A water-soluble glucan, namely, PD3, was isolated from the fruiting body of Dictyophora indusiata as the method reported previously. Its chemical structure was characterized by GC, FTIR, and 13C NMR. The results indicated that PD3 is a (1-3)-β-D-glucan, with (1-6)-β-glucopyranoside side branches. The chain conformation and morphology of PD3 in aqueous solution were investigated by viscometry, rheometer, and laser light scattering (LLS) measurements, atomic force microscopy (AFM), and transmission electron microscopy (TEM), respectively. The weight-average molecular mass (Mw), radius of gyration (Rg), hydrodynamic radius (Rh), and intrinsic viscosity ([η]) of PD3 in water were determined to be 5.1 x 10^5, 141 nm, 44 nm, and 1440 cm3 g-1, respectively, by LLS and viscometry. The structural parameter F (Rg/Rh) of PD3 was calculated to be 3.4, and the [η] dependence of CNaOH of PD3 is similar to that of triple helical polysaccharides Scleroglucan and Lentinan, suggesting that PD3 exists as a triple helical chain in water. This conclusion was further proved by rheological measurement and AFM observation. Interestingly, the [η] of PD3 dramatically decreased in a narrow range concentration of NaOH between 0.18 and 0.22 M, higher than that of Scleroglucan and Lentinan (both less than 0.1 M), indicating the helix-coil conformation ransition of PD3 is more difficult than that of Scleroglucan and Lentinan. Moreover, with the increase of concentration, PD3 trends to self-assemble to fibrous aggregates in aqueous solution as measured by TEM.

morphology, structure characterization, Chain conformation, (1-3)-β-D-glucan, Dictyophora indusiata

13C NMR data:
Linkage	Residue	C1	C2	C3	C4	C5	C6
3,3	bDGlcp	103.8	73.9	86.5	68.7	76.8	61.3
3,6	bDGlcp
3	bDGlcp	103.8	73.9	86.5	69.6	74.8	70.7
	bDGlcp	103.8	73.9	86.5	68.7	76.8	61.3


1H NMR data:
missing...

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@H]1[C@H](O)[C@@H](CO)O[C@@H](O[C@@H]2[C@@H](O)[C@H](O[C@@H]3[C@@H](O)[C@H]([*])O[C@H](CO)[C@H]3O)O[C@H](CO[C@@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@H]3O)[C@H]2O)[C@@H]1O

648.564 g/mol (C₂₄H₄₀R₂O₂₀, R = next and previous repeats, not counted in mol weight)

A water-soluble glucan, namely, PD3, was isolated from the fruiting body of Dictyophora indusiata as the method reported previously. Its chemical structure was characterized by GC, FTIR, and 13C NMR. The results indicated that PD3 is a (1-3)-β-D-glucan, with (1-6)-β-glucopyranoside side branches. The chain conformation and morphology of PD3 in aqueous solution were investigated by viscometry, rheometer, and laser light scattering (LLS) measurements, atomic force microscopy (AFM), and transmission electron microscopy (TEM), respectively. The weight-average molecular mass (Mw), radius of gyration (Rg), hydrodynamic radius (Rh), and intrinsic viscosity ([η]) of PD3 in water were determined to be 5.1 x 10^5, 141 nm, 44 nm, and 1440 cm3 g-1, respectively, by LLS and viscometry. The structural parameter F (Rg/Rh) of PD3 was calculated to be 3.4, and the [η] dependence of CNaOH of PD3 is similar to that of triple helical polysaccharides Scleroglucan and Lentinan, suggesting that PD3 exists as a triple helical chain in water. This conclusion was further proved by rheological measurement and AFM observation. Interestingly, the [η] of PD3 dramatically decreased in a narrow range concentration of NaOH between 0.18 and 0.22 M, higher than that of Scleroglucan and Lentinan (both less than 0.1 M), indicating the helix-coil conformation ransition of PD3 is more difficult than that of Scleroglucan and Lentinan. Moreover, with the increase of concentration, PD3 trends to self-assemble to fibrous aggregates in aqueous solution as measured by TEM.

morphology, structure characterization, Chain conformation, (1-3)-β-D-glucan, Dictyophora indusiata

There is only one chemically distinct structure:

SVGMWSMILES3D molIonize

 

[*]O[C@H]1[C@H](O)[C@@H](CO)O[C@@H](O[C@@H]2[C@@H](O)[C@H](O[C@@H]3[C@@H](O)[C@H](O[C@@H]4[C@@H](O)[C@H](O[C@@H]5[C@@H](O)[C@H]([*])O[C@H](CO)[C@H]5O)O[C@H](CO[C@@H]5O[C@H](CO)[C@@H](O)[C@H](O)[C@H]5O)[C@H]4O)O[C@H](CO)[C@H]3O)O[C@H](CO[C@@H]3O[C@H](CO)[C@@H](O)[C@H](O)[C@H]3O)[C@H]2O)[C@@H]1O

1134.987 g/mol (C₄₂H₇₀R₂O₃₅, R = next and previous repeats, not counted in mol weight)