One of the main limitations of the single-particle technique in cryo-EM is the attainable resolution.
We are collaborating with Stephen Harrison (HHMI, Harvard Medical School) to use virus particles as test specimens to develop better single particle image-processing methods. Virus particles have a high degree of symmetry and are stable in an aqueous solution, making them ideal for EM imaging.
We have used rotavirus particles to determine a structure of several of the capsid proteins to a resolution of 3.8 Å (Figure) . Rotavirus is also a good particle for the development and testing of new image processing methods .
Furthermore, we use helical viruses, such as TMV , to test new algorithms for helical particle processing.