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X‐Ray and stereochemical studies on xylan diacetate
Author(s) -
Gabbay S. M.,
Sundararajan P. R.,
Marchessault R. H.
Publication year - 1972
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1972.360110106
Subject(s) - chemistry , monoclinic crystal system , crystallography , fiber diffraction , intramolecular force , intermolecular force , fiber , xylan , stereochemistry , diffraction , x ray crystallography , crystal structure , molecule , organic chemistry , polysaccharide , optics , physics
By means of x‐ray fiber diffraction, it has been found that xylan diacetate crystallizes with two chains or four residues in a monoclinic cell (space group P 2 1 ): a = 7.64, b = 12.44, c (fiber axis) = 10.31 Å, and γ = 85°. Pairs of residues are related by a twofold screw axis in the c direction. Based on the observed fiber repeat and chain symmetry, the probable conformation of a pair of xylose diacetate residues joined via a β‐1,4′ linkage has been obtained by energy minimization methods. The conformations corresponding to a threefold screw axis and a twofold screw axis along the chain have been compared and the reason why xylan diacetate assumes a twofold screw axis seems to be due to intermolecular packing effects rather than intramolecular non‐bonded interactions.