Rna—protein Crosslink and Rna Chain Break Formation on Uv‐irradiation of Tobacco Mosaic Virus

The ability of UV‐irradiation (254 nm) to induce formation of RNA‐protein crosslinks in tobacco mosaic virus (TMV) particles have been studied by Cs2SO4 density gradient centrifugation, analytical centrifugation, nitrocellulose filter binding and two‐dimensional peptide mapping. RNA‐protein crosslinks were found to be formed on UV‐irradiation of TMV, but the parallel process of UV‐induced RNA chain breakage complicated their quantitation. Using speciall devised equations, the quantum yield of RNA‐protein crosslink formation was found to be 0.65 × 10−5 and that of RNA chain break formation 0.95 × 10−5.