𝔖 Bobbio Scriptorium
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Structure of β,D(1–>4′)-xylan hydrate

✍ Scribed by I. A. Nieduszynski; R. H. Marchessault

Publisher
Wiley (John Wiley & Sons)
Year
1972
Tongue
English
Weight
508 KB
Volume
11
Category
Article
ISSN
0006-3525

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✦ Synopsis

A structure is proposed for xylan hydrate as a result of investigations by x-ray fiber diffraction and computer-aided chain-packing methods. The unit-cell dimensions are a = b = 9.16 A, c (fiber axis) = 14.85 A, y = 120" and the proposed anti-parallel chain arrangement corresponds to a space group symmetry of P3221. Left-handed threefold screw helices are stabilized in this conformation by their interaction with chains of water molecules, so that a satisfactory hydrogen-bonding scheme is achieved. The proposed structure provides an explanation of the changes in the x-ray diagram with relative humidity and yields a very good structure factors agreement. An x-ray fiber diagram corresponding to a higher hydrate (xylan dihydrate) is presented. Comments are made on the possible role of xylan in nature and in technological processes.

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