Comparative investigations of the effects of X- and UV-irradiation on lysozyme in the absence or presence of additives

The radiation damage of lysozyme has been investigated in aqueous solution, after preceding X- and UV-irradiation in the absence or presence of various additives. Activity measurements and UV absorption and fluorescence spectroscopy turned out to be powerful screening techniques for disclosing the damages (inactivation, aggregation, loss of aromatics) and modifications (protection) provided by many additives. Advanced computer modeling approaches were used to visualize the protein atoms and the water molecules bound preferentially on. the protein surface. Correlations between the position of radiosensitive amino acid residues and occurring radiation damages are discussed. (C) 2003 Elsevier Science Ltd. All rights reserved.