Structural insights into the architecture of the hyperthermophilic Fusellovirus SSV1

- First three-dimensional structure of a spindle-shaped virus.
- Structure and dimensions of the SSV1 tail are consistent with the lattice spacing of the Sulfolobus S-layer.
- Geometric framework underlying the distinct spindle-shaped structure is proposed.

The structure and assembly of many icosahedral and helical viruses are well-characterized. However, the molecular basis for the unique spindle-shaped morphology of many viruses that infect Archaea remains unknown. To understand the architecture and assembly of these viruses, the spindle-shaped virus SSV1 was examined using cryo-EM, providing the first 3D-structure of a spindle-shaped virus as well as insight into SSV1 biology, assembly and evolution. Furthermore, a geometric framework underlying the distinct spindle-shaped structure is proposed.