单分子技术的i基序DNA动态结构实验研究

Experimental Study on i-Motif DNA Dynamic Structure of Single Molecule Technology

为探索i基序(i-motif)DNA结构的折叠过程,利用单分子荧光共振能量转移技术,对基因序列bcl2在不同pH值(6.2~8.0)条件下进行动态检测。结果表明:当pH=6.2时,bcl2序列的荧光传递效率分布在0.95处为单峰,即i-motif结构处于均匀、完全的折叠状态;随着pH值增加至8.0,荧光传递效率分布逐步向左移动,效率峰最终停留在0.40处,即i-motif结构在高pH值条件下的部分去折叠过程。荧光能量转移效率动态分布曲线拟合出6个峰,即i-motif结构具有6个折叠状态。证明了当pH值发生改变时,i-motif可以在多种折叠状态间进行自发地变构与转换,为进一步研究i-motif的生理功能提供参考。

In order to explore the folding process of intercalated motif(i-motif)DNA structure,the gene sequence bcl2 was dynamically detected at different pH values(6.2~8.0)by single-molecule fluorescence resonance energy transfer technology.The results showed that the fluorescence resonance energy transfer(FRET)efficiency distribution peaked at 0.95 under the condition of pH=6.2,indicating that the i-motif structure was in a uniform and completely folded state.As the pH value increased to 8.0,the FRET efficiency distribution gradually shifted to the left,and the FRET distribution peak finally stayed at 0.40,indicating the partial defolding process of the i-motif structure under high pH conditions.The dynamic fluorescence transfer efficiency curve was fitted 6 peaks,indicating that the i-motif structure had 6 folding states.It is proved that i-motif can spontaneously metamorphose and convert between multiple folding states when the pH value changes,providing a reference for further study on the physiological function of i-motif.