DNA Intercalation by Quinacrine and Methylene Blue: A Comparative Binding and Thermodynamic Characterization Study
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
DNA Intercalation by Quinacrine and Methylene Blue:
A Comparative Binding and Thermodynamic
Characterization Study
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| Creator |
Hossain, Maidul
Giri, Prabal Kumar, G Suresh |
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| Subject |
Chemistry
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| Description |
There is compelling evidence that cellular DNA is the target of many anticancer agents. Consequently, elucidation
of the molecular nature governing the interaction of small molecules to DNA is paramount to the progression of
rational drug design strategies. In this study, we have compared the binding and thermodynamic aspects of
two known DNA-binding agents, quinacrine (QNA) and methylene blue (MB), with calf thymus (CT) DNA. The
study revealed noncooperative binding phenomena for both the drugs to DNA with an affinity one order higher
for QNA compared to MB as observed from diverse techniques, but both bindings obeyed neighbor exclusion
principle. The data of the salt dependence of QNA and MB fromthe plot of log K versus log [Na+] revealed a slope
of 1.06 and 0.93 consistent with the values predicted by theories for the binding of monovalent cations, and
have been analyzed for contributions from polyelectrolytic and nonpolyelectrolytic forces. The binding of both
drugs was further characterized by strong stabilization of DNA against thermal strand separation in both optical
melting and differential scanning calorimetry studies. The binding data analyzed from the thermal denaturation
and from isothermal titration calorimetry (ITC) were in close proximity to those obtained from spectral titration
data. ITC results revealed the binding to be exothermic and favored by both negative enthalpy and positive
entropy changes. The heat capacity changes obtained from temperature dependence of enthalpy indicated�146
and�78 cal=(mol�K), respectively, for the binding of QNA and MB to CT DNA. Circular dichroism study further
characterized the structural changes on DNA upon intercalation of these molecules. Molecular aspects of interaction
of these molecules to DNA are discussed.
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| Date |
2008
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| Type |
Article
PeerReviewed |
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| Format |
application/pdf
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| Identifier |
http://www.eprints.iicb.res.in/279/1/DNA_AND_CELL_BIOLOGY%2C27(_2)%2C__81%2D90%2C2008[129].pdf
Hossain, Maidul and Giri, Prabal and Kumar, G Suresh (2008) DNA Intercalation by Quinacrine and Methylene Blue: A Comparative Binding and Thermodynamic Characterization Study. DNA and Cell Biology, 27 (2). pp. 81-90. |
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| Relation |
http://dx.doi.org/10.1089=dna.2007.0652
http://www.eprints.iicb.res.in/279/ |
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