[Optical rotatory dispersion by 5 viruses of the tobacco mosaic virus group and their components]

Optical rotatory dispersion (ORD) spectra in 250 to 350 nm region were measured for preparations of five TMV-like viruses (TMV vulgare, HR and U2 strains of TMV dolihosenation mosaic virus and cucumber virus 4) and also for RNA and protein preparations of these viruses. The data obtained testify against the possibility that the double peak with maxima at 286 and 293 nm observed in ORD of all the five viruses is due to interaction of tryptophan residues in virus coat protein with the RNA of the virul particle. The spectra of intravirus RNA of the five viruses, calculated as the difference between ORD of the intact virus and of its coat protein, were found to differ significantly from each other and from ORD of free RNA. ORD spectra of hybrid viruses, reconstituted from RNA of one virus and coat protein of another, proved to be identical to the ORD of the virus, whose protein was used in reconstitution. We suppose that the difference in ORD of the intravirus RNA of the five viruses reflect differences of RNA-protein interactions in them.