FIG 1.

Schematic diagrams of PspA, PspC, and representative proline-rich domains. (A) Schematic diagram of serotype 3 strain WU2 PspA and serotype 4 strain TIGR4 PspC. Shown for PspA is the N-terminal α-helix region, composed of the α-helix domain (αHD) and clade defining region (CDR), the proline-rich domain (PRD), and C-terminal choline-binding domain (CBD) composed of multiple choline-binding repeats (CBR). The α-helix region of PspC is composed of the factor H binding region (FH bind), two R domains (R1 and R2), and the PRD. This is followed by the CBD. (B) Schematic diagrams of PRDs from group 1, 2, and 3. Groups 1 and 2 are composed of different proline-repeating sequences. Group 3 shares aspects of both group 1 and group 2 but is characterized by the presence of the nonproline block (NPB). The red arrow indicates the NPB.