Intramolecular energy transfer in the lysozyme–eosin complex

Abstract

Energy transfer from hen lysozyme to a complexed eosin molecule has been investigated with single photon counting and conventional spectrofluorimetry. Transfer takes place with approximately unit efficiency from one of the two strongly emitting tryptophyl residues, leading to partial quenching of the u.v. protein fluorescence and enhanced visible emission from the dye. In conjunction with reported work on fluorescence and photodynamic inactivation of lysozyme by singlet oxygen, the results indicate that the donor is tryptophyl residue 108 and that the dye acceptor is located in a nearby hydrophobic environment.