NMR structure-based optimization of Staphylococcus aureus sortase A pyridazinone inhibitors

Albert H. Chan, Sung Wook Yi, Ethan M. Weiner, Brendan R. Amer, Christopher K. Sue, Jeff Wereszczynski, Carly A. Dillen, Silvia Senese, Jorge Z. Torres, J. Andrew McCammon, Lloyd S. Miller, Michael E. Jung, Robert T. Clubb

Research output: Contribution to journalEditorialpeer-review

12 Scopus citations

Abstract

Staphylococcus aureus is a leading cause of hospital-acquired infections in the USA and is a major health concern as methicillin-resistant S. aureus and other antibiotic-resistant strains are common. Compounds that inhibit the S. aureus sortase (SrtA) cysteine transpeptidase may function as potent anti-infective agents as this enzyme attaches virulence factors to the bacterial cell wall. While a variety of SrtA inhibitors have been discovered, the vast majority of these small molecules have not been optimized using structure-based approaches. Here we have used NMR spectroscopy to determine the molecular basis through which pyridazinone-based small molecules inhibit SrtA. These inhibitors covalently modify the active cysteine thiol and partially mimic the natural substrate of SrtA by inducing the closure of an active site loop. Computational and synthetic chemistry methods led to second-generation analogues that are ~70-fold more potent than the lead molecule. These optimized molecules exhibit broad-spectrum activity against other types of class A sortases, have reduced cytotoxicity, and impair SrtA-mediated protein display on S. aureus cell surface. Our work shows that pyridazinone analogues are attractive candidates for further development into anti-infective agents, and highlights the utility of employing NMR spectroscopy and solubility-optimized small molecules in structure-based drug discovery.

Original languageEnglish (US)
Pages (from-to)327-344
Number of pages18
JournalChemical Biology and Drug Design
Volume90
Issue number3
DOIs
StatePublished - Sep 2017

Keywords

  • NMR
  • Sortase
  • SrtA
  • Staphylococcus aureus
  • molecular docking
  • molecular dynamics
  • protein structure
  • protein–inhibitor complex
  • transpeptidase

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Medicine
  • Pharmacology
  • Drug Discovery
  • Organic Chemistry

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