Magnesium chelatase

Enzyme

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
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PMC| articles
PubMed| articles
NCBI| proteins

Protein family

Magnesium chelatase, ChlI subunit

Identifiers
Symbol| Mg_chelatse_chII
Pfam| PF01078
InterPro| IPR000523
| Available protein structures:

Pfam  | structures / ECOD
PDB| RCSB PDB; PDBe; PDBj
PDBsum| structure summary
PDB| PDB: 1g8p​

Protein family

CobN/magnesium chelatase

Identifiers
Symbol| CobN/Mg_chltase
Pfam| PF02514
InterPro| IPR003672
| Available protein structures:

Pfam  | structures / ECOD
PDB| RCSB PDB; PDBe; PDBj
PDBsum| structure summary

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 + Mg2+
\+ ATP + H
2O ⇌ {\displaystyle \rightleftharpoons } 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

[edit]

* Biosynthesis of chlorophylls

## References

[edit]

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.

* 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.
* 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.
* 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.

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Enzymes: Phosphoric ester and nitrogen-metal ligases (EC 6.5-6.6)

6.5: Phosphoric Ester|

* DNA ligase

6.6: Nitrogen-Metal|

* Magnesium chelatase
* Cobalt chelatase

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Enzymes

Activity|

* Active site
* Binding site
* Catalytic triad
* Oxyanion hole
* Enzyme promiscuity
* Diffusion-limited enzyme
* Cofactor
* Enzyme catalysis

Regulation|

* Allosteric regulation
* Cooperativity
* Enzyme inhibitor
* Enzyme activator

Classification|

* EC number
* Enzyme superfamily
* Enzyme family
* List of enzymes

Kinetics|

* Enzyme kinetics
* Eadie–Hofstee diagram
* Hanes–Woolf plot
* Lineweaver–Burk plot
* Michaelis–Menten kinetics

Types|

* EC1 Oxidoreductases (list)
* EC2 Transferases (list)
* EC3 Hydrolases (list)
* EC4 Lyases (list)
* EC5 Isomerases (list)
* EC6 Ligases (list)
* EC7 Translocases (list)

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