Tetrapyrrole methylase (IPR000878)
Short name: 4pyrrol_Mease
- Tetrapyrrole methylase (IPR000878)
- Cobalamin (vitamin B12) biosynthesis CbiE, precorrin-6Y methyltransferase (IPR012818)
- Cobalamin (vitamin B12) biosynthesis CobM/CbiF, precorrin-4 C11-methyltransferase (IPR006362)
- Precorrin-2 C(20)-methyltransferase domain (IPR006364)
- Precorrin-3B C17-methyltransferase domain (IPR006363)
- Uroporphyrin-III C-methyltransferase (IPR006366)
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:220.127.116.11) (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:18.104.22.168), 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:22.214.171.124), which introduces a methyl group at C-11 on precorrin-4 to produce precorrin-5 during cobalamin biosynthesis [PMID: 16866557].
- Sirohaem synthase CysG (EC:126.96.36.199), 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:188.8.131.52), 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].