Crystal structures of leucyl/phenylalanyl-tRNA-protein transferase and its complex with an aminoacyl-tRNA analog

Kyoko Suto, Yoshihiro Shimizu, Kazunori Watanabe, Takuya Ueda, Shuya Fukai, Osamu Nureki, Kozo Tomita

Research output: Contribution to journalArticlepeer-review

53 Citations (Scopus)


Eubacterial leucyl/phenylalanyl-tRNA protein transferase (L/F-transferase), encoded by the aat gene, conjugates leucine or phenylalanine to the N-terminal Arg or Lys residue of proteins, using Leu-tRNALeu or Phe-tRNA Phe as a substrate. The resulting N-terminal Leu or Phe acts as a degradation signal for the ClpS-ClpAP-mediated N-end rule protein degradation pathway. Here, we present the crystal structures of Escherichia coli L/F-transferase and its complex with an aminoacyl-tRNA analog, puromycin. The C-terminal domain of L/F-transferase consists of the GCN5-related N-acetyltransferase fold, commonly observed in the acetyltransferase superfamily. The p-methoxybenzyl group of puromycin, corresponding to the side chain of Leu or Phe of Leu-tRNALeu or Phe-tRNAPhe, is accommodated in a highly hydrophobic pocket, with a shape and size suitable for hydrophobic amino-acid residues lacking a branched β-carbon, such as leucine and phenylalanine. Structure-based mutagenesis of L/F-transferase revealed its substrate specificity. Furthermore, we present a model of the L/F-transferase complex with tRNA and substrate proteins bearing an N-terminal Arg or Lys.

Original languageEnglish
Pages (from-to)5942-5950
Number of pages9
JournalEMBO Journal
Issue number24
Publication statusPublished - Dec 13 2006
Externally publishedYes


  • Aminoacyl-tRNA
  • N-end rule
  • Protein stability
  • Transferase

ASJC Scopus subject areas

  • General Neuroscience
  • Molecular Biology
  • General Biochemistry,Genetics and Molecular Biology
  • General Immunology and Microbiology


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