Structural and mutational analysis of tRNA intron-splicing endonuclease from Thermoplasma acidophilum DSM 1728: Catalytic mechanism of tRNA intron-splicing endonucleases

Kwan Kim Young, Kenji Mizutani, Kyung Hee Rhee, Ki Hyun Nam, Ho Lee Won, Hye Lee Eun, Eunice Eunkyeong Kim, Sam Yong Park, Kwang Yeon Hwang

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In archaea, RNA endonucleases that act specifically on RNA with bulge-helix-bulge motifs play the main role in the recognition and excision of introns, while the eukaryal enzymes use a measuring mechanism to determine the positions of the universally positioned splice sites relative to the conserved domain of pre-tRNA. Two crystallographic structures of tRNA intron-splicing endonuclease from Thermoplasma acidophilum DSM 1728 (EndA Ta have been solved to 2.5-Å and 2.7-Å resolution by molecular replacement, using the 2.7-Å resolution data as the initial model and the single-wavelength anomalous-dispersion phasing method using selenomethionine as anomalous signals, respectively. The models show that EndA Ta is a homodimer and that it has overall folding similar to that of other archaeal tRNA endonucleases. From structural and mutational analyses of H236A, Y229F, and K265I in vitro, we have demonstrated that they play critical roles in recognizing the splice site and in cleaving the pre-tRNA substrate.

Original languageEnglish
Pages (from-to)8339-8346
Number of pages8
JournalJournal of Bacteriology
Issue number22
Publication statusPublished - 2007 Nov 1


ASJC Scopus subject areas

  • Applied Microbiology and Biotechnology
  • Immunology

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