The recent outbreak of coronavirus disease (COVID-19) caused by SARS-CoV-2 infection in Wuhan, China has posed a serious threat to global public health. To develop specific anti-coronavirus therapeutics and prophylactics, the molecular mechanism that underlies viral infection must first be defined. Therefore, we herein established a SARS-CoV-2 spike (S) protein-mediated cell–cell fusion assay and found that SARS-CoV-2 showed a superior plasma membrane fusion capacity compared to that of SARS-CoV. We solved the X-ray crystal structure of six-helical bundle (6-HB) core of the HR1 and HR2 domains in the SARS-CoV-2 S protein S2 subunit, revealing that several mutated amino acid residues in the HR1 domain may be associated with enhanced interactions with the HR2 domain. We previously developed a pan-coronavirus fusion inhibitor, EK1, which targeted the HR1 domain and could inhibit infection by divergent human coronaviruses tested, including SARS-CoV and MERS-CoV. Here we generated a series of lipopeptides derived from EK1 and found that EK1C4 was the most potent fusion inhibitor against SARS-CoV-2 S protein-mediated membrane fusion and pseudovirus infection with IC50s of 1.3 and 15.8 nM, about 241- and 149-fold more potent than the original EK1 peptide, respectively. EK1C4 was also highly effective against membrane fusion and infection of other human coronavirus pseudoviruses tested, including SARS-CoV and MERS-CoV, as well as SARSr-CoVs, and potently inhibited the replication of 5 live human coronaviruses examined, including SARS-CoV-2. Intranasal application of EK1C4 before or after challenge with HCoV-OC43 protected mice from infection, suggesting that EK1C4 could be used for prevention and treatment of infection by the currently circulating SARS-CoV-2 and other emerging SARSr-CoVs.
【저자키워드】 electron microscopy, membrane fusion, 【초록키워드】 COVID-19, Treatment, coronavirus disease, SARS-CoV-2, viral infection, coronavirus, S protein, SARS-CoV, SARS-COV-2 infection, Infection, HCoV-OC43, peptide, molecular mechanism, MERS-CoV, IC50, Replication, X-ray, outbreak, mice, inhibitor, S2 subunit, SARS-CoV-2 spike, Interaction, global public health, domain, circulating, plasma membrane, SARS-CoV-2 S, pseudovirus infection, HR1 domain, SARSr-CoVs, amino acid residue, effective, Wuhan, China, human coronavirus, defined, tested, develop, examined, caused, inhibit, inhibited, mutated, pseudovirus, the SARS-CoV-2, 【제목키워드】 SARS-CoV-2, inhibition, Spike protein, inhibitor,