کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5377001 | 1504334 | 2006 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Femtosecond spectroscopic study of carminic acid-DNA interactions
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
شیمی
شیمی تئوریک و عملی
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چکیده انگلیسی
Photo-excited carminic acid and carminic acid-DNA complexes in a buffer solution at pH 7 have been examined using a variety of spectroscopy techniques, that are in particular, the femtosecond resolved fluorescence upconversion and transient absorption spectroscopy. The observation of dual fluorescence emission, one peaks at 470Â nm and the other at 570Â nm, indicates to an excited-state (S1) intramolecular proton transfer (ESIPT). A detailed analysis of the transient absorption measurements of an aqueous carminic-acid solution at pH 7 yielded four lifetimes for the excited-state (S1): 8, 15, 33 and 46Â ps. On the other hand, only two lifetimes, 34 and 47Â ps, were observed by fluorescence upconversion spectroscopy because of the detection limitation to the long wavelength edge of the carminic-acid spectrum. The four S1 lifetimes were ascribed to the coexistence of respectively two tautomer (normal and tautomer) forms of carminic acid, in the non-dissociated state (CAH) and in the deprotonated state (CAâ). The fluorescence upconversion measurements of carminic acid-DNA complexes exhibited a prolongation of the fluorescence lifetimes. This effect was accepted as evidence for the formation of intercalation complexes between the carminic acid and the DNA. The intercalative binding of the carminic acid to DNA was confirmed by the fluorescence titration experiments resulting to a binding constant of 2Â ÃÂ 105Â Mâ1 that is typical for anthracycline-DNA complexes.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Chemical Physics - Volume 325, Issues 2â3, 20 June 2006, Pages 509-518
Journal: Chemical Physics - Volume 325, Issues 2â3, 20 June 2006, Pages 509-518
نویسندگان
Radu Comanici, Bianca Gabel, Thomas Gustavsson, Dimitra Markovitsi, Christian Cornaggia, Stanislas Pommeret, Catalin Rusu, Carola Kryschi,