Structural elucidation of a branch-on-branch β-glucan from Hericium erinaceus with A HPAEC-PAD-MS system

• Published in: Carbohydrate polymers Vol. 251; p. 117080
• Main Authors: Xie, Bingying, Yi, Lin, Zhu, Yiting, Chang, Xiaoming, Hao, Jie, Pang, Li, Ouyang, Yilan, Yuan, Sheng, Zhang, Zhenqing
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2021
• Subjects: beta-Glucans - chemistry; Carbohydrate Conformation; Carbohydrate Sequence; Chromatography, High Pressure Liquid - methods; Chromatography, Ion Exchange - methods; Fruiting Bodies, Fungal - chemistry; Hericium - chemistry; Hericium erinaceus; HPACE-PAD; Molecular Weight; Monosaccharides - analysis; MS/MS; Oligosaccharides - chemistry; Sequence analysis; Tandem Mass Spectrometry - methods; β-Glucan; HPACE-PAD; β-Glucan; MS/MS; Sequence analysis; Hericium erinaceus
• ISSN: 0144-8617; 1879-1344
• DOI: 10.1016/j.carbpol.2020.117080

•A 1−6 glucanase was firstly used to digest a β-glucan from H. erinaceus.•The oligosaccharides in the digested products were analyzed with HPAEC-MS.•The sequences of enzyme resistant oligosaccharides were elucidated with MS/MS.•A branch-on-branch structure of the β-glucan was estimated. A water-soluble β-glucan from fruiting body of Hericium erinaceus was obtained after water extraction, purification and fractionation. Analyses of monosaccharide composition, molecular weight and linkage mode demonstrated that it is a β-glucan with 1→3 and 1→6 linkage modes and a molecular weight of 13.3 kDa. An endo-1,6-β-d-glucanase was used to digest the β-glucan and the digested products over time were analyzed with a HPAEC-PAD-MS platform. The linkage mode of each glycosidic bond in the digested oligosaccharides were confirmed with MS/MS. At the end of digestion, enzyme resistant oligosaccharides were observed as several 1→6 linked glucoses with one or two 1→3 linked glucose residues. All these domains are more like constructional pieces from a branch-on-branch glucan, in which multiple 1→6 linked glucan chains are hooked through one or two 1→3 linked glucose residues. Averagely, there is a 1→3 linkage per six 1→6 linked glucoses in this branch-on-branch β-glucan.