Structural elucidation of the polysaccharide moiety of a glycopeptide (GLPCW-II) from Ganoderma lucidum fruiting bodies

A water-soluble glycopeptide (GLPCW-II) was isolated from the fruiting bodies of Ganoderma lucidum by DEAE-Sepharose Fast-Flow and Sephacryl S-300 High Resolution Chromatography. The glycopeptide had a molecular weight of 1.2 × 104 Da (determined by HPLC), and consisted of ∼90% carbohydrate and ∼8% protein as determined using the phenol-sulfuric acid method and the BCATM protein assay reagent kit, respectively. The polysaccharide moiety was composed mainly of d-Glc, l-Fuc, and d-Gal in the ratio of 1.00:1.09:4.09. To facilitate structure–activity studies, the structure of the GLPCW-II polysaccharide moiety was elucidated using 1H and 13C NMR spectroscopy including COSY, TOCSY, HMBC, HSQC, and ROESY, combined with GC–MS of methylated derivatives, and shown to consist of repeating units with the following structure:Figure optionsDownload as PowerPoint slide

Figure optionsDownload as PowerPoint slide