¹³ Cβ-Valine and ¹³ Cγ-Leucine Methine Labeling To Probe Protein Ligand Interaction

Precise information regarding the interaction between proteins and ligands at molecular resolution is crucial for effectively guiding the optimization process from initial hits to lead compounds in early stages of drug development. In this study, we introduce a novel aliphatic side chain isotope-labeling scheme to directly probe interactions between ligands and aliphatic sidechains using NMR techniques. To demonstrate the applicability of this method, we selected a set of Brd4-BD1 binders and analyzed ¹ H chemical shift perturbation resulting from CH-π interaction of H_β -Val and H_γ -Leu as CH donors with corresponding ligand aromatic moieties as π acceptors.