Stabilized coronavirus spikes are resistant to conformational changes induced by receptor recognition or proteolysis.
Level 5 - mechanism / opinion, no new human data
In vitro structural biology (cryo-EM) study (mechanism/bench research).
PubMed 30356097 · doi:10.1038/s41598-018-34171-7
What was done
Researchers performed cryo-electron microscopy (cryo-EM) structural analyses of an engineered, stabilized trimeric SARS-CoV spike (S) glycoprotein that incorporates mutations preventing transition from the pre-fusion to post-fusion state. They assessed the structural impacts of trypsin cleavage at the S1/S2 junction and binding interactions with the ACE2 receptor.
What was found
Neither ACE2 receptor binding nor trypsin-mediated cleavage at the S1/S2 site induced large conformational changes within the stabilized SARS-CoV spike trimer. Furthermore, these events did not expose the secondary cleavage site (S2'). The abstract reports no quantitative structural resolution measurements or binding kinetics.
Why it matters
Understanding how stabilizing mutations lock coronavirus spike proteins in their pre-fusion conformation during receptor engagement and proteolysis provides foundational insights for coronavirus vaccine and antigen engineering.
Limits
The study is entirely in vitro, utilizing an engineered, stabilized protein construct rather than native wild-type virus dynamics in physiological tissue environments. The abstract provides no quantitative metrics, cryo-EM resolution values, or in vivo immunological outcomes.
Cited by
- supports Structural biologist Dr. Jason McLellan engineered two-proline mutations to lock viral surface proteins into the pre-fusion conformation initially for Respiratory Syncytial Virus (RSV) and subsequently for MERS-CoV.