Spectral properties and G-quadruplex DNA binding selectivities of a series of unsymmetrical perylene diimides
Küçük Resim Yok
Tarih
2007
Yazarlar
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Elsevier Science Sa
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
A series of new unsymmetrical perylene diimides have been synthesized to investigate their binding selectivities to G-quadruplex DNA structure, a unique four-stranded DNA motif, which is significant to the regulation of telomerase activity. The structures of the perylene diimides have been characterized by IR spectrophotometer, H-1 NMR, C-13 NMR, MS, TGA and time-resolved instruments. Spectrochemical behaviors have been investigated by visible absorption and fluorescence emission spectra. The spectral characterization of the compounds has been investigated in five common organic solvents of different polarity and in water (in 170 mM phosphate buffer at pH 6). Marked red shifts of absorbance and fluorescence emission bands of the compounds in aqueous solution are compared with the other organic solutions. The fluorescence quantum yields are determined low in more polar solvents and also calculated to be about less than about 0.05 in aqueous solution because of the aggregation effects. Photodegradation rate constants (k(p)) of the synthesized compounds have been compared under xenon lamp irradiation in acetonitrile solution. Binding abilities of the synthesized perylene diimides to different form of DNA strands have been investigated by visible absorption and fluorescence spectroscopy in the phosphate buffer solutions. Also, pH-dependent aggregation and G-quadruplex DNA binding selectivity of these ligands have been compared. Among these ligands, N-(2,6-diisopropylphenyl)-N'-(4-pyridyl)-perylene-3,4,9,10-tetracarboxylic diimide (PYPER) has been found to be the most selective interactive ligand for G-quadruplex formed in the G4'-DNA structure. PYPER has shown a significant selectivity to G4'-DNA which is comprised of d(TTAGGG) repeats, known as human telomeres, in the phosphate buffer at pH 6. The absorption maximum of the PYPER/G4'-DNA complex has given bathochromic shift of 7 nm with respect to the absorption maximum of DNA-free solution of PYPER in phosphate buffer at pH 6. Fluorescence quenching experiments between PYPER and G4'-DNA show that PYPER demonstrates about a 9.3-fold selectivity for binding to G4'-DNA versus ds-DNA base pairs with the bimolecular rate constant of 0.95 x 10(12) M-1 s(-1). (c) 2006 Elsevier B.V. All rights reserved.
Açıklama
Anahtar Kelimeler
perylene diimide, fluorescence quenching, G-quadruplex DNA, human telomerase, anti-cancer agent
Kaynak
Journal of Photochemistry and Photobiology A-Chemistry
WoS Q Değeri
Q2
Scopus Q Değeri
Q2
Cilt
185
Sayı
1
