Laser- and cryogenic probe-assisted NMR enables hypersensitive analysis of biomolecules at submicromolar concentration.
Solution-state NMR typically requires 100 μM to 1 mM samples. This limitation prevents applications to mass-limited and aggregation-prone target molecules. Photochemically induced dynamic nuclear polarization was adapted to data collection on low-concentration samples by radiofrequency gating, enabling rapid 1D NMR spectral acquisition on aromatic amino acids and proteins bearing aromatic residues at nanomolar concentration, i.e., a full order of magnitude below other hyperpolarization techniques in liquids. Both backbone H1-C13 and side-chain resonances were enhanced, enabling secondary and tertiary structure analysis of proteins with remarkable spectral editing, via the 13C PREPRINT pulse sequence. Laser-enhanced 2D NMR spectra of 5 μM proteins at 600 MHz display 30-fold better S/N than conventional 2D data collected at 900 MHz. Sensitivity enhancements achieved with this technology, denoted as low-concentration photo-CIDNP (LC-photo-CIDNP), depend only weakly on laser intensity, highlighting the opportunity of safer and more cost-effective hypersensitive NMR applications employing low-power laser sources.
['Okuno|Yusuke|Y|', 'Mecha|Miranda F|MF|', 'Yang|Hanming|H|', 'Zhu|Lingchao|L|', 'Fry|Charles G|CG|', 'Cavagnero|Silvia|S|']
D007834:Lasers D009682:Magnetic Resonance Spectroscopy D019906:Nuclear Magnetic Resonance, Biomolecular D010777:Photochemistry D011506:Proteins
NMR amino acids proteins hyperpolarization photo-CIDNP