Surface charge distribution of Vps25. (A) Surface potential representation of Vps25 with regions where electrostatic potential <-10 kBT are red, while those >+10 kBT are blue (kB, Boltzmann constant; T, absolute temperature). (B) Horizontal rotation (180°). Exposed residues are labeled for orientation. Note that one face of the molecule carries a mainly negative charge (A) while the other one carries a mainly positive charge (B).