No Laughing Matter: The Unmaking of the Greenhouse Gas Dinitrogen Monoxide by Nitrous Oxide Reductase - The Metal-Driven Biogeochemistry of Gaseous Compounds in the Environment - page 182

Figure 3 Structure of the copper enzyme N 2 O reductase (PDB ID 3SBR). (a)N 2 OR is the product
of the nosZ gene, and the peptide chain is organized into two distinct domains that harbor one of
the metal centers each. The N-terminal domain attains a seven-bladed ʲ -propeller fold that
coordinates the tetranuclear active site Cu Z through seven histidine residues at its hub.
The C-terminal domain shows a cupredoxin fold similar to type-I copper proteins and binds the
dinuclear mixed-valent Cu A center. (b) The distance between the two metals centers within a
single polypeptide chain is above 40 , but the enzyme forms stable homodimers in a head-to-tail

arrangements that brings the Cu A site of one monomer within a distance of 10 Å from the Cu Z site
of the other and vice versa .

Å