H. Ihmels et al., Acridizinium salts as a novel class of DNA-binding and site-selective DNA-photodamaging chromophores, PHOTOCHEM P, 74(4), 2001, pp. 505-511
It was demonstrated that the interaction of the aminoacridizinium salts 2a-
2d with DNA depends on the substitution pattern of the chromophore. Spectro
photometric and fluorometric titrations of the acridizinium salts 2a-2d wit
h natural and synthetic polynucleotides reveal that the degree of interacti
on of the acridizinium salts 2a-2d with the nucleic acid differs significan
tly. The binding mode of the dyes with DNA was evaluated by circular dichro
ism and linear dichroism spectroscopy and compared with the parent system 2
c. Whereas the 9-aminoacridizinium (2a) mainly intercalates into DNA, the s
alts 2b-c show a higher degree of association to the DNA backbone. The inte
rcalated aminoacridizinium 2a caused few strand breaks upon UVA exposure, w
hereas the salts 2b-2d exhibit relatively efficient DNA-damaging properties
. All acridizinium salts showed a sequence-selective strand cleavage for gu
anine-rich DNA regions.