In silico analyses of E2 structure and accessibility. (A) Secondary structure and solvent accessibility of the SAV3 E2 protein was estimated using the PredictProtein server and TMpred. Relative solvent accessibility is illustrated by black bars and predicted secondary structures are shown as red (sheet), green (loop) or blue (helix) lines. The predicted transmembrane helix is indicated. (B) Alignment of a partial SAV3 E2 sequence with a region of E2 from SINV and RRV previously suggested to be located on the protein surface. E2206 is indicated for SAV by red colour. E2200, E2216 and E2218 are indicated for RRV since they previously have been shown to be located on the very distal part of the spike .