Beitrag zur Feinstruktur des Tabakmosaikvirus

Abstract

Tobacco-mosaic virus (TM virus) consists of rod-shaped nucleoproteid molecules with a mol. wt. of 23,000,000. The breadth of the rods is about 15 m[mu], and the length, about 200-300 m[mu]. The apparatus used to det. the light absorption of oriented virus molecules in polarized light consists of a quartz capillary which is placed directly in front of the slit of a quartz spectrograph and through which the stream of virus soln. can be forced under various pressures. Behind the tube of the spectrograph is a thin cal-cite plate so cut that on a photographic plate 2 superimposed spectra are formed which are polarized perpendicularly to each other. The light absorption along the long axis of the virus molecule differs from that perpendicular to this axis. In the absorption curve in which the electric light vector is perpendicular to the long axis of the molecule, there is a small max. at 2900 A which is due to trypto-phane. The ribonucleic acid (max. at 2590 A) is so oriented in the framework of the virus molecule that the planes of the purine (and probably pyrimidine rings) are parallel to each other and are probably perpendicular to the long axis of the molecule. The protein framework itself must be so constructed that the plane of the indole ring of tryptophane is perpendicular to the long axis of the molecule. There must be great regularity in the fine structure of the virus molecule.