capsular polysaccharide
capsular polysaccharide
A polysaccharide capsule that is found on the cell surface of a broad range of bacterial species and often involved in mediating direct interactions between the bacteria and its environment. Due to these interactions, capsular polysaccharides have been implicated as important virulence factors for many bacterial pathogens. The molecules are highly hydrated and composed of repeating single monosaccharide units which are joined together by glycosidic linkages. They can be homo- or heteropolymers and can be substituted  with organic molecules such as acetyl groups, or or inorganic molecules such as phosphate.