FIG 5.

(a and b) Interacting regions of E1 and E2 observed in our model of the heterodimer are shown schematically (a) and illustrated on our model colored as shown in panel a (b). (c) Pairs of residues identified by interface alanine scanning as making significant energetic contributions to the E1/E2 binding free energy are illustrated on our model. E1 is shown in light gray, and E2 is in pale green. Predicted E1/E2 interface residues for which in silico mutation to Ala significantly affected E1/E2 binding free energy are colored on a scale according to increased prediction score from blue to red to yellow (highest binding free energy difference).