Characterization of an Endo-1,3-fucanase from the Glycoside Hydrolase 107 Family

Sulfated fucans are functional polysaccharides derived from marine food, including brown algae and echinoderms, and are widely studied for their nutritional value and bioactive properties. Endo-1,3-fucanases are ideal tools for the research and development of sulfated fucans. However, the current understanding of the subsite specificity of endo-1,3-fucanases from the GH107 family remains limited, which hinders their potential applications of fucanases. This study identified an endo-1,3-fucanase, Fun107Y_Wa, from the GH107 family and performed a detailed analysis, including phylogenetic analysis, molecular biology, enzymology, UPLC-HRMS, and NMR techniques. The catalytic activity of Fun107Y_Wa reached its maximum under conditions of 40 °C and pH 8. Fun107Y_Wa acted in a processive endoacting manner, revealing the catalytic mechanism of endo-1,3-fucanases in GH107. Moreover, Fun107Y_Wa accommodated Fuc<i>p</i>(2OSO₃^-), Fuc<i>p</i>(2OSO₃^-), Fuc<i>p</i>(2,4OSO₃^-), and Fuc<i>p</i> at the -2 to +2 subsites. This subsite specificity was distinct from all members of the GH107 family, further clarifying the diversity of subsite specificity of endo-1,3-fucanases from the family. This study enhances the understanding of subsite specificity of endo-1,3-fucanase from the GH107 family, offering a valuable tool for the research and development of sulfated fucans.