Optimization of 1 H decoupling eliminates sideband artifacts in 3D TROSY-based triple resonance experiments

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Optimization of 1 H decoupling eliminates sideband artifacts in 3D TROSY-based triple resonance experiments

Abstract

TROSY-based triple resonance experiments are essential for protein backbone assignment of large biomolecular systems by solution NMR spectroscopy. In a survey of the current Bruker pulse sequence library for TROSY-based experiments we found that several sequences were plagued by artifacts that affect spectral quality andÂ*hamper data analysis. Specifically, these experiments produce sidebands in the 13C(t 1) dimension with inverted phase corresponding to 1HN resonance frequencies, with approximately 5% intensity of the parent 13C crosspeaks. These artifacts originate from the modulation of the 1HN frequency onto the resonance frequency of 13Cα and/or 13Cβ and are due to 180° pulses imperfections used for 1H decoupling during the 13C(t 1) evolution period. These sidebands can become severe for CAi, CAiâ??1 and/or CBi, CBiâ??1 correlation experiments such as TROSY-HNCACB. Here, we implement three alternative decoupling strategies that suppress these artifacts and, depending on the scheme employed, boost the sensitivity up to 14% on Bruker spectrometers. A class of comparable Agilent/Varian pulse sequences that use WALTZ16 1H decoupling can also be improved by this method resulting in up to 60â??80% increase in sensitivity.



Source: Journal of Biomolecular NMR