Extended Data Fig. 7: Molecular basis of NTD-mediated coronavirus entry.
a-c, Package efficiency of PSVs carrying indicated sarbecoviruses spike glycoproteins (a) and the indicated mutants (b, c). Western blot was conducted by detecting the conserved S2P6 epitope. VSV-M serves as a loading control. Blots representative of two independent transfection assays for pseudovirus production. d, Structures of SARS-CoV-2 BA.4/5 spike trimer without antibody binding (left), or in complex with S2L20 (right). Dashed boxes highlighted the N370-glycan spatially proximate to the S2L20. e, Heatmap showing the inhibitory efficacy of indicated SARS-CoV-2 neutralizing antibodies against PSV entry in HEK293T-hACE2 or HEK293T-S2L20, with BSA as a control. Data are representative results of two independent neutralization assays and plotted by the mean (n = 3 wells of independently infected cells). f, Structures of SARS-CoV-2 BA.2 spike trimers with (upper) or without (lower) the binding of NTD-targeting 4A8, along with the side-view (top) and top-view (bottom) cryoEM structures of SARS-CoV-2 Wuhan-Hu-1 spike trimers with the binding of NTD-targeting CV3-13 and DH1052. Orange: NTD; Green: CTD; Red: S2L20; Magenta: 4A8; Blue: CV3-13; Pink: DH1052. g, CryoEM data processing workflow and validation of the S2L20-bound SARS-CoV-2 S CryoEM structure. h, Negative stain microscopy of prefusion SARS-CoV-2 S-glycoprotein (without stabilizing proline substitutions) incubated without antibody, or with S2H14, S2X28, or S2L20 as indicated. S2H14 is known to promote the transition to the postfusion state and was used as a control37. Scale bars: 10 nm. Data representative of images captured from two independent experiments with similar results. i, Top-view and side-view CryoEM structures depicting soluble mCEACAM1a (cyan) in complex with MHV spike trimer (gray). NTD and CTD of MHV S are indicated in orange and green, respectively.
