基于原子力显微镜研究固-液界面单链DNA结合蛋白纤维分形结构的形成机制

Formation mechanism of single-stranded DNA binding protein fibers fractal structure at liquid-solid interface studied by atomic force microscopy

单链DNA结合蛋白(SSBP)可以在修饰了1-十六烷基硫醇单层膜的金基底(HDT/Au)上由4-氨基噻吩(4-ATP)诱导自组装形成原纤维。利用原子力显微镜对SSBP自组装形成的分形结构进行了纳米尺度表征和成像,以及结构分析。结果显示,在HDT/Au基底上,酰胺类物质可以诱导蛋白质纤维的形成,而烷基硫醇或羧基硫醇不能在HDT/Au底物上诱导蛋白质原纤维的形成。这表明正电荷酰胺与蛋白质之间的静电力为蛋白质原纤维的自组装提供了促进聚合的驱动力。酰胺类物质诱导分枝状蛋白质纤维的形成,而不是更致密的单丝紧密堆积,为发展一种全新的、空间可控的蛋白质界面自组装方法提供了依据。

Single-stranded DNA binding protein(SSBP)could self-assemble into fibrils by 4-aminothiophene(4-ATP)on a gold substrate modified with 1-hexadecyl mercaptan monolayer membrane(HDT/Au).The nanoscale characterization and imaging of the branched patterns formed by the self-assembly of proteins were observed via atomic force microscopy(AFM)for structural analysis.The results showed that amides could induce the formation of protein fibers on HDT/Au substrates,while alkanethiols or carboxythiols could not.It suggested that electrostatic forces between positively charged amides and proteins provided the driving forces to promote aggregation for the self-assembly of protein fibrils.The formation of branched-like protein fibrils rather than the more compact close-packing of single filaments induced by amide substances might provide a basis for the development of a new and spatially controllable protein interface self-assembly method.