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Literature summary for 1.2.1.70 extracted from

  • Farah, C.; Levican, G.; Ibba, M.; Orellana, O.
    Effect of hydrogen peroxide on the biosynthesis of heme and proteins potential implications for the partitioning of Glu-tRNA(Glu) between these pathways (2014), Int. J. Mol. Sci., 15, 23011-23023 .
    View publication on PubMedView publication on EuropePMC

Activating Compound

Activating Compound Comment Organism Structure
protein GSAM stimulation of GluTR by glutamate semialdehyde 1-2 aminomutase, GSAM. GluTR activity is stimulated upon formation ofa complex with protein GSAM. This effect is observed only when GluTR contained a heme/protein ratio of 1/12. GluTR activity and the stimulation of this enzyme by protein GSAM are reduced by treatment with H2O2 Acidithiobacillus ferrooxidans

Cloned(Commentary)

Cloned (Comment) Organism
recombinant overexpression of His6-tagged enzyme in Escherichia coli strain BL21(DE3) Acidithiobacillus ferrooxidans

Inhibitors

Inhibitors Comment Organism Structure
H2O2 inactivates the enzyme. H2O2 decreases the stimulation of GluTR by glutamate semialdehyde 1-2 aminomutase, GSAM Acidithiobacillus ferrooxidans
heme feedback inhibition Acidithiobacillus ferrooxidans

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required Acidithiobacillus ferrooxidans

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
L-glutamyl-tRNAGlu + NADPH + H+ Acidithiobacillus ferrooxidans
-
L-glutamate 1-semialdehyde + NADP+ + tRNAGlu
-
?

Organism

Organism UniProt Comment Textmining
Acidithiobacillus ferrooxidans B7J8J0
-
-

Purification (Commentary)

Purification (Comment) Organism
recombinant His6-tagged enzyme from Escherichia coli strain BL21(DE3) by nickel affinity chromatography Acidithiobacillus ferrooxidans

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
L-glutamyl-tRNAGlu + NADPH + H+
-
Acidithiobacillus ferrooxidans L-glutamate 1-semialdehyde + NADP+ + tRNAGlu
-
?

Synonyms

Synonyms Comment Organism
GluTR
-
Acidithiobacillus ferrooxidans

Temperature Optimum [°C]

Temperature Optimum [°C] Temperature Optimum Maximum [°C] Comment Organism
37
-
assay at Acidithiobacillus ferrooxidans

pH Optimum

pH Optimum Minimum pH Optimum Maximum Comment Organism
7.2
-
assay at Acidithiobacillus ferrooxidans

Cofactor

Cofactor Comment Organism Structure
heme enzyme preparations with one molecule of heme bound per four GluTR subunits (heme/protein ratio of 1/4) have an increased inactivation rate by H2O2 compared to enzymes with one heme per twelve GluTR subunits (heme/protein ratio of 1/12) Acidithiobacillus ferrooxidans
NADP+
-
Acidithiobacillus ferrooxidans
NADPH
-
Acidithiobacillus ferrooxidans

General Information

General Information Comment Organism
metabolism glutamyl-tRNA reductase (GluTR) is the key enzyme for heme biosynthesis. The flow of glutamyl-tRNA is diverted from heme biosynthesis towards protein synthesis under oxidative stress conditions. In the C5 pathway, 5-aminolevulinic acid is synthesized from Glu-tRNAGlu in two steps. First, the glutamate moiety of Glu-tRNAGlu is reduced to glutamate semialdehyde (GSA) by glutamyl-tRNA reductase (GluTR), and then GSA is converted to 5-aminolevulinic acid by the glutamate semialdehyde 1-2 aminomutase (GSAM) Acidithiobacillus ferrooxidans
physiological function in chemolithoautotrophic bacteria like Acidithiobacillus ferrooxidans that use the C5 pathway to synthesize tetrapyrroles, high demand for Glu-tRNAGlu for heme biosynthesis is expected, due to the high cytochrome content required for respiration using poor electron donors, such as ferrous ions. This bacterium has a complex system of glutamyl-tRNA formation composed of two non-discriminating glutamyl-tRNA synthetases (GluRS1 and GluRS2) and up to four tRNAGlu isoacceptors, with GluRS1 serving as the main enzyme for Glu-tRNAGlu formation. Three out of four glutamyl-tRNAs can act as donors for both heme and protein synthesis, while the fourth is not a substrate of GluTR and likely acts exclusively in protein synthesis Acidithiobacillus ferrooxidans