Fig. 3

Comparison of USUV-E structure with other reported crystal and cryo-EM pre-fusion flaviviral E-structures. a Superimposition of the crystal E-structures. The pre-fusion E-structures selected for comparison include those from DENV2 (PDB code: 1tg8, 1oan, 1oke, 4ut6, 4ut9, 4uta, 4utb, and 4utc), DENV3 (PDB code: 1uzg), DENV4 (PDB code: 3uaj), WNV (PDB code: 2hg0), JEV (PDB code: 3p54, 5mv1, 5mv2), TBEV (PDB code: 1svb), and ZIKV (PDB code: 5gzn, 5gzo, 5jhl, 5jhm, 5lbs, 5lbv, 5n0a, and 5n09). The USUV-E structure is colored red for DI, yellow for DII, and blue for DIII, respectively, and the rest E-structures are colored grey. The right panel is yielded by rotation of the structure for about 90° around a vertical axis. Clearly shown is that while the DI and DIII domains could be well aligned, DII connects to DI in a more extended manner in USUV-E, resulting in an obviously enlarged inter-domain angle. b A quantitative comparison of the DI-DII domain-angle variations characterized in panel a. For each structure, its DI-DII domain-angle was compared to those of other structures, and the angle-difference was calculated for each structure pairs and then plotted as black dots. The angle-difference of USUV-E (relative to other flaviviral E proteins) was marked with red triangle. The mean values was represented with horizontal green lines. c Superimposition of our structure with representative cryo-EM pre-fusion E-structures including those from JEV (PDB code: 5ywo, 5wsn), ZIKV (PDB code: 6co8), and DENV-2 (PDB code: 3J27). The molecules are oriented and colored the same as in panel a