A unique fucosylated chondroitin sulfate type II with strikingly homogeneous and neatly distributed α-fucose branches

Fucosylated chondroitin sulfates (FCSs) and sulfated fucans (SFs) are conspicuous components of the body wall of sea cucumbers (Holothuroidea). FCSs are composed of a central core of chondroitin sulfate (CS) decorated with branches of mono-or both mono-and disaccharides of a-fucose (FCS types I and II, respectively). FCSs type II have heterogeneous and irregularly distributed a-fucose branches; however, the novel FCS type II from Holothuria lentiginosa described herein via solution nuclear magnetic resonance has strikingly homogeneous alpha-fucose branches neatly distributed along its CS core. This FCS is built up of three distinct sequential units composed of the typical CS disaccharides of FCSs, rich in beta-galactosamine-4,6diS, decorated with branches of alpha-Fucp-2,4diS, alpha-Fucp-3,4diS or alpha-Fucp[1 -> 3]alpha-Fucp-4S[1 -> linked to the position 3- of the beta-glucuronic acid. Conformational analyses of these repetitive units revealed a fairly rigid structure despite of the high sulfate content of their alpha-fucose branches. We also determined the structure of the SF from H. lentiginosa as a repetitive tetrasaccharide sequence composed of. 3] alpha-Fucp-2,4diS[1 -> 3] alpha-Fucp[1 -> 3]alpha-Fucp-2S[1 -> 3]alpha-Fucp-2S[1 ->. Furthermore, we determined that the nonsulfated alpha-fucose units present in FCS type II did not interfere with their anticoagulant potencies and affinities to calcium. FCS is an autapomorphic molecular character of the class Holothuroidea and the composition of their alpha-fucose branches differs in a species-specific manner. Branches containing alpha-Fucp-2,4diS are the most common within the extant holothurians, being found in 90% of the FCSs characterized thus far.