Structural Biology of Coronavirus Membrane Proteins

The structural biology of coronavirus membrane proteins encompasses the detailed characterisation of the spike (S), envelope (E) and membrane (M) proteins that together orchestrate virion assembly, host‐cell entry and pathogenesis. High-resolution techniques such as cryo-electron microscopy, nuclear magnetic resonance spectroscopy and X-ray crystallography have revealed that the trimeric S glycoprotein projects from the viral surface, mediating receptor binding and membrane fusion through a series of conformational rearrangements. The small E protein adopts an α-helical topology and oligomerises to form viroporin channels, contributing to virion budding, envelope curvature and host inflammatory responses. The abundant M protein, with three transmembrane helices and a luminal glycosylated domain, provides the architectural scaffold that determines particle shape and interacts with S and E during assembly. Together, these membrane proteins define the physical properties of the virion, modulate host-cell trafficking pathways and serve as targets for vaccine design and antiviral intervention.

Research from Nature Portfolio

Recent studies have elucidated how precise structural motifs within the S protein regulate its intracellular itinerary and incorporation into virions or virus-like particles. One report demonstrated that a single C-terminal residue beneath the transmembrane helix governs coatomer binding and dissociation, thus controlling S delivery from the cis-Golgi to the assembly compartment and dictating its fusogenic potential. Another investigation employed a proteomic screen of the S cytoplasmic tail to map interactions with COPI and COPII coat complexes, ERM actin regulators and an autophagy adaptor. It was shown that suboptimal retention signals permit S to escape early secretory compartments, accumulate at the cell surface and drive syncytium formation, linking trafficking signals to viral spread and pathogenesis.

Structural Biology of Coronavirus Membrane Proteins publication trend

The graph below shows the total number of articles in structural biology of coronavirus membrane proteins across all publications each year (not limited to Nature Index journals).

Technical terms

Transmembrane domain: A stretch of hydrophobic amino acids that spans the lipid bilayer, anchoring a protein within the membrane.

Viroporin: A class of small viral membrane proteins that oligomerise to form ion-conducting pores, altering host-cell ion homeostasis.

COPI/COPII: Coatomer protein complexes responsible for retrograde and anterograde transport between the endoplasmic reticulum and Golgi apparatus.

Virus-like particle (VLP): A non-infectious assembly of viral structural proteins that mimics the organisation of native virions, used to study protein incorporation and immunogenicity.

α-Helical bundle: A structural motif in which multiple α-helices assemble into a stable oligomeric complex, often forming the core of membrane channels.

References

1. A single C-terminal residue controls SARS-CoV-2 spike trafficking and incorporation into VLPs. Nature Communications (2023).
2. Sequences in the cytoplasmic tail of SARS-CoV-2 Spike facilitate expression at the cell surface and syncytia formation. Nature Communications (2021).
3. Structural model of the SARS coronavirus E channel in LMPG micelles. Biochimica et Biophysica Acta (BBA) - Biomembranes (2018).
4. Sars‐CoV‐2 Envelope and Membrane Proteins: Structural Differences Linked to Virus Characteristics?. BioMed Research International (2020).
5. SARS-CoV-2 envelope protein causes acute respiratory distress syndrome (ARDS)-like pathological damages and constitutes an antiviral target. Cell Research (2021).