Molecular design of protein-based nanocapsules for stimulus-responsive characteristics
Molecular design of protein-based nanocapsules for stimulus-responsive characteristics
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DOI：
10.1016/j.bmc.2008.11.013
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发表时间：
2009-01-01
影响因子：
3.5
通讯作者：
Hashizume, Makoto
中科院分区：
文献类型：
--
作者：
Sao, Kentaro;Murata, Masaharu;Hashizume, Makoto
Hsp16.5是一种来自高温考古子的小分子热休克蛋白，由24个亚基组成的均一复合体，分子量约为400 kDa。这种复合体在生理条件下自组织，其结构为具有小孔的纳米球形胶囊。此外，这种天然纳米胶囊表现出非常高的热稳定性。在本文中，我们将纳米胶囊功能化，以控制结构对外部刺激的响应，如蛋白酶信号和温度。为此，使用基因工程策略，在纳米胶囊的外表面引入了几个突变(Mut1-10)，以创建特定的蛋白酶Xa因子的切割位点。得到的突变体在大肠杆菌中得到了高水平的表达。其中一个突变体Mut6具有最容易获得的切割位点，位于胶囊表面的三角形孔洞，形成了一个类似于观察到的野生型蛋白质的球形组装。Mut6对因子Xa的敏感性最高，酶消化后的Mut6在加热后结构不可逆地解离。相反，由野生型Hsp16.5组成的纳米胶囊不受双重刺激的影响。这些结果表明，Mut6起到了刺激反应纳米胶囊的作用。基于蛋白质的纳米胶囊的这种特性具有作为多功能智能系统的诱人潜力。(C)2008爱思唯尔有限公司。保留所有权利。
Hsp16.5, a small heat-shock protein (sHSP) from hyperthermophilic archaeon, forms a homogeneous complex comprised of 24 subunits with a molecular mass of 400 kDa. This complex self-organizes under physiological conditions, and the structure of the complex is a nanoscale spherical capsule with small pores. Furthermore, this natural nanocapsule exhibits very high thermal stability. In this paper, we functionalized the nanocapsule to control the structure in response to external stimuli such as a protease signal and temperature. For this purpose, several mutations (Mut1 - 10) to create a cleavage site for a specific protease, Factor Xa, were introduced on the outer surface of the nanocapsule using a genetic engineering strategy. The resulting mutants were expressed to high levels in Escherichia coli. One of these mutants, Mut6, which has the most accessible cleavage site located at the triangular pore on the surface of the capsule, formed a spherical assembly similar to that observed for the wild-type protein. Mut6 showed the highest sensitivity to Factor Xa, and the structure of the protease digested Mut6 disassembled irreversibly after heating. In contrast, the nanocapsule comprising the wild-type Hsp16.5 was not influenced by the dual stimuli. These results suggest that Mut6 acts as a stimulus-responsive nanocapsule. Such a characteristic of the protein-based nanocapsule has attractive potential as a versatile intelligent system. (c) 2008 Elsevier Ltd. All rights reserved.