N. Milanovich et al., BINDING OF TO-PRO-3 AND TOTO-3 TO DNA - FLUORESCENCE AND HOLE-BURNINGSTUDIES, Journal of physical chemistry, 100(21), 1996, pp. 9181-9186
The thiazole orange derivative, TO-PRO-3, and its dimeric analogue, TO
TO-3, bind strongly to both double- and single-stranded DNA. Both the
bound and the free dye undergo efficient nonphotochemical hole burning
. From the structure of the hole burned and the fluorescence line-narr
owed spectra, it is concluded that there are multiple modes of binding
of the dyes to DNA. burned vibronic band structure are similar to tho
se of the free dye. It is proposed that the molecules in this mode are
externally bound to the DNA chain. Molecules in the other binding mod
e are characterized by a strong interaction with DNA. These are propos
ed to be molecules in intercalated or base-stacked configurations.