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.
Department of Food Science and Technology, Cranfield University, Silsoe College, Bedford, UK.
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Ojinnaka
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Colquhoun
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Morris
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