Magnesium chelatase

Magnesium chelatase
Magnesium chelatase hetero12mer, Rhodobacter capsulatus
Identifiers
EC no.	6.6.1.1
CAS no.	9074-88-8
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 / QuickGO
Search PMC articles PubMed articles NCBI proteins

Magnesium chelatase, ChlI subunit
Identifiers
Symbol	Mg_chelatse_chII
Pfam	PF01078
InterPro	IPR000523
Available protein structures: PDB   PDB: 1g8p ​ IPR000523 PF01078 (ECOD; PDBsum)   AlphaFold IPR000523 PF01078

CobN/magnesium chelatase
Identifiers
Symbol	CobN/Mg_chltase
Pfam	PF02514
InterPro	IPR003672
Available protein structures: PDB   IPR003672 PF02514 (ECOD; PDBsum)   AlphaFold IPR003672 PF02514

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:

protoporphyrin IX

+ ATP + H₂O

 

 

Mg²⁺

2 H⁺

 

 

 

magnesium protoporphyrin

+ ADP + P_i

 

The four substrates of this enzyme are protoporphyrin IX, magnesium ion, adenosine triphosphate (ATP), and water. Its products are magnesium protoporphyrin IX, adenosine diphosphate (ADP), phosphate (P_i), and two protons. ^{[3] [4] [5]}

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. ^[6]

See also

• Biosynthesis of chlorophylls

References

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.
3. Walker CJ, Weinstein JD (1991). "In vitro assay of the chlorophyll biosynthetic enzyme Mg-chelatase: resolution of the activity into soluble and membrane-bound fractions". Proc. Natl. Acad. Sci. U.S.A. 88 (13): 5789–93. Bibcode:1991PNAS...88.5789W. doi: 10.1073/pnas.88.13.5789 . PMC   51963 . PMID   11607197.
4. Walker CJ, Willows RD (Oct 15, 1997). "Mechanism and regulation of Mg-chelatase". Biochem. J. 327 (2): 321–33. doi:10.1042/bj3270321. PMC   1218797 . PMID   9359397.
5. Al-Karadaghi S; Hansson, A; Hansson, M; Olsen, JG; Gough, S; Willows, RD; Al-Karadaghi, S (2001). "Interplay between an AAA module and an integrin I domain may regulate the function of magnesium chelatase". J. Mol. Biol. 311 (1): 111–22. doi:10.1006/jmbi.2001.4834. PMID   11469861.
6. Enzyme 6.6.1.1 at KEGG Pathway Database.