The metalloclusters of carbon monoxide dehydrogenase/acetyl-CoA synthase: a story in pictures

Abstract

Eight Ni proteins are known and three of these, CO dehydrogenase (CODH), acetyl-CoA synthase (ACS), and hydrogenase, are Ni-Fe-S proteins. In the last three years, the long-awaited structures of CODH and ACS have been solved. The bioinorganic community was shocked, as the structures of the active sites of CODH and ACS, the C- and A-cluster, respectively, which each had been predicted to consist of a [Fe(4)S(4)] cluster bridged to a single Ni, revealed unexpected compositions and arrangements. Crystal structures of ACS revealed major differences in protein conformation and in A-cluster composition; for example, a [Fe(4)S(4)] cluster bridged to a binuclear center in which one of the metal binding sites was occupied by Ni, Cu, or Zn. Recent studies have revealed Ni-Ni to be the active state, unveiled the source of the heterogeneity that had plagued studies of CODH/ACS for decades, and produced a metal-replacement strategy to generate highly active and nearly homogeneous enzyme.

The Role of PerR in O2-Affected Gene Expression ofClostridium acetobutylicum

“…Supporting its functional role during glycolysis, genes encoding the enzymes responsible for the subsequent reactions in this pathway (triosephophateisomerase, phosphoglyceromutase, and eno- Table 2). The other highly activated gene translates into a protein which belongs to the Ni-containing carbon monoxide (CO) dehydrogenase (CODH) family, which includes actual CODHs and acetyl-CoA synthases of methanogenic and acetogenic organisms (12). The PerR regulon of C. acetobutylicum.…”

Effect of trace metals on ethanol production from synthesis gas by the ethanologenic acetogen, Clostridium ragsdalei

“…was removed (0X) from the medium. All the key metalloenzymes of acetyl-CoA pathway (CODH, FDH, and H 2 ase) are iron-sulfur proteins [5,10,32]. Hence, a reduction in enzyme activities (CODH, FDH, H 2 ase, and ADH) and ethanol production by C. ragsdalei upon elimination of Fe 2?…”

Acetyl‐coenzyme A Synthases and Nickel‐Containing Carbon Monoxide Dehydrogenases

“…These 4 years represent somewhat of a watershed; so much changed or was clarifi ed during this period that the years prior now seem like the dark ages! Reviews by Drennan et al [7] and Volbeda and Fontecilla-Camps [8][9][10] stress these structural advances. The arrival of these structures immediately stimulated activity in modeling the novel active sites of these enzymes, and reviews by Riordan [11], Hegg [12], Evans [13], and Harrop and Mascharak [14] highlight these advances.…”