Crystal structure of a bacterial non-haem iron hydroxylase that catalyses the biological oxidation of methane

The 2.2 & Aring; crystal structure of the 251K α₂β₂γ₂ dimeric hydroxylase protein of methane mono-oxygenase from Methylococcus capsulatus (Bath) reveals the geometry of the catalytic di-iron core. The two iron atoms are bridged by exogenous hydroxide and acetate ligands and further coordinated by four glutamate residues, two histidine residues and a water molecule. The dinuclear iron centre lies in a hydrophobic active-site cavity for binding methane. An extended canyon runs between αβ pairs, which have many long α-helices, for possible docking of the reductase and coupling proteins required for catalysis.