Crystal structure of Legionella pneumophila type IV secretion system effector LegAS4

Jonghyeon Son, Chang Hwa Jo, Ravichandran N. Murugan, Jeong Kyu Bang, Kwang Yeon Hwang, Woo Cheol Lee

Research output: Contribution to journalArticlepeer-review

9 Citations (Scopus)


The SET domain of LegAS4, a type IV secretion system effector of Legionella pneumophila, is a eukaryotic protein motif involved in histone methylation and epigenetic modulation. The SET domain of LegAS4 is involved in the modification of Lys4 of histone H3 (H3K4) in the nucleolus of the host cell, thereby enhancing heterochromatic rDNA transcription. Moreover, LegAS4 contains an ankyrin repeat domain of unknown function at its C-terminal region. Here, we report the crystal structure of LegAS4 in complex with S-adenosyl-l-methionine (SAM). Our data indicate that the ankyrin repeats interact extensively with the SET domain, especially with the SAM-binding amino acids, through conserved residues. Conserved surface analysis marks Glu159, Glu203, and Glu206 on the SET domain serve as candidate residues involved in interaction with the positively charged histone tail. Conserved surface residues on the ankyrin repeat domain surround a small pocket, which is suspected to serve as a binding site for an unknown ligand.

Original languageEnglish
Pages (from-to)817-824
Number of pages8
JournalBiochemical and biophysical research communications
Issue number4
Publication statusPublished - 2015 Oct 2

Bibliographical note

Funding Information:
We thank the staff scientists at beamline 5C of PAL and 17A of Photon Factory for support with the collection of diffraction data. This work was supported by a National Research Foundation of Korea (NRF) grant NRF-2013R1A1A2059835 awarded to WCL. Additionally, WCL and KYH were supported by a Korea University research promotion grant. This work was partly supported by the Korea Basic Science Institute 's Research Program grant T35418 awarded to JKB.

Publisher Copyright:
© 2015 Elsevier Inc.


  • Ankyrin repeat
  • LegAS4
  • Legionella pneumophila
  • RomA
  • SET domain

ASJC Scopus subject areas

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology


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