NMR Study of the Sequence-Specific Binding of the Δ - Tris(ethylenediamine)cobalt(III) Cation with d(TCGGGATCCCGA) 2

1H NMR spectroscopy was used to study the binding of Δ-Co(en)33+ to the dodecanucleotide d(TCGGGATCCCGA)2. Intermolecular NOE cross peaks between the metal complex methylene protons and the dodecanucleotide unambiguously establish that Δ-Co(en)33+ selectively binds at GG sequences in the major groove. The NMR experiments indicated that the dodecanucleotide maintains a B-type DNA conformation upon metal complex binding.