Three-dimensional structure of guaran

The galactosyl side chains were inadvertently fixed in the improper beta-D configuration in a previously reported morphology of guaran [R. Chandraseka ran, A. Radha, and K. Okuyama, Carbohydr. Res. 306 (1998) 243-255]. This de fect has mow been rectified. In the correct alpha-D configuration, the 2-fo ld guaran helix is stabilized by periodic intramolecular hydrogen bonds bet ween the galactosyl side chains and the mannan main chain. Ordered water mo lecules are responsible for the formation and association of sheets of guar an helices in the crystalline lattice. The crystallographic R-value is 0.14 fbr the revised model. The guaran molecular structure and packing arrangem ent are readily amenable to the entire galactomannan family. (C) 1998 Elsev ier Science Ltd. All rights reserved.