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1.
《中国化学快报》2023,34(12):108355
Replicating extraordinarily high membrane transport selectivity of protein channels in artificial channel is a challenging task. In this work, we demonstrate that a strategic application of steric code-based social self-sorting offers a novel means to enhance ion transport selectivities of artificial ion channels, alongside with boosted ion transport activities. More specifically, two types of mutually compatible sterically bulky groups (benzo-crown ether and tert-butyl group) were appended onto a monopeptide-based scaffold, which can order the bulky groups onto the same side of a one-dimensionally aligned H-bonded structure. Strong steric repulsions among the same type of bulky groups (either benzo-crown ethers or tert-butyl groups), which are forced into proximity by H-bonds, favor the formation of hetero-oligomeric ensembles that carry an alternative arrangement of sterically compatible benzo-crown ethers and tert-butyl groups, rather than homo-oligomeric ensembles containing a single type of either benzo-crown ethers or tert-butyl groups. Coupled with side chain tuning, this social self-sorting strategy delivers highly active hetero-oligomeric K+-selective ion channel (5F12‧BF12)n, displaying the highest K+/Na+ selectivity of 20.1 among artificial potassium channels and an excellent EC50 value of 0.50 μmol/L (0.62 mol% relative to lipids) in terms of single channel concentration 相似文献
2.
Pengyang Xin Huiyuan Kong Yonghui Sun Lingyu Zhao Haodong Fang Haofeng Zhu Tao Jiang Jingjing Guo Qian Zhang Wenpei Dong Chang‐Po Chen 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(9):2805-2810
A class of artificial K+ channels formed by pillararene‐cyclodextrin hybrid molecules have been designed and synthesized. These channels efficiently inserted into lipid bilayers and displayed high selectivity for K+ over Na+ in fluorescence and electrophysiological experiments. The cation transport selectivity of the artificial channels is tunable by varying the length of the linkers between pillararene and cyclodexrin. The shortest channel showed specific transmembrane transport preference for K+ over all alkali metal ions (selective sequence: K+ > Cs+ > Rb+ > Na+ > Li+), and is rarely observed for artificial K+ channels. The high selectivity of this artificial channel for K+ over Na+ ensures specific transmembrane translocation of K+, and generated stable membrane potential across lipid bilayers. 相似文献
3.
《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(41):12842-12845
Potassium ion channels specifically transport K+ ions over Na+ ions across a cell membrane. A queue of four binding sites in the K+ channel pore plays significant roles during highly selective conduction. A kind of aromatic helical oligomer was synthesized that can selectively bind K+ over Na+. By aromatic stacking of helical oligomers, a type of artificial K+ channels with contiguous K+ binding sites was constructed. Such artificial channels exhibited exceptionally high K+/Na+ selectivity ratios during transmembrane ion conduction. 相似文献
4.
Arundhati Roy Himanshu Joshi Ruijuan Ye Jie Shen Feng Chen Aleksei Aksimentiev Huaqiang Zeng 《Angewandte Chemie (International ed. in English)》2020,59(12):4806-4813
Reported herein is a series of pore‐containing polymeric nanotubes based on a hydrogen‐bonded hydrazide backbone. Nanotubes of suitable lengths, possessing a hollow cavity of about a 6.5 Å diameter, mediate highly efficient transport of diverse types of anions, rather than cations, across lipid membranes. The reported polymer channel, having an average molecular weight of 18.2 kDa and 3.6 nm in helical height, exhibits the highest anion‐transport activities for iodide (EC50=0.042 μm or 0.028 mol % relative to lipid), whcih is transported 10 times more efficiently than chlorides (EC50=0.47 μm ). Notably, even in cholesterol‐rich environment, iodide transport activity remains high with an EC50 of 0.37 μm . Molecular dynamics simulation studies confirm that the channel is highly selective for anions and that such anion selectivity arises from a positive electrostatic potential of the central lumen rendered by the interior‐pointing methyl groups. 相似文献
5.
