Abstract:The sulfation of extracellular polysaccharides of Ganoderma lucidum(GLP)from the submerged fermentation broth can dramatically enhance their antitumor activity. The structure and conformation of GLP might change due to the sulfation. The structure of the sulfated GLP was analysized with glycosyl residual composition analysis,IR,UV and NMR. The polysaccharide consists of rhamnose,arabinose,mannose,glucose and galactose with a molar ratio of 9∶3∶2∶4∶48. The main chain of the polysaccharide may consist of the unit of α-D-Glc(1→6)or the side chain is mixed of α-D-Glc,Rha,α-D-Man,and Ara. The sulfate groups may be connected to C-3,C-4,and C-6 of the sugar unit. Meanwhile,the sulfated polysaccharides present very different conformation comparing to the native polysaccharides. The sulfated polysaccharides possessed a triple helix whereas the native polysaccharide preferred the single helical,which was also confirmed by x-ray diffraction.