Department of Medicinal Chemistry, Faculty of Pharmacy, Kermanshah University of Medical Sciences, Kermanshah, Islamic Republic of Iran.
Spectrochim Acta A Mol Biomol Spectrosc. 2011 Sep;79(5):1004-12. doi: 10.1016/j.saa.2011.04.012. Epub 2011 Apr 15.
We report a multispectroscopic, voltammetric and theoretical hybrid of QM/MM study of the interaction between double-stranded DNA containing both adenine-thymine and guanine-cytosine alternating sequences and chloridazon (CHL) herbicide. The electrochemical behavior of CHL was studied by cyclic voltammetry on HMDE, and the interaction of ds-DNA with CHL was investigated by both cathodic differential pulse voltammetry (CDPV) at a hanging mercury drop electrode (HMDE) and anodic differential pulse voltammetry (ADPV) at a glassy carbon electrode (GCE). The constant bonding of CHL-DNA complex that was obtained by UV/vis, CDPV and ADPV was 2.1×10(4), 5.1×10(4) and 2.6×10(4), respectively. The competition fluorescence studies revealed that the CHL quenches the fluorescence of DNA-ethidium bromide complex significantly and the apparent Stern-Volmer quenching constant has been estimated to be 1.71×10(4). Thermal denaturation study of DNA with CHL revealed the ΔTm of 8.0±0.2°C. Thermodynamic parameters, i.e., enthalpy (ΔH), entropy (ΔS°), and Gibbs free energy (ΔG) were 98.45 kJ mol(-1), 406.3 J mol(-1) and -22.627 kJ mol(-1), respectively. The ONIOM, based on the hybridization of QM/MM (DFT, 6.31++G(d,p)/UFF) methodology, was also performed using Gaussian 2003 package. The results revealed that the interaction is base sequence dependent, and the CHL has more interaction with ds-DNA via the GC base sequence. The results revealed that CHL may have an interaction with ds-DNA via the intercalation mode.
我们报告了一种多光谱、伏安法和量子力学/分子力学（QM/MM）混合的研究，研究了含有腺嘌呤-胸腺嘧啶和鸟嘌呤-胞嘧啶交替序列的双链 DNA 与氯唑草酮（CHL）除草剂之间的相互作用。通过在 HMDE 上进行循环伏安法研究了 CHL 的电化学行为，并通过在悬汞滴电极（HMDE）上进行阴极差分脉冲伏安法（CDPV）和在玻璃碳电极（GCE）上进行阳极差分脉冲伏安法（ADPV）研究了 ds-DNA 与 CHL 的相互作用。通过紫外/可见、CDPV 和 ADPV 获得的 CHL-DNA 配合物的恒定键合分别为 2.1×10(4)、5.1×10(4)和 2.6×10(4)。竞争荧光研究表明，CHL 显著猝灭 DNA-溴化乙锭复合物的荧光，并且已估计表观 Stern-Volmer 猝灭常数为 1.71×10(4)。用 CHL 对 DNA 的热变性研究表明，ΔTm 为 8.0±0.2°C。热力学参数，即焓（ΔH）、熵（ΔS°）和吉布斯自由能（ΔG）分别为 98.45 kJ mol(-1)、406.3 J mol(-1)和-22.627 kJ mol(-1)。还使用 Gaussian 2003 软件包基于 QM/MM（DFT、6.31++G(d,p)/UFF）混合方法进行了 ONIOM 计算。结果表明，这种相互作用是碱基序列依赖的，CHL 通过 GC 碱基序列与 ds-DNA 有更多的相互作用。结果表明，CHL 可能通过嵌入模式与 ds-DNA 相互作用。