A non‐ionic cryptand‐22 surfactant consisting of a macrocyclic cryptand‐22 polar head and a long paraffinic chain (C10H21‐Cryptand‐22) was synthesized and characterized. The critical micellar concentration (CMC) of the cryptand surfactant in ROH/H2O mixed solvent was determined by the pyrene fluorescence probe method. In general, the cmc of the cryptand surfactant increased upon decreasing the polarity of the surfactant solution. The cryptand surfactant also can behave as a pseudo cationic surfactant by protonation of cryptand‐22 or complexation with metal ions. Effects of protonation and metal ions on the cmc of the cryptand surfactant were investigated. A preliminary application of the cryptand surfactant as an ion‐transport carrier for metal ions, e.g., Li+, Na+, K+ and Sr2+, through an organic liquid‐membrane was studied. The transport ability of the cryptand surfactant for these metal ions was in the order: K+ ≥ Na+ < Li+ < Sr2+. A comparison of the ion‐transport ability of the cryptand surfactant with other macrocyclic polyethers, e.g., dibenzo‐18‐crown‐6, 18‐crown‐6 and benzo‐15‐crown‐5, was studied and discussed. Among these macrocyclic polyethers, the cryptand surfactant was the best ion‐transport carrier for Na+, Li+ and Sr2+ ions. Furthermore, a foam extraction system using the cryptand surfactant to extract the cupric ion was also investigated. 相似文献
6.
Squalyl Crown Ether Self‐Assembled Conjugates: An Example of Highly Selective Artificial K+ Channels
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Dr. Zhanhu Sun Dr. Arnaud Gilles Istvan Kocsis Dr. Yves‐Marie Legrand Eddy Petit Dr. Mihail Barboiu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(6):2158-2164
The natural KcsA K+ channel, one of the best‐characterized biological pore structures, conducts K+ cations at high rates while excluding Na+ cations. The KcsA K+ channel is of primordial inspiration for the design of artificial channels. Important progress in improving conduction activity and K+/Na+ selectivity has been achieved with artificial ion‐channel systems. However, simple artificial systems exhibiting K+/Na+ selectivity and mimicking the biofunctions of the KcsA K+ channel are unknown. Herein, an artificial ion channel formed by H‐bonded stacks of squalyl crown ethers, in which K+ conduction is highly preferred to Na+ conduction, is reported. The K+‐channel behavior is interpreted as arising from discreet stacks of dimers resulting in the formation of oligomeric channels, in which transport of cations occurs through macrocycles mixed with dimeric carriers undergoing dynamic exchange within the bilayer membrane. The present highly K+‐selective macrocyclic channel can be regarded as a biomimetic alternative to the KcsA channel. 相似文献
7.
Prof. Dr. Jie Shen Deepa R Zhongyan Li Hyeonji Oh Harekrushna Behera Dr. Himanshu Joshi Prof. Dr. Manish Kumar Prof. Dr. Aleksei Aksimentiev Prof. Dr. Huaqiang Zeng 《Angewandte Chemie (International ed. in English)》2023,62(39):e202305623
Unlike many other biologically relevant ions (Na+, K+, Ca2+, Cl−, etc) and protons, whose cellular concentrations are closely regulated by highly selective channel proteins, Li+ ion is unusual in that its concentration is well tolerated over many orders of magnitude and that no lithium-specific channel proteins have so far been identified. While one naturally evolved primary pathway for Li+ ions to traverse across the cell membrane is through sodium channels by competing with Na+ ions, highly sought-after artificial lithium-transporting channels remain a major challenge to develop. Here we show that sulfur-containing organic nanotubes derived from intramolecularly H-bonded helically folded aromatic foldamers of 3.6 Å in hollow cavity diameter could facilitate highly selective and efficient transmembrane transport of Li+ ions, with high transport selectivity factors of 15.3 and 19.9 over Na+ and K+ ions, respectively. 相似文献
8.
