FIG. 1.

(A) Structure of the repeating unit of the type 8 pneumococcal capsular polysaccharide (21). The corresponding structure of the type 3 capsule (41) is shown for comparison. (B) Genetic organization of the S. pneumoniae 6028/95 strain containing the cap8 genes. The capsular gene clusters of types 1 (38), 2 (20), 3 (4), and 33F (30) are compared with type 8 in the text and are also included here. Small arrows correspond to interrupted genes. White and dashed arrows indicate capsular genes and putative insertion sequence elements, respectively. Capsular genes showing more than 90% identical nucleotides in comparisons of sequences of different serotypes are represented by identical shading. The locations of promoters () and putative transcription terminators (☻) are indicated.