The genetic organization of the nirD locus of Pseudomonas stutzeri ZoBell, necessary for a catalytically active cytochrome cd1 (EC 1.9.3.2), was determined. The locus comprises the unidirectionally transcribed open reading frames nirFDLGH, downstream of nirMC of the nir gene cluster, and immediately upstream of the norCB operon encoding nitric oxide (NO) reductase (EC 1.7.99.7). Notable sequence relatedness was found between NirF and cytochrome cd1 (NirS), within NirDLGH, and between NirM and NirC, suggesting several gene duplication events in this region. The derived NirF protein (391 amino acids, M(r) 43,137) has 23.8% identity (51.1% overall similarity) with NirS, but lacks the N-terminal heme-c-binding domain of NirS. Insertional mutagenesis of the five open reading frames resulted in the loss of respiratory nitrite reductase activity in vivo and in vitro. Mutant strains, when induced with nitrate for denitrification, synthesized a periplasmic cytochrome cd1 lacking heme d1. The defect was caused by the inability of the cell to synthesize heme d1. The nirD locus is proposed to encode a multimeric and multifunctional enzyme complex involved in the synthesis of heme d1. Mutations in nirFDLGH lowered substantially the expression level of norCB. Nir- mutants, unable to generate NO in vivo, provide indirect evidence for an NO sensor and an inducer role of NO for its cognate reductase.
Download full-text PDF |
Source |
|---|
Publication Analysis
Top Keywords
Similar Publications
A review on -type and -type denitrifiers a scientometric approach coupled with case studies.
Environ Sci Process Impacts
February 2022
School of Ecology and Environment, Beijing Technology and Business University, Beijing 100048, China.
The denitrification process plays an important role in improving water quality and is a source/sink of nitrous oxide to the atmosphere. The second important rate-limiting step of the denitrification process is catalyzed by two enzymes with different structures and unrelated evolutionary relationships, namely, the Cu-type nitrite reductase encoded by the gene and the cytochrome cd1-type nitrite reductase encoded by the gene. Although some relevant reviews have been published on denitrifiers, most of these reviews do not include statistical analysis, and do not compare the and communities in-depth.
View Article and Find Full Text PDFRapid detection of cytochrome cd1-containing nitrite reductase encoding gene nirS of denitrifying bacteria with loop-mediated isothermal amplification assay.
Sci Rep
October 2020
Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao, 266071, China.
The cytochrome cd1-containing nitrite reductase, nirS, plays an important role in biological denitrification. Consequently, investigating the presence and abundance of nirS is a commonly used approach to understand the distribution and potential activity of denitrifying bacteria, in addition to denitrifier communities. Herein, a rapid method for detecting nirS gene with loop-mediated isothermal amplification (LAMP) was developed, using Pseudomonas aeruginosa PAO1 (P.
View Article and Find Full Text PDFSyntrophic Growth of Accelerates Anaerobic Denitrification.
Front Microbiol
July 2018
MOE Key Laboratory of Pollution Processes and Environmental Criteria, Tianjin Key Laboratory of Environmental Remediation and Pollution Control, Nankai University, Tianjin, China.
Nitrate is considered as a contamination since it's over discharging to water incurs environmental problems. However, nitrate is an ideal electron sink for anaerobic pollutant degraders desiring electron acceptors due to the high redox potential. Unfortunately, not all degraders can directly reduce nitrate, and the anaerobic direct interspecies electron transfer (DIET) between degraders and denitrifiers has not been confirmed yet.
View Article and Find Full Text PDFRedundant roles of Bradyrhizobium oligotrophicum Cu-type (NirK) and cd1-type (NirS) nitrite reductase genes under denitrifying conditions.
FEMS Microbiol Lett
March 2018
Graduate School of Life Sciences, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
Reduction of nitrite to nitric oxide gas by respiratory nitrite reductases (NiRs) is the key step of denitrification. Denitrifiers are strictly divided into two functional groups based on whether they possess the copper-containing nitrite reductase (CuNiR) encoded by nirK or the cytochrome cd1 nitrite reductase (cdNiR) encoded by nirS. Recently, some organisms carrying both nirK and nirS genes have been found.
View Article and Find Full Text PDFAttached and Suspended Denitrifier Communities in Pristine Limestone Aquifers Harbor High Fractions of Potential Autotrophs Oxidizing Reduced Iron and Sulfur Compounds.
Microb Ecol
August 2017
Aquatic Geomicrobiology, Institute of Ecology, Friedrich Schiller University Jena, Dornburger Strasse 159, 07743, Jena, Germany.
Oxygen and nitrate availability as well as the presence of suitable organic or inorganic electron donors are strong drivers of denitrification; however, the factors influencing denitrifier abundance and community composition in pristine aquifers are not well understood. We explored the denitrifier community structure of suspended and attached groundwater microorganisms in two superimposed limestone aquifer assemblages with contrasting oxygen regime in the Hainich Critical Zone Exploratory (Germany). Attached communities were retrieved from freshly crushed parent rock material which had been exposed for colonization in two groundwater wells (12.
View Article and Find Full Text PDFWant AI Summaries of new PubMed Abstracts delivered to your In-box?
Enter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!