Polymorphism in crystalline (1→3)-α- d-glucan from fungal cell-walls

• Published in: Carbohydrate research 1979, Vol.71 (1), p.51-64
• Main Authors: Jelsma, Jaap, Kreger, Dirk R.
• Format: Article
• Language: English
• ISSN: 0008-6215; 1873-426X
• DOI: 10.1016/S0008-6215(00)86060-7

The crystallization of (1→3)-α- d-glucan of four fungal species, Laetiporus sulphureus, Piptoporus betulinus, Schizophyllum commune, and Aspergillus nidulans, has been investigated by X-ray diffraction. The glucan crystallized as three polymorphs (I–III). Polymorph I was observed only in native tissue of L. sulphureus and P. betulinus. Polymorph II appeared on precipitation from alkaline solution, and III arose after drying. In native tissues, a complete change of the glucan into polymorph III occurred after moderate drying (at 60°), but in precipitates only after preceding severe drying (at 95° in vacuo). Polymorph III changed reversibly into II upon hydration. With L. sulphureus, there were small but significant differences between the X-ray patterns of polymorph I, which depended on the tissue investigated (trama or context). Precipitation of the native polymorph (I) was observed in one instance, but could not be reproduced. Improved X-ray patterns of the three polymorphs were obtained after treatment of samples with hot, dilute HCl. This treatment led to a change from polymorph I into II in powdered but not in unimpaired native tissues.