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Updated: May 25, 2026

Anaerobic Protein Purification and Kinetic Analysis via Oxygen Electrode for Studying DesB Dioxygenase Activity and Inhibition
Published on: October 3, 2018
Crystal structure of quinol-dependent nitric oxide reductase from Geobacillus stearothermophilus
Yushi Matsumoto1, Takehiko Tosha, Andrei V Pisliakov
1Biometal Science Laboratory, RIKEN SPring-8 Center, Sayo, Hyogo, Japan.
Abstract:
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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