Catalytic peptide of human glutaminyl-tRNA synthetase is essential for its assembly to the aminoacyl-tRNA synthetase

Taeho Kim, Sang Gyu Park, Jee Eun Kim, Wongi Seol, Young Gyu Ko, Sunghoon Kim

Research output: Contribution to journalArticlepeer-review

35 Citations (Scopus)

Abstract

Human glutaminyl-tRNA synthetase (QRS) is one of several mammalian aminoacyl-tRNA synthetases (ARSs) that form a macromolecular protein complex. To understand the mechanism of QRS targeting to the multi-ARS complex, we analyzed both exogenous and endogenous QRSs by immunoprecipitation after overexpression of various Myc-tagged QRS mutants in human embryonic kidney 293 cells. Whereas a deletion mutant containing only the catalytic domain (QRS-C) was targeted to the multi-ARS complex, a mutant QRS containing only the N-terminal appended domain (QRS-N) was not. Deletion mapping showed that the ATP-binding Rossman fold was necessary for targeting of QRS to the multi- ARS complex. Furthermore, exogenous Myc-tagged QRS-C was co- immunoprecipitated with endogenous QRS. Since glutaminylation of tRNA was dramatically increased in cells transfected with the full-length QRS, but not with either QRS-C or QRS-N, both the QRS catalytic domain and the N-terminal appended domain were required for full aminoacylation activity. When QRS-C was overexpressed, arginyl-tRNA synthetase and p43 were released from the multi-ARS complex along with endogenous QRS, suggesting that the N-terminal appendix of QRS is required to keep arginyl-tRNA synthetase and p43 within the complex. Thus, the eukaryote-specific N-terminal appendix of QRS appears to stabilize the association of other components in the multi-ARS complex, whereas the C-terminal catalytic domain is necessary for QRS association with the multi-ARS complex.

Original languageEnglish
Pages (from-to)21768-21772
Number of pages5
JournalJournal of Biological Chemistry
Volume275
Issue number28
DOIs
Publication statusPublished - 2000 Jul 14

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Molecular Biology
  • Cell Biology

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