DNA intercalation of methylene blue and quinacrine: new insights into base and sequence specificity from structural and thermodynamic studies with polynucleotidesw
IR@IICB: CSIR-Indian Institute of Chemical Biology, Kolkata
View Archive Info| Field | Value | |
| Title |
DNA intercalation of methylene blue and quinacrine: new insights into
base and sequence specificity from structural and thermodynamic studies
with polynucleotidesw
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| Creator |
Hossain, Maidul
Kumar, G Suresh |
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| Subject |
Chemistry
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| Description |
The binding of the known DNA intercalators methylene blue and quinacrine with four
sequence specific polynucleotides, viz. poly(dG-dC).poly(dG-dC), poly(dG).poly(dC),
poly(dA-dT).poly(dA-dT) and poly(dA).poly(dT), have been compared using absorbance,
fluorescence, competition dialysis and thermal melting and the thermodynamic aspects of the
interaction studied. In all the cases, non-cooperative binding phenomena obeying neighbor
exclusion principle was observed though the affinity was remarkably higher for quinacrine and the
nature of the binding was characterized to be true intercalation. The data on the salt dependence
of binding derived from the plot of logK vs. log[Na+] revealed a slope of around 1.0, consistent
with the values predicted by the theories for the binding of monovalent cations, and contained
contributions from polyelectrolytic and non-polyelectrolytic forces. The bindings were
characterized by strong stabilization of the polynucleotides against thermal strand separation in
both optical melting as well as differential scanning calorimetry studies. The data analyzed from
the thermal melting and isothermal titration calorimetry studies were in close proximity to those
obtained from absorption spectral titration data. Isothermal titration calorimetry results revealed
the bindings to poly(dG-dC).poly(dG-dC), poly(dG).poly(dC) and poly(dA-dT).poly(dA-dT) to
be exothermic and favoured by both negative enthalpy and large favourable positive entropy
changes, while that to poly(dA).poly(dT) was endothermic and entropy driven. The heat capacity
changes obtained from temperature dependence of enthalpy gave negative values to all
polynucleotides. New insights on the molecular aspects of interaction of these molecules to DNA
have emerged from these studies
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| Date |
2009
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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/245/1/MOLECULAR_BIOSYSTEMS%2C_5(11)%2C1311%2D1322%2C2009[124].pdf
Hossain, Maidul and Kumar, G Suresh (2009) DNA intercalation of methylene blue and quinacrine: new insights into base and sequence specificity from structural and thermodynamic studies with polynucleotidesw. Molecular BioSystems, 5 (11). pp. 1311-1322. |
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| Relation |
http://dx.doi.org/10.1039/b909563b
http://www.eprints.iicb.res.in/245/ |
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