Abstract
The ongoing pandemic of COVID-19, caused by SARS-CoV-2, has substantially increased the risk to global public health. Multiple vaccines and neutralizing antibodies (nAbs) have been authorized for preventing and treating SARS-CoV-2 infection. However, the emergence and spread of the viral variants may limit the effectiveness of these vaccines and antibodies. Fusion inhibitors targeting the HR1 domain of the viral S protein have been shown to broadly inhibit SARS-CoV-2 and its variants. In theory, peptide inhibitors targeting the HR2 domain of the S protein should also be able to inhibit viral infection. However, previously reported HR1-derived peptide inhibitors targeting the HR2 domain exhibit poor inhibitory activities. Here, we engineered a novel HR1 trimer (HR1MFd) by conjugating the trimerization motif foldon to the C terminus of the HR1-derived peptide. HR1MFd showed significantly improved inhibitory activity against SARS-CoV-2, SARS-CoV-2 variants of concern (VOCs), SARS-CoV, and MERS-CoV. Mechanistically, HR1MFd possesses markedly increased α-helicity, thermostability, higher HR2 domain binding affinity, and better inhibition of S protein-mediated cell-cell fusion compared to the HR1 peptide. Therefore, HR1MFd lays the foundation to develop HR1-based fusion inhibitors against SARS-CoV-2. IMPORTANCE Peptides derived from the SARS-CoV-2 HR1 region are generally poor inhibitors. Here, we constructed a trimeric peptide HR1MFd by fusing the trimerization motif foldon to the C terminus of the HR1 peptide. HR1MFd was highly effective in blocking transductions by SARS-CoV-2, SARS-CoV-2 variants, SARS-CoV, and MERS-CoV pseudoviruses. In comparison with HR1M, HR1MFd adopted a much higher helical conformation, better thermostability, increased affinity to the viral HR2 domain, and better inhibition of S protein-mediated cell-cell fusion. Overall, HR1MFd provides the information to develop effective HR1-derived peptides as fusion inhibitors against SARS-CoV-2 and its variants.
Keywords: HR1; SARS-CoV-2; foldon; fusion inhibitor; trimer.
【저자키워드】 SARS-CoV-2, fusion inhibitor, HR1, foldon, trimer., 【초록키워드】 neutralizing antibody, antibodies, viral infection, Vaccine, S protein, Neutralizing antibodies, SARS-CoV, SARS-COV-2 infection, SARS-CoV-2 variant, peptide, MERS, MERS-CoV, inhibitors, variants, binding affinity, Spread, SARS-CoV-2 variants, VOCs, Effectiveness, peptides, Viral variants, cell-cell fusion, inhibitor, information, fusion, viral variant, affinity, Peptide Inhibitors, pseudoviruses, global public health, NAbs, domain, activities, foundation, trimer, inhibitory activity, viral S protein, theory, Multiple, motif, HR1 domain, pandemic of COVID-19, inhibitory, C terminus, effective, limit, Peptide inhibitor, MERS-CoV pseudoviruses, trimeric, shown, develop, caused, significantly, reported, inhibit, provide, adopted, the S protein, much higher, fusing, increased the risk, inhibit SARS-CoV-2, the SARS-CoV-2, treating SARS-CoV-2 infection, 【제목키워드】 activity, novel, potency, Improved,