3-DIMENSIONAL C-13-C-13-CORRELATED EXPERIMENTS ON OLIGOSACCHARIDES

The use of three-dimensional 1H-detected 13C-13C-correlated experiments is demonstrated for the purpose of assigning all of the ring proton and carbon resonances from a digalactosyl diacylglyceride sample, uniformly 13C-enriched to 15% by microbiological methods. In addition to improving the previously published phase-cycled pulse sequences (Y. Q. Gosser, K. P. Howard, and J. H. Prestegard, J. Magn. Reson. Ser. B101, 126, 1993), we illustrate the efficacy of incorporating pulsed field gradients for coherence-pathway selection and solvent suppression. The gradient version of the experiment yields dramatic improvements in the overall resolution and suppression of artifacts, thus increasing the efficiency of the experiment to the point where applicability to NMR assignments of 13C-enriched oligosaccharides can become routine. © 1993 Academic Press, Inc.