INTERACTIONS OF THE ECORV RESTRICTION-ENDONUCLEASE WITH FLUORESCENT OLIGODEOXYNUCLEOTIDES

A self-complementary dodecadeoxyribonucleotide that contains the recog nition sequence for the R . EcoRV ENase was synthesised with a primary amino group at its 5' terminus. The 5' amino function was labeled wit h the fluorescent dye 5-[dimethylamino] napthalene-1-sulfonyl chloride . The labeled oligodeoxyribonucleotide in its duplex form was shown to be a suitable substrate for kinetic studies on the ENase and that no significant dye-DNA or dye-protein interactions occurred. Finally, the binding of R . EcoRV to the labeled DNA was followed by detecting the fluorescence resonance energy transfer between the tryptophans of the protein and the fluorescent labels of the DNA.