Functional Domains of NosR, a Novel Transmembrane Iron-Sulfur Flavoprotein Necessary for Nitrous Oxide Respiration

Wunsch, Patrick; Zumft, Walter G.

doi:10.1128/jb.187.6.1992-2001.2005

Cited by 93 publications

(86 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…NosDFYLX are all thought to be important for NosZ assembly and activation, but a clear function for these polypeptides is yet to be demonstrated (16). Similarly, previous studies have not formally identified a function for the NosR protein (15)(16)(17) and its involvement in the Cu-dependency of the Nos system has never been reported. Nevertheless, nosR occurs adjacent to nosZ in the vast majority of denitrifier genomes, underpinning its involvement in N 2 O reduction.…”

Section: Resultsmentioning

confidence: 98%

“…Notably, all known homologs of NosC contain a CXXCXXC motif that may bind a redox active cofactor, the significance of which is unknown. NosR is a transmembrane iron-sulfur cluster containing flavoprotein required for reduction of N 2 O that also contains two putative metal binding CXXXCP motifs (15)(16)(17), noted for their ability to bind Cu in some proteins, as discussed below. NosDFYLX are all thought to be important for NosZ assembly and activation, but a clear function for these polypeptides is yet to be demonstrated (16).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Copper control of bacterial nitrous oxide emission and its impact on vitamin B ₁₂ -dependent metabolism

Sullivan

Gates

Appia-Ayme

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

118

116

View full text Add to dashboard Cite

Global agricultural emissions of the greenhouse gas nitrous oxide (N 2 O) have increased by around 20% over the last 100 y, but regulation of these emissions and their impact on bacterial cellular metabolism are poorly understood. Denitrifying bacteria convert nitrate in soils to inert di-nitrogen gas (N 2 ) via N 2 O and the biochemistry of this process has been studied extensively in Paracoccus denitrificans. Here we demonstrate that expression of the gene encoding the nitrous oxide reductase (NosZ), which converts N 2 O to N 2 , is regulated in response to the extracellular copper concentration. We show that elevated levels of N 2 O released as a consequence of decreased cellular NosZ activity lead to the bacterium switching from vitamin B 12 -dependent to vitamin B 12 -independent biosynthetic pathways, through the transcriptional modulation of genes controlled by vitamin B 12 riboswitches. This inhibitory effect of N 2 O can be rescued by addition of exogenous vitamin B 12 .denitrification | transcription | NosR | NosC G lobal atmospheric loading of the ozone-depleting greenhouse gas, nitrous oxide (N 2 O), is on the increase (1). Molecule for molecule, its radiative potential is ∼300-fold higher than carbon dioxide (2, 3), comprising ∼9% of global radiative forcing by greenhouse gases (4). In addition, atmospheric N 2 O is stable for ∼120 y. Approximately 70% of anthropogenic N 2 O loading arises from agriculture, mainly from the use of nitrogencontaining fertilizers by soil microbes for dissimilatory purposes. Taken together, these features make N 2 O an important target for mitigation strategies (5).N 2 O is an intermediate in the sequential reduction of nitrate (NO 3 − ) to di-nitrogen (N 2 ), via nitrite (NO 2 − ), nitric oxide (NO), and N 2 O, a process known as denitrification (6). Under certain conditions, the final step in denitrification is dispensed with and N 2 O is released into the atmosphere. One limiting factor in this process is copper (Cu) availability, the metal cofactor required by the N 2 O reductase (NosZ) that destroys N 2 O (5, 7, 8). During Cu-limitation the catalytic capacity of the Nos system may be exceeded by the rate of the preceding reactions that generate N 2 O (i.e., NO 3 − , NO 2 − , and NO reduction) and thus, N 2 O is emitted by denitrifying bacteria (7, 9, 10).Much attention has been given to the cytotoxic properties of NO as a free-radical and oxidant, but N 2 O is often described as a relatively inert intermediate of the nitrogen cycle. However, N 2 O exhibits cytotoxicity, as it is known to bind to and inactivate vitamin B 12 (B 12 ), an essential cellular cofactor in B 12 -dependent enzymes involved in methionine and DNA synthesis (11,12). B 12 also acts as a ligand for B 12 riboswitches that modulate gene expression in the absence of this cofactor (13,14). The possible impact of environmental N 2 O emissions on B 12 metabolism in microbiological communities has largely been ignored. As levels of N 2 O increase in the environment, there is a compelling argument for ...

show abstract

Section: Resultsmentioning

confidence: 98%

Section: Resultsmentioning

confidence: 99%

Copper control of bacterial nitrous oxide emission and its impact on vitamin B ₁₂ -dependent metabolism

Sullivan

Gates

Appia-Ayme

et al. 2013

Proc. Natl. Acad. Sci. U.S.A.

