BrlR from Pseudomonas aeruginosa is a receptor for both cyclic di-GMP and pyocyanin

Nat Commun. 2018 Jul 2;9(1):2563. doi: 10.1038/s41467-018-05004-y.

Abstract

The virulence factor pyocyanin and the intracellular second messenger cyclic diguanylate monophosphate (c-di-GMP) play key roles in regulating biofilm formation and multi-drug efflux pump expression in Pseudomonas aeruginosa. However, the crosstalk between these two signaling pathways remains unclear. Here we show that BrlR (PA4878), previously identified as a c-di-GMP responsive transcriptional regulator, acts also as a receptor for pyocyanin. Crystal structures of free BrlR and c-di-GMP-bound BrlR reveal that the DNA-binding domain of BrlR contains two separate c-di-GMP binding sites, both of which are involved in promoting brlR expression. In addition, we identify a pyocyanin-binding site on the C-terminal multidrug-binding domain based on the structure of the BrlR-C domain in complex with a pyocyanin analog. Biochemical analysis indicates that pyocyanin enhances BrlR-DNA binding and brlR expression in a concentration-dependent manner.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Anti-Bacterial Agents / pharmacology
  • Anti-Bacterial Agents / therapeutic use
  • Bacterial Proteins / chemistry
  • Bacterial Proteins / isolation & purification
  • Bacterial Proteins / metabolism*
  • Binding Sites
  • Biofilms / drug effects
  • Crystallography, X-Ray
  • Cyclic GMP / analogs & derivatives*
  • Cyclic GMP / chemistry
  • Cyclic GMP / metabolism
  • Drug Resistance, Multiple, Bacterial / genetics
  • Gene Expression Regulation, Bacterial
  • Humans
  • Microbial Sensitivity Tests
  • Molecular Docking Simulation
  • Protein Domains
  • Pseudomonas Infections / drug therapy*
  • Pseudomonas Infections / virology
  • Pseudomonas aeruginosa / pathogenicity
  • Pseudomonas aeruginosa / physiology*
  • Pyocyanine / metabolism*
  • Recombinant Proteins / chemistry
  • Recombinant Proteins / isolation & purification
  • Recombinant Proteins / metabolism
  • Transcription Factors / chemistry
  • Transcription Factors / isolation & purification
  • Transcription Factors / metabolism*
  • Virulence Factors / metabolism*

Substances

  • Anti-Bacterial Agents
  • Bacterial Proteins
  • Recombinant Proteins
  • Transcription Factors
  • Virulence Factors
  • bis(3',5')-cyclic diguanylic acid
  • Pyocyanine
  • Cyclic GMP