Figure 1.
Presentation of different truncated versions of HEV pORF2. E2s (aa 459–606), the shortest version to form dimer, harbors the major neutralizing epitopes, and its crystal structure was determined with a high resolution of 2.0 Å. p239 (aa 368–606) is the vaccine antigen in Hecolin® in a particulate form.8,9 p495 (aa 112–608), which can form VLP with T = 1 icosahedral symmetry, is used in the other HEV vaccine which has been tested in a phase II clinical trial.17,91 p595 (aa 14–608) also can form a particle (T = 3) which is more similar to the native virions.15 The structure of T = 3 VLP was acquired by using the T = 1 VLP (PDB ID: 2ZTN) as a template to build the homology model with the spatial information of side chain because the reconstruction model from cryo-EM data of T = 3 VLP (PDB ID: 3IYO) only recorded the information of αC atoms. The peptide located at aa 368–459 is supposed to play a key role in inducing multimerization of p239.