STRUCTURAL CHARACTERIZATION OF 2 HEXASACCHARIDES AND AN OCTASACCHARIDE FROM CHONDROITIN SULFATE-C CONTAINING THE UNUSUAL SEQUENCE (4-SULFO)-N-ACETYLGALACTOSAMINE BETA-1-4-(2-SULFO)-GLUCURONIC ACID BETA-1-3-(6-SULFO)-N-ACETYLGALACTOSAMINE

The structures of two hexasaccharides and an octasaccharide, isolated from shark cartilage chondroitin sulphate C after partial chondroitin ABC lyase digestion, have been elucidated by disaccharide analysis, li quid secondary-ion mass spectrometry, and H-1/C-13 NMR spectroscopy. I n the case of the octasaccharide, the order of the internal disacchari de units was deduced from a novel one-dimensional TOCSY/ROESY excitati on sculpting experiment [Gradwell M. J., Kogelberg, H. & Frenkiel, T. A. (1997) J. Magn. Reson. 124, 267-270] which incorporates two double- pulsed field-gradient spin-echo sequences. The oligosaccharides each c ontain the unusual motif GalNAc(4SO(3)(-))beta 1-4GlcA(2SO(3))beta 1-3 GalNAc(6SO(3)(-)). From the adjoining sequences in the oligosaccharide s, it is apparent that this motif occurs interspersed with typical cho ndroitin sulphate-C disaccharides, GlcA beta 1-3GalNAc(6SO(3)(-)). Suc h differentially sulphated domains along the glycosaminoglycan chains are potential sites for specific recognition processes.