A drug discovery toolbox for Nuclear Magnetic Resonance (NMR) characterization of ligands and their targets

Information about the structure, dynamics, and ligand-binding properties of biomolecules can be derived from Nuclear Magnetic Resonance (NMR) spectroscopy and provides valuable information for drug discovery. A multitude of experimental approaches provides a wealth of information that can be tailored to the system of interest. Methods to study the behavior of ligands upon target binding enable the identification of weak binders in a robust manner that is critical for the identification of truly novel binding interactions. This is particularly important for challenging targets. Observing the solution behavior of biomolecules yields information about their structure, dynamics, and interactions. This review describes the breadth of approaches that are available, many of which are under-utilized in a drug-discovery environment, and focuses on recent advances that continue to emerge.

Discovery of Protein-Protein Interaction Inhibitors of Replication Protein A

Replication Protein A (RPA) is a ssDNA binding protein that is essential for DNA replication and repair. The initiation of the DNA damage response by RPA is mediated by protein-protein interactions involving the N-terminal domain of the 70 kDa subunit with partner proteins. Inhibition of these interactions increases sensitivity towards DNA damage and replication stress and may therefore be a potential strategy for cancer drug discovery. Towards this end, we have discovered two lead series of compounds, derived from hits obtained from a fragment-based screen, that bind to RPA70N with low micromolar affinity and inhibit the binding of an ATRIP-derived peptide to RPA. These compounds may offer a promising starting point for the discovery of clinically useful RPA inhibitors.