Details

Autor(en) / Beteiligte

• Lee, Jung Ho
• Sekhar, Ashok
• Cavagnero, Silvia

Titel

1H-Detected 13C Photo-CIDNP as a Sensitivity Enhancement Tool in Solution NMR

Ist Teil von

• Journal of the American Chemical Society, 2011-06, Vol.133 (21), p.8062-8065

Ort / Verlag

United States: American Chemical Society

Erscheinungsjahr

2011

Quelle

MEDLINE

Beschreibungen/Notizen

• NMR is a powerful yet intrinsically insensitive technique. The applicability of NMR to chemical and biological systems would be substantially extended by new approaches going beyond current signal-to-noise capabilities. Here, we exploit the large enhancements arising from 13C photochemically induced dynamic nuclear polarization (13C photo-CIDNP) in solution to improve biomolecular NMR sensitivity in the context of heteronuclear correlation spectroscopy. The 13C-PRINT pulse sequence presented here involves an initial 13C nuclear spin polarization via photo-CIDNP followed by conversion to anti-phase coherence and transfer to 1H for detection. We observe substantial enhancements, up to ≫200-fold, relative to the dark (laser off) experiment. Resonances of both side-chain and backbone CH pairs are enhanced for the three aromatic residues Trp, His, and Tyr, the σ32 peptide, and the drkN SH3 protein. The sensitivity of this experiment, defined as signal-to-noise per square root of unit time (S/N)t, is unprecedented in the NMR polarization enhancement literature dealing with polypeptides in solution. Up to a 16-fold larger (S/N)t than for the 1H–13C SE-HSQC reference sequence is achieved, for the σ32 peptide. Data collection time is reduced up to 256-fold, highlighting the advantages of 1H-detected 13C photo-CIDNP in solution NMR.