Tetrapyrrole methylase, subdomain 2 (IPR014776)
Short name: 4pyrrole_Mease_sub2
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].
This entry represents the C-terminal subdomain 2 from several tetrapyrrole methylases, which consist of two non-similar domains. 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:188.8.131.52) (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:184.108.40.206), 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:220.127.116.11), which introduces a methyl group at C-11 on precorrin-4 to produce precorrin-5 during cobalamin biosynthesis [PMID: 16866557].
- Sirohaem synthase CysG (EC:18.104.22.168), 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:22.214.171.124), which carries out the methylation step during the modification of a specific histidine residue of elongation factor 2 (EF-2) during diphthine synthesis.
- G3DSA:3.30.950.10 (G3DSA:3.30.950.10)