Physical properties of Bushy Stunt virus protein

Abstract

has not hitherto been possible to determine accurately the molecular size or weight of any of the virus proteins. X-ray diffraction patterns show in the case of tobacco mosaic virus protein that the cross sectional area of the rod-shaped molecules is 20,100 sq. A. [Bawden et al. 1936] and assuming the rod to be cylindrical this corresponds to a diameter of approximately 16m,u. The same technique fails to give any indication of the length of the molecule and it is not at all certain that the molecular units have all the same length. Sedimentation, osmosis and diffusion measurements are also unsatisfactory when applied to the anisotropic plant viruses owing to the combination of large molecular size with gross asymmetry which they possess.