The D614G mutation in the SARS-CoV-2 spike protein reduces S1 shedding and increases infectivity

ABSTRACT

SARS coronavirus 2 (SARS-CoV-2) isolates encoding a D614G mutation in the viral spike (S) protein predominate over time in locales where it is found, implying that this change enhances viral transmission. We therefore compared the functional properties of the S proteins with aspartic acid (S^D614) and glycine (S^G614) at residue 614. We observed that retroviruses pseudotyped with S^G614 infected ACE2-expressing cells markedly more efficiently than those with S^D614. This greater infectivity was correlated with less S1 shedding and greater incorporation of the S protein into the pseudovirion. Similar results were obtained using the virus-like particles produced with SARS-CoV-2 M, N, E, and S proteins. However, S^G614 did not bind ACE2 more efficiently than S^D614, and the pseudoviruses containing these S proteins were neutralized with comparable efficiencies by convalescent plasma. These results show S^G614 is more stable than S^D614, consistent with epidemiological data suggesting that viruses with S^G614 transmit more efficiently.