title: Chain conformation of sulfated derivatives of beta-glucan from sclerotia of Pleurotus tuber-regium.
abstract: Six water-insoluble (1-->3)-beta-D-glucan fractions TM8-1 to TM8-6 with weight-average molecular mass Mw ranging from 5.76 to 77.4x10(4) obtained from the sclerotia of Pleurotus tuber-regium were sulfated to produce the water-soluble fractions S-TM8-1 to S-TM8-6 with Mw from 6.0 to 64.8x10(4). The degree of substitution (DS) of S-TM8 fractions was analyzed by elemental analysis (EA) to be 1.14-1.74. The 13C NMR results indicated that the C-6 was fully substituted, and C-2, C-4 were partially substituted by the sulfo-groups. The Mw and the intrinsic viscosity [eta] of the S-TM8 fractions were measured, respectively, by size-exclusion chromatography combined with laser light scattering (SEC-LLS), LLS and viscometry in phosphate buffer solution (PBS) at 37 degrees C. The dependences of [eta] and radius of gyration <s2>z(1/2) on Mw for the S-TM8 samples were found to be [eta]=1.89x10(-2) Mw(0.70) (cm3/g) and <s2>z(1/2)=1.12x10(-4) Mw(0.81) (nm) in the Mw range tested. Based on current theories for a wormlike chain model, the molar mass per unit contour length ML and persistence length q of the S-TM8 were calculated to be 990 nm(-1) and 8.5 nm, respectively. The relatively higher q value suggested a more expanded flexible chain of S-TM8 in PBS. The water-solubility and relatively expanded chain conformation of the STM8 fractions were considered to be significant to their antiviral activity.
authors.affiliation: Department of Chemistry, Wuhan University, Wuhan 430072, China.
authors.forename: Mei
authors.initials: M
authors.lastname: Zhang
authors.forename: Lina
authors.initials: L
authors.lastname: Zhang
authors.forename: Yifeng
authors.initials: Y
authors.lastname: Wang
authors.forename: Peter Chi Keung
authors.initials: PC
authors.lastname: Cheung
mesh_terms: D000465:Algorithms; D002236:Carbohydrate Conformation; D002850:Chromatography, Gel; D005936:Glucans / Q000737:chemistry*; D008027:Light; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D020076:Pleurotus / Q000737:chemistry* / Q000502:physiology; D012542:Scattering, Radiation; D013055:Spectrophotometry, Infrared; D013451:Sulfonic Acids / Q000737:chemistry; D013455:Sulfur / Q000032:analysis; D014783:Viscosity; D047071:beta-Glucans
chemical_list: D005936:Glucans; D013451:Sulfonic Acids; D047071:beta-Glucans; C013880:chlorosulfonic acid; D013455:Sulfur; C033363:beta-1,3-glucan