12 resultats
The composition of membrane-bound electron-transferring proteins from denitrifying cells of Haloarcula marismortui was compared with that from the aerobic cells. Accompanying nitrate reductase catalytic NarGH subcomplex, cytochrome b-561, cytochrome b-552, and halocyanin-like blue copper protein
The narC locus required for assimilatory nitrate reduction in the cyanobacterium Synechococcus sp. strain PCC 7942 was found to carry a mobA gene for molybdopterin guanine dinucleotide biosynthesis. Insertional inactivation of this gene blocked production of nitrate reductase in Synechococcus cells.
The bc(1) respiratory complex III constitutes a key energy-conserving respiratory electron transporter between complex I (type I NADH dehydrogenase) and II (succinate dehydrogenase) and the final nitrogen oxide reductases (Nir, Nor and Nos) in most denitrifying bacteria. However, we show that the
A cytochrome c (NarC) is encoded as the first gene of the operon for nitrate respiration in Thermus thermophilus. NarC is required for anaerobic growth and for the synthesis of active nitrate reductase (NR). The alpha and delta subunits (NarG, NarJ) of the NR were constitutively expressed in
The nar operon, coding for the respiratory nitrate reductase of Thermus thermophilus (NRT), encodes a di-heme b-type (NarJ) and a di-heme c-type (NarC) cytochrome. The role of both cytochromes and that of a putative chaperone (NarJ) in the synthesis and maturation of NRT was studied. Mutants of T.
The chlorate-resistant (chlR) mutants are pleiotropically defective in molybdoenzyme activity. The inactive derivative of the molybdoenzyme, respiratory nitrate reductase, present in the cell-free extract of a chlB mutant, can be activated by the addition of protein FA, the probable active product
In Escherichia coli the presence of nitrate prevents the utilization of fumarate as an anaerobic electron acceptor. The induction of the narC operon encoding the nitrate reductase is coupled to the repression of the frd operon encoding the fumarate reductase. This coupling is mediated by nitrate as
The Haloferax mediterranei nar operon has been sequenced and its regulation has been characterized at transcriptional level. The nar operon encodes seven open reading frames(ORFs) (ORF1 narB, narC, ORF4, narG, narH, ORF7 and narJ). ORF1, ORF4 and ORF7 are open reading frames with no assigned
Escherichia coli, which can utilize O2, nitrate, fumarate, or trimethylamine N-oxide (Me3NO) as terminal electron acceptor, preferentially utilizes the one with the highest redox potential. Thus O2 prevents induction of nitrate, fumarate, and Me3NO reductases, and nitrate curtails the induction of
The chlD gene in Escherichia coli is required for the incorporation and utilization of molybdenum when the cells are grown with low concentrations of molybdate. We constructed chlD-lac operon fusions and measured expression of the fusion, Mo cofactor, and nitrate reductase activities under a variety
Respiratory reduction of nitrate and nitrite is encoded in Thermus thermophilus by the respective transferable gene clusters. Nitrate is reduced by a heterotetrameric nitrate reductase (Nar) encoded along transporters and regulatory signal transduction systems within the nitrate respiration
Bacterial denitrification is expressed in response to the concurrent exogenous signals of low-oxygen tension and nitrate or one of its reduction products. The mechanism by which nitrate-dependent gene activation is effected was investigated in the denitrifying bacterium Pseudomonas stutzeri ATCC