Figure 2.

3a Protein topology and sequence alignment among corona viruses (A) 3a protein topology. (B) Multiple sequence alignment of 3a protein from corona viruses. Secondary structures [alpha helices (coils) and beta strands (arrows)] observed in the EM structure by Kern et al. (41) are indicated. Transmembrane regions (gray), novel mutations in CoV-2 (red), TRAF-binding motif (blue), epitopes for natural antibodies against 3A (orange), cysteines involved in dimer formation (magenta), internalization signal (purple), ER trafficking motif (green) and caveolin binding motif (cyan) are shown. Triangles indicate mutations suggested to affect 3a ion channel activity; dots indicate potentially critical residues inferred from the new EM structure.