Spatially selective heteronuclear multiple-quantum coherence (HMQC) spectroscopy for bio-molecular NMR studies

摘要

Spatially selective heteronuclear multiple-quantum coherence (SS HMQC) NMR spectroscopy was devised for solution studies of proteins. Due to ‘time-staggered’ acquisition of free induction decays (FIDs) in different slices, SS HMQC allows one to employ long delays for longitudinal nuclear spin relaxation at high repetition rates for the acquisition of the FIDs. To also achieve high intrinsic sensitivity, SS HMQC was implemented by combing a single spatially selective ¹H excitation pulse with non-selective ¹H 180° pulses. High-quality spectra could be obtained within 66 seconds for a 7.6 kDa uniformly ¹³C,¹⁵N-labeled protein, and within 45 and 90 seconds for, respectively, two uniformly ²H,¹³C,¹⁵N-labeled but isoleucine, leucine and valine methyl group protonated proteins with molecular weights of 7.5 and 43 kDa.