The structure of quinol-dependent nitric oxide reductase (qNOR) from G. stearothermophilus, which catalyzes the reduction of NO to produce the major ozone-depleting gas N(2)O, has been characterized at 2.5 Å resolution. The overall fold of qNOR is similar to that of cytochrome c-dependent NOR (cNOR), and some structural features that are characteristic of cNOR, such as the calcium binding site and hydrophilic cytochrome c domain, are observed in qNOR, even though it harbors no heme c. In contrast to cNOR, structure-based mutagenesis and molecular dynamics simulation studies of qNOR suggest that a water channel from the cytoplasm can serve as a proton transfer pathway for the catalytic reaction. Further structural comparison of qNOR with cNOR and aerobic and microaerobic respiratory oxidases elucidates their evolutionary relationship and possible functional conversions.
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http://dx.doi.org/10.1038/nsmb.2213 | DOI Listing |
Nat Commun
June 2023
Molecular Biophysics Group, Department of Biochemistry and Systems Biology, Institute of Systems, Molecular and Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool, L69 7ZB, England.
Quinol-dependent nitric oxide reductases (qNORs) are considered members of the respiratory heme-copper oxidase superfamily, are unique to bacteria, and are commonly found in pathogenic bacteria where they play a role in combating the host immune response. qNORs are also essential enzymes in the denitrification pathway, catalysing the reduction of nitric oxide to nitrous oxide. Here, we determine a 2.
View Article and Find Full Text PDFIUCrJ
May 2020
Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, United Kingdom.
is carried by nearly a billion humans, causing developmental impairment and over 100 000 deaths a year. A quinol-dependent nitric oxide reductase (qNOR) plays a critical role in the survival of the bacterium in the human host. X-ray crystallographic analyses of qNOR, including that from (qNOR) reported here at 3.
View Article and Find Full Text PDFSci Adv
August 2019
Molecular Biophysics Group, Institute of Integrative Biology, Faculty of Health and Life Sciences, University of Liverpool, Liverpool L69 7ZB, UK.
Quinol-dependent nitric oxide reductases (qNORs) are membrane-integrated, iron-containing enzymes of the denitrification pathway, which catalyze the reduction of nitric oxide (NO) to the major ozone destroying gas nitrous oxide (NO). Cryo-electron microscopy structures of active qNOR from and an activity-enhancing mutant have been determined to be at local resolutions of 3.7 and 3.
View Article and Find Full Text PDFSci Rep
February 2018
Department of Biochemistry and Biophysics, Stockholm University, Svante Arrhenius väg 16C, 10691, Stockholm, Sweden.
Bacterial nitric oxide reductases (NORs) catalyse the reduction of NO to NO and HO. NORs are found either in denitrification chains, or in pathogens where their primary role is detoxification of NO produced by the immune defense of the host. Although NORs belong to the heme-copper oxidase superfamily, comprising proton-pumping O-reducing enzymes, the best studied NORs, cNORs (cytochrome c-dependent), are non-electrogenic.
View Article and Find Full Text PDFBiochim Biophys Acta
July 2014
RIKEN SPring-8 Center, Kouto, Sayo, Hyogo 679-5148, Japan. Electronic address:
Nitric oxide reductase (NOR) catalyzes the reduction of nitric oxide to generate nitrous oxide. We recently reported on the crystal structure of a quinol-dependent NOR (qNOR) from Geobacillus stearothermophilus [Y. Matsumoto, T.
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