A novel type of catalytic copper cluster in nitrous oxide reductase

• Published in: Nature structural & molecular biology Vol. 7; no. 3; pp. 191 - 195
• Main Authors: Cambillau, Christian, Brown, Kieron, Tegoni, Mariella, Prudêncio, Miguel, Pereira, Alice S, Besson, Stephane, Moura, José J, Moura, Isabel
• Format: Journal Article
• Language: English
• Published: United States Nature Publishing Group 01.03.2000
• Subjects: Amino Acid Sequence; Azurin - analogs & derivatives; Azurin - metabolism; Binding Sites; Catalytic Domain; Copper - chemistry; Copper - metabolism; Crystallography, X-Ray; Dimerization; Histidine - metabolism; Hydrogen Bonding; Models, Molecular; Molecular Sequence Data; Nitrous Oxide - metabolism; nitrous-oxide reductase; Oxidation-Reduction; Oxidoreductases - chemistry; Oxidoreductases - metabolism; Protein Conformation; Protein Folding; Pseudomonas - enzymology; Pseudomonas nautica; Structure-Activity Relationship
• ISSN: 1072-8368; 1545-9993; 2331-365X; 1545-9985
• DOI: 10.1038/73288

Nitrous oxide (N2O) is a greenhouse gas, the third most significant contributor to global warming. As a key process for N2O elimination from the biosphere, N2O reductases catalyze the two-electron reduction of N2O to N2. These 2 × 65 kDa copper enzymes are thought to contain a CuA electron entry site, similar to that of cytochrome c oxidase, and a CuZ catalytic center. The copper anomalous signal was used to solve the crystal structure of N2O reductase from Pseudomonas nautica by multiwavelength anomalous dispersion, to a resolution of 2.4 Å. The structure reveals that the CuZ center belongs to a new type of metal cluster, in which four copper ions are liganded by seven histidine residues. N2O binds to this center via a single copper ion. The remaining copper ions might act as an electron reservoir, assuring a fast electron transfer and avoiding the formation of dead-end products.