Elektrophoretische Untersuchungen der Α-Proteine dreier Tabakmosaikvirus-Stämme

Abstract

The relations between the mobility of the ribonucleic acid (RNA)-free proteins of 3 strains of tobacco mosaic virus were studied. The proteins were prepared by alkaline degradation of the native virus. The degradation product used for electrophoretic measurements, the so-called A-protein (sedimentation constant 4.6 S; molecular weight, about 90,000) was carefully purified. Sedimentation measurements and electron microscopy verified that this protein, within the pH range of about 2.5-6.0, is reaggregated into rods. The electrophoretic mobility of these RNA-free rods is identical with that of the respective native virus. To explain these results it is presumed that the electrophoretic mobility is determined only by those acid and basic groups which are located on or near the surface of the migrating particle. Since in this case the RNA would be unable to influence the mobility of the native virus particles, the identical mobility of the complete virus and that of the respective RNA-free rod-like aggregates of A-protein becomes understandable. The changes in the mobility of the RNA-free proteins at about pH 2.5 and 6.0 accordingly, are explained by a non-homogeneous distribution principally of the basic groups. According to this assumption the basic groups would be situated mainly inside and not near the surface of the rods.