《Journal of membrane science》1999,163(2):367-372
The liquid membrane transport of Na+ ions by p-tert-butylcalix[6]arene and that of K+ ions by p-tert-butylcalix[8]arene were investigated by means of a bubbling pseudo-emulsion liquid membrane system. This system represents a proton-coupled transport with a flow of protons in the opposite direction. The driving force for the transport is the pH gradient between the source and receiving phases. When the pH difference between the two phases is sufficient, the carriers calix[6]arene(or calix[8]arene) can successfully transport Na+ (or K+) ions from the source phase with a lower Na+ (or K+) concentration into the receiving phase with a higher Na+ (or K+) concentration, like a Na+ (or K+) ion pump. 相似文献
9.
Selective Permeability of Uranyl Peroxide Nanocages to Different Alkali Ions: Influences from Surface Pores and Hydration Shells
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Yunyi Gao Fadi Haso Jennifer E. S. Szymanowski Jing Zhou Lang Hu Prof. Dr. Peter C. Burns Prof. Dr. Tianbo Liu 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(51):18785-18790
The precise guidance to different ions across the biological channels is essential for many biological processes. An artificial nanopore system will facilitate the study of the ion‐transport mechanism through nanosized channels and offer new views for designing nanodevices. Herein we reveal that a 2.5 nm‐sized, fullerene‐shaped molecular cluster Li48+mK12(OH)m[UO2(O2)(OH)]60?(H2O)n (m≈20 and n≈310) ( U60 ) shows selective permeability to different alkali ions. The subnanometer pores on the water–ligand‐rich surface of U60 are able to block Rb+ and Cs+ ions from passing through, while allowing Na+ and K+ ions, which possess larger hydrated sizes, to enter the interior space of U60 . An interestingly high entropy gain during the binding process between U60 and alkali ions suggests that the hydration shells of Na+/K+ and U60 are damaged during the interaction. The ion selectivity of U60 is greatly influenced by both the morphologies of the surface nanopores and the dynamics of the hydration shells. 相似文献
10.
Katsuya Ichihashi Daisuke Konno Kseniya Yu. Maryunina Katsuya Inoue Kazuhiro Toyoda Shogo Kawaguchi Yoshiki Kubota Yoko Tatewaki Tomoyuki Akutagawa Takayoshi Nakamura Sadafumi Nishihara 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2019,131(13):4213-4216
Artificial ion channels are of increasing interest because of potential applications in biomimetics, for example, for realizing selective ion permeability through the transport and/or exchange of selected ions. However, selective ion transport and/or exchange in the crystalline state is rare, and to the best of our knowledge, such a process has not been successfully combined with changes in the physical properties of a material. Herein, by soaking single crystals of Li2([18]crown‐6)3[Ni(dmit)2]2(H2O)4 ( 1 ) in an aqueous solution containing K+, we succeeded in complete ion exchange of the Li+ ions in 1 with K+ ions in the solution, while maintaining the crystalline state of the material. This ion exchange with K+ was selectively conducted even in mixed solutions containing K+ as well as Na+/Li+. Furthermore, remarkable changes in the physical properties of 1 resulted from the ion exchange. Our finding enables not only the realization of selective ion permeability but also the development of highly sensitive biosensors and futuristic ion exchange agents, for example. 相似文献
11.
Ge Su Min Zhang Wen Si Prof. Zhan‐Ting Li Prof. Jun‐Li Hou 《Angewandte Chemie (International ed. in English)》2016,55(47):14678-14682
Three unimolecular peptide channels have been designed and prepared by using the β‐helical conformation of gramicidin A (gA). The new peptides bear one to three NH3+ groups at the N‐end and one to three CO2? groups at the C‐end. These zwitterionic peptides were inserted into lipid bilayers in an orientation‐selective manner. Conductance experiments on planar lipid bilayers showed that this orientation bias could lead to observable directional K+ transport under multi‐channel conditions. This directional transport behavior can further cause the generation of a current across a planar bilayer without applying a voltage. More importantly, in vesicles with identical external and internal KCl concentrations, the channels can pump K+ across the lipid bilayer and cause a membrane potential. 相似文献
12.
