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-Structure paper
Title | Dimeric structures of quinol-dependent nitric oxide reductases (qNORs) revealed by cryo-electron microscopy. |
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Journal, issue, pages | Sci Adv, Vol. 5, Issue 8, Page eaax1803, Year 2019 |
Publish date | Aug 28, 2019 |
Authors | Chai C Gopalasingam / Rachel M Johnson / George N Chiduza / Takehiko Tosha / Masaki Yamamoto / Yoshitsugu Shiro / Svetlana V Antonyuk / Stephen P Muench / S Samar Hasnain / |
PubMed Abstract | 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 ...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 3.2 Å, respectively. They unexpectedly reveal a dimeric conformation (also confirmed for qNOR from ) and define the active-site configuration, with a clear water channel from the cytoplasm. Structure-based mutagenesis has identified key residues involved in proton transport and substrate delivery to the active site of qNORs. The proton supply direction differs from cytochrome c-dependent NOR (cNOR), where water molecules from the cytoplasm serve as a proton source similar to those from cytochrome c oxidase. |
External links | Sci Adv / PubMed:31489376 / PubMed Central |
Methods | EM (single particle) |
Resolution | 3.3 - 3.9 Å |
Structure data | |
Chemicals | ChemComp-HEM: ChemComp-FE: ChemComp-CA: ChemComp-LOP: ChemComp-LMT: ChemComp-HOH: |
Source |
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Keywords | OXIDOREDUCTASE / Proton Transfer / Membrane Protein / Homodimer |