Extended Data Fig. 2. Superior infectivity of G614 results from decreased S1 shedding and higher level of S protein in the virion.

a, A similar experiment as that shown in Fig. 2c but performed with an independently prepared PV batch. b, The same PVs used in the experiment shown in Fig. 2c were analyzed by SDS-PAGE and silver stain to avoid a potential bias caused by using the M2 antibody that recognizes N- and C-terminal Flag tags with different affinity. Although the S2 band is masked by an MLV-derived protein, the S1 band is clearly separated and much weaker in PV^D614 compared to that in PV^G614.