CATH Classification
| Level | CATH Code | Description |
|---|---|---|
|
3 | Alpha Beta |
|
3.40 | 3-Layer(aba) Sandwich |
|
3.40.1010 | Cobalt-precorrin-4 Transmethylase; domain 1 |
|
3.40.1010.10 | Cobalt-precorrin-4 Transmethylase; Domain 1 |
Domain Context
CATH Clusters
| Superfamily | Cobalt-precorrin-4 Transmethylase; Domain 1 |
| Functional Family | Siroheme synthase |
Enzyme Information
| 2.1.1.107 |
Uroporphyrinogen-III C-methyltransferase.
based on mapping to UniProt P21631
2 S-adenosyl-L-methionine + uroporphyrinogen III = 2 S-adenosyl-L- homocysteine + precorrin-2.
-!- This enzyme catalyzes two sequential methylation reactions, the first forming precorrin-1 and the second leading to the formation of precorrin-2. -!- It is the first of three steps leading to the formation of siroheme from uroporphyrinogen III. -!- The second step involves an NAD(+)-dependent dehydrogenation to form sirohydrochlorin from precorrin-2 (EC 1.3.1.76) and the third step involves the chelation of Fe(2+) to sirohydrochlorin to form siroheme (EC 4.99.1.4). -!- In Saccharomyces cerevisiae, the last two steps are carried out by a single bifunctional enzyme, Met8p. -!- In some bacteria, steps 1-3 are catalyzed by a single multifunctional protein called CysG, whereas in Bacillus megaterium, three separate enzymes carry out each of the steps, with SirA being responsible for the above reaction. -!- Also involved in the biosynthesis of cobalamin.
|
UniProtKB Entries (1)
| P21631 |
SUMT_SINSX
Sinorhizobium sp.
Uroporphyrinogen-III C-methyltransferase
|
PDB Structure
| PDB | 1S4D |
| External Links | |
| Method | X-RAY DIFFRACTION |
| Organism | Escherichia |
| Primary Citation |
Structure/Function Studies on a S-Adenosyl-l-methionine-dependent Uroporphyrinogen III C Methyltransferase (SUMT), a Key Regulatory Enzyme of Tetrapyrrole Biosynthesis
J.Mol.Biol.
|