EXAMINATION OF (PHENOTHIAZINYL)VINYL-PYRIDINIUM DYE’S CAPACITY OF INTERACTION WITH DNA

Abstract

The interaction of (E)-4-(2-(7-bromo-10-ethyl-10H-phenothiazin-3-yl)vinyl)-1-methylpyridin-1-ium (PVP) dyes with calf-thymus DNA was examined by spectrophotometric UV-vis absorption/emission titration and competitive ethidium bromide displacement. The association constant values were situated in 106 M-1 range, typical to cationic dyes containing the monocyanine chromophore system. The variation of the counterion of the cationic PVP dye from iodide to tetrafluoroborate produced dissimilarities in the interaction pattern with DNA. The PVP iodide competitively displaced the ethidium bromide (EB) from the EB-DNA system, thus suggesting the intercalation ability of the dye, while the PVP tetrafluoroborate did not supported the intercalation of the dye.

Keywords

• cyanine dyes, phenothiazine, DNA binding, association constant.