Halogenated nucleic acids: Base properties and conformation of fluorinated derivatives

Base-halogenated nucleic acid constituents have been of general biological interest since the discovery that they are incorporated into cellular macromolecules. Fluorinated based in particular are of special interest due to their antitumor and fungicidal properties. To obtain a more basic understanding of the physicochemical properties of these nucleic acid analogs, a comparative study of normal and fluorinated nucleic acid constituents and homopolynucleotides has been underway. The present study evaluates the effects of fluorine substitution on the base moiety from ultraviolet spectral properties and proton nuclear magnetic resonance spectroscopy. The results indicate marked effects on the pK/sub a/ of the base, changes in amount of base stacking interactions and alterations in the conformation of the rybosylfuranose