Millisecond dynamic of SARS-CoV-2 spike and its interaction with ACE2 receptor and small extracellular vesicles

J Extracell Vesicles. 2021 Dec;10(14):e12170. doi: 10.1002/jev2.12170.


SARS-CoV-2 spike protein (S) binds to human angiotensin-converting enzyme 2 (hACE2), allowing virus to dock on cell membrane follow by viral entry. Here, we use high-speed atomic force microscopy (HS-AFM) for real-time visualization of S, and its interaction with hACE2 and small extracellular vesicles (sEVs). Results show conformational heterogeneity of S, flexibility of S stalk and receptor-binding domain (RBD), and pH/temperature-induced conformational change of S. S in an S-ACE2 complex appears as an all-RBD up conformation. The complex acquires a distinct topology upon acidification. S and S2 subunit demonstrate different membrane docking mechanisms on sEVs. S-hACE2 interaction facilitates S to dock on sEVs, implying the feasibility of ACE2-expressing sEVs for viral neutralization. In contrary, S2 subunit docks on lipid layer and enters sEV using its fusion peptide, mimicking the viral entry scenario. Altogether, our study provides a platform that is suitable for real-time visualization of various entry inhibitors, neutralizing antibodies, and sEV-based decoy in blocking viral entry. Teaser: Comprehensive observation of SARS-CoV-2 spike and its interaction with receptor ACE2 and sEV-based decoy in real time using HS-AFM.

Keywords: ACE2; EV; High-speed AFM; SARS-CoV-2 spike; exosomes.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Angiotensin-Converting Enzyme 2 / chemistry
  • Angiotensin-Converting Enzyme 2 / metabolism*
  • Extracellular Vesicles / metabolism*
  • Humans
  • Hydrogen-Ion Concentration
  • Lipid Bilayers / metabolism
  • Microscopy, Atomic Force
  • Protein Binding
  • Protein Conformation
  • Protein Domains
  • Protein Subunits
  • SARS-CoV-2 / drug effects
  • SARS-CoV-2 / physiology
  • Spike Glycoprotein, Coronavirus / chemistry
  • Spike Glycoprotein, Coronavirus / metabolism*
  • Temperature
  • Virus Internalization


  • Lipid Bilayers
  • Protein Subunits
  • Spike Glycoprotein, Coronavirus
  • spike protein, SARS-CoV-2
  • ACE2 protein, human
  • Angiotensin-Converting Enzyme 2