Lack of Discrimination Against Non-proteinogenic Amino Acid Norvaline by Elongation Factor Tu from Escherichia coli

Cvetešić, Nevena and Akmačić, Irena and Gruić-Sovulj, Ita (2013) Lack of Discrimination Against Non-proteinogenic Amino Acid Norvaline by Elongation Factor Tu from Escherichia coli. Croatica Chemica Acta, 86 (1). pp. 73-82. ISSN 0011-1643

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Abstract

The GTP-bound form of elongation factor Tu (EF-Tu) brings aminoacylated tRNAs (aa-tRNA) to the A-site of the ribosome. EF-Tu binds all cognate elongator aa-tRNAs with highly similar affinities, and its weaker or tighter binding of misacylated tRNAs may discourage their participation in translation. Norvaline (Nva) is a non-proteinogenic amino acid that is activated and transferred to tRNALeu by leucyltRNA synthetase (LeuRS). No notable accumulation of Nva-tRNALeu has been observed in vitro, because of the efficient post-transfer hydrolytic editing activity of LeuRS. However, incorporation of norvaline into proteins in place of leucine does occur under certain conditions in vivo. Here we show that EF-Tu binds Nva-tRNALeu and Leu-tRNALeu with similar affinities, and that Nva-tRNALeu and Leu-tRNALeu dissociate from EF-Tu at comparable rates. The inability of EF-Tu to discriminate against norvaline may have driven evolution of highly efficient LeuRS editing as the main quality control mechanism against misincorporation of norvaline into proteins.

Item Type: Article
Keywords: EF-Tu; norvaline; non-proteinogenic amino acids; aminoacyl-tRNA synthetases; leucyl-tRNA synthetase; mistranslation
Date: May 2013
Subjects: NATURAL SCIENCES > Chemistry
Divisions: Faculty of Science > Department of Chemistry
Publisher: Hrvatsko kemijsko društvo
Related URLs:
Depositing User: Branka Maravic
Date Deposited: 24 Apr 2014 11:45
Last Modified: 24 Apr 2014 11:45
URI: http://digre.pmf.unizg.hr/id/eprint/946

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