Zaman Masihuz, Nusrat Saima, Zakariya Syed Mohammad, Khan Mohsin Vahid, Ajmal Mohammad Rehan, Khan Rizwan Hasan
Interdisciplinary Biotechnology Unit, Aligarh Muslim University, Aligarh, 202002, India.
J Mol Recognit. 2017 Aug;30(8). doi: 10.1002/jmr.2619. Epub 2017 Mar 14.
Nowadays, understanding of interface between protein and drugs has become an active research area of interest. These types of interactions provide structural guidelines in drug design with greater clinical efficacy. Thus, structural changes in catalase induced by clofazimine were monitored by various biophysical techniques including UV-visible spectrometer, fluorescence spectroscopy, circular dichroism, and dynamic light scattering techniques. Increase in absorption spectra (UV-visible spectrum) confers the complex formation between drug and protein. Fluorescence quenching with a binding constants of 2.47 × 10 M revealed that clofazimine binds with protein. Using fluorescence resonance energy transfer, the distance (r) between the protein (donor) and drug (acceptor) was found to be 2.89 nm. Negative Gibbs free energy change (ΔG°) revealed that binding process is spontaneous. In addition, an increase in α-helicity was observed by far-UV circular dichroism spectra by adding clofazimine to protein. Dynamic light scattering results indicate that topology of bovine liver catalase was slightly altered in the presence of clofazimine. Hydrophobic interactions are the main forces between clofazimine and catalase interaction as depicted by molecular docking studies. Apart from hydrophobic interactions, some hydrogen bonding was also observed during docking method. The results obtained from the present study may establish abundant in optimizing the properties of ligand-protein mixtures relevant for numerous formulations.
如今，对蛋白质与药物之间界面的理解已成为一个活跃的研究热点领域。这类相互作用为具有更高临床疗效的药物设计提供了结构指导。因此，采用紫外可见光谱仪、荧光光谱、圆二色光谱和动态光散射技术等多种生物物理技术监测了氯法齐明诱导的过氧化氢酶的结构变化。吸收光谱（紫外可见光谱）的增加表明药物与蛋白质之间形成了复合物。结合常数为2.47×10 M的荧光猝灭表明氯法齐明与蛋白质结合。利用荧光共振能量转移，发现蛋白质（供体）与药物（受体）之间的距离（r）为2.89 nm。负的吉布斯自由能变化（ΔG°）表明结合过程是自发的。此外，通过向蛋白质中添加氯法齐明，远紫外圆二色光谱观察到α-螺旋度增加。动态光散射结果表明，在氯法齐明存在下，牛肝过氧化氢酶的拓扑结构略有改变。分子对接研究表明，疏水相互作用是氯法齐明与过氧化氢酶相互作用的主要力量。除疏水相互作用外，对接过程中还观察到一些氢键。本研究获得的结果可能为优化与众多制剂相关的配体-蛋白质混合物的性质提供丰富的依据。
