Fig. 1. The D614G mutation is associated with enhanced infectivity.
a Cryo-EM structure of S1 (gray) and S2 (orange) heterodimer (PBD entry 6VXX). Residues 581-676, a C-terminal region of the S1 domain involved in S2 interaction, are shown in green. The black square area is magnified on the right. Residues within 5.5 Å of D614 are shown in a ball-and-stick representation. Aspartic acid 614 is shown in bright green. b A representation of the SARS-CoV-2 S protein (top) and D/G variation at residue 614 presented in logo plots at different time points between January 1st and May 30th, 2020 (bottom). c–e Mock- and hACE2-293T cells (c, d) or the same cells transfected to express hTMPRSS2 (e) were infected with the indicated PV. See Supplementary Figs. 1a–c and 2 for PV yields, TMPRSS2 expression in transfected HEK293T cells, and the sequences for various FKO mutations, respectively. f NCI-H1975 cells transduced to express hACE2 were infected with PVs. See Supplementary Fig. 3a for PV yields. The S proteins used in c–f have the FLAG tag at C-terminus. Mean values ± SEM of n = 5 (d), n = 3 (e), or n = 4 (f). Experiments conducted using two or three biologically independent PV batches are shown. The p values by two-way ANOVA (analysis of variance) with Sidak multiple comparisons test are indicated (d, e, f). NTD N-terminal domain, RBD receptor-binding domain, FP fusion peptide, HR1 and HR2 heptad-repeat regions 1 and 2, respectively, TM transmembrane region, CT cytoplasmic tail, GFP green fluorescent protein, FKO furin-cleavage knockout mutant, PV pseudovirus, M.F.I. mean fluorescence intensity.