Any feedback?
Please rate this page
(literature.php)
(0/150)

BRENDA support

Literature summary for 2.7.7.79 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 2.7.7.79

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 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

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.
p-tRNAHis + ATP + GTP + H2O Saccharomyces cerevisiae overall reaction pGp-tRNAHis + AMP + 2 diphosphate
-
 ?
p-tRNAHis + ATP + GTP + H2O Saccharomyces cerevisiae ATCC 204508 overall reaction pGp-tRNAHis + AMP + 2 diphosphate
-
 ?

Organism

Organism UniProt Comment Textmining
Saccharomyces cerevisiae P53215
-
-
Saccharomyces cerevisiae ATCC 204508 P53215
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
additional information tRNAHis guanylyltransferase clearly prefers a substrate carrying a CCA terminus. The 3'-CCA triplet and a discriminator position A73 act as positive elements for G-1 incorporation, ensuring the fidelity of G-1 addition. On the substrate lacking the CCA-end (tRNAHisDELTACCA), the enzyme is less efficient Saccharomyces cerevisiae ?
-
-
additional information tRNAHis guanylyltransferase clearly prefers a substrate carrying a CCA terminus. The 3'-CCA triplet and a discriminator position A73 act as positive elements for G-1 incorporation, ensuring the fidelity of G-1 addition. On the substrate lacking the CCA-end (tRNAHisDELTACCA), the enzyme is less efficient Saccharomyces cerevisiae ATCC 204508 ?
-
-
p-tRNAHis + ATP + GTP + H2O overall reaction Saccharomyces cerevisiae pGp-tRNAHis + AMP + 2 diphosphate
-
 ?
p-tRNAHis + ATP + GTP + H2O overall reaction Saccharomyces cerevisiae ATCC 204508 pGp-tRNAHis + AMP + 2 diphosphate
-
 ?

Synonyms

Synonyms Comment Organism
THG1
-
 Saccharomyces cerevisiae

Cofactor

Cofactor Comment Organism Structure
ATP
-
 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 tRNAHis guanylyltransferase posttranscriptionally adds a 5'-G-1 from GTP to yeast tRNAHis. The presence of this single G at the -1 position is critical for recognition of tRNAHis by the histidyl-tRNA synthetase (HisRS). Thg1 adds a single G-1 residue across from an A73 discriminator nucleotide, forming an unconventional non-Watson Crick base pair. This unusual 3'-5' nucleotidyltransferase protein is a member of a larger family of Watson Crick-dependent 3'-5' polymerase enzymes that share structural similarity with canonical 5'-3' DNA and RNA polymerases Saccharomyces cerevisiae