Tetrapyrrole methylase (IPR000878)

Short name: 4pyrrol_Mease

Overlapping homologous superfamilies

Domain relationships


Tetrapyrroles are large macrocyclic compounds derived from a common biosynthetic pathway [PMID: 11215515]. The end-product, uroporphyrinogen III, is used to synthesise a number of important molecules, including cobalamin (vitamin B12), haem, sirohaem, chlorophyll, coenzyme F430 and phytochromobilin [PMID: 17227226].

These enzymes catalyse the methylation of their substrates using S-adenosyl-L-methionine as a methyl source. Enzymes in this family include:

  • Uroporphyrinogen III methyltransferase (EC: (SUMT), which catalyses the conversion of uroporphyrinogen III to precorrin-2 at the first branch-point of the tetrapyrrole synthesis pathway, directing the pathway towards cobalamin or sirohaem synthesis [PMID: 15522295].
  • Precorrin-2 C20-methyltransferase CobI/CbiL (EC:, which introduces a methyl group at C-20 on precorrin-2 to produce precorrin-3A during cobalamin biosynthesis. This reaction is key to the conversion of a porphyrin-type tetrapyrrole ring to a corrin ring [PMID: 17229157]. In some species, this enzyme is part of a bifunctional protein.
  • Precorrin-4 C11-methyltransferase CobM/CbiF (EC:, which introduces a methyl group at C-11 on precorrin-4 to produce precorrin-5 during cobalamin biosynthesis [PMID: 16866557].
  • Sirohaem synthase CysG (EC:, domains 4 and 5, which synthesizes sirohaem from uroporphyrinogen III, at the first branch-point in the tetrapyrrole biosynthetic pathway, directing the pathway towards sirohaem synthesis [PMID: 14595395].
  • Diphthine synthase (EC:, which carries out the methylation step during the modification of a specific histidine residue of elongation factor 2 (EF-2) during diphthine synthesis.

This entry represents a tetrapyrrole methylase domain, which consist of two non-similar subdomains [PMID: 15522295].

GO terms

Biological Process

No terms assigned in this category.

Molecular Function

GO:0008168 methyltransferase activity

Cellular Component

No terms assigned in this category.

Contributing signatures

Signatures from InterPro member databases are used to construct an entry.