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Dioxygenases catalyze the incorporation of both atoms of molecular oxygen into substrates. Cleavage of aromatic rings is one of the most important function of dioxygenases. The substrates of ring-cleavage dioxygenases can be classified into two groups according to the mode of scission of the aromatic ring. Intradiol enzymes cleave the aromatic ring between two hydroxyl groups, whereas extradiol enzymes cleave the aromatic ring between a hydroxylated carbon and another adjacent nonhydroxylated carbon [1]. Intradiol dioxygenases require a nonheme ferric ion as a cofactor. The enzymes that belong to this family are:

• Protocatechuate 3,4-dioxygenase (EC 1.13.11.3) (3,4-PCD), an oligomeric enzyme complex which consists of 12 copies each of an α and a β subunits. Both subunits are evolutionary related.
• Catechol 1,2-dioxygenase (EC 1.13.11.1) (gene catA or clcA).
• Chlorocatechol 1,2-dioxygenase (EC 1.13.11.1) (gene tfdC).

As a signature pattern for these enzymes we selected a region that includes a tyrosine residue which, in 3,4-PCD, has been shown [2], to be implicated in the binding of the ferric iron atom.

Harayama S.

December 2004 / Pattern and text revised.

PROSITE method (with tools and information) covered by this documentation:

INTRADIOL_DIOXYGENAS, PS00083; Intradiol ring-cleavage dioxygenases signature  (PATTERN)

Consensus pattern: [LIVMF]-x-G-x-[LIVM]-x(4)-[GS]-x(2)-[LIVMA]-x(4)-[LIVM]-[DE]-[LIVMFYC]-x(6)-G-x-[FY] Y is an iron ligand Sequences known to belong to this class detected by the pattern: ALL Other sequence(s) detected in Swiss-Prot: NONE.

• Retrieve an alignment of Swiss-Prot true positive hits:   Clustal format, color, condensed view  / Clustal format, color  / Clustal format, plain text  / Fasta format • Retrieve the sequence logo from the alignment • Taxonomic tree view of all Swiss-Prot/TrEMBL entries matching PS00083 • Retrieve a list of all Swiss-Prot/TrEMBL entries matching PS00083 • Scan Swiss-Prot/TrEMBL entries against PS00083 • view ligand binding statistics

Matching PDB structures: 1DLM 1DLQ 1DLT 1DMH ... [ALL]

1	Authors	Harayama S., Rekik M.
	Title	Bacterial aromatic ring-cleavage enzymes are classified into two different gene families.
	Source	J. Biol. Chem. 264:15328-15333(1989).
	PubMed ID	2670937

2	Authors	Ohlendorf D.H., Lipscomb J.D., Weber P.C.
	Title	Structure and assembly of protocatechuate 3,4-dioxygenase.
	Source	Nature 336:403-405(1988).
	PubMed ID	3194022
	DOI	10.1038/336403a0

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