Spike protein conformations! Prefusion and postfusion.
Proteins have the ability to change shape in response to the environment or interactions with other proteins. The spike protein is no different.
🔸The vast majority of spike proteins found in the SARS-CoV-2 membrane prior to infecting a cell are in the PREFUSION conformation. It is therefore advantageous to have the spike protein produced (or delivered) by a vaccine to be in this conformation.
🔸The POSTFUSION conformation is most frequently adopted after the virus has interacted with the cell ACE2 receptor. This makes the postfusion conformation less ideal for the spike protein produced (or delivered) by a vaccine.
There are two current engineering strategies that shift the spike protein conformation toward prefusion (double proline stabilization and furin cleavage site mutation) and several of the COVID-19 vaccines adopted one or both of these strategies! The table below the figure indicates details.
*post edited from 21Jun21 morning to adjust wording around postfusion conformation.
Posted on Instagram on June 21, 2021.