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The aminoacyl-transfer RNA synthetases (aaRS) catalyse the attachment of an amino acid to its cognate transfer RNA molecule in a highly specific two-step reaction. These proteins differ widely in size and oligomeric state, and have limited sequence homology. Out of the 18 known aaRS, only 9 referred to as class I synthetases (GlnRS, TyrRS, MetRS, GluRS,(More)
To prevent potential errors in protein synthesis, some aminoacyl-transfer RNA (tRNA) synthetases have evolved editing mechanisms to hydrolyze misactivated amino acids (pre-transfer editing) or misacylated tRNAs (post-transfer editing). Class Ia leucyl-tRNA synthetase (LeuRS) may misactivate various natural and non-protein amino acids and then mischarge(More)
Aminoacyl-tRNA synthetases (aaRSs) are remarkable enzymes that are in charge of the accurate recognition and ligation of amino acids and tRNA molecules. The greatest difficulty in accurate aminoacylation appears to be in discriminating between highly similar amino acids. To reduce mischarging of tRNAs by non-cognate amino acids, aaRSs have evolved an(More)
The editing reactions catalyzed by aminoacyl-tRNA synthetases are critical for the faithful protein synthesis by correcting misactivated amino acids and misaminoacylated tRNAs. We report that the isolated editing domain of leucyl-tRNA synthetase from the deep-rooted bacterium Aquifex aeolicus (alphabeta-LeuRS) catalyzes the hydrolytic editing of both(More)
Recognition of tRNA by the cognate aminoacyl-tRNA synthetase during translation is crucial to ensure the correct expression of the genetic code. To understand tRNA(Leu) recognition sets and their evolution, the recognition of tRNA(Leu) by the leucyl-tRNA synthetase (LeuRS) from the primitive hyperthermophilic bacterium Aquifex aeolicus was studied by RNA(More)
High specificity in aminoacylation of transfer RNAs (tRNAs) with the help of their cognate aminoacyl-tRNA synthetases (aaRSs) is a guarantee for accurate genetic translation. Structural and mechanistic peculiarities between the different tRNA/aaRS couples, suggest that aminoacylation systems are unrelated. However, occurrence of tRNA mischarging by(More)
Here we report the construction of a yeast genetic screen designed to identify essential residues in tRNA(Arg). The system consists of a tRNA(Arg) knockout strain and a set of vectors designed to rescue and select for variants of tRNA(Arg). By plasmid shuffling we selected inactive tRNA mutants that were further analyzed by northern blotting. The mutational(More)
The fidelity of protein biosynthesis requires the aminoacylation of tRNA with its cognate amino acid catalyzed by aminoacyl-tRNA synthetase with high levels of accuracy and efficiency. Crucial bases in tRNALeu to aminoacylation or editing functions of leucyl-tRNA synthetase have been extensively studied mainly by in vitro methods. In the present study, we(More)
The leucine-specific domain (LSD) is a compact well-ordered module that participates in positioning of the conserved KMSKS catalytic loop in most leucyl-tRNA synthetases (LeuRSs). However, the LeuRS from Mycoplasma mobile (MmLeuRS) has a tetrapeptide GKDG instead of the LSD. Here, we show that the tetrapeptide GKDG can confer tRNA charging and post-transfer(More)
Faithful translation of the genetic code depends on accurate coupling of amino acids with cognate transfer RNAs (tRNAs) catalyzed by aminoacyl-tRNA synthetases. The fidelity of leucyl-tRNA synthetase (LeuRS) depends mainly on proofreading at the pre- and post-transfer levels. During the catalytic cycle, the tRNA CCA-tail shuttles between the synthetic and(More)