title: NosX function connects to nitrous oxide (N2O) reduction by affecting the Cu(Z) center of NosZ and its activity in vivo.
abstract: The effect of loss of the 34-kDa periplasmic NosX protein on the properties of N2O reductase was investigated with an N2O-respiration negative, double mutant of the paralogous genes nosX and nirX of Paracoccus denitrificans. In spite of absence of whole-cell N2O-reducing activity, the purified reductase was catalytically active, which attributes NosX a physiological role in sustaining the reaction cycle. N2O reductase exhibited the spectroscopic features of Cu(A) and the redox-inert, paramagnetic state, Cu(Z)*, of the catalytic center. Cu(Z)*, hitherto considered the result of spontaneous reaction of the reductase with dioxygen, attains cellular significance.
authors.affiliation: Institute of Applied Biosciences, Division of Molecular Microbiology, University of Karlsruhe, D-76128 Karlsruhe, Germany.
authors.forename: Patrick
authors.initials: P
authors.lastname: Wunsch
authors.forename: Heinz
authors.initials: H
authors.lastname: Körner
authors.forename: Frank
authors.initials: F
authors.lastname: Neese
authors.forename: Rob J M
authors.initials: RJ
authors.lastname: van Spanning
authors.forename: Peter M H
authors.initials: PM
authors.lastname: Kroneck
authors.forename: Walter G
authors.initials: WG
authors.lastname: Zumft
mesh_terms: D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D003300:Copper / Q000737:chemistry*; D004578:Electron Spin Resonance Spectroscopy; D008565:Membrane Proteins / Q000235:genetics / Q000378:metabolism; D009609:Nitrous Oxide / Q000737:chemistry*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D010231:Paracoccus denitrificans / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D001426:Bacterial Proteins; D008565:Membrane Proteins; C401643:NirX protein, Paracoccus denitrificans; D003300:Copper; D010088:Oxidoreductases; C022763:nitrous oxide reductase; D009609:Nitrous Oxide