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

Abstract

Abstract— 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.

UV LASER INDUCED RNA‐PROTEIN CROSSLINKS AND RNA CHAIN BREAKS IN TOBACCO MOSAIC VIRUS RNA in situ

“…1. The results of such calculations are presented in Table 1 together with the chain break and crosslink quantum yields for low-intensity UV irradiation of intravirus TMV RNA (Dobrov et al, 1986).…”

“…Only free (not crosslinked to protein) RNA molecules (or their fragments) remain in water phase. It was shown (Dobrov et al, 1986) that weight-average molecular weight of RNA which remains in solution after deproteinitation with phenol (MZ ) is related to weight-average molecular weight of RNA from non-irradiated TMV (M&' ) by the following equation:…”

“…, 1980), all were found to increase significantly with the increasing intensity of UVirradiation. Thus, it seemed probable that the efficiency of formation of RNA-protein crosslinks would also be increased under high-intensity laser pulse UV- irradiation. Previously we determined the quantum yield of RNA-protein crosslinks (and also of RNA chain breaks) on usual (low-intensity) UVirradiation of tobacco mosaic virus (TMV) (Dobrov et al, 1986). In the present work we have measured the quantum yields of formation of RNA-protein crosslinks and RNA chain breaks in TMV on highintensity nanosecond and picosecond UV-laser irradiation.…”

“…In most of these studies low-intensity mercury lamp radiation was used and the efficiency of RNA-protein crosslinking turned out to be rather low. The situation was further complicated by parallel formation of some other types of photoproducts including RNA chain breaks (Dobrov et al, 1986).…”

UV-Induced Nucleic Acid–Protein Cross-Linking: Manual on Planning of Irradiation Experiments and Calculation of Absorbed Dose and Quantum Yield

“…In the last two decades direct UV-induced cross-linking has become one of the most popular and relatively simple methods of identification of molecules and their segments involved in nucleic acid-protein interaction and recognition (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12). The use of powerful ultrashort UV laser pulses allows a reasonable number of cross-links to be obtained even with a single laser pulse of nanosecond (or picosecond) duration.…”