Shi Jie-Hua, Pan Dong-Qi, Wang Xiou-Xiou, Liu Ting-Ting, Jiang Min, Wang Qi
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China; State Key Laboratory Breeding Base of Green Chemistry Synthesis Technology, Zhejiang University of Technology, Hangzhou 310032, China.
College of Pharmaceutical Science, Zhejiang University of Technology, Hangzhou 310032, China.
J Photochem Photobiol B. 2016 Sep;162:14-23. doi: 10.1016/j.jphotobiol.2016.06.025. Epub 2016 Jun 15.
Artemether (AMT), a peroxide sesquiterpenoides, has been widely used as an antimalarial for the treatment of multiple drug-resistant strains of plasmodium falciparum malaria. In this work, the binding interaction of AMT with bovine serum albumin (BSA) under the imitated physiological conditions (pH7.4) was investigated by UV spectroscopy, fluorescence emission spectroscopy, synchronous fluorescence spectroscopy, Fourier transform infrared spectroscopy (FT-IR), circular dichroism (CD), three-dimensional fluorescence spectroscopy and molecular docking methods. The experimental results indicated that there was a change in UV absorption of BSA along with a slight red shift of absorption wavelength, indicating that the interaction of AMT with BSA occurred. The intrinsic fluorescence of BSA was quenched by AMT due to the formation of AMT-BSA complex. The number of binding sites (n) and binding constant of AMT-BSA complex were about 1 and 2.63×10(3)M(-1) at 298K, respectively, suggesting that there was stronger binding interaction of AMT with BSA. Based on the analysis of the signs and magnitudes of the free energy change (ΔG(0)), enthalpic change (ΔH(0)) and entropic change (ΔS(0)) in the binding process, it can be concluded that the binding of AMT with BSA was enthalpy-driven process due to |ΔH°|>|TΔS°|. The results of experiment and molecular docking confirmed the main interaction forces between AMT and BSA were van der Waals force. And, there was a slight change in the BSA conformation after binding AMT but BSA still retains its secondary structure α-helicity. However, it had been confirmed that AMT binds on the interface between sub-domain IIA and IIB of BSA.
蒿甲醚（AMT）是一种过氧化物倍半萜，已被广泛用作抗疟药，用于治疗多重耐药性恶性疟原虫疟疾。在本研究中，通过紫外光谱、荧光发射光谱、同步荧光光谱、傅里叶变换红外光谱（FT-IR）、圆二色光谱（CD）、三维荧光光谱和分子对接方法，研究了在模拟生理条件（pH7.4）下AMT与牛血清白蛋白（BSA）的结合相互作用。实验结果表明，BSA的紫外吸收发生变化，吸收波长略有红移，表明AMT与BSA发生了相互作用。由于形成了AMT-BSA复合物，AMT猝灭了BSA的固有荧光。在298K时，AMT-BSA复合物的结合位点数量（n）和结合常数分别约为1和2.63×10(3)M(-1)，表明AMT与BSA之间存在较强的结合相互作用。基于对结合过程中自由能变化（ΔG(0)）、焓变（ΔH(0)）和熵变（ΔS(0)）的符号和大小分析，可以得出结论，由于|ΔH°|>|TΔS°|，AMT与BSA的结合是焓驱动过程。实验和分子对接结果证实，AMT与BSA之间的主要相互作用力是范德华力。并且，结合AMT后BSA的构象有轻微变化，但BSA仍保留其二级结构α-螺旋度。然而，已证实AMT结合在BSA的亚结构域IIA和IIB之间的界面上。
