Miscellaneous (Black)
Substitution for aspartic acid by glycine at position 614 in the spike (S) protein of severe acute respiratory syndrome coronavirus 2 appears to facilitate rapid viral spread. The G614 strain and its recent variants are now the dominant circulating forms. In this article the authors report cryo-EM structures of a full-length G614 S trimer, which adopts three distinct prefusion conformations differing primarily by the position of one receptor- binding domain. A loop disordered in the D614 S trimer wedges between domains within a protomer in the G614 spike. This added interaction appears to prevent premature dissociation of the G614 trimer, effectively increasing the number of functional spikes and enhancing infectivity, and to modulate structural rearrangements for membrane fusion. These findings extend the understanding of viral entry and suggest an improved immunogen for vaccine development.
Zhang J, et al. Structural impact on SARS-CoV-2 spike protein by D614G substitution. Science. 2021 Mar 16:eabf2303. doi: 10.1126/science.abf2303
