between humic acid and Fe(III). (5/11)

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The bacterial stressosome: a modular system that has been adapted to control secondary messenger signaling. (6/11)

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Visualizing molecular juggling within a B12-dependent methyltransferase complex. (7/11)

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Electron bifurcation involved in the energy metabolism of the acetogenic bacterium Moorella thermoacetica growing on glucose or H2 plus CO2. (8/11)

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