Structure and conformation of acetan polysaccharide

• Published in: International journal of biological macromolecules Vol. 19; no. 3; pp. 149 - 156
• Main Authors: Ojinnaka, C., Jay, A.J., Colquhoun, I.J., Brownsey, G.J., Morris, E.R., Morris, V.J.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.10.1996
• Subjects: A. xylinium polysaccharide; Acetan; Acetylation; Binding Sites; Calorimetry, Differential Scanning; Carbohydrate Conformation; Carbohydrate Sequence; Circular Dichroism; DSC; Magnetic Resonance Spectroscopy; Models, Molecular; Molecular Sequence Data; NMR; Optical Rotation; Polysaccharides, Bacterial - chemistry; Polysaccharides, Bacterial - metabolism; Structure; NMR; Acetan; A. xylinium polysaccharide; DSC; Optical rotation; Structure; Circular dichroism
• ISSN: 0141-8130; 1879-0003
• DOI: 10.1016/0141-8130(96)01120-8

Acetan is an anionic bacterial polysaccharide. The chemical repeat unit consists of a cellobiose unit solubilished 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.