Impact of DNA on interactions between core proteins of Hepatitis B virus-like particles comprising different C-terminals.

Hepatitis B virus (HBV) virus-like particles (VLPs) are promising therapeutic agents derived from HBV core proteins (Cp). This study investigates the assembly dynamics of HBV VLPs, which is crucial for their potential as drug carriers or gene delivery systems. Coarse-grained molecular dynamics simulations explore the impact of C-terminal domain length (in the Cp ranging from Cp149 to wild-type Cp183) on Cp assembly and stability, particularly in the presence of DNA. Our findings reveal that the C-terminal nucleic acid binding region significantly influences Cp assembly and stability of trimers comprising Cp dimers. Shorter C-terminal domains (Cp164, Cp167) enhance stability and protein-protein interactions, while interactions between naturally occurring Cp183 are destabilized in the absence of DNA. Interestingly, DNA addition further stabilizes Cp assemblies, and this effect is influenced by the length of the nucleic acid binding region. Shorter C-terminal domains show less dependency on DNA content. This stabilization is attributed to electrostatic forces between positively charged C-terminal chains and negatively charged nucleic acids. Our study sheds light on the molecular mechanisms governing protein-protein and protein-DNA interactions in HBV VLP assembly, providing insights into Cp processability and informing the development of efficient gene therapy carriers using VLP technology.