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Article Dans Une Revue Nucleic Acids Research Année : 2010

Modular pathways for editing non-cognate amino acids by human cytoplasmic leucyl-tRNA synthetase.

Résumé

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 tRNA(Leu). It is known that the fidelity of prokaryotic LeuRS depends on multiple editing pathways to clear the incorrect intermediates and products in the every step of aminoacylation reaction. Here, we obtained human cytoplasmic LeuRS (hcLeuRS) and tRNA(Leu) (hctRNA(Leu)) with high activity from Escherichia coli overproducing strains to study the synthetic and editing properties of the enzyme. We revealed that hcLeuRS could adjust its editing strategy against different non-cognate amino acids. HcLeuRS edits norvaline predominantly by post-transfer editing; however, it uses mainly pre-transfer editing to edit alpha-amino butyrate, although both amino acids can be charged to tRNA(Leu). Post-transfer editing as a final checkpoint of the reaction was very important to prevent mis-incorporation in vitro. These results provide insight into the modular editing pathways created to prevent genetic code ambiguity by evolution.

Dates et versions

hal-00526390 , version 1 (14-10-2010)

Identifiants

Citer

Xin Chen, Jing-Jing Ma, Min Tan, Peng Yao, Qing-Hua Hu, et al.. Modular pathways for editing non-cognate amino acids by human cytoplasmic leucyl-tRNA synthetase.. Nucleic Acids Research, 2010, epub ahead of print. ⟨10.1093/nar/gkq763⟩. ⟨hal-00526390⟩

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