Protein Family Models

Multifunctional enzyme consisting of uroporphyrin-III C-methyltransferase, precorrin-2 dehydrogenase and sirohydrochlorin ferrochelatase; catalyzes the methylation of uroporphyrinogen III to form precorrin-2, then catalyzes formation of sirohydrochlorin from precorrin-2 and finally catalyzed the formation of siroheme from sirohydrochlorin

Gene:

cysG

Date:

2021-07-23

This HMM represents enzymes, or enzyme domains, with uroporphyrin-III C-methyltransferase activity. This enzyme catalyzes the first step committed to the biosynthesis of either siroheme or cobalamin (vitamin B12) rather than protoheme (heme). Cobalamin contains cobalt while siroheme contains iron. Siroheme is a cofactor for nitrite and sulfite reductases and therefore plays a role in cysteine biosynthesis; many members of this family are CysG, siroheme synthase, with an additional N-terminal domain and with additional oxidation and iron insertion activities.

Gene:

cobA

Date:

2021-04-27

This HMM represents a subfamily of CysG N-terminal region-related sequences. All sequences in the seed alignment for this model are N-terminal regions of known or predicted siroheme synthases. The C-terminal region of each is uroporphyrin-III C-methyltransferase (EC 2.1.1.107), which catalyzes the first step committed to the biosynthesis of either siroheme or cobalamin (vitamin B12) rather than protoheme (heme). The region represented by this model completes the process of oxidation and iron insertion to yield siroheme. Siroheme is a cofactor for nitrite and sulfite reductases, so siroheme synthase is CysG of cysteine biosynthesis in some organisms.

Date:

2021-04-27

Date:

2020-10-26