Ultrafast Fragment Screening Using Photo-Hyperpolarized (CIDNP) NMR

Abstract

While nuclear magnetic resonance (NMR) is regarded asa referencein fragment-based drug design, its implementation in a high-throughputmanner is limited by its lack of sensitivity resulting in long acquisitiontimes and high micromolar sample concentrations. Several hyperpolarizationapproaches could, in principle, improve the sensitivity of NMR alsoin drug research. However, photochemically induced dynamic nuclearpolarization (photo-CIDNP) is the only method that is directly applicablein aqueous solution and agile for scalable implementation using off-the-shelfhardware. With the use of photo-CIDNP, this work demonstrates thedetection of weak binders in the millimolar affinity range using lowmicromolar concentrations down to 5 mu M of ligand and 2 mu Mof target, thereby exploiting the photo-CIDNP-induced polarizationtwice: (i) increasing the signal-to-noise by one to two orders inmagnitude and (ii) polarization-only of the free non-bound moleculeallowing identification of binding by polarization quenching, yieldinganother factor of hundred in time when compared with standard techniques.The interaction detection was performed with single-scan NMR experimentsof a duration of 2 to 5 s. Taking advantage of the readiness of photo-CIDNPsetup implementation, an automated flow-through platform was designedto screen samples at a screening rate of 1500 samples per day. Furthermore,a 212 compounds photo-CIDNP fragment library is presented, openingan avenue toward a comprehensive fragment-based screening method.