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  • The EMBO Journal (2005) 24, 1430 - 1439
  • doi:10.1038/sj.emboj.7600618

Published online: 17 March 2005

Leucyl-tRNA synthetase from the ancestral bacterium Aquifex aeolicus contains relics of synthetase evolution

Ming-Wei Zhao1, Bin Zhu1, Rui Hao1, Min-Gang Xu1, Gilbert Eriani2 and En-Duo Wang1

  1. State Key Laboratory of Molecular Biology, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, The Chinese Academy of Sciences, Graduate School of the Chinese Academy of Sciences, Shanghai, PR China
  2. UPR9002, IBMC du CNRS and Université Louis Pasteur, Strasbourg, France

Correspondence to:

En-Duo Wang, Institute of Biochemistry and Cell Biology, Shanghai Institutes for Biological Sciences, 320 Yeu Yang Road, Shanghai 200031, China. Tel.: +86 21 549 21241; Fax: +86 21 549 21011; E-mail: edwang@sibs.ac.cn

Received 27 September 2004; Accepted 15 February 2005

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 mischarged tRNALeu and minihelixLeu. Within the domain, we have identified a crucial 20-amino-acid peptide that confers editing capacity when transplanted into the inactive Escherichia coli LeuRS editing domain. Likewise, fusion of the beta-subunit of alphabeta-LeuRS to the E. coli editing domain activates its editing function. These results suggest that alphabeta-LeuRS still carries the basic features from a primitive synthetase molecule. It has a remarkable capacity to transfer autonomous active modules, which is consistent with the idea that modern synthetases arose after exchange of small idiosyncratic domains. It also has a unique alphabeta-heterodimeric structure with separated catalytic and tRNA-binding sites. Such an organization supports the tRNA/synthetase coevolution theory that predicts sequential addition of tRNA and synthetase domains.

  • Keywords:

    • Aquifex aeolicus,
    • CP1 domain,
    • editing,
    • leucyl-tRNA synthetase,
    • tRNA