Gaitzsch Jens, Hirschi Stephan, Freimann Sven, Fotiadis Dimitrios, Meier Wolfgang
Department of Chemistry , University of Basel , Klingelbergstrasse 80 , 4058 Basel , Switzerland.
Institute of Biochemistry and Molecular Medicine , University of Bern , Bühlstrasse 28 , 3012 Bern , Switzerland.
Nano Lett. 2019 Apr 10;19(4):2503-2508. doi: 10.1021/acs.nanolett.9b00161. Epub 2019 Mar 28.
Nanoscopic artificial vesicles containing functional protein transporters are fundamental for synthetic biology. Energy-providing modules, such as proton pumps, are a basis for simple nanoreactors. We report on the first insertion of a functional transmembrane protein into asymmetric polymersomes from an ABC triblock copolymer. The polymer with the composition poly(ethylene glycol)-poly(diisopropylaminoethyl methacrylate)-poly(styrenesulfonate) (PEG-PDPA-PSS) was synthesized by sequential controlled radical polymerization. PEG and PSS are two distinctively different hydrophilic blocks, allowing for a specific orientation of our protein, the light-activated proton pump proteorhodopsin (PR), into the final proteopolymersome. A very interesting aspect of the PEG-PDPA-PSS triblock copolymers is that it allowed for simultaneous vesicle formation and oriented insertion of PR simply by adjusting the pH. The intrinsic positive charge of PR's intracellular surface was enhanced by a His-tag, which aligns readily with the negative charges of the PSS on the outside of the polymersomes. The directed insertion of PR was confirmed by a light-dependent pH change of the proteopolymersome solution, indicating the intended orientation. We have hereby demonstrated the first successful oriented insertion of a proton pump into an artificial asymmetric membrane.
包含功能性蛋白质转运体的纳米级人工囊泡是合成生物学的基础。诸如质子泵等能量供应模块是简单纳米反应器的基础。我们报道了首次将功能性跨膜蛋白从一种ABC三嵌段共聚物插入不对称聚合物囊泡中。通过顺序控制自由基聚合合成了具有聚（乙二醇）-聚（甲基丙烯酸二异丙基氨基乙酯）-聚（苯乙烯磺酸盐）（PEG-PDPA-PSS）组成的聚合物。PEG和PSS是两个截然不同的亲水嵌段，使得我们的蛋白质——光激活质子泵视紫质（PR）能够以特定方向插入最终的蛋白质聚合物囊泡中。PEG-PDPA-PSS三嵌段共聚物一个非常有趣的方面是，仅通过调节pH值就能同时形成囊泡并使PR定向插入。PR细胞内表面的固有正电荷通过一个His标签得到增强，该标签很容易与聚合物囊泡外部PSS的负电荷对齐。通过蛋白质聚合物囊泡溶液的光依赖性pH变化证实了PR的定向插入，表明了预期的方向。我们在此展示了首次成功地将质子泵定向插入人工不对称膜中。
