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Literature summary for 2.7.7.72 extracted from

  • Poehler, M.T.; Roach, T.M.; Betat, H.; Jackman, J.E.; Moerl, M.
    A temporal order in 5'-and 3'-processing of eukaryotic tRNAHis (2019), Int. J. Mol. Sci., 20, 1384 .
    View publication on PubMedView publication on EuropePMC
Search for more literature for 2.7.7.72

Protein Variants

Protein Variants Comment Organism
additional information Saccharomyces cerevisiae tRNAHis transcripts with and without G-1 are generated, carrying a C73 discriminator instead of the wild-type A73 position (tRNAHisDELTAG-1 A73C and tRNAHis+G-1 A73C). Due to the additional base pair G-1/C73, tRNAHis+G-1 A73C carries an extended acceptor stem with a base-paired discriminator position. This situation does not affect CCA-addition catalyzed by the CCA-adding enzyme and results in a similarly efficient CCA incorporation to tRNAHis+G-1 A73C compared to tRNAHisDELTAG-1 A73C. Both tRNAHis substrates with a cytosine at the discriminator position are readily accepted as substrates for CCA-addition, showing comparable band patterns like the wild-type tRNAHis containing an A73. Analysis of G-1 incorporation on tRNAHis A73C variants with and without 3'-CCA-end shows significant preference of Thg1 for tRNAHis containing the 3'-CCA, both in terms of rate and maximal amount of product formed in the reactions, kinetic analysis Saccharomyces cerevisiae

KM Value [mM]

KM Value [mM] KM Value Maximum [mM] Substrate Comment Organism Structure
additional information
-
 additional information steady-state Michaelis-Menten kinetics, overview. As the limited solubility properties of RNA do not allow for using excessive saturating conditions in these analyses, the obtained parameters represent apparent values typical for CCA-addition kinetics. Kinetic analysis of CCA-addition for both tRNA variants Saccharomyces cerevisiae
0.0016
-
 tRNAHisDELTAG-1 pH and temperature not specified in the publication, recombinant enzyme Saccharomyces cerevisiae
0.0029
-
 tRNAHis+G-1 pH and temperature not specified in the publication, recombinant enzyme Saccharomyces cerevisiae

Localization

Localization Comment Organism GeneOntology No. Textmining
cytosol
-
 Saccharomyces cerevisiae 5829
-

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required Saccharomyces cerevisiae

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
a tRNA precursor + 2 CTP + ATP Saccharomyces cerevisiae
-
 a tRNA with a 3' CCA end + 3 diphosphate
-
 ?
a tRNA precursor + 2 CTP + ATP Saccharomyces cerevisiae ATCC 204508
-
 a tRNA with a 3' CCA end + 3 diphosphate
-
 ?

Organism

Organism UniProt Comment Textmining
Saccharomyces cerevisiae P21269
-
-
Saccharomyces cerevisiae ATCC 204508 P21269
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
a tRNA precursor + 2 CTP + ATP
-
 Saccharomyces cerevisiae a tRNA with a 3' CCA end + 3 diphosphate
-
 ?
a tRNA precursor + 2 CTP + ATP
-
 Saccharomyces cerevisiae ATCC 204508 a tRNA with a 3' CCA end + 3 diphosphate
-
 ?
tRNAHis+G-1 + 2 CTP + ATP
-
 Saccharomyces cerevisiae tRNAHis+G-1 with a 3' CCA end + 3 diphosphate
-
 ?
tRNAHis+G-1 + 2 CTP + ATP
-
 Saccharomyces cerevisiae ATCC 204508 tRNAHis+G-1 with a 3' CCA end + 3 diphosphate
-
 ?
tRNAHisDELTAG-1 + 2 CTP + ATP
-
 Saccharomyces cerevisiae tRNAHisDELTAG-1 with a 3' CCA end + 3 diphosphate
-
 ?
tRNAHisDELTAG-1 + 2 CTP + ATP
-
 Saccharomyces cerevisiae ATCC 204508 tRNAHisDELTAG-1 with a 3' CCA end + 3 diphosphate
-
 ?

Synonyms

Synonyms Comment Organism
CCA-adding enzyme
-
 Saccharomyces cerevisiae

Turnover Number [1/s]

Turnover Number Minimum [1/s] Turnover Number Maximum [1/s] Substrate Comment Organism Structure
0.418
-
 tRNAHis+G-1 pH and temperature not specified in the publication, recombinant enzyme Saccharomyces cerevisiae
0.458
-
 tRNAHisDELTAG-1 pH and temperature not specified in the publication, recombinant enzyme Saccharomyces cerevisiae

General Information

General Information Comment Organism
metabolism in eukaryotes including yeast, both 3'-CCA and 5'-G-1 are added posttranscriptionally by tRNA nucleotidyltransferase and tRNAHis guanylyltransferase, respectively. These two cytosolic enzymes might compete for the same tRNA, but tRNAHis guanylyltransferase clearly prefers a substrate carrying a CCA terminus. Thus, although many tRNA maturation steps can occur in a rather random order, pathway where CCA-addition precedes G-1 incorporation is likely in Saccharomyces cerevisiae. The 3'-CCA triplet and a discriminator position A73 act as positive elements for G-1 incorporation, ensuring the fidelity of G-1 addition. Sequential order of tRNAHis processing, overview. The enzymes do not compete for the substrate. Instead, the differing substrate preferences lead to a sequential order of nucleotide incorporation at 5'- and 3'-ends, resulting in a mature tRNAHis in the cytosol Saccharomyces cerevisiae
physiological function the 3'-CCA triplet and a discriminator position A73 act as positive elements for G-1 incorporation, ensuring the fidelity of G-1 addition. The CCA-adding enzyme catalyzes CCA incorporation on tRNAHis lacking G-1 (tRNAHisDELTAG-1) and tRNAHis+G-1 from Saccharomyces cerevisiae Saccharomyces cerevisiae

kcat/KM [mM/s]

kcat/KM Value [1/mMs-1] kcat/KM Value Maximum [1/mMs-1] Substrate Comment Organism Structure
144.3
-
 tRNAHis+G-1 pH and temperature not specified in the publication, recombinant enzyme Saccharomyces cerevisiae
286.5
-
 tRNAHisDELTAG-1 pH and temperature not specified in the publication, recombinant enzyme Saccharomyces cerevisiae