James K. R. Kendall Benjamin R. G. Johnson Dr. Philip H. Symonds Guiseppi Imperato Richard J. Bushby Prof. James D. Gwyer Dr. Cees van Berkel Dr. Stephen D. Evans Prof. Lars J. C. Jeuken Dr. 《Chemphyschem》2010,11(10):2191-2198
Tethered bilayer lipid membranes (tBLM) are formed on 1) pure tether lipid triethyleneoxythiol cholesterol (EO3C) or on 2) mixed self‐assembled monolayers (SAMs) of EO3C and 6‐mercaptohexanol (6MH). While EO3C is required to form a tBLM with high resistivity, 6MH dilutes the cholesterol content in the lower leaflet of the bilayer forming ionic reservoirs required for submembrane hydration. Here we show that these ionic reservoirs are required for ion transport through gramicidin or valinomycin, most likely due to the thermodynamic requirements of ions to be solvated once transported through the membrane. Unexpectedly, electrochemical impedance spectroscopy (EIS) shows an increase of capacitance upon addition of gramicidin, while addition of valinomycin decreases the membrane resistance in the presence of K+ ions. We hypothesise that this is due to previously reported phase separation of EO3C and 6MH on the surface. This results in ionic reservoirs on the nanometre scale, which are not fully accounted for by the equivalent circuits used to describe the system. 相似文献
13.
Lei Zhang Chenyang Zhang Xin Dong Zeyuan Dong 《Angewandte Chemie (International ed. in English)》2023,62(6):e202214194
Lithium ions have been applied in the clinic in the treatment of psychiatric disorders. In this work, we report artificial supramolecular lithium channels composed of pore-containing small aromatic molecules. By adjusting the lumen size and coordination numbers, we found that one of the supramolecular channels developed shows unprecedented transmembrane transport of exogenous lithium ions with a Li+/Na+ selectivity ratio of 23.0, which is in the same level of that of natural Na+ channels. Furthermore, four coordination sites inside channels are found to be the basic requirement for ion transport function. Importantly, this artificial lithium channel displays very low transport of physiological Na+, K+, Mg2+, and Ca2+ ions. This highly selective Li+ channel may become an important tool for studying the physiological role of intracellular lithium ions, especially in the treatment of psychiatric disorders. 相似文献
14.
In‐Won Park Jaeduk Yoo Bohyang Kim Dr. Suman Adhikari Dr. Sung Kuk Kim Yerim Yeon Dr. Cally J. E. Haynes Jennifer L. Sutton Dr. Christine C. Tong Dr. Vincent M. Lynch Prof. Jonathan L. Sessler Prof. Philip A. Gale Prof. Chang‐Hee Lee 《Chemistry (Weinheim an der Bergstrasse, Germany)》2012,18(9):2514-2523
A ditopic ion‐pair receptor ( 1 ), which has tunable cation‐ and anion‐binding sites, has been synthesized and characterized. Spectroscopic analyses provide support for the conclusion that receptor 1 binds fluoride and chloride anions strongly and forms stable 1:1 complexes ([ 1? F]? and [ 1? Cl]?) with appropriately chosen salts of these anions in acetonitrile. When the anion complexes of 1 were treated with alkali metal ions (Li+, Na+, K+, Cs+, as their perchlorate salts), ion‐dependent interactions were observed that were found to depend on both the choice of added cation and the initially complexed anion. In the case of [ 1? F]?, no appreciable interaction with the K+ ion was seen. On the other hand, when this complex was treated with Li+ or Na+ ions, decomplexation of the bound fluoride anion was observed. In contrast to what was seen with Li+, Na+, K+, treating [ 1?F ]? with Cs+ ions gave rise to a stable, host‐separated ion‐pair complex, [F ?1? Cs], which contains the Cs+ ion bound in the cup‐like portion of the calix[4]pyrrole. Different complexation behavior was seen in the case of the chloride complex, [ 1? Cl]?. Here, no appreciable interaction was observed with Na+ or K+. In contrast, treating with Li+ produces a tight ion‐pair complex, [ 1? Li ? Cl], in which the cation is bound to the crown moiety. In analogy to what was seen for [ 1? F]?, treatment of [ 1? Cl]? with Cs+ ions gives rise to a host‐separated ion‐pair complex, [Cl ?1? Cs], in which the cation is bound to the cup of the calix[4]pyrrole. As inferred from liposomal model membrane transport studies, system 1 can act as an effective carrier for several chloride anion salts of Group 1 cations, operating through both symport (chloride+cation co‐transport) and antiport (nitrate‐for‐chloride exchange) mechanisms. This transport behavior stands in contrast to what is seen for simple octamethylcalix[4]pyrrole, which acts as an effective carrier for cesium chloride but does not operates through a nitrate‐for‐chloride anion exchange mechanism. 相似文献
15.
