@article{KienzlerFlehrGehneetal.2012,
  author    = {Kienzler, Andrea Altevogt Nee and Flehr, Roman and Gehne, S{\"o}ren and Kumke, Michael Uwe and Bannwarth, Willi},
  title     = {Verification and biophysical characterization of a New Three-Color Forster Resonance-Energy-Transfer (FRET) System in DNA},
  series = {Helvetica chimica acta},
  volume    = {95},
  journal   = {Helvetica chimica acta},
  number    = {4},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {0018-019X},
  doi       = {10.1002/hlca.201100460},
  pages     = {543 -- 555},
  year      = {2012},
  abstract  = {We report on a new three-color FRET system consisting of three fluorescent dyes, i.e., of a carbostyril (=quinolin-2(1H)-one)-derived donor D, a (bathophenanthroline)ruthenium complex as a relay chromophore A1, and a Cy dye as A2 (FRET=Forster resonance-energy-transfer) (cf. Fig. 1). With their widely matching spectroscopic properties (cf. Fig. 2), the combination of these dyes yielded excellent FRET efficiencies. Furthermore, fluorescence lifetime measurements revealed that the long fluorescence lifetime of the Ru complex was transferred to the Cy dye offering the possibility to measure the whole system in a time-resolved mode. The FRET system was established on double-stranded DNA (cf. Fig. 3) but it should also be generally applicable to other biomolecules.},
  language  = {en}
}
@article{KasyanenkoUnksovBakulevetal.2018,
  author    = {Kasyanenko, Nina and Unksov, Ivan and Bakulev, Vladimir and Santer, Svetlana},
  title     = {DNA interaction with head-to-tail associates of cationic surfactants prevents formation of compact particles},
  series = {Molecules},
  volume    = {23},
  journal   = {Molecules},
  number    = {7},
  publisher = {MDPI},
  address   = {Basel},
  issn      = {1420-3049},
  doi       = {10.3390/molecules23071576},
  pages     = {14},
  year      = {2018},
  abstract  = {Cationic azobenzene-containing surfactants are capable of condensing DNA in solution with formation of nanosized particles that can be employed in gene delivery. The ratio of surfactant/DNA concentration and solution ionic strength determines the result of DNA-surfactant interaction: Complexes with a micelle-like surfactant associates on DNA, which induces DNA shrinkage, DNA precipitation or DNA condensation with the emergence of nanosized particles. UV and fluorescence spectroscopy, low gradient viscometry and flow birefringence methods were employed to investigate DNA-surfactant and surfactant-surfactant interaction at different NaCl concentrations, [NaCl]. It was observed that [NaCl] (or the Debye screening radius) determines the surfactant-surfactant interaction in solutions without DNA. Monomers, micelles and non-micellar associates of azobenzene-containing surfactants with head-to-tail orientation of molecules were distinguished due to the features of their absorption spectra. The novel data enabled us to conclude that exactly the type of associates (together with the concentration of components) determines the result of DNA-surfactant interaction. Predomination of head-to-tail associates at 0.01 M < [NaCl] < 0.5 M induces DNA aggregation and in some cases DNA precipitation. High NaCl concentration (higher than 0.8 M) prevents electrostatic attraction of surfactants to DNA phosphates for complex formation. DAPI dye luminescence in solutions with DNA-surfactant complexes shows that surfactant tails overlap the DNA minor groove. The addition of di- and trivalent metal ions before and after the surfactant binding to DNA indicate that the bound surfactant molecules are located on DNA in islets.},
  language  = {en}
}
@article{FudickarBauchIhmelsetal.2021,
  author    = {Fudickar, Werner and Bauch, Marcel and Ihmels, Heiko and Linker, Torsten},
  title     = {DNA-triggered enhancement of singlet oxygen production by pyridinium alkynylanthracenes},
  series = {Chemistry - a European journal},
  volume    = {27},
  journal   = {Chemistry - a European journal},
  number    = {54},
  publisher = {Wiley-VCH},
  address   = {Weinheim},
  issn      = {1521-3765},
  doi       = {10.1002/chem.202101918},
  pages     = {13591 -- 13604},
  year      = {2021},
  abstract  = {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.},
  language  = {en}
}