An Adaptive Mutation in Enterococcus faecium LiaR Associated with Antimicrobial Peptide Resistance Mimics Phosphorylation and Stabilizes LiaR in an Activated State

Milya Davlieva, Angel Tovar-Yanez, Kimberly DeBruler, Paul G. Leonard, Michael R. Zianni, Cesar A. Arias, Yousif Shamoo

Research output: Contribution to journalArticlepeer-review

14 Scopus citations

Abstract

The cyclic antimicrobial lipopeptide daptomycin (DAP) triggers the LiaFSR membrane stress response pathway in enterococci and many other Gram-positive organisms. LiaR is the response regulator that, upon phosphorylation, binds in a sequence-specific manner to DNA to regulate transcription in response to membrane stress. In clinical settings, non-susceptibility to DAP by Enterococcus faecium is correlated frequently with a mutation in LiaR of Trp73 to Cys (LiaRW73C). We have determined the structure of the activated E. faecium LiaR protein at 3.2 Å resolution and, in combination with solution studies, show that the activation of LiaR induces the formation of a LiaR dimer that increases LiaR affinity at least 40-fold for the extended regulatory regions upstream of the liaFSR and liaXYZ operons. In vitro, LiaRW73C induces phosphorylation-independent dimerization of LiaR and provides a biochemical basis for non-susceptibility to DAP by the upregulation of the LiaFSR regulon. A comparison of the E. faecalis LiaR, E. faecium LiaR, and the LiaR homolog from Staphylococcus aureus (VraR) and the mutations associated with DAP resistance suggests that physicochemical properties such as oligomerization state and DNA specificity, although tuned to the biology of each organism, share some features that could be targeted for new antimicrobials.

Original languageEnglish (US)
Pages (from-to)4503-4519
Number of pages17
JournalJournal of Molecular Biology
Volume428
Issue number22
DOIs
StatePublished - Nov 6 2016

Keywords

  • E. faecium
  • LiaR
  • X-ray
  • daptomycin resistance
  • response regulator

ASJC Scopus subject areas

  • Structural Biology
  • Molecular Biology

Fingerprint

Dive into the research topics of 'An Adaptive Mutation in Enterococcus faecium LiaR Associated with Antimicrobial Peptide Resistance Mimics Phosphorylation and Stabilizes LiaR in an Activated State'. Together they form a unique fingerprint.

Cite this