CATH Classification
Level | CATH Code | Description |
---|---|---|
3 | Alpha Beta | |
3.40 | 3-Layer(aba) Sandwich | |
3.40.50 | Rossmann fold | |
3.40.50.1400 |
Domain Context
CATH Clusters
Superfamily | 3.40.50.1400 |
Functional Family | Sirohydrochlorin cobaltochelatase CbiKP |
Enzyme Information
4.99.1.4 |
Sirohydrochlorin ferrochelatase.
based on mapping to UniProt Q72EC8
Siroheme + 2 H(+) = sirohydrochlorin + Fe(2+).
-!- This enzyme catalyzes the third of three steps leading to the formation of siroheme from uroporphyrinogen III. -!- The first step involves the donation of two S-adenosyl-L-methionine- derived methyl groups to carbons 2 and 7 of uroporphyrinogen III to form precorrin-2 (EC 2.1.1.107) and the second step involves an NAD(+)-dependent dehydrogenation to form sirohydrochlorin from precorrin-2 (EC 1.3.1.76). -!- 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 SirB being responsible for the above reaction.
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4.99.1.3 |
Sirohydrochlorin cobaltochelatase.
based on mapping to UniProt Q72EC8
Cobalt-sirohydrochlorin + 2 H(+) = sirohydrochlorin + Co(2+).
-!- This enzyme is a type II chelatase, being either a monomer (CbiX) or a homodimer (CibK) and being ATP-independent. -!- CbiK from Salmonella enterica uses precorrin-2 as the substrate to yield cobalt-precorrin-2. -!- The enzyme contains two histidines at the active site that are thought to be involved in the deprotonation of the tetrapyrrole substrate as well as in metal binding. -!- CbiX from Bacillus megaterium inserts cobalt at the level of sirohydrochlorin (factor-II) rather than precorrin-2.
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UniProtKB Entries (1)
Q72EC8 |
CBIKP_DESVH
Desulfovibrio vulgaris str. Hildenborough
Sirohydrochlorin cobaltochelatase CbiKP
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PDB Structure
PDB | 2XVZ |
External Links | |
Method | X-RAY DIFFRACTION |
Organism | |
Primary Citation |
Evolution in a Family of Chelatases Facilitated by the Introduction of Active Site Asymmetry and Protein Oligomerization.
Proc.Natl.Acad.Sci.USA
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