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bioRxiv · 10.1101/2021.07.14.452405

The 4.4 A structure of the giant Melbournevirus virion belonging to the Marseilleviridae family

Burton-Smith, R. N.·Reddy, H. K. N.·Svenda, M.·Abergel, C.·Okamoto, K.·Murata, K.
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Abstract

Members of Marseilleviridae, one family of icosahedral giant viruses classified in 2012 have been identified worldwide in all types of environments. The virion shows a characteristic internal membrane extrusion at the five-fold vertices of the capsid, but its structural details need to be elucidated. We now report the 4.4 [A] cryo-electron microscopy structure of the Melbournevirus capsid. An atomic model of the major capsid protein (MCP) shows a unique cup structure on the trimer that accommodates additional proteins. A polyalanine model of the penton base protein shows internally extended N- and C-terminals, which indirectly connect to the internal membrane extrusion. The Marseilleviruses share the same orientational organisation of the MCPs as PBCV-1 and CroV, but do not appear to possess a protein akin to the "tape measure" of these viruses. Minor capsid proteins named PC-{beta}, zipper, and scaffold are proposed to control the dimensions of the capsid during assembly.

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Burton-Smith, R. N., Reddy, H. K. N., Svenda, M., Abergel, C., Okamoto, K., Murata, K.. 2021-07-14. The 4.4 A structure of the giant Melbournevirus virion belonging to the Marseilleviridae family. https://doi.org/10.1101/2021.07.14.452405

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