Nitrous-oxide reductase is part of a bacterial respiratory system which is activated under anaerobic conditions in the presence of nitrate or nitrous oxide. 2 Fe(III)-[cytochrome c] + H2O + N2 = 2 Fe(II)-[cytochrome c] + 2 H(+) + nitrous oxide Binds 2 calcium ions per subunit. Binds 6 Cu cations. Each subunit contains 2 copper centers; Cu(A) (binuclear) and Cu(Z) (tetranuclear). Cu(Z) is thought to be the site of nitrous oxide reduction. Nitrogen metabolism; nitrate reduction (denitrification); dinitrogen from nitrate: step 4/4. Homodimer. Predicted to be exported by the Tat system. The position of the signal peptide cleavage has not been experimentally proven. The N-terminus is blocked. Belongs to the NosZ family. In the C-terminal section; belongs to the cytochrome c oxidase subunit 2 family.