Tyrosine Fluorescence Energy Transfer as a Probe for Interactions of Proteins with DNA

The fluorescence decay of the aromatic amino acid tyrosine, as well as of symmetric tripeptides is monoexponential, the fluorescence lifetimes can be understood on the basis of a simple empirical equation for first order rate constants of energy transfer from tyrosine to neighboring amino acids. Fluorescence energy transfer from tyrosine to DNA in protein‐DNA complexes can be used to elucidate the role of Tyr‐DNA interaction in the formation of inverted DNA, a postulated new type of DNA structure and gives information on differences of the role of the positively charged amino acids lysine and arginine in electrostatic protein‐DNA interaction.