title: The hoxZ gene of the Azotobacter vinelandii hydrogenase operon is required for activation of hydrogenase.
abstract: The roles of the product of the hoxZ gene immediately downstream of the hydrogenase gene (hoxKG) in Azotobacter vinelandii were investigated by constructing and characterizing a mutant with the center of the hoxZ gene deleted. The strain lacking the functional hoxZ gene product exhibited a low rate of H2 oxidation with O2 as the electron acceptor relative to that of the wild-type strain. Nevertheless, when the enzyme was exogenously activated and methylene blue was used as the electron acceptor from hydrogenase, rates of H2 oxidation comparable to those in the wild-type strain were observed. These results suggest that the gene product of hoxZ plays a role in activating and maintaining hydrogenase in a reduced active state. The product of hoxZ could also be the linkage necessary for transfer of electrons from H2 to the electron transport chain.
authors.affiliation: Laboratory for Nitrogen Fixation Research, Oregon State University, Corvallis 97331-2902.
authors.forename: L A
authors.initials: LA
authors.lastname: Sayavedra-Soto
authors.forename: D J
authors.initials: DJ
authors.lastname: Arp
mesh_terms: D016948:Azotobacter vinelandii / Q000201:enzymology / Q000235:genetics*; D001483:Base Sequence; D002849:Chromatography, Gas; D004789:Enzyme Activation; D005798:Genes, Bacterial; D006859:Hydrogen / Q000378:metabolism; D006864:Hydrogenase / Q000235:genetics* / Q000378:metabolism; D008969:Molecular Sequence Data; D009876:Operon; D010084:Oxidation-Reduction; D010957:Plasmids
chemical_list: D006859:Hydrogen; D006864:Hydrogenase