Deconstructing Protein Binding of Sulfonamides and Sulfonamide Analogs

Sulfonamides are one of the most important pharmacophores in medicinal chemistry and sulfonamide analogs have gained substantial interest in recent years. However, the protein interactions of sulfonamides and especially of their analogs are underexplored. Using FKBP12 as a model system, we describe the synthesis of optically pure sulfenamide, sulfinamide and sulfonimidamide analogs of a well characterized sulfonamide ligand. This allowed us to precisely determine the binding contributions of each sulfonamide oxygen atom and the consequence of nitrogen replacements. We also present high resolu-tion cocrystal structures of sulfonamide analogs buried in the pocket of a protein target. This revealed intimate contacts with the protein, including an unprecedented hydrogen bond acceptor of sulfonimidamides. The use of sulfonamide analogs ena-bled new exit vectors that allowed to remodel a subpocket in FKBP12. Our results illuminate the protein interaction potential of sulfonamides/sulfonamide analogs and will aid in their rational design.