Electrostatic surface potential maps for SVHP, SVHP L38K, and VHP. (a) Ribbon diagram of villin headpiece (1YU5) with key F-actin-binding residues depicted and labeled, drawn in the same orientation as b-d. Solvent accessible surface maps of (b) villin headpiece (1YU5), (c) the minimized average structure of supervillin headpiece, and (d) model of the L38K mutant of supervillin headpiece produced with Modeller 9v1 (Sali and Blundell, 1993) and colored by electrostatic potential from red (−0.3) though white (0.0) to blue (0.3).