Structural analysis of sulfated fucans by high-field NMR.
The structures of several sulfated polysaccharides isolated from marine organisms have been determined by a combination of degradative and spectroscopic techniques. For two sulphated fucans, one isolated from the sea cucumber L. grisea, and one from the sea urchin L. variegatus, a novel type of polysaccharide structure is proposed based on the analysis of one- and two-dimensional nuclear magnetic resonance (NMR) spectra. Both polysaccharides are linear, 1-->3 linked alpha-L-fucans in which a four-residue repeating unit is defined by specific patterns of sulfation at the 2- and 4-positions. The four residues give rise to spin systems which may be identified by 2-dimensional 1H-1H correlated spectroscopy (COSY), and the sequence of the residues is deduced from inter-residue nuclear Overhauser enhancements which produce cross-peaks in the NOESY spectrum. To the best of our knowledge, these are the first polysaccharides for which a regular repeating unit is defined by the pattern of sulfate substitution alone.
Mulloy
B
B
Laboratory of Molecular Structure, National Institute for Biological Standards and Control, Hertfordshire, UK.
Ribeiro
A C
AC
Vieira
R P
RP
Mourão
P A
PA
D000818:Animals; D009682:Magnetic Resonance Spectroscopy; D011134:Polysaccharides / Q000737:chemistry*; D012616:Sea Cucumbers / Q000737:chemistry*; D012617:Sea Urchins / Q000737:chemistry*
D011134:Polysaccharides