C-terminal domain of type I, class II extradiol dioxygenases, catalytic domain
This family contains the C-terminal, catalytic domain of type I, class II extradiol dioxygenases. Dioxygenases catalyze the incorporation of both atoms of molecular oxygen into substrates using a variety of reaction mechanisms, resulting in the cleavage of aromatic rings. Two major groups of dioxygenases have been identified according to the cleavage site; extradiol enzymes cleave the aromatic ring between a hydroxylated carbon and an adjacent non-hydroxylated carbon, whereas intradiol enzymes cleave the aromatic ring between two hydroxyl groups. Extradiol dioxygenases are classified into type I and type II enzymes. Type I extradiol dioxygenases include class I and class II enzymes. These two classes of enzymes show sequence similarity; the two-domain class II enzymes evolved from a class I enzyme through gene duplication. The extradiol dioxygenases represented in this family are type I, class II enzymes, and are composed of the N- and C-terminal domains of similar structure fold, resulting from an ancient gene duplication. The active site is located in a funnel-shaped space of the C-terminal domain. A catalytically essential metal, Fe(II) or Mn(II), presents in all the enzymes in this family.