Structure of Belladonna Mottle Virus: Cross-Rotation Function Studies with Southern Bean Mosaic Virus

Belladonna mottle virus, which belongs to the tymovirus group of RNA plant viruses, crystallizes in rhombohedral space group R3 with $\alpha = 295.38 \AA$ and $\alpha = 59.86^{\circ}$. Cross-rotation function studies between belladonna mottle virus and southern bean mosaic virus reveal that the structure of this tymovirus is similar to those of sobemo viruses. A procedure for computing an icosahedrally averaged rotation function was developed as a general method for a more precise determination of the orientation of a symmetric molecule in an unknown cell. These studies suggest that it might be possible to obtain a high-resolution structure of belladonna mottle virus starting from phases derived from a model based on southern bean mosaic virus