Comparison of Structure and Dynamics of ORF8 Binding with Different Protein Partners Through Simulation Studies

ORF8 is the second most mutated protein in SARS-CoV-2. It can form oligomers such as trimers and can bind to the IL-17RA/RC receptor. To understand the possible role of ORF8 in SARS-CoV-2, the first step of this study involved predicting the ORF8 trimer structure and the complex structure of the ORF8 monomer bound to the IL-17RA receptor using docking and molecular dynamics simulation methods. It was found that ORF8 molecules bound to the central ORF8 molecule through covalent and noncovalent interactions exhibit similar RMSD and RMSF values as the central ORF8 molecule and form a similar buried surface area, but display different numbers of hydrogen bonds and varying dynamic correlations. Additionally, trimer formation increases the dynamic correlation of the noncovalently bound ORF8 unit. ORF8 can bind with the IL-17RA receptor stably. Regions on ORF8, including C25–I47, L60–S67, T80–C90, and S103–E110, and regions on IL-17RA, including L1–H63 and D122–M165, are involved in the binding interface of the complex. ORF8 becomes less rigid when bound to IL-17RA than in its monomer, dimer, and trimer forms. Based on dihedral angle correlation predictions, binding of ORF8 to IL-17RA reduces internal correlations within ORF8 while strengthening correlations within IL-17RA. The G50–T80 region of ORF8 appears to be critical for interaction with IL-17RA, and the L1–V150 region of IL-17RA should be critical for its dynamics once bound to ORF8. These results help elucidate the structure and dynamics of ORF8 in SARS-CoV-2.