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Literature summary for 6.1.1.9 extracted from

  • Starosta, A.L.; Lassak, J.; Peil, L.; Atkinson, G.C.; Woolstenhulme, C.J.; Virumaee, K.; Buskirk, A.; Tenson, T.; Remme, J.; Jung, K.; Wilson, D.N.
    A conserved proline triplet in Val-tRNA synthetase and the origin of elongation factor P (2014), Cell Rep., 9, 476-483 .
    View publication on PubMedView publication on EuropePMC
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Protein Variants

Protein Variants Comment Organism
additional information generation of three single ValS Pro-to-Gly mutants, ValS-GPP, ValS-PGP, and ValS-PPG, as well as a triple PPP-to-GGG mutant (ValS-GGG). The ability of the ValS mutants to charge tRNAVal with [14C]valine is assessed and compared to wild-type ValS. All ValS mutants are less efficient than the wild-type, the ValS-PPG and ValS-GGG mutants are completely devoid of activity, whereas the ValS-PGP and ValS-GPP mutants retain some activity but at lower levels than the wild-type enzyme Escherichia coli

Metals/Ions

Metals/Ions Comment Organism Structure
Mg2+ required Escherichia coli

Natural Substrates/ Products (Substrates)

Natural Substrates Organism Comment (Nat. Sub.) Natural Products Comment (Nat. Pro.) Rev. Reac.
ATP + L-valine + tRNAVal Escherichia coli
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 AMP + diphosphate + L-valyl-tRNAVal
-
 ?

Organism

Organism UniProt Comment Textmining
Escherichia coli P07118
-
-

Substrates and Products (Substrate)

Substrates Comment Substrates Organism Products Comment (Products) Rev. Reac.
ATP + L-valine + tRNAVal
-
 Escherichia coli AMP + diphosphate + L-valyl-tRNAVal
-
 ?
ATP + L-valine + tRNAVal charging of tRNAVal by ValS occurs in two steps: firstly, valine is activated with ATP to form Val-AMP leading to the release of pyrophosphate, and secondly, the valine is then transferred to the tRNAVal to form Val-tRNAVal, with a concomitant release of AMP Escherichia coli AMP + diphosphate + L-valyl-tRNAVal
-
 ?

Synonyms

Synonyms Comment Organism
Val-tRNA synthetase
-
 Escherichia coli
ValRS
-
 Escherichia coli
valS
-
 Escherichia coli

Cofactor

Cofactor Comment Organism Structure
ATP
-
 Escherichia coli

Expression

Organism Comment Expression
Escherichia coli expression of ValS in vivo and in vitro requires the elongation factor P (EF-P), the downregulation of ValS in the absence of active EF-P is specific, the lack of EF-P leads to a strong downregulation of ValS. The lack of YfcM (DELTAyfcM), which hydroxylates the lysinylated EF-P, does not lead to downregulation of ValS. ValS expression is also dependent on EF-P in vitro down

General Information

General Information Comment Organism
evolution the proline triplet in ValS, the tRNA synthetase that charges tRNAVal with valine, is the only single polyproline stretch that is invariant across all domains of life. The critical role of the proline triplet for ValS activity may explain why bacterial cells co-evolved the EF-P rescue system. Nature has evolved not only specialized translation factors to overcome stalling at polyproline stretches, but also evolved independent sets of modification enzymes to activate these factors. This in itself implies that the benefits of retaining polyproline stretches significantly outweigh the cost of implementing and maintaining the EF-P and a/eIF5A rescue systems Escherichia coli
additional information expression of ValS is strictly dependent on the presence of active elongation factor P (EF-P) in vivo and in vitro Escherichia coli
physiological function the proline triplet located in the active site of ValS is important for efficient charging of tRNAVal with valine preventing formation of mischarged Thr-tRNAVal, as well as for efficient growth of Escherichia coli in vivo. The critical role of the proline triplet for ValS activity may explain why bacterial cells co-evolved the EF-P rescue system Escherichia coli