Heinrich Rüterjans

1H NMR study of the interaction of bacteriophage λ Cro protein with the O R 3 operator

The 17 base pair operator OR3 oligonucleotide, which is the preferential binding site for the Cro repressor of phage λ, was studied by two-dimensional NMR spectroscopy. A sequential assignment procedure based on two-dimensional Nuclear Overhauser Effect (NOESY) and scalar coupling correlated (COSY) NMR spectroscopy, together with the knowledge of the oligodesoxynucleotide sequence, made it possible to assign the non-exhangeable base protons and the H1′ and the H2′-H2″ sugar protons of the OR3 operator DNA. The pattern of the observed NOE connectivities is consistent with a right-handed helical DNA structure. The base and sugar proton assignments provide the necessary information for further studies of the OR3 operator — Cro repressor interaction.