Zhao Zhixing, Zhang Miaomiao, Tang Bailing, Weng Peimin, Zhang Yueyang, Yan Xiaosheng, Li Zhao, Jiang Yun-Bao
The MOE Key Laboratory of Spectrochemical Analysis and Instrumentation, Department of Chemistry, College of Chemistry and Chemical Engineering, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), Xiamen University, Xiamen, China.
Front Chem. 2021 Jan 12;8:621323. doi: 10.3389/fchem.2020.621323. eCollection 2020.
Diverse classes of anion transporters have been developed, most of which focus on the transmembrane chloride transport due to its significance in living systems. Fluoride transport has, to some extent, been overlooked despite the importance of fluoride channels in bacterial survival. Here, we report the design and synthesis of a cyclic azapeptide (a peptide-based -amidothiourea, ), as a transporter for fluoride transportation through a confined cavity that encapsulates fluoride, together with acyclic control compounds, the analogs and . Cyclic receptor exhibits more stable β-turn structures than the control compounds and and affords a confined cavity containing multiple inner -NH protons that serve as hydrogen bond donors to bind anions. It is noteworthy that the cyclic receptor shows the capacity to selectively transport fluoride across a lipid bilayer on the basis of the osmotic and fluoride ion-selective electrode (ISE) assays, during which an electrogenic anion transport mechanism is found operative, whereas no transmembrane transport activity was found with and , despite the fact that and are also able to bind fluoride via the thiourea moieties. These results demonstrate that the encapsulation of an anionic guest within a cyclic host compound is key to enhancing the anion transport activity and selectivity.
已经开发出多种类型的阴离子转运体，其中大多数由于其在生命系统中的重要性而专注于跨膜氯离子转运。尽管氟离子通道在细菌存活中具有重要意义，但氟离子转运在一定程度上被忽视了。在此，我们报告了一种环状氮杂肽（一种基于肽的氨基硫脲）的设计与合成，它作为一种转运体，可通过包裹氟离子的受限腔进行氟离子转运，同时还合成了无环对照化合物、类似物和。环状受体比对照化合物和具有更稳定的β-转角结构，并提供了一个包含多个内部-NH质子的受限腔，这些质子作为氢键供体来结合阴离子。值得注意的是，基于渗透和氟离子选择性电极（ISE）测定，环状受体显示出跨脂质双分子层选择性转运氟离子的能力，在此过程中发现一种电生阴离子转运机制起作用，而和尽管也能够通过硫脲部分结合氟离子，但未发现跨膜转运活性。这些结果表明，在环状主体化合物中包裹阴离子客体是增强阴离子转运活性和选择性的关键。
