Structural basis of biological N2O generation by bacterial nitric oxide reductase.
Nitric oxide reductase (NOR) is an iron-containing enzyme that catalyzes the reduction of nitric oxide (NO) to generate a major greenhouse gas, nitrous oxide (N(2)O). Here, we report the crystal structure of NOR from Pseudomonas aeruginosa at 2.7 angstrom resolution. The structure reveals details of the catalytic binuclear center. The non-heme iron (Fe(B)) is coordinated by three His and one Glu ligands, but a His-Tyr covalent linkage common in cytochrome oxidases (COX) is absent. This structural characteristic is crucial for NOR reaction. Although the overall structure of NOR is closely related to COX, neither the D- nor K-proton pathway, which connect the COX active center to the intracellular space, was observed. Protons required for the NOR reaction are probably provided from the extracellular side.
RIKEN SPring-8 Center, 1-1-1 Kouto, Sayo, Hyogo 679-5148, Japan.
Tomoya
T
Hino
Yushi
Y
Matsumoto
Shingo
S
Nagano
Hiroshi
H
Sugimoto
Yoshihiro
Y
Fukumori
Takeshi
T
Murata
So
S
Iwata
Yoshitsugu
Y
Shiro
D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000378:metabolism; D020134:Catalytic Domain; D018360:Crystallography, X-Ray; D045304:Cytochromes c / Q000737:chemistry; D004579:Electron Transport; D003576:Electron Transport Complex IV / Q000737:chemistry / Q000378:metabolism; D006418:Heme / Q000737:chemistry; D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D007501:Iron / Q000737:chemistry; D008565:Membrane Proteins / Q000737:chemistry / Q000378:metabolism; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009569:Nitric Oxide / Q000378:metabolism*; D009609:Nitrous Oxide / Q000378:metabolism*; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000737:chemistry* / Q000378:metabolism*; D011487:Protein Conformation; D055503:Protein Multimerization; D017433:Protein Structure, Secondary; D017434:Protein Structure, Tertiary; D021122:Protein Subunits; D011522:Protons; D011550:Pseudomonas aeruginosa / Q000201:enzymology* / Q000378:metabolism
D001426:Bacterial Proteins; D008565:Membrane Proteins; D021122:Protein Subunits; D011522:Protons; D009569:Nitric Oxide; D006418:Heme; D045304:Cytochromes c; D007501:Iron; D010088:Oxidoreductases; C034747:nitric-oxide reductase; C414443:cbb3 oxidase; D003576:Electron Transport Complex IV; D009609:Nitrous Oxide