Structure of β-chitin or parallel chain systems of poly-β-(1→4)-N-acetyl-D-glucosamine

✍ Scribed by J. Blackwell

• Publisher: Wiley (John Wiley & Sons)
• Year: 1969
• Tongue: English
• Weight: 988 KB
• Volume: 7
• Category: Article
• ISSN: 0006-3525
• DOI: 10.1002/bip.1969.360070302

✦ Synopsis

The structure of @-chitin has been reexamined in an x-ray diffraction study of the highly crystalline material available from pogonophore tubes. Oriented specimens were prepared by suspending the dispersed deproteinieed tube in a fibrin clot which was then stretched into an oriented fiber. The x-ray diffraction patterns of pogonophore @-chitin were explained by proposing that this material consists of a mixture of two structural phases which have been named 8-chitins A and B. This view was confirmed by the preparation of specimens which gave only the diffraction pattern of the A phase by treating the tubes with diaphanol. Both A and B phases gave rise to a series of hydrate structures. The lowest hydrate of @-chitin A has been studied in detail and shown to consist of an anhydrous system of parallel chitin chains. For this form, the unit cell was monoclinic with dimensions a = 4.85 A, b = 10.38 b (fiber axis), c = 9.26 A, and 8 = Y7.5", and space group Pdl. Reasonable agreement was obtained between the observed x-ray intensities and those calculated for such a structure. Examination of the @-chitin of Loligo pen and diatom spines showed that these materials also consist of these A and B phases.