RT Journal Article SR Electronic(1) A1 Dobrov, E. N. A1 Kust, S. V. A1 Tikchonenko, T. I.YR 1972 T1 The Structure of Single-Stranded Virus RNA in situ. A Study of Absorption Spectra and Optical Rotatory Dispersion of Tobacco Mosaic Virus and Potato Virus X Preparations JF Journal of General Virology, VO 16 IS 2 SP 161 OP 172 DO https://doi.org/10.1099/0022-1317-16-2-161 PB Microbiology Society, SN 1465-2099, AB SUMMARY The secondary structure of RNA in particles of two plant viruses with helical symmetry (tobacco mosaic virus (TMV) and potato virus X (PVX)) was studied by determining their RNA extinction spectra in situ. The true values of extinction of light-scattering virus suspensions were calculated by extrapolation. To determine the degree of hyperchromicity of internal RNA, the spectra of suspensions of intact and disrupted TMV and PVX were compared. Virus particles were disrupted by heating or by sodium dodecyl sulphate. The contribution of protein to the total extinction of virus was taken into account during calculations of hyperchromicity of internal RNA. It was shown that RNA in particles of both viruses is in a fully hyperchromic state. The interaction of both internal RNA's with formaldehyde was also investigated. The reaction of RNA in situ with formal-dehyde was followed by the increase in extinction of the virus suspensions in the 280 to 290 nm. spectral region. It was found the amino-groups of the bases of internal PVX RNA readily react with formaldehyde. On the other hand, the TMV RNA in situ was completely resistant to formaldehyde. A substantial difference in the optical rotatory dispersion (ORD) curves of two viruses was also revealed. The differences in reactivity with formaldehyde and in ORD curves of TMV and PVX probably reflect the different character of RNA-protein interactions in particles of the two viruses., UL https://www.microbiologyresearch.org/content/journal/jgv/10.1099/0022-1317-16-2-161