激光扫描共聚焦表面等离子体共振系统实时监测单链DNA构象变化

脱氧核糖核酸(DNA)是染色体的重要组成部分,是一种主要的遗传物质,很多实验方法与理论模型被用来研究DNA与一些重要生物物种相互作用引起的构象变化。采用激光扫描共聚焦表面等离子体共振(LSCI-SPR)系统研究了一种特定单链DNA(ssDNA)分别与其互补DNA(cDNA)和汞离子(Hg~(2+))作用后的构象变化。将一端有荧光分子的ssDNA修饰在表面等离子体共振系统传感芯片上,通过观察荧光图像的变化来确定ssDNA与cDNA及Hg~(2+)之间相互作用而导致的构象变化,并通过动力学曲线计算出二者的结合速率分别为3.33×10~(-5) s~(-1)和1.42×10~(-4) s~(-1)。对于ssDNA-cDNA的相互作用,荧光图像没有变化。对于ssDNA-Hg~(2+)的相互作用,在通入Hg~(2+)后荧光发生猝灭。这些结果表明,激光扫描共聚焦表面等离子体共振系统在高灵敏实时监测ssDNA与其他特殊生物分子作用产生的构象变化和计算动力学参数方面有着广阔的应用前景。

Monitoring the single-stranded DNA comformational change by a laser scanning confocal imaging-surface plasmon resonance system in real time

Deoxyribonucleic acid (DNA) is a major component of chromosome and the main genetic material.Many methods have been applied to study the comformational change to investigate the interaction between DNA and other important biology materials by experimental and theoretical study.In this paper,a specific single-stranded DNA was chosen to investigate the conformation change by the interaction with Hg²⁺ions and its complementary DNA.We use a laser scanning confocal imaging-surface plasmon resonance (LSCI-SPR) system to monitor the interact process based on a SPR sensor.At the same time,the fluorescence images recorded identify the mechanisms induce the different conformational changes for ssDNA-DNA and ssDNA-Hg²⁺ions interaction.We can estimate the associate rates from the kinetic curve are 3.33×10^-5 s^-1 and 1.42×10^-4 s^-1.For ssDNA-cDNA interaction,the fluorescence images are not changed.For ssDNA-Hg²⁺ ions interaction,the fluorescence images dim because the SPR on the gold film surface can quench fluorescence within a certain distance.These results indicate the LSCI-SPR have potential application to monitor the conformation change of ssDNA,get the dynamic constants and investigate the mechanisms in real time for some specific biology molecular-molecular interaction with high sensitivity.