C Cryo-EM reconstructions of the Spike⋅Re5D06 complex (Appendix Table S2). SARS-CoV-2 Spike (Hsieh et al., 2020) was incubated with an excess of Re5D06, purified by size exclusion chromatography and vitrified immediately for structural characterization by cryo-EM (Appendix Fig S8). The two conformational classes detected were refined to high resolution (2.8 Å global). The sharpened maps are shown at low contour levels. The protomers of the homotrimeric Spike are shown in white, tan or gray, respectively, and are further color-coded as indicated. See Appendix Fig S8-12 for details and more information. 