Magnesium chelatase

magnesium chelatase
Identifiers
EC number	6.6.1.1
CAS number	Template:CAS
Databases
IntEnz	IntEnz view
BRENDA	BRENDA entry
ExPASy	NiceZyme view
KEGG	KEGG entry
MetaCyc	metabolic pathway
PRIAM	profile
PDB structures	RCSB PDB PDBe PDBsum
Gene Ontology	AmiGO / EGO
Search PMC articles PubMed articles NCBI proteins

Magnesium chelatase, ChlI subunit
Identifiers
Symbol	Mg_chelatse_chII
Pfam	PF01078
InterPro	IPR000523
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

CobN/magnesium chelatase
Identifiers
Symbol	CobN/Mg_chltase
Pfam	PF02514
InterPro	IPR003672
Available protein structures: Pfam structures PDB RCSB PDB; PDBe; PDBj PDBsum structure summary

Magnesium-chelatase is a three-component enzyme that catalyses the insertion of Mg²⁺ into protoporphyrin IX. This is the first unique step in the synthesis of bacteriochlorophyll. 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:

480px

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

The 4 substrates of this enzyme are ATP, protoporphyrin IX, Mg²⁺, and H₂O, whereas its 4 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 participates in porphyrin and chlorophyll metabolism.