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Literature summary for 6.6.1.1 extracted from

  • Davison, P.A.; Hunter, C.N.
    Abolition of magnesium chelatase activity by the gun5 mutation and reversal by Gun4 (2011), FEBS Lett., 585, 183-186.
    View publication on PubMed

Activating Compound

Activating Compound Comment Organism Structure
Gun4 addition of Gun4 up to 0.0005 mM stimulates the wild type enzyme 2-3fold. Up to 0.001 mM Gun4 resurrects the inactive gun5 and cch mutant Mg-chelatase reactions to the level seen in the wild type with no Gun4 present, particularly in the case of mutant gun5 Synechocystis sp.

Cloned(Commentary)

Cloned (Comment) Organism
mutant enzymes are expressed in Escherichia coli Synechocystis sp.

Protein Variants

Protein Variants Comment Organism
A942V the (gun5) mutation abolishes activity of Mg-chelatase subunit H. Increasing the ChlH concentration up to 0.02 mM restores approximately 50% activity in the presence of the gun5 mutation. The addition of Gun4 restores Mg-chelatase activity of the gun5 mutant enzyme Synechocystis sp.
P595L the (cch) mutation abolishes activity of Mg-chelatase subunit H. Increasing the ChlH concentration up to 0.02 mM fully restores activity in the presence of the cch mutation. The addition of Gun4 restores Mg-chelatase activity of the cch mutant enzyme Synechocystis sp.

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required Synechocystis sp.

Molecular Weight [Da]

Molecular Weight [Da] Molecular Weight Maximum [Da] Comment Organism
39000
-
1 * 148000 + 1 * 39000 + 1 * 73000, subunits ChlH, ChlI and ChlD Synechocystis sp.
73000
-
1 * 148000 + 1 * 39000 + 1 * 73000, subunits ChlH, ChlI and ChlD Synechocystis sp.
148000
-
1 * 148000 + 1 * 39000 + 1 * 73000, subunits ChlH, ChlI and ChlD Synechocystis sp.

Organism

Organism UniProt Comment Textmining
Synechocystis sp.
-
-
-

Purification (Commentary)

Purification (Comment) Organism
mutant enzymes are purified by Ni2+ affinity column chromatography Synechocystis sp.

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + protoporphyrin IX + Mg2+ + H2O
-
Synechocystis sp. ADP + phosphate + Mg-protoporphyrin IX + H+
-
?

Subunits

Subunits Comment Organism
heterotrimer 1 * 148000 + 1 * 39000 + 1 * 73000, subunits ChlH, ChlI and ChlD Synechocystis sp.

Synonyms

Synonyms Comment Organism
ChlH subunit of the magnesium chelatase Synechocystis sp.
ChlHID
-
Synechocystis sp.
Mg-chelatase
-
Synechocystis sp.

General Information

General Information Comment Organism
metabolism magnesium chelatase catalyses the first committed step of chlorophyll biosynthesis Synechocystis sp.