Magnesium-chelatase is a three-component enzyme (EC 6.6.1.1) that catalyses the insertion of Mg2+ into protoporphyrin IX. This is the first unique step in the synthesis of chlorophyll and bacteriochlorophyll.[1][2] As a result, it is thought that Mg-chelatase has an important role in channeling intermediates into the (bacterio)chlorophyll branch in response to conditions suitable for photosynthetic growth:

Magnesium chelatase
Magnesium chelatase hetero12mer, Rhodobacter capsulatus
Identifiers
EC no.6.6.1.1
CAS no.9074-88-8
Databases
IntEnzIntEnz view
BRENDABRENDA entry
ExPASyNiceZyme view
KEGGKEGG entry
MetaCycmetabolic pathway
PRIAMprofile
PDB structuresRCSB PDB PDBe PDBsum
Gene OntologyAmiGO / QuickGO
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PMCarticles
PubMedarticles
NCBIproteins
Magnesium chelatase, ChlI subunit
Identifiers
SymbolMg_chelatse_chII
PfamPF01078
InterProIPR000523
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary
PDBPDB: 1g8p
CobN/magnesium chelatase
Identifiers
SymbolCobN/Mg_chltase
PfamPF02514
InterProIPR003672
Available protein structures:
Pfam  structures / ECOD  
PDBRCSB PDB; PDBe; PDBj
PDBsumstructure summary

protoporphyrin IX + Mg2+
+ ATP + H
2
O
ADP + phosphate + Mg-protoporphyrin IX + 2 H+

The four substrates of this enzyme are ATP, protoporphyrin IX, Mg2+, and H2O; its four products are ADP, phosphate, Mg-protoporphyrin IX, and H+.

This enzyme belongs to the family of ligases, specifically those forming nitrogen-D-metal bonds in coordination complexes. The systematic name of this enzyme class is Mg-protoporphyrin IX magnesium-lyase. Other names in common use include protoporphyrin IX magnesium-chelatase, protoporphyrin IX Mg-chelatase, magnesium-protoporphyrin IX chelatase, magnesium-protoporphyrin chelatase, magnesium-chelatase, Mg-chelatase, and Mg-protoporphyrin IX magnesio-lyase. This enzyme is part of the biosynthetic pathway to chlorophylls.

See also

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References

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  1. ^ Willows, Robert D. (2003). "Biosynthesis of chlorophylls from protoporphyrin IX". Natural Product Reports. 20 (6): 327–341. doi:10.1039/B110549N. PMID 12828371.
  2. ^ Bollivar, David W. (2007). "Recent advances in chlorophyll biosynthesis". Photosynthesis Research. 90 (2): 173–194. doi:10.1007/s11120-006-9076-6. PMID 17370354. S2CID 23808539.