Single-molecule imaging reveals allosteric stimulation of SARS-CoV-2 spike receptor binding domain by host sialic acid.
Marco A Díaz-SalinasAastha JainNatasha D DurhamJames B MunroPublished in: Science advances (2024)
Conformational dynamics of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike glycoprotein (S) mediate exposure of the binding site for the cellular receptor, angiotensin-converting enzyme 2 (ACE2). The N-terminal domain (NTD) of S binds terminal sialic acid (SA) moieties on the cell surface, but the functional role of this interaction in virus entry is unknown. Here, we report that NTD-SA interaction enhances both S-mediated virus attachment and ACE2 binding. Through single-molecule Förster resonance energy transfer imaging of individual S trimers, we demonstrate that SA binding to the NTD allosterically shifts the S conformational equilibrium, favoring enhanced exposure of the ACE2-binding site. Antibodies that target the NTD block SA binding, which contributes to their mechanism of neutralization. These findings inform on mechanisms of S activation at the cell surface.
Keyphrases
- single molecule
- cell surface
- energy transfer
- angiotensin converting enzyme
- sars cov
- respiratory syndrome coronavirus
- angiotensin ii
- quantum dots
- high resolution
- living cells
- binding protein
- atomic force microscopy
- coronavirus disease
- dna binding
- molecular dynamics
- small molecule
- molecular dynamics simulations
- fluorescence imaging
- transcription factor
- photodynamic therapy