UV-INDUCED NUCLEIC-ACID PROTEIN CROSS-LINKING - MANUAL ON PLANNING OFIRRADIATION EXPERIMENTS AND CALCULATION OF ABSORBED DOSE AND QUANTUM YIELD

We have developed methods of photochemical quantitation of photobiolog ical studies on UV-induced nucleic acid-protein cross-linking, Cases r elating to incoherent low-intensity UV sources, laser UV sources and h igh-intensity laser UV sources are considered. In the case of low-inte nsity UV radiation the most important point is the correct determinati on of absorbed dose, The laser UV pulse energy is easily measured and the short-pulse irradiation also has the advantage of ''freezing'' the conformation of complexes under study, However, the use of high-inten sity laser UV irradiation leads to realizations of two-quantum process es both in nucleic acid chromophores-bases and in solvent-water, which complicates singificantly the processing of results, In this paper me thods for calculating the absorbed dose and the quantum yield of cross -linking for all above-mentioned cases are given as well as practical advice.