Laser- and cryogenic probe-assisted NMR enables hypersensitive analysis of biomolecules at submicromolar concentration

Significance Despite its prominent role in structural biology, NMR spectroscopy is hampered by extremely poor sensitivity. In this work, we develop a laser-assisted methodology, LC-photo-CIDNP, to enhance NMR sensitivity for the detection of amino acids and proteins in solution down to nanomolar concentration. Our method is significant because it enables detection of nanomolar concentrations of aromatic amino acids (Trp and Tyr), either in their free state or within proteins, in only a few seconds. Hence, the LC-photo-CIDNP approach renders data collection thousands of times faster than laser-free NMR experiments performed on higher-field spectrometers. Further, LC-photo-CIDNP is readily applicable to both 1D and 2D data collection mode. Rapid detection of proteins in solution at nanomolar concentration by NMR spectroscopy is unprecedented.