A Morphing [4Fe-3S-nO]-Cluster within a Carbon Monoxide Dehydrogenase Scaffold.

Ni,Fe-containing carbon monoxide dehydrogenases (CODHs) catalyze the reversible reduction of CO to CO. Several anaerobic microorganisms encode multiple CODHs in their genome, of which some, despite being annotated as CODHs, lack a cysteine of the canonical binding motif for the active site Ni,Fe-cluster. Here, we report on the structure and reactivity of such a deviant enzyme, termed CooS-V .

When the inhibitor tells more than the substrate: the cyanide-bound state of a carbon monoxide dehydrogenase.

Carbon monoxide dehydrogenase (CODH) is a key enzyme for reversible CO interconversion. To elucidate structural and mechanistic details of CO binding at the CODH active site (C-cluster), cyanide is frequently used as an iso-electronic substitute and inhibitor. However, previous studies revealed conflicting results on the structure of the cyanide-bound complex and the mechanism of cyanide-inhibition.

How the [NiFe4S4] Cluster of CO Dehydrogenase Activates CO2 and NCO(-).

Ni,Fe-containing CO dehydrogenases (CODHs) use a [NiFe4S4] cluster, termed cluster C, to reversibly reduce CO2 to CO with high turnover number. Binding to Ni and Fe activates CO2, but current crystal structures have insufficient resolution to analyze the geometry of bound CO2 and reveal the extent and nature of its activation. The crystal structures of CODH in complex with CO2 and the isoelectronic inhibitor NCO(-) are reported at true atomic resolution (dmin ≤1.

Carbon monoxide. Toxic gas and fuel for anaerobes and aerobes: carbon monoxide dehydrogenases.

Carbon monoxide (CO) pollutes the atmosphere and is toxic for respiring organisms including man. But CO is also an energy and carbon source for phylogenetically diverse microbes living under aerobic and anaerobic conditions. Use of CO as metabolic fuel for microbes relies on enzymes like carbon monoxide dehydrogenase (CODH) and acetyl-CoA synthase (ACS), which catalyze conversions resembling processes that eventually initiated the dawn of life.

Structural basis for organohalide respiration.

Organohalide-respiring microorganisms can use a variety of persistent pollutants, including trichloroethene (TCE), as terminal electron acceptors. The final two-electron transfer step in organohalide respiration is catalyzed by reductive dehalogenases. Here we report the x-ray crystal structure of PceA, an archetypal dehalogenase from Sulfurospirillum multivorans, as well as structures of PceA in complex with TCE and product analogs.

The extended reductive acetyl-CoA pathway: ATPases in metal cluster maturation and reductive activation.

The reductive acetyl-coenzyme A (acetyl-CoA) pathway, also known as the Wood-Ljungdahl pathway, allows reduction and condensation of two molecules of carbon dioxide (CO2) to build the acetyl-group of acetyl-CoA. Productive utilization of CO2 relies on a set of oxygen sensitive metalloenzymes exploiting the metal organic chemistry of nickel and cobalt to synthesize acetyl-CoA from activated one-carbon compounds. In addition to the central catalysts, CO dehydrogenase and acetyl-CoA synthase, ATPases are needed in the pathway.

Recombinant portal protein from Staphylococcus epidermidis bacteriophage CNPH82 is a 13-subunit oligomer.

The portal protein cn3 of bacteriophage CNPH82 is predicted to serve as a gateway for translocation of viral genome into preformed pro-capsid, like portal proteins from other double-stranded DNA tailed bacteriophages. The host of bacteriophage CNPH82 is the opportunistic human pathogenic bacterium Staphylococcus epidermidis, a major cause of nosocomial infections. The portal protein of this phage has been cloned, overexpressed and purified.