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Subnanometer-Resolution Structural Determination of Hemagglutinin from Cryo-Electron Tomography of Influenza Viruses
08:19

Subnanometer-Resolution Structural Determination of Hemagglutinin from Cryo-Electron Tomography of Influenza Viruses

Published on: November 7, 2025

Parainfluenza virus type 5 (PIV-5) morphology revealed by cryo-electron microscopy

Olivier Terrier1, Jean-Paul Rolland, Manuel Rosa-Calatrava

  • 1Université de Lyon, F-69000 Lyon, France. olivier.terrier@sante.univ-lyon1.fr

Virus Research
|February 3, 2009
PubMed

Insights

Cryo-electron microscopy (cryo-EM) offers a clearer view of parainfluenza type 5 (PIV-5) virion structure. This study reveals PIV-5 virions are mostly spherical, with less shape variation than previously thought.

Area of Science:

  • Virology
  • Microscopy
  • Structural Biology

Background:

  • Parainfluenza type 5 (PIV-5) virion morphology knowledge relies on conventional transmission electron microscopy (CTEM) of negatively stained samples.
  • CTEM may introduce artifacts, potentially affecting the perceived pleiomorphy of viral structures.

Purpose of the Study:

  • To investigate the ultrastructure of intact PIV-5 virions using cryo-electron microscopy (cryo-EM).
  • To provide a more accurate and detailed morphological description of PIV-5.

Main Methods:

  • Examination of frozen-hydrated intact PIV-5 virions.
  • Application of cryo-electron microscopy (cryo-EM) for high-resolution imaging.
  • Quantitative analysis of virion shape, phospholipid bilayer thickness, spike length, and glycoprotein spike density.

Main Results:

  • Cryo-EM revealed a higher proportion of spherical PIV-5 virions (70%) compared to CTEM observations.
  • Observed lower pleiomorphy in frozen-hydrated PIV-5 virions, suggesting CTEM may overestimate shape variability.
  • Quantified average phospholipid bilayer thickness, spike length, and determined approximately 2000 glycoprotein spikes per virion.

Conclusions:

  • Cryo-EM provides a more precise ultrastructural view of PIV-5 morphology.
  • The findings refine our understanding of PIV-5 virion structure, particularly its shape and surface protein organization.

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