Structure and conformation of acetan polysaccharide.
Acetan is an anionic bacterial polysaccharide. The chemical repeat unit consists of a cellobiose unit solubilised by attachment of a charged pentasaccharide sidechain to one of the glucose residues. The repeat unit contains two sites of acetylation. 1H and 13C NMR studies, coupled with both basic-methylation and mild-methylation studies, have shown that acetylation occurs at C6 on the (1,2)D-Man and the (1,34)D-Glc residues. A variety of techniques including NMR, optical rotation, circular dichroism and DSC show evidence for a thermoreversible conformational order (helix)-disorder (coil) transition for acetan in aqueous solution. The studies suggest that acetylation of the backbone does not prevent helix formation.
Ojinnaka
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Department of Food Science and Technology, Cranfield University, Silsoe College, Bedford, UK.
Jay
A J
AJ
Colquhoun
I J
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Brownsey
G J
GJ
Morris
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Morris
V J
VJ
D000107:Acetylation; D001665:Binding Sites; D002152:Calorimetry, Differential Scanning; D002236:Carbohydrate Conformation; D002240:Carbohydrate Sequence; D002942:Circular Dichroism; D009682:Magnetic Resonance Spectroscopy; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009904:Optical Rotation; D011135:Polysaccharides, Bacterial / Q000737:chemistry* / Q000378:metabolism*
D011135:Polysaccharides, Bacterial; C068545:acetan