Substrate Synthesis and Inhibitor Design for Synthetase DesD from Streptomyces coelicolor

Abstract

The increasing incidence of drug‐resistant microorganisms poses one of the most severe public health threats to modern society, sparking the need for entirely new classes of antibiotics. Because iron scavenging is vital for pathogen respiration and DNA synthesis, microbial siderophores synthesis represents a large class of previously understudied antiobiotic targets. Desferrioxamine siderophore synthetase DesD catalyzes the ATP‐dependent macrocyclization of ω‐aminocarboxylic acid‐derived cyclodimeric siderophores, and is a model enzyme for NIS synthetases, increasingly associated with bacterial virulence. With aid of x‐ray crystallography and isothermal titration calorimetry, the Hoffmann lab is working to characterize the structure and function of DesD.Collaboration with the Kingsbury group has facilitated organic synthesis of substrates and substrate analogs towards this characterization of DesD. Optimal syntheses of DesD substrates and substrate analogs was successfully accomplished utilizing condition and catalyst screening, gas chromatograph assay, and standard Schlenk technique and glove box handling of compounds. Purity was confirmed using 1H NMR, 13C NMR, IR, and elemental analysis. We are currently employing these substrates in crystallographic structural work and binding studies of DesD to characterize the binding interactions. The utility of this work will be realized in the design and direct synthesis of inhibitors of DesD, which will then provide a basic framework for generation of a new class of antibiotics focused on siderophore inhibition.