Species-specific differences in the regulation of the aminoacylation activity of mammalian tryptophanyl-tRNA synthetases.

Department of Life Sciences, Graduate School of Arts and Sciences, The University of Tokyo, Tokyo, Japan. wakasugi@bio.c.u-tokyo.ac.jp

FEBS letters 2010 Jan 4

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Tryptophanyl-tRNA synthetases (TrpRSs) catalyze the aminoacylation of tRNA(Trp). Previously, I demonstrated that Zn(2+)-depleted human TrpRS is enzymatically inactive and that binding of Zn(2+) or heme to human TrpRS stimulates its aminoacylation activity. In the present study, bovine and mouse TrpRSs were found to be constitutively active regardless of the presence of Zn(2+) or ferriprotoporphyrin IX chloride. Mutagenesis experiments demonstrated that the human H130R mutant is constitutively active and that the bovine R135H, E438A double mutant binds with Zn(2+) or heme to enhance its aminoacylation activity as does human wild-type TrpRS. These results provide the first evidence of species-specific regulation of TrpRS activity.

Citation

Keisuke Wakasugi. Species-specific differences in the regulation of the aminoacylation activity of mammalian tryptophanyl-tRNA synthetases. FEBS letters. 2010 Jan 4;584(1):229-32