原子力显微镜研究单链DNA引导单链DNA蛋白质分形自组装

Investigation of the fractal self-assembly of SSBP induced by ssDNA with atomic force microscopy

基于单链DNA(single-stranded DNA,ss DNA)和单链DNA键合蛋白质(ss DNA binding protein SSBP)的高亲和力,在十六烷基硫醇修饰的金基底(HDT/Au)上构建了SSBP的分形结构。利用高分辨原子力显微镜表征了SSBP的枝状结构,在不同的组装时间下,SSBP在HDT/Au基底形成不同结构的可控形貌,形成的自组装结构具有高度有序性,可以有效地阻止生物分子的相互交叉或重叠。利用这种二维自组装方法形成的蛋白质纤维结构的变化遵循有限扩散凝聚(Diffusionlimited aggregation,DLA)过程。SSBP和ss DNA之间的高亲和力是整个自组装过程的驱动力,由DNA引导蛋白质构筑的分形结构提供了一种构建形貌可控的蛋白质纳米纤维的新方法。

By the high affinity between single-stranded DNA （ssDNA） and ssDNA binding protein （SSBP）, the SSBP fractal structures were formed on the gold substrate modified by 1-hexadecanethiol （HDT）. The nanoscaled imaging of the SSBP branched patterns were imaged via high resolution atomic force microscopy （AFM） imaging. Under different incubation time, SSBP assembled in a controlled manner into different morphologies on the HDT/Au. The assembly structures showed highly well-ordered organization and could effectively prevent the biomolecules from mutual contacting and overlapping. The structural changes of protein fibers formed by the two-dimensional assembled approach followed the diffusion limited aggregation （DLA） process. It provides a simple way to fabricate shape-controllable protein nanowires at designated positions.