Experiments aimed at the elucidation of the chemistry and mechanism of BU-nucleic acid protein photocrosslinking will be performed. The importance of an electron transfer mechanism will be established. N-acyl amino acid amides and dipeptide amides chemically linked to 5-bromouracil and 1-methyl-5-bromouracil at the 6-position will be synthesized and investigated for photochemical reactivity as a model for the photochemistry of a nucleic acid protein complex. The results of this investigation will lead to the developments of the BU-nucleic acid protein photocrosslinking technique as a powerful method for the study of important protein nucleic interactions.