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Interaction of anticancer drug mitoxantrone with DNA hexamer sequence d-(CTCGAG)2 by absorption, fluorescence and circular dichroism spectroscopy

Paper ID Volume ID Publish Year Pages File Format Full-Text
30588 44489 2013 7 PDF Available
Title
Interaction of anticancer drug mitoxantrone with DNA hexamer sequence d-(CTCGAG)2 by absorption, fluorescence and circular dichroism spectroscopy
Abstract

•Binding of mitoxantrone to d(CTCGAG) duplex studied at various drug/DNA ratios.•Absorbance and fluorescence spectra show that two binding modes exist.•Multiple mitoxantrone molecules bind to DNA at high drug concentrations.•Circular dichroism binding isotherms give stoichiometry of 0.25, and 0.5.•Mitoxantrone stacks with terminal base pairs forming sandwiched structure with DNA.

The interaction of mitoxantrone with d-(CTCGAG)2 has been studied by absorption, fluorescence and circular dichroism (CD) spectroscopy. The hypochromism and quenching of fluorescence showed that about four mitoxantrone molecules may be binding externally to DNA hexamer sequence at high drug to nucleic (D/N) acid duplex ratios (28.0–1.1). At lower D/N ratios (1.0–0.2), a red shift in absorption maxima at 610 and 660 nm by 15 and 20 nm, respectively and a red shift in emission maxima by 11 nm accompanied by increase in absorbance and emission has been observed. The equilibrium constant for binding at low (1.0–0.2) and high (28.0–1.1) D/N ratios is 1.8 × 105 M−1 and 1.38 × 106 M−1, respectively. The CD spectra show change in intensity of bands accompanied by appearance of induced bands at 325 nm and 650–700 nm. The 251 nm band shows blue shift at D/N ratio of 0.25 and 0.5. The binding isotherms show stoichiometry of 0.25 and 0.5 mitoxantrone molecules binding per duplex. The results suggest stacking of aromatic chromophore of mitoxantrone with terminal base pair of DNA strand forming a sandwiched structure of mitoxantrone between four and two duplex molecules. These investigations are relevant to the formation of ternary complex with topoisomerase enzyme and hence an understanding of anti tumor action of mitoxantrone.

Graphical abstractInteraction of mitoxantrone with d-(CTCGAG)2 DNA sequence.Figure optionsDownload full-size imageDownload as PowerPoint slide

Keywords
Drug–DNA interaction; Mitoxantrone-d(CTCGAG)2 complex; Absorbance and fluorescence; Circular dichroism; Biphasic mode of interaction
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Interaction of anticancer drug mitoxantrone with DNA hexamer sequence d-(CTCGAG)2 by absorption, fluorescence and circular dichroism spectroscopy
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Publisher
Database: Elsevier - ScienceDirect
Journal: Journal of Photochemistry and Photobiology B: Biology - Volume 123, 5 June 2013, Pages 48–54
Authors
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Subjects
Physical Sciences and Engineering Chemical Engineering Bioengineering
Get Full-Text Now
Don't Miss Today's Special Offer
Price was $35.95
You save - $31
Price after discount Only $4.95
100% Money Back Guarantee
Full-text PDF Download
Online Support
Any Questions? feel free to contact us