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Leucyl‐tRNA synthetase from the ancestral bacterium Aquifex aeolicus contains relics of synthetase evolution
Author(s) -
Zhao MingWei,
Zhu Bin,
Hao Rui,
Xu MinGang,
Eriani Gilbert,
Wang EnDuo
Publication year - 2005
Publication title -
the embo journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 7.484
H-Index - 392
eISSN - 1460-2075
pISSN - 0261-4189
DOI - 10.1038/sj.emboj.7600618
Subject(s) - aquifex aeolicus , biology , transfer rna , amino acid , amino acyl trna synthetases , rna editing , aminoacyl trna synthetase , escherichia coli , protein subunit , biochemistry , genetics , gene , rna
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 (αβ‐LeuRS) catalyzes the hydrolytic editing of both mischarged tRNA Leu and minihelix Leu . 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 β‐subunit of αβ‐LeuRS to the E. coli editing domain activates its editing function. These results suggest that αβ‐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 αβ‐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.