The Dual Role of the 2'-OH Group of A76 tRNA Tyr in the Prevention of d-tyrosine Mistranslation.

Autor: Rybak MY; Department of Protein Synthesis Enzymology, Institute of Molecular Biology and Genetics of the NAS of Ukraine, 150 Zabolotnogo Str., 03143 Kyiv, Ukraine. Electronic address: mariia.rybak@gmail.com., Kovalenko OP; Department of Protein Synthesis Enzymology, Institute of Molecular Biology and Genetics of the NAS of Ukraine, 150 Zabolotnogo Str., 03143 Kyiv, Ukraine., Tukalo MA; Department of Protein Synthesis Enzymology, Institute of Molecular Biology and Genetics of the NAS of Ukraine, 150 Zabolotnogo Str., 03143 Kyiv, Ukraine.
Jazyk: angličtina
Zdroj: Journal of molecular biology [J Mol Biol] 2018 Aug 17; Vol. 430 (17), pp. 2670-2676. Date of Electronic Publication: 2018 Jun 25.
DOI: 10.1016/j.jmb.2018.06.036
Abstrakt: Aminoacyl-tRNA-synthetases are crucial enzymes for initiation step of translation. Possessing editing activity, they protect living cells from misincorporation of non-cognate and non-proteinogenic amino acids into proteins. Tyrosyl-tRNA synthetase (TyrRS) does not have such editing properties, but it shares weak stereospecificity in recognition of d-/l-tyrosine (Tyr). Nevertheless, an additional enzyme, d-aminoacyl-tRNA-deacylase (DTD), exists to overcome these deficiencies. The precise catalytic role of hydroxyl groups of the tRNA Tyr A76 in the catalysis by TyrRS and DTD remained unknown. To address this issue, [ 32 P]-labeled tRNA Tyr substrates have been tested in aminoacylation and deacylation assays. TyrRS demonstrates similar activity in charging the 2' and 3'-OH groups of A76 with l-Tyr. This synthetase can effectively use both OH groups as primary sites for aminoacylation with l-Tyr, but demonstrates severe preference toward 2'-OH, in charging with d-Tyr. In both cases, the catalysis is not substrate-assisted: neither the 2'-OH nor the 3'-OH group assists catalysis. In contrast, DTD catalyzes deacylation of d-Tyr-tRNA Tyr specifically from the 3'-OH group, while the 2'-OH assists in this hydrolysis.
(Copyright © 2018 Elsevier Ltd. All rights reserved.)
Databáze: MEDLINE
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