Precise Structure and Anticoagulant Activity of Fucosylated Glycosaminoglycan from <i>Apostichopus japonicus</i>: Analysis of Its Depolymerized Fragments

• Main Authors: Ruowei Guan, Yuan Peng, Lutan Zhou, Wenqi Zheng, Xixi Liu, Pin Wang, Qingxia Yuan, Na Gao, Longyan Zhao, Jinhua Zhao
• Format: Article
• Language: English
• Published: MDPI AG 2019-03-01
• Series: Marine Drugs
• Subjects: <i>Apostichopus japonicus</i>; fucosylated glycosaminoglycan; oligosaccharide; unambiguous structure; anti-Fxase
• Online Access: https://www.mdpi.com/1660-3397/17/4/195

<i>Apostichopus japonicus</i> is one of the most economically important species in sea cucumber aquaculture in China. Fucosylated glycosaminoglycan from <i>A. japonicus</i> (AjFG) has shown multiple pharmacological activities. However, results from studies on the structure of AjFG are still controversial. In this study, the deaminative depolymerization method that is glycosidic bond-selective was used to prepare the depolymerized products from AjFG (dAjFG), and then a series of purified oligosaccharide fragments such as tri-, hexa-, nona-, and dodecasaccharides were obtained from dAjFG by gel permeation chromatography. The 1D/2D NMR and ESI-MS spectrometry analyses showed that these oligosaccharides had the structural formula of <span style="font-variant: small-caps;">l</span>-FucS-&#945;1,3-<span style="font-variant: small-caps;">d</span>-GlcA-&#946;1,3-{<span style="font-variant: small-caps;">d</span>-GalNAc_4S6S-&#946;1,4-[<span style="font-variant: small-caps;">l</span>-FucS-&#945;1,3-]<span style="font-variant: small-caps;">d</span>-GlcA-&#946;1,3-}<i>_n</i>-<span style="font-variant: small-caps;">d</span>-anTal-diol_4S6S (<i>n</i> = 0, 1, 2, 3; FucS represents Fuc_2S4S, Fuc_3S4S, or Fuc_4S). Thus, the unambiguous structure of native AjFG can be rationally deduced: it had the backbone of {-4-<span style="font-variant: small-caps;">d</span>-GlcA-&#946;1,3-<span style="font-variant: small-caps;">d</span>-GalNAc_4S6S-&#946;1-}<i>_n</i>, which is similar to chondroitin sulfate E, and each <span style="font-variant: small-caps;">d</span>-GlcA residue in the backbone was branched with a <span style="font-variant: small-caps;">l</span>-FucS monosaccharide at <i>O</i>-3. Bioactivity assays confirmed that dAjFG and nonasaccharides and dodecasaccharides from AjFG had potent anticoagulant activity by intrinsic FXase inhibition while avoiding side effects such as FXII activation and platelet aggregation.