This Article Full Text Full Text (PDF) Other Versions of this Article: JVI.01107-07v1 81/22/12406    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Abergel, C. Articles by Claverie, J.-M. Search for Related Content PubMed PubMed Citation Articles by Abergel, C. Articles by Claverie, J.-M.

 Previous Article  |  Next Article 

Journal of Virology, November 2007, p. 12406-12417, Vol. 81, No. 22
0022-538X/07/$08.00+0     doi:10.1128/JVI.01107-07
Copyright © 2007, American Society for Microbiology. All Rights Reserved.

Virus-Encoded Aminoacyl-tRNA Synthetases: Structural and Functional Characterization of Mimivirus TyrRS and MetRS

Structural and Genomic Information Laboratory, CNRS-UPR2589, Institut de Biologie Structurale & Microbiologie IFR88, Université de la Méditerranée, 163 avenue de Luminy, Case 934, 13288 Marseille, Cedex 9, France,¹ Architecture et Réactivité de l'ARN, CNRS-UPR 9002, IBMC, and Université Louis Pasteur, 15 rue René Descartes, 67084 Strasbourg, France²

Received 22 May 2007/ Accepted 4 September 2007

Aminoacyl-tRNA synthetases are pivotal in determining how the genetic code is translated in amino acids and in providing the substrate for protein synthesis. As such, they fulfill a key role in a process universally conserved in all cellular organisms from their most complex to their most reduced parasitic forms. In contrast, even complex viruses were not found to encode much translation machinery, with the exception of isolated components such as tRNAs. In this context, the discovery of four aminoacyl-tRNA synthetases encoded in the genome of mimivirus together with a full set of translation initiation, elongation, and termination factors appeared to blur what was once a clear frontier between the cellular and viral world. Functional studies of two mimivirus tRNA synthetases confirmed the MetRS specificity for methionine and the TyrRS specificity for tyrosine and conformity with the identity rules for tRNA^Tyr for archea/eukarya. The atomic structure of the mimivirus tyrosyl-tRNA synthetase in complex with tyrosinol exhibits the typical fold and active-site organization of archaeal-type TyrRS. However, the viral enzyme presents a unique dimeric conformation and significant differences in its anticodon binding site. The present work suggests that mimivirus aminoacyl-tRNA synthetases function as regular translation enzymes in infected amoebas. Their phylogenetic classification does not suggest that they have been acquired recently by horizontal gene transfer from a cellular host but rather militates in favor of an intricate evolutionary relationship between large DNA viruses and ancestral eukaryotes.

Published ahead of print on 12 September 2007.