Structural Characterization of Nanoscale Meshworks within a Nucleoporin FG Hydrogel
Structural Characterization of Nanoscale Meshworks within a Nucleoporin FG Hydrogel
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DOI：
10.1021/bm300412q
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发表时间：
2012-06-01
影响因子：
6.2
通讯作者：
Techert, Simone
中科院分区：
文献类型：
--
作者：
Petri, Marcel;Frey, Steffen;Techert, Simone
核孔复合物（NPCs）的渗透性屏障控制着细胞质和细胞核之间所有大分子的交换。它由苯基丙氨酸（FG）重复结构域组成，明显组织为FG水凝胶。以前已经证明，从酵母核孔蛋白Nsp1p衍生的FG水凝胶再现了真正的NPCs的选择性。在这里，我们结合了时间分辨光学光谱和x射线散射技术来表征这种凝胶。数据表明，在凝胶过程中，以牺牲非结构化元素为代价形成了结构层次。在最大尺度上，相关长度接近16.5 nm的富蛋白结构域是明显的。在较小的长度尺度上，发现了平均直径约为3 nm的水通道，这可能代表了核孔被动筛分作用的物理结构。富含蛋白质的结构域包含典型的β -链和β -片间距离分别为1.3 nm和0.47 nm的β -结构。在凝胶过程中，低聚物的形成伴随着苯基丙氨酸转移到疏水微环境中，这支持了这一过程是由疏水崩溃驱动的观点。
The permeability barrier of nuclear pore complexes (NPCs) controls all exchange of macromolecules between the cytoplasm and the cell nucleus. It consists of phenylalanineglycine (FG) repeat domains apparently organized as an FG hydrogel. It has previously been demonstrated that an FG hydrogel derived from the yeast nucleoporin Nsp1p reproduces the selectivity of authentic NPCs. Here we combined time-resolved optical spectroscopy and X-ray scattering techniques to characterize such a gel. The data suggest a hierarchy of structures that form during gelation at the expense of unstructured elements. On the largest scale, protein-rich domains with a correlation length of similar to 16.5 nm are evident. On a smaller length scale, aqueous channels with an average diameter of similar to 3 nm have been found, which possibly represent the physical structures accounting for the passive sieving effect of nuclear pores. The protein-rich domains contain characteristic beta-structures with typical inter-beta-strand and inter-beta-sheet distances of 1.3 and 0.47 nm, respectively. During gelation, the formation of oligomeric associates is accompanied by the transfer of phenylalanines into a hydrophobic microenvironment, supporting the view that this process is driven by a hydrophobic collapse.