RESEARCH SUMMARY

The structural polymorphism observed in macromolecules and macromolecular assemblies is an intrinsic feature required for all fundamental processes in biology. The structure of viral capsids provides a paradigm in the analysis of non-equivalent interactions among identical subunits.

Structural polymorphism, together with the extensive use of symmetry, is an example of nature’s efficient use of limited coding capacity as viruses only need a few different proteins to build an infectious particle with a number of essential functions.

On the other hand, elucidation of virus structures at the highest possible resolution is required to understand their structure-function relationship, including those related to morphogenesis and antigenicity. To reveal the three-dimensional structure at subnanometer resolution of such complex assemblies we mostly use cryo-electron microscopy (cryo-EM) and image processing techniques.

We have been investigating several different complex viral systems: a number of double-stranded RNA viruses such as Infectious Bursal Disease virus (IBDV), Penicillium chrysogenum virus (PcV), and Helminthosporium victoriae 190S virus (Hv190SV), and virus-like particles of Rabbit hemorrhagic disease virus (RHDV).

Our studies, in combination with genetic, structure and sequence modeling, and biophysical analysis, intend to establish the molecular basis of the conformational flexibility to switch among quasi-equivalent conformational states and their functional implications, which can provide clues in new vaccine design and/or immunization strategies.