4'-SCF -Labeling Constitutes a Sensitive F NMR Probe for Characterization of Interactions in the Minor Groove of DNA.

Fluorinated nucleotides are invaluable for F NMR studies of nucleic acid structure and function. Here, we synthesized 4'-SCF -thymidine (T ) and incorporated it into DNA by means of solid-phase DNA synthesis. NMR studies showed that the 4'-SCF group exhibited a flexible orientation in the minor groove of DNA duplexes and was well accommodated by various higher order DNA structures. The three magnetically equivalent fluorine atoms in 4'-SCF -DNA constitute an isolated spin system, offering high F NMR sensitivity and excellent resolution of the positioning of T within various secondary and tertiary DNA structures. The high structural adaptability and high sensitivity of T make it a valuable F NMR probe for quantitatively distinguishing diverse DNA structures with single-nucleotide resolution and for monitoring the dynamics of interactions in the minor groove of double-stranded DNA.