1H-detected 1H−1H correlation spectroscopy of a stereo-array isotope labeled amino acid under fast magic-angle spinning

The combined use of selective deuteration, stereo-array isotope labeling (SAIL), and fast magic-angle spinning effectively suppresses the 1H−1H dipolar couplings in organic solids. This method provided the high-field 1H NMR linewidths comparable to those achieved by combined rotation and multiple-pulse spectroscopy. This technique was applied to two-dimensional 1H-detected 1H−1H polarization transfer CHH experiments of valine. The signal sensitivity for the 1H-detected CHH experiments was greater than that for the 13C-detected 1H−1H polarization transfer experiments by a factor of 2-4. We obtained the 1H−1H distances in SAIL valine by CHH experiments with an accuracy of about 0.2 Å by using a theory developed for 1H−1H polarization transfer in 13C-labeled organic compounds.