Acetyl-coenzyme A synthase

Mononuclear Ni complexes have been investigated as functional models for individual steps of the reactions mediated by the CODH/acetyl coenzyme A synthase.2018-2020 These are mentioned in the respective sections on mononuclear Ni complexes. The dinuclear type (770) complexes are... 

Hegg, E.L. (2004) Unravelling the structure and mechanism of acetyl-coenzyme A synthase, Acc. Chem. Res., 37, 775-783. 

Acetyl-coenzyme A Synthase see Acyl-coenzyme A Synthase (below). 

Acetyl coenzyme A synthase of C. thermoaceticum has a (aP)2 dimer-of-dimers structure with subunit molecular masses 78 kDa (a) and 71 kDa (P). Analysis indicated 12 Fe, 14 S, 2 Ni, 1 Zn per ap dimer. CO dehydrogenase activity resides in the P subunit (AcsA). This subunit has 46% identity (75% homology) with the R. rubrum C00S protein and appears to contain cluster C. Cluster A is located at least partially in the a subunit (AcsA) ACS of Methanosarcina barkeri comprises five subunits a, 84-93 kDa P, 63 kDa y, 53 kDa 8, 51 kDa , 20 kDa [141], The CODH activity is associated with the a subunit. 

Acetyl coenzyme A synthase of C. thermoaceticum is able to catalyze the whole reaction for reductive synthesis of acetyl coenzyme A from carbon dioxide, a methylated corrinnoid/iron-sulfur protein, and coenzyme A. The enzyme catalyzes several exchange reactions [147-149] ... 

In addition to simple coordination, the CO could be involved as a reducing agent. The water-gas shift reaction occurs in the bacterial enzyme, CO dehydrogenase/ acetyl coenzyme A synthase ([53] and references therein) but it has not been observed in mammals. However, in vitro, CO reduces aquocobalamin, vitamin B12a, Com, to vitamin B12r, Co11, [54—57] which raises the possibility that the water gas shift reaction could occur in humans. 

Carbon Monoxide Dehydrogenase/acetyl Coenzyme A Synthase (CODH/ACS) 7... 

CARBON MONOXIDE DEHYDROGENASE/ ACETYL COENZYME A SYNTHASE (CODH/ACS)... 

Carbon monoxide dehydrogenase/acetyl coenzyme A synthase (CODH/ACS) describes two different classes of enzymes carbon monoxide dehydrogenase (CODH) isolated from Rhodospirillum rubrum or Carboxydothermus hydrogenoformans reversibly oxidizes CO to CO2 according to equation (2), and the bifunctional CODH/ACS enzyme from Moorella thermoacetica catalyzes the reversible reduction of CO2 to CO (CODH) and acetyl coenzyme assembly/disassembly (ACS) (equation 3). ... 

The active site of carbon monoxide dehydrogenase has been shown to contain an asymmetric [Ni-4Fe-5S] cluster. There have been two recent independent reports of X-ray stmctures for the biftmctional enzyme carbon monoxide dehydrogenase/acetyl-coenzyme A synthase. In both stmctures, Ni is also bound in the acetyl-coenzyme A synthase within a N2S2 environment originating from amide N- and thiolate S-donors. The latter donors bridge to either a Cu, Zn, or Ni, which in turn is coimected to a 4Fe4S cluster. ... 

Often, the same enzyme also acts as an acetyl coenzyme-A synthase carbon monoxide, a methyl group, and coenzyme-A are bound at the active site and the condensation reaction to form acetyl coenzyme-A is catalyzed (81),... 

Ni(I) alkyl chemistry, which may have some relevance to the acetyl coenzyme A synthase mechanism, has also been observed in nickel... 

The two thiolate-bridged nickel-copper complexes in Fig. 6.6 have been prepared by reaction of [N2S2]Ni-type complexes with [Cu(CO)(PhTtBu)], the latter available via the carbonylation of [Cu(MeCN)(PhTt Bu)]. These complexes can be employed as model for the catalytic site of the acetyl coenzyme A synthase.14... 

Acetyl coenzyme A synthase is a NiFeS protein that catalyzes the assembly/disassembly of acetate from the constituents of a methyl group (equivalent), CO, and the thiol, coenzyme A (CoA) (Equation (3)). The reversibility of the transformation allows a convenient in vitro assay... 

Structural and spectroscopic models of the A-cluster of acetyl coenzyme A synthase/carbon monoxide dehydrogenase 05CCR(249)3007. 

Carbon Monoxide Dehydrogenase (COdH) and Acetyl Coenzyme A Synthase (ACS)... 

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