TY  - JOUR
A1  - Fudickar, Werner
A1  - Bauch, Marcel
A1  - Ihmels, Heiko
A1  - Linker, Torsten
T1  - DNA-triggered enhancement of singlet oxygen production by pyridinium alkynylanthracenes
JF  - Chemistry - a European journal
N2  - There is an ongoing interest in O-1(2) sensitizers, whose activity is selectively controlled by their interaction with DNA. To this end, we synthesized three isomeric pyridinium alkynylanthracenes 2 o-p and a water-soluble trapping reagent for O-1(2). In water and in the absence of DNA, these dyes show a poor efficiency to sensitize the photooxygenation of the trapping reagent as they decompose due to electron transfer processes. In contrast, in the presence of DNA O-1(2) is generated from the excited DNA-bound ligand. The interactions of 2 o-p with DNA were investigated by thermal DNA melting studies, UV/vis and fluorescence spectroscopy, and linear and circular dichroism spectroscopy. Our studies revealed an intercalative binding with an orientation of the long pyridyl-alkynyl axis parallel to the main axis of the DNA base pairs. In the presence of poly(dA : dT), all three isomers show an enhanced formation of singlet oxygen, as indicated by the reaction of the latter with the trapping reagent. With green light irradiation of isomer 2 o in poly(dA : dT), the conversion rate of the trapping reagent is enhanced by a factor >10. The formation of O-1(2) was confirmed by control experiments under anaerobic conditions, in deuterated solvents, or by addition of O-1(2) quenchers. When bound to poly(dG : dC), the opposite effect was observed only for isomers 2 o and 2 m, namely the trapping reagent reacted significantly slower. Overall, we showed that pyridinium alkynylanthracenes are very useful intercalators, that exhibit an enhanced photochemical O-1(2) generation in the DNA-bound state.
KW  - Anthracene
KW  - DNA
KW  - intercalations
KW  - photochemistry
KW  - singlet oxygen
Y1  - 2021
U6  - https://doi.org/10.1002/chem.202101918
SN  - 1521-3765
VL  - 27
IS  - 54
SP  - 13591
EP  - 13604
PB  - Wiley-VCH
CY  - Weinheim
ER  -