Barceló Francisca, Capó Damiana, Portugal José
Departament de Biologia Fundamental i Ciencies de la Salut, Universitat de les Illes Balears, Palma de Mallorca, Spain.
Nucleic Acids Res. 2002 Oct 15;30(20):4567-73. doi: 10.1093/nar/gkf558.
Characterization of the thermodynamics of DNA- drug interactions is a very useful part in rational drug design. Isothermal titration calorimetry (ITC), differential scanning calorimetry (DSC) and UV melting experiments have been used to analyze the multivalent (intercalation plus minor groove) binding of the antitumor antibiotic chartreusin to DNA. Using DNA UV melting studies in the presence of the ligand and the binding enthalpy determined by ITC, we determined that the binding constant for the interaction was 3.6 x 10(5) M(-1) at 20 degrees C, in a solution containing 18 mM Na(+). The DNA-drug interaction was enthalpy driven, with a DeltaH(b) of -7.07 kcal/mol at 20 degrees C. Binding enthalpies were determined by ITC in the 20-35 degrees C range and used to calculate a binding-induced change in heat capacity (DeltaCp) of -391 cal/mol K. We have obtained a detailed thermodynamic profile for the interaction of this multivalent drug, which makes possible a dissection of DeltaG(obs) into the component free energy terms. The hydrophobic transfer of the chartreusin chromophore from the solution to the DNA intercalating site is the main contributor to the free energy of binding.
DNA与药物相互作用的热力学特性表征是合理药物设计中非常有用的一部分。等温滴定量热法（ITC）、差示扫描量热法（DSC）和紫外熔解实验已被用于分析抗肿瘤抗生素黄绿青霉素与DNA的多价（嵌入加小沟）结合。利用在配体存在下的DNA紫外熔解研究以及ITC测定的结合焓，我们确定在含有18 mM Na⁺的溶液中，20℃时相互作用的结合常数为3.6×10⁵ M⁻¹。DNA与药物的相互作用是由焓驱动的，20℃时的ΔH(b)为 -7.07 kcal/mol。通过ITC在20 - 35℃范围内测定结合焓，并用于计算结合诱导的热容变化（ΔCp）为 -391 cal/mol K。我们获得了这种多价药物相互作用的详细热力学概况，这使得将ΔG(obs)分解为各自由能项成为可能。黄绿青霉素发色团从溶液到DNA嵌入位点的疏水转移是结合自由能的主要贡献者。
