Fig 1.

S. pneumoniae type 2 capsular polysaccharide repeat unit structure and Wzy-dependent pathway. (Top) Repeat unit structure. Letters below each glycosidic linkage represent the glycosyltransferase known or predicted to catalyze the linkage. (Bottom) Wzy-dependent model for synthesis of the type 2 repeat unit. The number of repeat units (n) is estimated to be 1,000 to 2,000, based on the molecular size of isolated polymer used in vaccine preparations (23). Figure adapted from references 25 and 55).