Fig. 5. (A) Ribbon diagram of the lowest energy structure of R1B (3–51) (top), compared with another RNA-binding protein, S15 (24–71) (bottom). The conserved basic residues in both families are indicated. (B) Electrostatic surface potential of R1B [in front view, same orientation as in (A)] and S15 [slightly rotated compared with (A)], and 180° rotated view. Positive and negative charges are shown in blue and red, respectively. The figures were generated using GRASP (Nicholls et al., 1991).