Structural Dynamics of SARS-CoV-2 Spike Protein Variants

The spike glycoprotein of SARS-CoV-2 undergoes intricate conformational changes that govern receptor engagement, immune recognition and membrane fusion. Variants of concern (VOCs) harbour amino acid substitutions that shift the equilibrium between closed, receptor-inaccessible states and open, receptor-binding states. These dynamic alterations modulate binding to the human ACE2 receptor and affect exposure of neutralising epitopes. Advanced techniques—such as cryogenic electron microscopy, hydrogen–deuterium exchange mass spectrometry and molecular dynamics simulations—have revealed how subdomains within the receptor-binding domain (RBD) and the N-terminal domain (NTD) coordinate transitions between conformations, while glycan shields and hinge regions impart flexibility. Understanding the structural dynamics of emerging variants informs vaccine antigen design and the development of fusion inhibitors, underpins surveillance of immune escape and guides therapeutic strategies against current and future coronavirus threats.

Research from Nature Portfolio

Recent studies have employed hydrogen–deuterium exchange mass spectrometry to map conformational shifts in spike variants, linking specific mutations to altered dynamics of the RBD-associated subdomain and NTD. Alpha, Beta and Delta spikes preferentially sample open conformations, and ACE2 binding further increases flexibility in core helices to prime the fusion machinery. In contrast, the Omicron spike tends towards a predominantly closed state, reducing antibody accessibility; yet its core helices display pre-primed characteristics for membrane fusion even without receptor engagement. These insights elucidate evolutionary trajectories that balance immune evasion with fusion competence.

Structural Dynamics of SARS-CoV-2 Spike Protein Variants publication trend

The graph below shows the total number of articles in structural dynamics of sars-cov-2 spike protein variants across all publications each year (not limited to Nature Index journals).

Technical terms

Conformational dynamics: The ensemble of structural states that a protein adopts and the rates at which it transitions between them.

Receptor-binding domain (RBD): The region of the spike responsible for direct interaction with the ACE2 receptor on host cells.

N-terminal domain (NTD): A subunit of the spike that contributes to antigenic variability and can influence overall spike flexibility.

Prefusion conformation: The metastable state of the spike before it refolds to trigger membrane fusion.

Hydrogen–deuterium exchange mass spectrometry (HDX-MS): A technique measuring hydrogen exchange rates to infer protein flexibility and solvent accessibility.

Lipid bilayer: A two-layered membrane model composed of lipid molecules, used to mimic the viral or host cell membrane environment.

References

1. Structural dynamics in the evolution of SARS-CoV-2 spike glycoprotein. Nature Communications (2023).
2. Bottom-up Assembled Synthetic SARS-CoV‑2 Miniviruses Reveal Lipid Membrane Affinity of Omicron Variant Spike Glycoprotein. ACS Nano (2023).
3. In Silico Discovery of Small Molecule Modulators Targeting the Achilles’ Heel of SARS-CoV‑2 Spike Protein. ACS Central Science (2023).
4. Effect of natural mutations of SARS-CoV-2 on spike structure, conformation, and antigenicity. Science (2021).