Interaction of a tryptophan-containing peptide with chromatin core particles. A fluorescence study.

The binding of a tetrapeptide lysyltryptophylglycyllysine to nucleosome core particles has been investigated using UV absorption and fluorescence spectroscopy. Modifications of the absorption spectra and fluorescence quenching of the tryptophyl residue are consistent with stacking between the indole ring and nucleic acid bases. Therefore DNA interactions with histones do not prevent stacking of the tryptophyl residue with nucleic acid bases in the peptide-core particle complexes. The number of peptide binding sites is reduced to half that of naked DNA.