Characterisation of heterogeneous arabinoxylans by direct imaging of individual molecules by atomic force microscopy.
Carbohydr Res
; 338(8): 771-80, 2003 Apr 04.
Article
em En
| MEDLINE
| ID: mdl-12668097
ABSTRACT
Atomic force microscopy has been used to characterise populations of extracted water-soluble wheat endosperm arabinoxylans. The adsorbed molecules are extended structures with an estimated Kuhn statistical segment length of 128 nm, suggesting that they adopt an ordered helical structure. However, estimates of the molecular weight distribution, coupled with size exclusion data, suggest that, in solution, the polysaccharides behave as semi-flexible coils, with a Kuhn length of 16 nm. These data imply that adsorption of the arabinoxylan structures onto mica promotes formation of the helical structure. Adoption of this ordered structure is fortunate because it has permitted characterisation of branching observed in a small proportion (approximately 15%) of the population of otherwise linear molecules. The degree of branching has been found to increase with the contour length of the molecules. Degradation of the polysaccharides with xylanase has been used to confirm that both the backbone and branches are based on beta-(1-->4) linked D-xylopyranosyl residues.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Xilanos
Idioma:
En
Revista:
Carbohydr Res
Ano de publicação:
2003
Tipo de documento:
Article
País de afiliação:
Reino Unido