Department of Physics, Indian Institute of Technology (Indian School of Mines), Dhanbad, Jharkhand, 826004, India.
Department of Biochemistry and Medical Biotechnology, School of Tropical Medicine, Kolkata, West Bengal, 700073, India.
Anal Bioanal Chem. 2020 Apr;412(11):2565-2577. doi: 10.1007/s00216-020-02483-1. Epub 2020 Feb 13.
In the present work, biophysical insight into the binding interactions of the protein, hen egg white (HEW) lysozyme (Lyz) with an anticancer drug, 6-mercaptopurine (6-MP)' was investigated by using a combination of spectroscopic and computational tools. 6-MP, a synthetic analog of natural purines, is a well-known anticancer drug and antiviral agent that inhibits the synthesis of RNA, DNA, and proteins. Lysozyme is a single-chain protein that can combine with endogenous and exogenous substances to exert its antiviral, antibacterial, and antitumor effects. The intrinsic fluorescence of lysozyme was quenched with the increased addition of 6-MP. The quenching mechanism was found to be static in nature as shown by the fluorescence lifetime and excitation spectrum measurements. The conformational changes of Lyz in the presence of 6-MP were monitored both at the ensemble and single-molecule level by using synchronous fluorescence spectroscopy, circular dichroism (CD), and fluorescence correlation spectroscopy (FCS). Molecular docking results predicted the probable binding sites for 6-MP on Lyz. The experimental findings are in good agreement with the results obtained by the molecular dynamics (MD) simulation study. Graphical abstract.
在本工作中，通过结合光谱和计算工具，研究了蛋白质鸡卵清溶菌酶（Lyz）与抗癌药物 6-巯基嘌呤（6-MP）的结合相互作用的生物物理见解。6-MP 是天然嘌呤的合成类似物，是一种众所周知的抗癌药物和抗病毒剂，可抑制 RNA、DNA 和蛋白质的合成。溶菌酶是一种单链蛋白，可与内源性和外源性物质结合，发挥其抗病毒、抗菌和抗肿瘤作用。溶菌酶的固有荧光随着 6-MP 的增加而猝灭。荧光寿命和激发光谱测量表明，猝灭机制本质上是静态的。通过同步荧光光谱、圆二色性（CD）和荧光相关光谱（FCS），在集合和单分子水平上监测了 Lyz 在 6-MP 存在下的构象变化。分子对接结果预测了 6-MP 在 Lyz 上的可能结合位点。实验结果与分子动力学（MD）模拟研究的结果吻合较好。
