The crystal structures of the a-subunit of the α2β 2 tetrameric Glycyl-tRNA synthetase

Kemin Tan, Min Zhou, Rongguang Zhang, Wayne F. Anderson, Andrzej Joachimiak*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

10 Scopus citations

Abstract

Aminoacyl-tRNA synthetases (AARSs) are ligases (EC.6.1.1.-) that catalyze the acylation of amino acids to their cognate tRNAs in the process of translating genetic information from mRNA to protein. Their amino acid and tRNA specificity are crucial for correctly translating the genetic code. Glycine is the smallest amino acid and the glycyl-tRNA synthetase (GlyRS) belongs to Class II AARSs. The enzyme is unusual because it can assume different quaternary structures. In eukaryotes, archaebacteria and some bacteria, it forms an α2 homodimer. In some bacteria, GlyRS is an α2β2 heterotetramer and shows a distant similarity to α2 GlyRSs. The human pathogen eubacterium Campylobacter jejuni GlyRS (CjGlyRS) is an α2β 2heterotetramer and is similar to Escherichia coli GlyRS; both are members of Class IIc AARSs. The twostep aminoacylation reaction of tetrameric GlyRSs requires the involvement of both a- and b-subunits. At present, the structure of the GlyRS α2β2class and the details of the enzymatic mechanism of this enzyme remain unknown. Here we report the crystal structures of the catalytic a-subunit of CjGlyRS and its complexes with ATP, and ATP and glycine. These structures provide detailed information on substrate binding and show evidence for a proposed mechanism for amino acid activation and the formation of the glycyl-adenylate intermediate for Class II AARSs.

Original languageEnglish (US)
Pages (from-to)233-239
Number of pages7
JournalJournal of Structural and Functional Genomics
Volume13
Issue number4
DOIs
StatePublished - Dec 2012

Keywords

  • ATP binding
  • Catalytic subunit
  • Gly-tRNA synthetase
  • Glycine binding

ASJC Scopus subject areas

  • Structural Biology
  • Biochemistry
  • Genetics

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