title: Discovery of the first small-molecule CsrA-RNA interaction inhibitors using biophysical screening technologies.
abstract: CsrA is a global post-transcriptional regulator protein affecting mRNA translation and/or stability. Widespread among bacteria, it is essential for their full virulence and thus represents a promising anti-infective drug target. Therefore, we aimed at the discovery of CsrA-RNA interaction inhibitors. Results & methodology: We followed two strategies: a screening of small molecules (A) and an RNA ligand-based approach (B). Using surface plasmon resonance-based binding and fluorescence polarization-based competition assays, (A) yielded seven small-molecule inhibitors, among them MM14 (IC50 of 4 µM). (B) resulted in RNA-based inhibitor GGARNA (IC50 of 113 µM).
  
  
  
  The first small-molecule inhibitors of the CsrA-RNA interaction were discovered exhibiting micromolar affinities. These hits represent tools to investigate the effects of CsrA-RNA interaction inhibition on bacterial virulence.
authors.affiliation: Department of Drug Design & Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.|German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.
authors.forename: Christine K
authors.initials: CK
authors.lastname: Maurer
authors.affiliation: Department of Drug Design & Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.|German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.
authors.forename: Martina
authors.initials: M
authors.lastname: Fruth
authors.affiliation: Department of Drug Design & Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.|German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Empting
authors.affiliation: Clemens-Schöpf-Institute for Organic Chemistry & Biochemistry, Technical University Darmstadt, Alarich-Weiss Straße 4, 64287 Darmstadt, Germany.
authors.forename: Olga
authors.initials: O
authors.lastname: Avrutina
authors.affiliation: German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.|Department of Molecular Infection Biology, Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors.forename: Jörn
authors.initials: J
authors.lastname: Hoßmann
authors.affiliation: German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.|Department of Microbial Natural Products, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
authors.forename: Suvd
authors.initials: S
authors.lastname: Nadmid
authors.affiliation: Institute of Organic Chemistry I, Saarland University, Campus C4.2, 66123 Saarbrücken, Germany.
authors.forename: Jan
authors.initials: J
authors.lastname: Gorges
authors.affiliation: German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.|Department of Microbial Natural Products, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
authors.forename: Jennifer
authors.initials: J
authors.lastname: Herrmann
authors.affiliation: Institute of Organic Chemistry I, Saarland University, Campus C4.2, 66123 Saarbrücken, Germany.
authors.forename: Uli
authors.initials: U
authors.lastname: Kazmaier
authors.affiliation: German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.|Department of Molecular Infection Biology, Helmholtz Centre for Infection Research (HZI), Inhoffenstraße 7, 38124 Braunschweig, Germany.
authors.forename: Petra
authors.initials: P
authors.lastname: Dersch
authors.affiliation: German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.|Department of Microbial Natural Products, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
authors.forename: Rolf
authors.initials: R
authors.lastname: Müller
authors.affiliation: Department of Drug Design & Optimization, Helmholtz Institute for Pharmaceutical Research Saarland (HIPS), Helmholtz Centre for Infection Research (HZI), Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.|German Centre for Infection Research (DZIF), PartnerSite Hannover-Braunschweig, 30625 Hannover, Germany.|Department of Pharmaceutical & Medicinal Chemistry, Saarland University, Campus E8.1, 66123 Saarbrücken, Germany.
authors.forename: Rolf W
authors.initials: RW
authors.lastname: Hartmann
mesh_terms: D004353:Drug Evaluation, Preclinical / Q000379:methods*; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000378:metabolism*; D009696:Nucleic Acids / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D009841:Oligonucleotides / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D011485:Protein Binding / Q000187:drug effects; D012313:RNA / Q000737:chemistry / Q000378:metabolism*; D016601:RNA-Binding Proteins / Q000737:chemistry / Q000378:metabolism*; D012097:Repressor Proteins / Q000737:chemistry / Q000378:metabolism*; D054852:Small Molecule Libraries / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: C093587:CsrA protein, E coli; D029968:Escherichia coli Proteins; D009696:Nucleic Acids; D009841:Oligonucleotides; D016601:RNA-Binding Proteins; D012097:Repressor Proteins; D054852:Small Molecule Libraries; D012313:RNA
keywords: CsrA/RsmA protein family; anti-virulence strategy; fluorescence polarization; library screening; protein–nucleic acid interaction; surface plasmon resonance spectroscopy