Structure-Guided Discovery of the Novel Covalent Allosteric Site and Covalent Inhibitors of Fructose-1,6-Bisphosphate Aldolase to Overcome the Azole Resistance of Candidiasis

J Med Chem. 2022 Feb 10;65(3):2656-2674. doi: 10.1021/acs.jmedchem.1c02102. Epub 2022 Jan 31.

Abstract

Fructose-1,6-bisphosphate aldolase (FBA) represents an attractive new antifungal target. Here, we employed a structure-based optimization strategy to discover a novel covalent binding site (C292 site) and the first-in-class covalent allosteric inhibitors of FBA from Candida albicans (CaFBA). Site-directed mutagenesis, liquid chromatography-mass spectrometry, and the crystallographic structures of APO-CaFBA, CaFBA-G3P, and C157S-2a4 revealed that S268 is an essential pharmacophore for the catalytic activity of CaFBA, and L288 is an allosteric regulation switch for CaFBA. Furthermore, most of the CaFBA covalent inhibitors exhibited good inhibitory activity against azole-resistant C. albicans, and compound 2a11 can inhibit the growth of azole-resistant strains 103 with the MIC80 of 1 μg/mL. Collectively, this work identifies a new covalent allosteric site of CaFBA and discovers the first generation of covalent inhibitors for fungal FBA with potent inhibitory activity against resistant fungi, establishing a structural foundation and providing a promising strategy for the design of potent antifungal drugs.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Allosteric Site
  • Antifungal Agents / chemical synthesis
  • Antifungal Agents / metabolism
  • Antifungal Agents / pharmacology*
  • Azoles / chemical synthesis
  • Azoles / metabolism
  • Azoles / pharmacology*
  • Biofilms / drug effects
  • Candida albicans / drug effects
  • Candida albicans / physiology
  • Candida parapsilosis / drug effects
  • Drug Resistance, Fungal / drug effects*
  • Enzyme Inhibitors / chemical synthesis
  • Enzyme Inhibitors / metabolism
  • Enzyme Inhibitors / pharmacology*
  • Fructose-Bisphosphate Aldolase / antagonists & inhibitors*
  • Fructose-Bisphosphate Aldolase / chemistry
  • Fructose-Bisphosphate Aldolase / metabolism
  • Fungal Proteins / antagonists & inhibitors*
  • Fungal Proteins / chemistry
  • Fungal Proteins / metabolism
  • Microbial Sensitivity Tests
  • Molecular Structure
  • Protein Binding
  • Structure-Activity Relationship

Substances

  • Antifungal Agents
  • Azoles
  • Enzyme Inhibitors
  • Fungal Proteins
  • Fructose-Bisphosphate Aldolase