Structural basis for the recognition of isoleucyl-adenylate and an antibiotic, mupirocin, by isoleucyl-tRNA synthetase

J Biol Chem. 2001 Dec 14;276(50):47387-93. doi: 10.1074/jbc.M109089200. Epub 2001 Oct 2.


An analogue of isoleucyl-adenylate (Ile-AMS) potently inhibits the isoleucyl-tRNA synthetases (IleRSs) from the three primary kingdoms, whereas the antibiotic mupirocin inhibits only the eubacterial and archaeal IleRSs, but not the eukaryotic enzymes, and therefore is clinically used against methicillin-resistant Staphylococcus aureus. We determined the crystal structures of the IleRS from the thermophilic eubacterium, Thermus thermophilus, in complexes with Ile-AMS and mupirocin at 3.0- and 2.5-A resolutions, respectively. A structural comparison of the IleRS.Ile-AMS complex with the adenylate complexes of other aminoacyl-tRNA synthetases revealed the common recognition mode of aminoacyl-adenylate by the class I aminoacyl-tRNA synthetases. The Ile-AMS and mupirocin, which have significantly different chemical structures, are recognized by many of the same amino acid residues of the IleRS, suggesting that the antibiotic inhibits the enzymatic activity by blocking the binding site of the high energy intermediate, Ile-AMP. In contrast, the two amino acid residues that concomitantly recognize Ile-AMS and mupirocin are different between the eubacterial/archaeal IleRSs and the eukaryotic IleRSs. Mutagenic analyses revealed that the replacement of the two residues significantly changed the sensitivity to mupirocin.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Monophosphate / chemistry*
  • Amino Acid Sequence
  • Amino Acids / chemistry
  • Amino Acyl-tRNA Synthetases / metabolism
  • Anti-Bacterial Agents / chemistry*
  • Anti-Bacterial Agents / pharmacology*
  • Binding Sites
  • Crystallography, X-Ray
  • Fatty Acids / chemistry
  • Inhibitory Concentration 50
  • Isoleucine / chemistry*
  • Isoleucine-tRNA Ligase / metabolism*
  • Kinetics
  • Models, Chemical
  • Models, Molecular
  • Molecular Sequence Data
  • Mupirocin / chemistry*
  • Mupirocin / pharmacology*
  • Mutagenesis, Site-Directed
  • Phosphates / chemistry
  • Protein Conformation
  • Protein Structure, Secondary
  • Sequence Homology, Amino Acid
  • Staphylococcus aureus / metabolism
  • Thermus thermophilus


  • Amino Acids
  • Anti-Bacterial Agents
  • Fatty Acids
  • Phosphates
  • Isoleucine
  • Adenosine Monophosphate
  • pelargonic acid
  • Mupirocin
  • Amino Acyl-tRNA Synthetases
  • Isoleucine-tRNA Ligase

Associated data

  • PDB/1JZQ
  • PDB/1JZS