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CATH Superfamily 3.40.1010.10

Tetrapyrrole methylase, N-terminal domain

The name of this superfamily has been modified since the most recent official CATH+ release (v4_3_0). At the point of the last release, this superfamily was named:

"
Cobalt-precorrin-4 Transmethylase; Domain 1
".

Functional Families

Overview of the Structural Clusters (SC) and Functional Families within this CATH Superfamily. Clusters with a representative structure are represented by a filled circle.
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FunFam 6: Siroheme synthase, putative

There are 1 EC terms in this cluster

Please note: EC annotations are assigned to the full protein sequence rather than individual protein domains. Since a given protein can contain multiple domains, it is possible that some of the annotations below come from additional domains that occur in the same protein, but have been classified elsewhere in CATH.

Note: The search results have been sorted with the annotations that are found most frequently at the top of the list. The results can be filtered by typing text into the search box at the top of the table.

EC Term Annotations Evidence
Uroporphyrinogen-III C-methyltransferase. [EC: 2.1.1.107]
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.
 2 O74468 P36150
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