title: Crystal structure of quinol-dependent nitric oxide reductase from Geobacillus stearothermophilus.
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.
authors.affiliation: Biometal Science Laboratory, RIKEN SPring-8 Center, Sayo, Hyogo, Japan.
authors.forename: Yushi
authors.initials: Y
authors.lastname: Matsumoto
authors.forename: Takehiko
authors.initials: T
authors.lastname: Tosha
authors.forename: Andrei V
authors.initials: AV
authors.lastname: Pisliakov
authors.forename: Tomoya
authors.initials: T
authors.lastname: Hino
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Sugimoto
authors.forename: Shingo
authors.initials: S
authors.lastname: Nagano
authors.forename: Yuji
authors.initials: Y
authors.lastname: Sugita
authors.forename: Yoshitsugu
authors.initials: Y
authors.lastname: Shiro
mesh_terms: D019943:Amino Acid Substitution; D018360:Crystallography, X-Ray; D001411:Geobacillus stearothermophilus / Q000737:chemistry / Q000201:enzymology*; D006873:Hydroquinones / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D016297:Mutagenesis, Site-Directed; D050505:Mutant Proteins / Q000235:genetics / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D009609:Nitrous Oxide / Q000378:metabolism; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism; D011487:Protein Conformation
chemical_list: D006873:Hydroquinones; D050505:Mutant Proteins; D009569:Nitric Oxide; D010088:Oxidoreductases; C034747:nitric-oxide reductase; D009609:Nitrous Oxide