Literature summary for 3.1.3.25 extracted from

Li, Z.; Stieglitz, K.; Shrout, A.; Wei, Y.; Weis, R.; Stec, B.; Roberts, M.
Mobile loop mutations in an archaeal inositol monophosphatase: Modulating three-metal ion assisted catalysis and lithium inhibition (2010), Protein Sci., 19, 309-318.

Search for more literature for 3.1.3.25

Crystallization (Commentary)

Crystallization (Comment)	Organism
MJ0109 with bound metal ions, Mg2+, Zn2+, or Mn2+, crystal structure analysis, PDB ID 1DK4	Methanocaldococcus jannaschii

Protein Variants

Protein Variants	Comment	Organism
D26A	site-directed mutagenesis, the mutant shows no significant change in the Mg2+ requirement for optimal activity	Methanocaldococcus jannaschii
D38A	site-directed mutagenesis, the mutant shows an increased Km for Mg2+, but little effect on kcat compared to the wild-type enzyme, the mutant has a dramatically enhanced sensitivity to Li+ compared to the wild-type, with an IC50 of 12 mM. Electron density map for MJ0109 D38A mobile loop and active site with and without bound Li+, overview	Methanocaldococcus jannaschii
E39A	site-directed mutagenesis, the mutant shows no significant change in the Mg2+ requirement for optimal activity	Methanocaldococcus jannaschii
E41A	site-directed mutagenesis, the mutant shows no significant change in the Mg2+ requirement for optimal activity	Methanocaldococcus jannaschii

Inhibitors

Inhibitors	Comment	Organism	Structure
Ca2+	-	Methanocaldococcus jannaschii
Li+	specific mode of action for lithium inhibition in the IMPase superfamily, lithium ion inhibition of the archaeal IMPase is very poor with an IC50 of about 250 mM, mutant D38A enzyme has a dramatically enhanced sensitivity to Li+ with an IC50 of 12 mM	Methanocaldococcus jannaschii
Mg2+	tight binding of Mg2+ to the protein affects the secondary structure	Methanocaldococcus jannaschii

Metals/Ions

Metals/Ions	Comment	Organism	Structure
Mg2+	the enzyme requires 5-10 mM Mg21 for optimum catalysis, three to four ions are tightly bound in the absence of ligands. Asp38 coordinates the third metal ion in the substrate complex, but with sufficient flexibility in the loop such that other acidic residues can position the Mg2+ in the active site in the absence of Asp38. Thermodynamic parameters for Mg2+ binding, overview	Methanocaldococcus jannaschii
additional information	metal coordination and binding structures of MJ0109, metal 1 is coordinated by Asp84, Asp201, and two phosphate oxygens from substrate or product in a tetrahedral conformation. Metal 2 is coordinated by Asp84, Asp81, Glu65, a phosphate oxygen, and a water molecule. Metal 3 binding involves Asp38, detailed overview	Methanocaldococcus jannaschii

Natural Substrates/ Products (Substrates)

Natural Substrates	Organism	Comment (Nat. Sub.)	Natural Products	Comment (Nat. Pro.)	Rev.	Reac.
myo-inositol 1-phosphate + H2O	Methanocaldococcus jannaschii	-	myo-inositol + phosphate	-	?

Organism

Organism	UniProt	Comment	Textmining
Methanocaldococcus jannaschii	-	-	-

Substrates and Products (Substrate)

Substrates	Comment Substrates	Organism	Products	Comment (Products)	Rev.	Reac.
myo-inositol 1-phosphate + H2O	-	Methanocaldococcus jannaschii	myo-inositol + phosphate	-	?

Synonyms

Synonyms	Comment	Organism
IMPase	-	Methanocaldococcus jannaschii
inositol monophosphatase	-	Methanocaldococcus jannaschii
MJ0109	-	Methanocaldococcus jannaschii

Temperature Optimum [°C]

Temperature Optimum [°C]	Temperature Optimum Maximum [°C]	Comment	Organism
85	-	assay at	Methanocaldococcus jannaschii

Temperature Stability [°C]

Temperature Stability Minimum [°C]	Temperature Stability Maximum [°C]	Comment	Organism
additional information	-	the archaeal IMPase is extremely stable and active over a wide temperature range	Methanocaldococcus jannaschii

IC50 Value

IC50 Value	IC50 Value Maximum	Comment	Organism	Inhibitor	Structure
12	-	mutant D38A, pH not specified in the publication, 85°C	Methanocaldococcus jannaschii	Li+
240	-	wild-type enzyme, pH not specified in the publication, 85°C	Methanocaldococcus jannaschii	Li+

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Release 2023.1 (January 2023)