Structures of oligosaccharides derived from Cladosiphon okamuranus fucoidan by digestion with marine bacterial enzymes

A fucoidan-utilizing marine bacterium, Fucophilus fucoidanolyticus, was cultivated in medium containing fucoidan from Cladosiphon okamuranus. The C. okamuranus fucoidan was digested into oligosaccharides with the intracellular enzymes of F. fucoidanolyticus, and their structures were determined by nuclear magnetic resonance analyses. Some of their structures are represented by one general structural formula, (-3L-Fucpalpha1-3L-Fucp(4-O-sulfate)alpha1-3L-Fucp(4-O-sulfate)alpha1-3(D-GlcpUAalpha1-2)L-Fucpalpha1)-3L-Fucpalpha1-3L-Fucp(4-O-sulfate)alpha1-3L-Fucp(4-O-sulfate) alpha1-3L-Fucp (m = 0, 1, 2, or 3). We concluded that all oligosaccharides obtained were derived from a sulfated-fucose-containing polysaccharide of C. okamuranus, which has a repeating unit of (-3L-Fucpalpha1-3L-Fucp(4-O-sulfate)alpha1-3L-Fucp(4-O-sulfate)alpha1-3 (D-GlcpUAalpha1-2) L-Fucpalpha1-).