Line narrowing in methyl-TROSY using zero-quantum 1H-13C NMR spectroscopy.

An enhanced sensitivity zero-quantum correlation experiment is proposed for recording (1)H-(13)C correlations of methyl groups in highly deuterated, methyl protonated large proteins. The zero-quantum spectra benefit from TROSY-effects in which both intra- and inter-methyl dipolar relaxation interactions are minimized. Applications to malate synthase G at 5 degrees C (81 kDa single polypeptide chain enzyme, correlation time of 118 ns) and lysine decarboxylase at 45 degrees C (810 kDa decameric enzyme) are presented showing significant improvements in resolution relative to corresponding HMQC data sets, with only slight decreases (approximately 10%) in sensitivity.