石墨烯与抑癌基因p53 DNA片段相互作用的分子模拟与光谱学验证

Studies on the Interaction between Graphene and p53-DNA by Molecular Dynamics Simulations and Spectroscopic Methods

石墨烯(graphene,G)及其衍生物由于具有独特的理化性质,被广泛应用于能源、生物医学等领域,但尚缺乏其对生物体和环境潜在危害的研究。采用分子动力学模拟并结合光谱学方法(紫外可见吸收光谱、紫外变温实验及荧光光谱),分析了石墨烯与抑癌基因p53启动子区DNA片段(p53-DNA)间的相互作用,并探讨了相关作用机制。石墨烯的部分芳香环与p53-DNA碱基的芳香环之间存在π-π堆积作用,两者可以通过嵌插作用进行结合,同时还通过沟槽作用进一步结合。光谱实验进一步证实,在石墨烯作用下,p53-DNA的熔点(Tm)值升高,EB-DNA体系发生静态荧光淬灭,说明石墨烯能与p53-DNA结合;同时,p53-DNA与石墨烯结合后在260 nm处的吸光度升高,说明石墨烯对p53-DNA的双螺旋结构具有一定的破坏作用。上述研究结果从分子水平上分析了石墨烯与p53-DNA间的相互作用机制,有助于进一步阐明石墨烯的毒性作用机理。

Graphene and its derivatives have been widely used in the fields ranging from energy to biomedicine because of its peculiar physical and chemical properties. However, limited attention has been paid to potential haz- ards of graphene to organisms and environments. In this study, the interaction between graphene and the promoter region of p53 gene （p53-DNA） was investigated using molecular dynamics simulation （MD） technology and spectroscopic methods based on the combination of UV-vis absorption, DNA melting point test and fluorescent spectra, followed by the illustration of the interaction mechanism. MD results showed that some aromatic moieties of graphene could intercalate into the p53-DNA base pairs, which relied on π-π stacking interaction between aromatic moieties of graphene and p53-DNA base, and the other parts of graphene could further combine with p53-DNA by groove binding. Moreover, spectroscopic tests exhibited that graphene could increase the melting point （Tin） of p53- DNA and lead to static fluorescence quenching of EB-DNA system, suggesting that graphene was indeed able to bind with p53-DNA. Meanwhile, the ascent of absorbance of 260 nm was found in the p53-DNA as a result of the combination of graphene and p53-DNA, which meant graphene posed some effect on the double helix structure of p53-DNA. In conclusion, the mechanism of interaction between graphene and p53-DNA was investigated at molecular level in this study, which contributed to a further understanding of the toxicological effects of graphene.