a–j, Electrostatic-potential surface maps of eE2(ΔHVR1) in complex (a, b), tCD81-LEL–eE2(ΔHVR1) complex (c, d), tCD81-LEL in complex (e, f) and free form (g, h), and full-length eE2 free form (i, j). The surfaces are coloured by electrostatic potential corresponding to +5 kcal/(mol·e) (blue) and −5 kcal/(mol·e) (red) at 298 K calculated at pH 7.5 (a, c, e, g, i) and 5.0 (b, d, f, h, j) as labelled. Panels a, b, i, and j are depicted in the same orientation; panels e–h are depicted in the same orientation. a, b, tCD81-LEL is shown as a transparent, blue ribbon diagram. e, f, The eE2(ΔHVR1)-binding surface is outlined with a dotted line.