Virus particle dynamics derived from CryoEM studies

• CryoEM captures the dynamic character of the sample at the moment of freezing.
• A maximum likelihood algorithm determines the continuous variability of the sample.
• The algorithm is explained and a practical application to virus particle maturation provided.

The direct electron detector has revolutionized electron cryo-microscopy (CryoEM). Icosahedral virus structures are routinely produced at 4 Å resolution or better and the approach has largely displaced virus crystallography, as it requires less material, less purity and often produces a structure more rapidly. Largely ignored in this new era of CryoEM is the dynamic information in the data sets that was not available in X-ray structures. Here we review an approach that captures the dynamic character of viruses displayed in the CryoEM ensemble of particles at the moment of freezing. We illustrate the approach with a simple model, briefly describe the details and provide a practical application to virus particle maturation.