Evidence the Isc iron-sulfur cluster biogenesis machinery is the source of iron for [NiFe]-cofactor biosynthesis in Escherichia coli.

[NiFe]-hydrogenases have a bimetallic NiFe(CN)CO cofactor in their large, catalytic subunit. The 136 Da Fe(CN)CO group of this cofactor is preassembled on a distinct HypC-HypD scaffold complex, but the intracellular source of the iron ion is unresolved. Native mass spectrometric analysis of HypCD complexes defined the [4Fe-4S] cluster associated with HypD and identified + 26 to 28 Da and + 136 Da modifications specifically associated with HypC.

A redox-active HybG-HypD scaffold complex is required for optimal ATPase activity during [NiFe]-hydrogenase maturation in Escherichia coli.

Four Hyp proteins build a scaffold complex upon which the Fe(CN) CO group of the [NiFe]-cofactor of hydrogenases (Hyd) is made. Two of these Hyp proteins, the redox-active, [4Fe-4S]-containing HypD protein and the HypC chaperone, form the basis of this scaffold complex. Two different scaffold complexes exist in Escherichia coli, HypCD, and the paralogous HybG-HypD complex, both of which exhibit ATPase activity.

Exchange of a Single Amino Acid Residue in the HybG Chaperone Allows Maturation of All H-Activating [NiFe]-Hydrogenases in .

The biosynthesis of the NiFe(CN)CO organometallic cofactor of [NiFe]-hydrogenase (Hyd) involves several discreet steps, including the synthesis of the Fe(CN)CO group on a HypD-HypC scaffold complex. HypC has an additional function in transferring the Fe(CN)CO group to the apo-precursor of the Hyd catalytic subunit. Bacteria that synthesize more than one Hyd enzyme often have additional HypC-type chaperones specific for each precursor.

Native mass spectrometry identifies the HybG chaperone as carrier of the Fe(CN)CO group during maturation of E. coli [NiFe]-hydrogenase 2.

[NiFe]-hydrogenases activate dihydrogen. Like all [NiFe]-hydrogenases, hydrogenase 2 of Escherichia coli has a bimetallic NiFe(CN)CO cofactor in its catalytic subunit. Biosynthesis of the Fe(CN)CO group of the [NiFe]-cofactor occurs on a distinct scaffold complex comprising the HybG and HypD accessory proteins.

Hypoxia-induced synthesis of respiratory nitrate reductase 2 of Streptomyces coelicolor A3(2) depends on the histidine kinase OsdK in mycelium but not in spores.

The three nitrate reductases (Nar) of the saprophytic aerobic actinobacterium Streptomyces coelicolor A3(2) contribute to survival when oxygen becomes limiting. In the current study, we focused on synthesis of the Nar2 enzyme, which is the main Nar enzyme present and active in exponentially growing mycelium. Synthesis of Nar2 can, however, also be induced in spores after extended periods of anoxic incubation.

Cytochrome bcc-aa3 Oxidase Supercomplexes in the Aerobic Respiratory Chain of Streptomyces coelicolor A3(2).

Streptomyces coelicolor A3(2), an obligately aerobic, oxidase-positive, and filamentous soil bacterium, lacks a soluble cytochrome c in its respiratory chain, having instead a membrane-associated diheme c-type cytochrome, QcrC. This necessitates complex formation to allow electron transfer between the cytochrome bcc and aa3 oxidase respiratory complexes. Combining genetic complementation studies with in-gel cytochrome oxidase activity staining, we demonstrate that the complete qcrCAB-ctaCDFE gene locus on the chromosome, encoding, respectively, the bcc and aa3 complexes, is required to manifest a cytochrome oxidase enzyme activity in both spores and mycelium of a qcr-cta deletion mutant.

Activity of Spore-Specific Respiratory Nitrate Reductase 1 of A3(2) Requires a Functional Cytochrome Oxidase Supercomplex.

Spores have strongly reduced metabolic activity and are produced during the complex developmental cycle of the actinobacterium Resting spores can remain viable for decades, yet little is known about how they conserve energy. It is known, however, that they can reduce either oxygen or nitrate using endogenous electron sources. uses either a cytochrome oxidase or a cytochrome oxidase supercomplex to reduce oxygen, while nitrate is reduced by Nar-type nitrate reductases, which typically oxidize quinol directly.