An x-ray scattering investigation of wild cucumber mosaic virus and a related protein

X-ray scattering data are presented on solutions of wild cucumber mosaic virus and the associated "top component" particles which have little or no RNA. The radii of gyration are 112 A and 135 A for bottom and top component, respectively. The radial density distribution within each particle is calculated by Fourier inversion of the scattered amplitudes. The virus particle or bottom component has approximately uniform density with an outer radius of about 140 A. The transform of the top component shows an almost hollow center extending out to 105 A with a surrounding shell of high density about 35 A thick. Thus the RNA would appear to occupy the region inside 105 A and does not overlap appreciably the region occupied by protein. The virus has associated with it approximately 0.38 gm of water per gm of virus, resulting in an average electron density of 1.25 times that of water.