Discovery of Small Molecule Interleukin 17A Inhibitors with Novel Binding Mode and Stoichiometry: Optimization of DNA-Encoded Chemical Library Hits to In Vivo Active Compounds

Dysregulation of IL17A drives numerous inflammatory and autoimmune disorders with inhibition of IL17A using antibodies proven as an effective treatment. Oral anti-IL17 therapies are an attractive alternative option, and several preclinical small molecule IL17 inhibitors have previously been described. Herein, we report the discovery of a novel class of small molecule IL17A inhibitors, identified via a DNA-encoded chemical library screen, and their subsequent optimization to provide in vivo efficacious inhibitors. These new protein-protein interaction (PPI) inhibitors bind in a previously undescribed mode in the IL17A protein with two copies binding symmetrically to the central cavities of the IL17A homodimer.

Readily Accessible High-Throughput Experimentation: A General Protocol for the Preparation of ChemBeads and EnzyBeads

Chemical- and enzyme-coated beads (ChemBeads and EnzyBeads) were introduced recently as a universal strategy for the accurate dispensing of various solids in submilligram quantities using automated instrumentation or manual dispensing. The coated beads are prepared using a resonant acoustic mixer (RAM)-an instrument that may be available only to well-established facilities. In this study, we evaluated alternative coating methods for preparing ChemBeads and EnzyBeads without the use of a RAM. We also evaluated the effects of bead sizes on loading accuracy using 4 coating methods and 12 solids (9 chemicals and 3 enzymes) as test subjects. While our original RAM coating method is the most versatile for the broadest range of solids, high-quality ChemBeads and EnzyBeads that are suitable for high-throughput experimentation can be prepared using alternative methods. These results should make ChemBeads and EnzyBeads readily accessible as the core technology for setting up high-throughput experimentation platforms.

Chemoenzymatic macrocycle synthesis using resorcylic acid lactone thioesterase domains

A key missing tool in the chemist's toolbox is an effective biocatalyst for macrocyclization. Macrocycles limit the conformational flexibility of small molecules, often improving their ability to bind selectively and with high affinity to a target, making them a privileged structure in drug discovery. Macrocyclic natural product biosynthesis offers an obvious starting point for biocatalyst discovery via the native macrocycle forming biosynthetic mechanism. Herein we demonstrate that the thioesterase domains (TEs) responsible for macrocyclization of resorcylic acid lactones are promising catalysts for the chemoenzymatic synthesis of 12- to 18-member ring macrolactones and macrolactams. The TE domains responsible for zearalenone and radicicol biosynthesis successfully generate resorcylate-like 12- to 18-member macrolactones and a 14-member macrolactam. In addition these enzymes can also macrolactonize a non-resorcylate containing depsipeptide, suggesting they are versatile biocatalysts. Simple saturated omega-hydroxy acyl chains are not macrocyclized, nor are the alpha-beta unsaturated derivatives, clearly outlining the scope of the substrate tolerance. These data dramatically expand our understanding of substrate tolerance of these enzymes and are consistent with our understanding of the role of TEs in iterative polyketide biosynthesis. In addition this work shows these TEs to be the most substrate tolerant polyketide macrocyclizing enzymes known, accessing resorcylate lactone and lactams as well as cyclicdepsipeptides, which are highly biologically relevant frameworks.