ABSTRACT
Invasive fungal infections are accompanied by high mortality rates that range up to 90%. At present, only three different compound classes are available for use in the clinic, and these often suffer from low bioavailability, toxicity, and drug resistance. These issues emphasize an urgent need for novel antifungal agents. Herein, we report the identification of chemically versatile benzamide and picolinamide scaffolds with antifungal properties. Chemogenomic profiling and biochemical assays with purified protein identified Sec14p, the major phosphatidylinositol/phosphatidylcholine transfer protein in Saccharomyces cerevisiae, as the sole essential target for these compounds. A functional variomics screen identified resistance-conferring residues that localized to the lipid-binding pocket of Sec14p. Determination of the X-ray co-crystal structure of a Sec14p-compound complex confirmed binding in this cavity and rationalized both the resistance-conferring residues and the observed structure-activity relationships. Taken together, these findings open new avenues for rational compound optimization and development of novel antifungal agents.
Subject(s)
Antifungal Agents/metabolism , Benzamides/chemistry , Picolinic Acids/chemistry , Amides/chemistry , Amides/metabolism , Amides/pharmacology , Amino Acid Sequence , Antifungal Agents/chemistry , Antifungal Agents/pharmacology , Aspergillus/drug effects , Benzamides/metabolism , Benzamides/pharmacology , Binding Sites , Candida albicans/drug effects , Crystallography, X-Ray , Drug Resistance, Fungal/drug effects , Microbial Sensitivity Tests , Molecular Dynamics Simulation , Mutagenesis, Site-Directed , Phospholipid Transfer Proteins/chemistry , Phospholipid Transfer Proteins/genetics , Phospholipid Transfer Proteins/metabolism , Picolinic Acids/metabolism , Picolinic Acids/pharmacology , Protein Structure, Tertiary , Saccharomyces cerevisiae/drug effects , Saccharomyces cerevisiae/metabolism , Saccharomyces cerevisiae Proteins/chemistry , Saccharomyces cerevisiae Proteins/genetics , Saccharomyces cerevisiae Proteins/metabolism , Sequence Alignment , Structure-Activity RelationshipABSTRACT
Macrocyclic natural products (NPs) and analogues thereof often show high affinity, selectivity, and metabolic stability, and methods for the synthesis of NP-like macrocycle collections are of major current interest. We report an efficient solid-phase/cyclorelease method for the synthesis of a collection of macrocyclic depsipeptides with bipartite peptide/polyketide structure inspired by the very potent F-actin stabilizing depsipeptides of the jasplakinolide/geodiamolide class. The method includes the assembly of an acyclic precursor chain on a polymeric carrier, terminated by olefins that constitute complementary fragments of the polyketide section and cyclization by means of a relay-ring-closing metathesis (RRCM). The method was validated in the first total synthesis of the actin-stabilizing cyclodepsipeptide seragamide A and the synthesis of a collection of structurally diverse bipartite depsipeptides.
