InterPro domain: IPR008076

Cyanate hydratase or cyanase catalyses the reaction of cyanate with bicarbonate to produce ammonia and carbon dioxide, allowing the host organisms to overcome the toxicity of environmental cyanate [ 1 ]. The enzyme is also known as cyanate lyase and cyanate hydrolase.

The cyanate lyase monomer is composed of two domains: an N-terminal domainthat shows structural similarity to the DNA-binding alpha-helix bundlemotif, and a C-terminal domain that has an 'open fold' that shows no structural similarity to other proteins [ 2 ].

The enzyme is active as a homodecamer of 17kDa subunits, and displayshalf-site binding of substrates or substrate analogues. The dimer structurereveals the C-terminal domains to be intertwined; the decamer is formedfrom a pentamer of these dimers. The active site of the enzyme is locatedbetween dimers and comprises residues from four adjacent subunitsof the homodecamer.

1. Structural properties of cyanase. Denaturation, renaturation, and role of sulfhydryls and oligomeric structure in catalytic activity. J. Biol. Chem. 262, 10120-6