Mechanism of inactivation of tobacco mosaic virus with ozone

The inactivation mechanism of tobacco mosaic virus (TMV) in a phosphate buffer (pH 6.9) by ozone was studied. We previously reported that the damage of naked TMV-RNA occurred at the guanine moiety of RNA (Shinriki et al., Biochim. biophys. Acta 655, 323, 1981). In this paper, we clarified the mode of the inactivation of TMV by using tritium-labeled TMV (TMV ∗) prepared by the reconstitution of tritium-labeled TMV-RNA (TMV-RNA ∗) and coat protein of TMV. It was found that the amount of extracted TMV-RNA ∗ from ozone-treated TMV ∗ decreased with the advance of ozonization, and that there was good correlation between the loss of infectivity and the decrease of recovery of TMV-RNA ∗. When TMV lost its infectivity due to ozone, tryptophan and tyrosine of the coat protein were also degraded by ozone. Polyacrylamide gel electrophoretic analysis of the substance produced during ozonization showed that the coat protein subunits were aggregated with each other and cross-linked with TMV-RNA ∗. From these results, it was concluded that the inability of uncoating is the major cause of the TMV inactivation by ozone.