Molecular basis of alanine discrimination in editing site

Masaaki Sokabe, Ayuko Okada, Min Yao, Takashi Nakashima, Isao Tanaka

Research output: Contribution to journalArticlepeer-review

52 Citations (Scopus)


AlaX is the homologue of the class II alanyl-tRNA synthetase editing domain and has been shown to exhibit autonomous editing activity against mischarged tRNAAla. Here, we present the structures of AlaX from the archaeon Pyrococcus horikoshii in apo form, complexed with zinc, and with noncognate amino acid L-serine and zinc. Together with mutational analysis, we demonstrated that the conserved Thr-30 hydroxyl group located near the β-methylene of the bound serine is responsible for the discrimination of noncognate serine from cognate alanine, based on their chemical natures. Furthermore, we confirmed that the conserved Gin-584 in alanyl-tRNA synthetase, which corresponds to Thr-30 of AlaX, is also critical for discrimination. These observations strongly suggested conservation of the chemical discrimination among trans- and cis-editing of tRNAAla.

Original languageEnglish
Pages (from-to)11669-11674
Number of pages6
JournalProceedings of the National Academy of Sciences of the United States of America
Issue number33
Publication statusPublished - Aug 16 2005
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • General


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