D
IPR019478

Sirohaem synthase, dimerisation domain

InterPro entry
Short nameSirohaem_synthase_dimer_dom
Overlapping
homologous
superfamilies
 

Description

Bacterial sulphur metabolism depends on the iron-containing porphinoid sirohaem. CysG is a multi-functional enzyme with S-adenosyl-L-methionine (SAM)-dependent bismethyltransferase, dehydrogenase and ferrochelatase activities. CysG synthesizes sirohaem from uroporphyrinogen III via reactions which encompass two branchpoint intermediates in tetrapyrrole biosynthesis, diverting flux first from protoporphyrin IX biosynthesis and then from cobalamin (vitamin B12) biosynthesis. CysG is a dimer. Its dimerisation region is 74 residues long, and acts to hold the two structurally similar protomers held together asymmetrically through a number of salt-bridges across complementary residues within the dimerisation region
[1]
. CysG dimerisation produces a series of active sites, accounting for CysG's multi-functionality, catalysing four diverse reactions:


 * Two SAM-dependent methylations
 * NAD+-dependent tetrapyrrole dehydrogenation
 * Metal chelation

References

1.CysG structure reveals tetrapyrrole-binding features and novel regulation of siroheme biosynthesis. Stroupe ME, Leech HK, Daniels DS, Warren MJ, Getzoff ED. Nat. Struct. Biol. 10, 1064-73, (2003). View articlePMID: 14595395

GO terms

molecular function

  • None

cellular component

  • None

Cross References

Contributing Member Database Entry
This website requires cookies, and the limited processing of your personal data in order to function. By using the site you are agreeing to this as outlined in our Privacy Notice and Terms of Use.