title: Copper control of bacterial nitrous oxide emission and its impact on vitamin B12-dependent metabolism.
abstract: Global agricultural emissions of the greenhouse gas nitrous oxide (N2O) 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 (N2) via N2O 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 N2O to N2, is regulated in response to the extracellular copper concentration. We show that elevated levels of N2O released as a consequence of decreased cellular NosZ activity lead to the bacterium switching from vitamin B12-dependent to vitamin B12-independent biosynthetic pathways, through the transcriptional modulation of genes controlled by vitamin B12 riboswitches. This inhibitory effect of N2O can be rescued by addition of exogenous vitamin B12.
authors.affiliation: School of Biological Sciences, University of East Anglia, Norwich Research Park, Norwich NR4 7TJ, United Kingdom.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Sullivan
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Gates
authors.forename: Corinne
authors.initials: C
authors.lastname: Appia-Ayme
authors.forename: Gary
authors.initials: G
authors.lastname: Rowley
authors.forename: David J
authors.initials: DJ
authors.lastname: Richardson
mesh_terms: D000383:Agriculture / Q000379:methods; D003300:Copper / Q000494:pharmacology*; D005308:Fertilizers / Q000032:analysis*; D015964:Gene Expression Regulation, Bacterial / Q000187:drug effects / Q000502:physiology*; D057232:Global Warming; D046228:Microarray Analysis; D009609:Nitrous Oxide / Q000378:metabolism* / Q000633:toxicity; D010088:Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D010231:Paracoccus denitrificans / Q000187:drug effects / Q000378:metabolism*; D060888:Real-Time Polymerase Chain Reaction; D058928:Riboswitch / Q000502:physiology; D014805:Vitamin B 12 / Q000235:genetics / Q000378:metabolism*
chemical_list: D005308:Fertilizers; D058928:Riboswitch; D003300:Copper; D010088:Oxidoreductases; C022763:nitrous oxide reductase; D009609:Nitrous Oxide; D014805:Vitamin B 12
keywords: NosC; NosR; denitrification; transcription