The Discovery of the Fucoidan-Active Endo-1→4-α-L-Fucanase of the GH168 Family, Which Produces Fucoidan Derivatives with Regular Sulfation and Anticoagulant Activity.

Sulfated polysaccharides of brown algae, fucoidans, are known for their anticoagulant properties, similar to animal heparin. Their complex and irregular structure is the main bottleneck in standardization and in defining the relationship between their structure and bioactivity. Fucoidan-active enzymes can be effective tools to overcome these problems. In the present work, we identified the gene fwf5 encoding the fucoidan-active endo-fucanase of the GH168 family in the marine bacterium Wenyingzhuangia fucanilytica CZ1127T. The biochemical characteristics of the recombinant fucanase FWf5 were investigated. Fucanase FWf5 was shown to catalyze the endo-type cleavage of the 1→4-O-glycosidic linkages between 2-O-sulfated α-L-fucose residues in fucoidans composed of the alternating 1→3- and 1→4-linked residues of sulfated α-L-fucose. This is the first report on the endo-1→4-α-L-fucanases (EC 3.2.1.212) of the GH168 family. The endo-fucanase FWf5 was used to selectively produce high- and low-molecular-weight fucoidan derivatives containing either regular alternating 2-O- and 2,4-di-O-sulfation or regular 2-O-sulfation. The polymeric 2,4-di-O-sulfated fucoidan derivative was shown to have significantly greater in vitro anticoagulant properties than 2-O-sulfated derivatives. The results have demonstrated a new type specificity among fucanases of the GH168 family and the prospects of using such enzymes to obtain standard fucoidan preparations with regular sulfation and high anticoagulant properties.

Fucoidans from brown algae Laminaria longipes and Saccharina cichorioides: Structural characteristics, anticancer and radiosensitizing activity in vitro.

The sulfated α-l-fucans ScF and LlF were obtained from brown algae of the Laminariaceae family (Saccharina cichorioides and Laminaria longipes). According to spectroscopy NMR, the LlF fucan predominantly contained the →3)-α-l-Fucp-(2SO3-)-(1→4)-α-l-Fucp-(1→2)-α-l-Fucp-(4SO3-)-(1→ repeating units, with small amounts of disaccharide 1,4-linked fragments and 3-sulfated fucose residues. Mass spectrometric analysis revealed the presence of the following fragments in the fucan structure: α-l-Fucp-(2SO3-)-(1→4)-α-l-Fucp-(2SO3-)-(1→3)-α-l-Fucp-(4SO3-); α-l-Fucp-(2,4SO3-)-(1→3)-α-l-Fucp-(1→3)-α-l-Fucp-(4SO3-); α-l-Fucp-(2SO3-)-(1→2)-α-l-Fucp; α-l-Fucp-(2SO3-)-(1→2)-α-l-Fucp-(4SO3-); α-l-Fucp-(2SO3-)-(1→3)-α-l-Fucp; α-l-Fucp-(2,4SO3-)-(1→3)-α-l-Fucp; α-l-Fucp-(4SO3-)-(1→4)-α-l-Fucp; and α-l-Fucp-(4SO3-)-(1→4)-α-l-Fucp-(2SO3-). Both ScF and LlF fucoidans inhibited colony formation and growth of melanoma and colon cancer cells and sensitize-tested cancer cells to X-ray radiation to a comparable degree.