Structural studies of uniformly 13C labeled galactolipid/water systems were initiated with Magic-Angle Spinning NMR at 400 MHz. In particular, multidimensional solution state coherence transfer schemes were employed in conjunction with MAS to obtain novel high resolution chemical correlation spectra of fluid phase lipids (1H-13C-HETCOR, 1H-13C-HSQC, 13C-13C-TOCSY). We plan to extend these techniques to the measurement of long range 13C-1H J couplings in order to determine the interglycosidic torsion angle of the digalactosyl moiety in addition to the angle that the digalactosyl group makes with the glycerol backbone. Long range J couplings will be suplemented by 13C-1H dipolar couplings obtained with a newly developed solid state NMR technique. In particular, a novel 2D sequence using Proton Detected Local Fields and recoupling of the dipolar interaction in the indirect dimension enables the determination of both magnitude and sign of the dipolar interactions at each carbon site. These techniques provide us with information previously available through use of 2H NMR, which requires isotopic labeling, in addition to the sign of the order parameter, previously unavailable with standard methods. The extension of these techniques to unlabeled phospholipids was initiated and introduces only minor losses in sensitivity.
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