118

116

View full text Add to dashboard Cite

show abstract

“…Simultaneous disruption of the genes encoding two ApbE orthologs (NosX and NirX; Fig. 2) in P. denitrificans cells eliminates their NO reductase activity (47), which can now be explained by defective maturation of the regulator of NO reductase transcription NosR, which contains a covalently bound FMN residue (16).…”

Section: Discussionmentioning

confidence: 99%

“…In Na ϩ -NQR (11), RNF (15), and closely related proteins, such as regulator of NO reductase transcription (NosR) (16) and urocanate reductase (UrdA) (17), FMN is bound by a phosphoester bond through a Thr residue. Other acceptors of flavins in flavoproteins include His, Tyr, and Cys residues that form C-N, C-O, and C-S bonds, respectively, mostly through the 8␣C atom of the flavin (e.g., in succinate dehydrogenase, fumarate reductase, sarcosine oxidase, trimethylamine dehydrogenase, and p-cresol methylhydroxylase) (18).…”

Section: Namentioning

confidence: 99%

Alternative Pyrimidine Biosynthesis Protein ApbE Is a Flavin Transferase Catalyzing Covalent Attachment of FMN to a Threonine Residue in Bacterial Flavoproteins

Bertsova

Fadeeva

Kostyrko

et al. 2013

Journal of Biological Chemistry

View full text Add to dashboard Cite

Background:The ApbE protein with unknown function is widespread in bacteria. Results: ApbE catalyzes Mg 2ϩ -dependent FMN transfer from FAD to Thr residues of flavoproteins in vitro and in vivo. Conclusion: ApbE is a novel modifying enzyme involved in the maturation of flavoproteins. Significance: Broad distribution of ApbE suggests a wide utilization of flavoproteins containing FMN attached via a phosphoester bond.

show abstract

“…The periplasmic domain of the transmembrane iron-sulfur flavoprotein NosR is essential for NosZ function (37). The periplasmic lipoprotein NosL anchored to the outer membrane is a copper binding protein involved in NosZ maturation (38,39).…”

mentioning

confidence: 99%

Protein Network of the Pseudomonas aeruginosa Denitrification Apparatus

et al. 2016

View full text Add to dashboard Cite

Oxidative phosphorylation using multiple-component, membrane-associated protein complexes is the most effective way for a cell to generate energy. Here, we systematically investigated the multiple protein-protein interactions of the denitrification apparatus of the pathogenic bacterium Pseudomonas aeruginosa. During denitrification, nitrate (Nar), nitrite (Nir), nitric oxide (Nor), and nitrous oxide (Nos) reductases catalyze the reaction cascade of NO 3؊ ¡ NO 2؊ ¡ NO ¡ N 2 O ¡ N 2 . Genetic experiments suggested that the nitric oxide reductase NorBC and the regulatory protein NosR are the nucleus of the denitrification protein network. We utilized membrane interactomics in combination with electron microscopy colocalization studies to elucidate the corresponding protein-protein interactions. The integral membrane proteins NorC, NorB, and NosR form the core assembly platform that binds the nitrate reductase NarGHI and the periplasmic nitrite reductase NirS via its maturation factor NirF. The periplasmic nitrous oxide reductase NosZ is linked via NosR. The nitrate transporter NarK2, the nitrate regulatory system NarXL, various nitrite reductase maturation proteins, NirEJMNQ, and the Nos assembly lipoproteins NosFL were also found to be attached. A number of proteins associated with energy generation, including electron-donating dehydrogenases, the complete ATP synthase, almost all enzymes of the tricarboxylic acid (TCA) cycle, and the Sec system of protein transport, among many other proteins, were found to interact with the denitrification proteins. This deduced nitrate respirasome is presumably only one part of an extensive cytoplasmic membrane-anchored protein network connecting cytoplasmic, inner membrane, and periplasmic proteins to mediate key activities occurring at the barrier/interface between the cytoplasm and the external environment. IMPORTANCEThe processes of cellular energy generation are catalyzed by large multiprotein enzyme complexes. The molecular basis for the interaction of these complexes is poorly understood. We employed membrane interactomics and electron microscopy to determine the protein-protein interactions involved. The well-investigated enzyme complexes of denitrification of the pathogenic bacterium Pseudomonas aeruginosa served as a model. Denitrification is one essential step of the universal N cycle and provides the bacterium with an effective alternative to oxygen respiration. This process allows the bacterium to form biofilms, which create low-oxygen habitats and which are a key in the infection mechanism. Our results provide new insights into the molecular basis of respiration, as well as opening a new window into the infection strategies of this pathogen.

show abstract

Functional Domains of NosR, a Novel Transmembrane Iron-Sulfur Flavoprotein Necessary for Nitrous Oxide Respiration

Cited by 93 publications

References 58 publications

Copper control of bacterial nitrous oxide emission and its impact on vitamin B ₁₂ -dependent metabolism

Copper control of bacterial nitrous oxide emission and its impact on vitamin B ₁₂ -dependent metabolism

Alternative Pyrimidine Biosynthesis Protein ApbE Is a Flavin Transferase Catalyzing Covalent Attachment of FMN to a Threonine Residue in Bacterial Flavoproteins

Protein Network of the Pseudomonas aeruginosa Denitrification Apparatus

Contact Info

Product

Resources

About

Functional Domains of NosR, a Novel Transmembrane Iron-Sulfur Flavoprotein Necessary for Nitrous Oxide Respiration

Cited by 93 publications

References 58 publications

Copper control of bacterial nitrous oxide emission and its impact on vitamin B 12 -dependent metabolism

Copper control of bacterial nitrous oxide emission and its impact on vitamin B 12 -dependent metabolism

Alternative Pyrimidine Biosynthesis Protein ApbE Is a Flavin Transferase Catalyzing Covalent Attachment of FMN to a Threonine Residue in Bacterial Flavoproteins

Protein Network of the Pseudomonas aeruginosa Denitrification Apparatus

Contact Info

Product

Resources

About

Copper control of bacterial nitrous oxide emission and its impact on vitamin B ₁₂ -dependent metabolism

Copper control of bacterial nitrous oxide emission and its impact on vitamin B ₁₂ -dependent metabolism