Disease relevance of QARS

• However, some bacterial species, such as Escherichia coli, do possess a GlnRS activity, which is responsible for Gln-tRNA(Gln) formation [1].
• QARS has improved the communications network between various stakeholders and has enabled the tracking of the notification of passengers potentially exposed to infectious diseases [2].
• Aminoacylation studies show that chloroplasts, plant and animal mitochondria, as well as cyanobacteria, lack any detectable glutaminyl-tRNA synthetase activity [3].
• In the Bacteria, GlnRS genes have been identified in a total of 10 species from three highly diverse taxonomic groups: Thermus/Deinococcus, Proteobacteria gamma/beta subdivision, and Bacteroides/Cytophaga/Flexibacter [4].

High impact information on QARS

• The cocrystal structure of the class I glutaminyl-tRNA synthetase with tRNAGln revealed an uncoupling of the first (1.72) base pair of tRNAGln, and tRNAMet was proposed by others to have a similar base-pair uncoupling when bound to methionyl-tRNA synthetase [5].
• The latter pathway is widespread among bacteria and organelles that, accordingly, lack GlnRS [1].
• Our data suggest that bacterial GlnRS has a eukaryotic origin and was acquired by a mechanism of horizontal gene transfer [1].
• In the cytoplasm of eukaryotic cells, both GluRS and GlnRS activities can be detected [1].
• An EcoRI polymorphism for the glutaminyl-tRNA synthetase (QARS) gene on chromosome 1q [6].

Biological context of QARS

• A cold-trapping experiment revealed that the nonenzymatic rate of Gln-AMP hydrolysis is too slow to account for the rapid AMP formation; hence, the hydrolysis of Gln-AMP to form glutamine and AMP must be directly catalyzed by the GlnRS x tRNA(2'HGln) complex [7].
• Exons encoding the highly conserved part of human glutaminyl-tRNA synthetase [8].
• Solvation dynamics at the active site of an enzyme, glutaminyl-tRNA synthetase (GlnRS), was studied using a fluorescence probe, acrylodan, site-specifically attached at cysteine residue C229, near the active site [9].
• Dynamics of compact denatured states of glutaminyl-tRNA synthetase probed by bis-ANS binding kinetics [10].
• To date, GLN transporters, cellular hydration, glutaminyl-tRNA synthetase, ATP levels, mRNA stability, and glutathione economy have been variably implicated in GLN-dependent survival signaling [11].

Anatomical context of QARS

• Southern blots of restricted DNA from a panel of rodent-human cell lines and in situ chromosome hybridization gave identical results showing that the human gene locus for glutaminyl-tRNA synthetase resides on the distal long arm of chromosome 1 [12].

Associations of QARS with chemical compounds

• Glutamine-dependent antiapoptotic interaction of human glutaminyl-tRNA synthetase with apoptosis signal-regulating kinase 1 [13].
• Glutaminyl-tRNA synthetase generates Gln-tRNA(Gln) 10(7)-fold more efficiently than Glu-tRNA(Gln) and requires tRNA to synthesize the activated aminoacyl adenylate in the first step of the reaction [7].
• We propose that stable retention of glutaminyl-tRNA synthetase in prokaryotic organisms following a horizontal gene transfer event from eukaryotic organisms (Lamour et al. 1994) was dependent on the evolving pool of glutamate and glutamine tRNAs in the organisms that acquired glutaminyl-tRNA synthetase by this mechanism [14].
• We have now attempted to retrace one of the key steps in this process by selecting glutaminyl-tRNA synthetase mutants displaying enhanced glutamic acid recognition [15].

Other interactions of QARS

• The human QARS locus: assignment of the human gene for glutaminyl-tRNA synthetase to chromosome 1q32-42 [12].
• By contrast, binding of ArgRS or GlnRS to p38 was much weaker (>5 microM) [16].

References