Crystallization and preliminary X-ray diffraction analysis of recombinant hepatitis E virus-like particle

Area of Science:

• Virology
• Structural Biology
• Vaccine Development

Background:

• Hepatitis E virus (HEV) is a leading cause of enterically transmitted hepatitis globally.
• Current therapeutic and prophylactic options for HEV infection are limited.
• The HEV major structural protein is encoded by open reading frame 2 (ORF2).

Purpose of the Study:

• To develop a potential oral vaccine against Hepatitis E virus.
• To characterize virus-like particles (VLPs) engineered for vaccine potential.

Main Methods:

• Protein engineering of a fusion construct combining partial ORF3 and ORF2 proteins.
• Production and purification of virus-like particles.
• X-ray crystallography for structural determination of the VLPs.

Main Results:

• Successfully produced VLPs from a fusion protein (partial ORF3 residues 70-123 fused to ORF2 residues 112-608).
• Obtained single crystals of the VLPs.
• Determined crystal structure belonging to space group P2(1)2(1)2(1) with unit-cell parameters a=337, b=343, c=346 Å.
• Resolved the structure to 8.3 Å resolution, with one particle per asymmetric unit.

Conclusions:

• The engineered VLPs represent a promising platform for an oral HEV vaccine.
• Structural insights into the VLP composition are crucial for vaccine design.
• Further studies are warranted to assess the immunogenicity and efficacy of this VLP-based vaccine candidate.