To this end, ISTA researchers used the harmless vaccinia virus, available in the lab, as a model poxvirus. They examined whole, mature vaccinia virus virions, as well as virus cores isolated and purified from them – and this, in the truest sense of the word, from every possible angle.
"We combined 'classic' single-particle cryo-EM with cryo-electron tomography, subtomogram averaging, and AlphaFold analysis to obtain an overall overview of the poxvirus core," say the researchers.
Cryo-electron tomography enables scientists to reconstruct 3D volumes of a biological sample up to the size of an entire virus by taking images while tilting the sample incrementally. Cryo-electron tomography made it possible to achieve nanometer-scale resolution for the entire virus, its core, and its interior.
Furthermore, the researchers were able to fit the AlphaFold models like a puzzle into the observed shapes and identify molecules that make up the poxvirus core. Among these, the core protein candidate A10 stood out as one of the most important components.
Project Funding:
This project was funded by grants from the Chan Zuckerberg Initiative (DAF2021-234754 and DOI https://doi.org/10.37921/812628ebpcwg) and the Austrian Science Fund (FWF) (P31445).
Original Publication:
Datler J, Hansen JM, et al. 2024. Multi-modal cryo-EM reveals trimers of protein A10 to form the palisade layer in poxvirus cores. Nature Structural & Molecular Biology.
DOI: https://doi.org/10.1038/s41594-023-01201-6
Further information:
https://ista.ac.at/en/research/schur-group/ Schur Group at the Institute of Science and Technology Austria (ISTA)
