EC Number   |
General Information |
Reference |
|---|
    6.1.1.1 | physiological function |
aa-tRNA synthesis is a two-step reaction: activation of an amino acid with ATP to form aminoacyl adenylate, followed by transfer of the aminoacyl moiety to the 3' end of the tRNA. The error rate of this first step of translation is largely dependent on the specificity of the aaRS, that is selection of the correct amino acid and tRNA from the respective cellular pools of predominantly noncognate substrates. aaRSs select their cognate tRNAs by exploiting sequence-specific differences between various tRNAs during binding and aminoacylation. Translation of Tyr codons is highly prone to Phe isincorporation during amino acid limitation inCHOcells. CHO cell TyrRS is error-prone and readily aminoacylates tRNATyr with Phe, cf. EC 6.1.1.20. Steady-state kinetic analyses of CHO cytoplasmic tyrosyl-tRNA synthetase reveals a 25fold lower specificity for Tyr over Phe as compared with previously characterized bacterial enzymes, consistent with the observed increase in translation error rates during tyrosine limitation |
745300 |
| 6.1.1.1 | physiological function |
although native TyrRS has no known cytokine functions, natural proteolysis of secreted TyrRS releases TyrRSMini, which not only has the same aminoacylation activity as native TyrRS when occuring as a dimer, the monomer is inactive, but TyrRSMini also has strong activity for stimulating migration of polymorphonuclear leukocytes. The migration-stimulating activity is dependent on an ELR tripeptide motif, similar to that in CXC cytokines like IL-8, and also has the familiar bell-shaped concentration dependence seen for CXC cytokines. But TyrRSMini does not induce internalization of CXCR1/2. The TyrRSMini monomer is an agonist, while TyrRSMini dimer is an antagonist of induced PMN cell migration |
715585 |
| 6.1.1.1 | physiological function |
aminoacyl-tRNA synthetases (aaRSs) are housekeeping enzymes essential for protein synthesis. Apart from their parent aminoacylation activity, several aaRSs perform non-canonical functions in diverse biological processes. Leishmania tyrosyl-tRNA synthetase (LdTyrRS) performs aminoacylation and acts as a mimic of host CXC chemokine. Non-canonical function of Leishmania donovani tyrosyl-tRNA synthetase. The enzyme is essential. The released, extracellular LdTyrRS functions as a neutrophil chemoattractant. LdTyrRS specifically binds to host macrophages with its ELR (Glu-Leu-Arg) peptide motif. The ELR-CXCR2 receptor interaction mediates this binding. This interaction triggers enhanced secretion of the proinflammatory cytokines TNF-alpha and interleukin-6 by host macrophages. Possible immunomodulating role of LdTyrRS in Leishmania infection. Triggering of cytokine secretion by LdTyrRS, overview |
-, 745348 |
| 6.1.1.1 | physiological function |
aminoacyl-tRNA synthetases (aaRSs) for glycine, alanine, serine and tyrosine play important roles in fibroin synthesis |
746475 |
| 6.1.1.1 | evolution |
analysis of evolutionary conservation of KMSKS motif in tyrosyl-tRNA synthetases, YRSs, two YRSs of Pyrococcus horikoshii and Leishmania major have an overall root mean squared deviation calculated as 3.2 A, although the primary sequences for ATP recognition motifs in Pyrococcus horikoshii and Leishmania major YRSs are identical (KMSKS). The KMSKS loop in YRSs is evolutionarily conserved and mediates inter-molecular interactions between YRS and ATP, Conformational landscape of KMSKS loops in YRSs, overview |
-, 745655 |
| 6.1.1.1 | physiological function |
CYT-18 also promotes self-splicing of group I intron RNAs by stabilizing the functional structure in the conserved core |
705174 |
| 6.1.1.1 | more |
dissociating quaternary structures regulating novel functions of other tRNA synthetases |
715585 |
| 6.1.1.1 | evolution |
domain organization of TyrRS from eukaryotes and prokaryotes, overview |
-, 745348 |
| 6.1.1.1 | more |
enzyme MtTyrRS contains the HIGH-like and KFGKS catalytic motifs that catalyze amino acid activation with ATP.The conformational mobility of MtTyrRS catalytic KFGKS loop is analyzed by 100-ns all-atoms molecular dynamics simulations of the free enzyme and its complexes with different substrates: tyrosine, ATP, and the tyrosyl-adenylate intermediate. In the closed state of the active site, the KFGKS loop, readily adopts different stable conformations depending on the type of bound substrate. The closed state of the loop is stabilized by dynamic formation of two antiparallel beta-sheets at flanking ends which hold the KFGKS fragment inside the active center. Molecular dynamics simulations, conformation of the MtTyrRS catalytic loop in substrate?bound states, detailed overview |
-, 744822 |
| 6.1.1.1 | malfunction |
lysine acetylation can be a possible mechanism for modulating aminoacyl-tRNA synthetases enzyme activities, thus affecting translation. Of recombinantly expressed site-specifically acetylated TyrRS variants, TyrRS-85AcK and -235AcK show dramatic decreases in activity. Variant TyrRS-238AcK has no detectable activity, while variants TyrRS-144AcK and -355AcK have similar activities compared to the wild-type TyrRS. TyrRS-85AcK has a fivefold increase in the KM value for ATP, indicating its role in ATP binding. TyrRS-235AcK has slightly changed KM values for both ATP and tyrosine but a 200fold decrease in catalytic efficiency, suggesting its role in catalysis. K235 and K238 of TyrRS characterized in this study are the two lysine residues in the KMSKS motif. Kinetics for acetylated mutant variants, overview |
744707 |
