Spectroscopic and electrochemical study of interactions between DNA and different salts of 1,4-dihydropyridine AV-153

1,4-dihydropyridines (1,4-DHP) possess important biochemical and pharmacological properties, including antimutagenic and DNA-binding activity. The latter activity was first described for water-soluble 1,4-DHP with carboxylic group in position 4, the sodium salt of the 1,4-DHP derivative AV-153 among others. Some data show the modification of physicochemical properties and biological activities of organic compounds by metal ions that form the salts. We demonstrated the different affinity to DNA and DNA-protecting capacity of AV-153 salts, depending on the salt-forming ion (Na, K, Li, Rb, Ca, Mg). This study aimed to use different approaches to collate data on the DNA-binding mode of AV-153-Na and five other AV-153 salts. All the AV-153 salts in this study quenched the ethidium bromide and DNA complex fluorescence, which points to an intercalation binding mode. For some of them, the intercalation binding was confirmed using cyclic voltammetry and circular dichroism spectroscopy. It was shown that in vitro all AV-153 salts can interact with four DNA bases. The FTIR spectroscopy data showed the interaction of AV-153 salts with both DNA bases and phosphate groups. A preference for base interaction was observed as the AV-153 salts interacted mostly with G and C bases. However, the highest differences were detected in the spectral region assigned to phosphate groups, which might indicate either conformational changes of DNA molecule (B form to A or H form) or partial denaturation of the molecule. According to the UV/VIS spectroscopy data, the salts also interact with the human telomere repeat, both in guanine quadruplex (G4) and single-stranded form; Na and K salts manifested higher affinity to G4, Li and Rb –to single-stranded DNA.

Development of viscometric methods for studying the interaction of various porphyrins with DNA. Part IV: Meso-tetra-(4N-allylpyridyl) porphyrin and its Cu-, Co- and Zn-containing derivatives

The influence of water soluble cationic meso-tetra-(4N-allylpyridyl) porphyrin (H2TAlPyP4) and its metal complexes with Cu, Co and Zn on hydrodynamic and spectral behavior of DNA solutions has been studied by viscometry, CD and UV-vis spectroscopy methods. The results were compared with the results of previously conducted similar studies on meso-tetra-(3N-allylpyridyl) porphyrin (H2TAllPyP3). It has been shown that the change in position of peripheral radicals on the pyridylic ring has absolutely no effect on the rules of interaction of investigated porphyrins with DNA in the case of outside binders CoTAllPyP4 and ZnTAllPyP4. Planar porphyrin H2TAllPyP4 interacts with DNA predominantly by the intercalation mode at low relative concentrations of [Formula: see text] ([Formula: see text] [Porphyrin]/[DNA]) and by external binding mode at high values of [Formula: see text]. CuTAllPyP4 shows unusual behavior by interacting with DNA via a non-classical (partial) intercalation binding mode. It was shown that H[Formula: see text]TAllPyP3 and its metal complexes bind to DNA much more intensely than H2TAllPyP4 and its metal complexes.

Study on the interaction of berberine with nucleic acids in the presence of silver nanoparticles, and the fluorometric determination of nucleic acids

The partial intercalation binding between BER and ctDNA, and the anti-photobleaching ability of BER were both strengthened by AgNPs. A metal enhanced fluorescence-based sensitive method for the determination of nucleic acids was obtained.

5-Methyl-Benzofuro[3,2-b]quinoline Derivatives as DNA Binders

Several derivatives of 5-methyl-benzofuro [3,2-quinoline (O-isostere of cryptolepine) were synthesized. Spectrometric experiments and molecular modeling indicated that these derivatives interacted with duplex DNA by intercalation binding mode. The derivatives with aniline substituent exhibited superior DNA binding affinity to that of lead compound 5-methyl-benzofuro [3,2-quinoline.