A pan-coronavirus fusion inhibitor targeting the HR1 domain of human coronavirus spike

Xia, Shuai; Yan, Lei; Xu, Wei; Agrawal, Anurodh Shankar; Algaissi, Abdullah; Tseng, Chien-Te K.; Wang, Qian; Du, Lanying; Tan, Wenjie; Wilson, Ian A.; Jiang, Shibo; Yang, Bei; Lu, Lu

SL-CoVs, including WIV1, Rs3367, and SHC014 CoVs, all manifest potential for human infection (9) (10) (11) . To further assess the breadth of fusion inhibitory activity, as demonstrated by EK1, we established cell-cell fusion assays mediated by the S protein of these SL-CoVs ( fig. S2) . Notably, many studies have suggested diversity in the receptor-binding motif (RBM) of SL-CoV's RBD (9-11), which plays an important role in binding the cellular receptor and serves as an effective target site for the development of CoV-specific antibodies or vaccines (32) . Specifically, the RBM of SHC014 CoV has only 80% similarity and 64% identity to that of SARS-CoV, and an antibody targeting the SARS-CoV RBD could not prevent infection mediated by the SHC014 S protein (9) (10) (11) 17) . In contrast, the HR1 and HR2 sequences of SL-CoV are 100% identical to those of SARS-CoV ( fig. S2B ). Correspondingly, EK1 exhibited greater inhibitory activity than the autologous peptide SARS-HR2P against cell-cell fusion mediated by the S protein of the three SL-CoVs tested (Fig. 2 , F to H), while an EK1-scrambled peptide showed no inhibitory activity on cell-cell fusion mediated by any of these CoV S proteins (Fig. 2, A to H) .