Dr. Thomas Schwarze Janine Riemer Dr. Sascha Eidner Prof. Hans‐Jürgen Holdt 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(32):11306-11310
A highly K+‐selective two‐photon fluorescent probe for the in vitro monitoring of physiological K+ levels in the range of 1–100 mM is reported. The two‐photon excited fluorescence (TPEF) probe shows a fluorescence enhancement (FE) by a factor of about three in the presence of 160 mM K+, independently of one‐photon (OP, 430 nm) or two‐photon (TP, 860 nm) excitation and comparable K+‐induced FEs in the presence of competitive Na+ ions. The estimated dissociation constant (Kd) values in Na+‐free solutions (KdOP=(28±5) mM and KdTP=(36±6) mM ) and in combined K+/Na+ solutions (KdOP=(38±8) mM and KdTP=(46±25) mM ) reflecting the high K+/Na+ selectivity of the fluorescent probe. The TP absorption cross‐section (σ2PA) of the TPEF probe+160 mM K+ is 26 GM at 860 nm. Therefore, the TPEF probe is a suitable tool for the in vitro determination of K+. 相似文献
16.
Thermal Responsive Ion Selectivity of Uranyl Peroxide Nanocages: An Inorganic Mimic of K+ Ion Channels
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Yunyi Gao Jennifer E. S. Szymanowski Xinyu Sun Prof. Dr. Peter C. Burns Prof. Dr. Tianbo Liu 《Angewandte Chemie (International ed. in English)》2016,55(24):6887-6891
An actinyl peroxide cage cluster, Li48+mK12(OH)m[UO2(O2)(OH)]60 (H2O)n (m≈20 and n≈310; U60), discriminates precisely between Na+ and K+ ions when heated to certain temperatures, a most essential feature for K+ selective filters. The U60 clusters demonstrate several other features in common with K+ ion channels, including passive transport of K+ ions, a high flux rate, and the dehydration of U60 and K+ ions. These qualities make U60 (a pure inorganic cluster) a promising ion channel mimic in an aqueous environment. Laser light scattering (LLS) and isothermal titration calorimetry (ITC) studies revealed that the tailorable ion selectivity of U60 clusters is a result of the thermal responsiveness of the U60 hydration shells. 相似文献
17.
《Journal of membrane science》1997,132(2):245-253
Polypyrrole membranes containing four different dopant ions were prepared galvanostatically from aqueous solutions of pyrrole (0.1 M) and the appropriate counter ion salt (0.1 M). The transport of mono-valent cations through each membrane was achieved by applying a potential gradient across the membranes. The influence of a number of set up parameters on the flux of K+ ions across a PPy/pTS membrane was assessed, as well as the relative selectivities of the four membrane types for the mono-valent cations; Li+, Na+, K+, Rb+ and Cs+. 相似文献
18.
The facilitated transfer of alkali metal ions (Na+, K+, Rb+, and Cs+) by 25,26,27,28‐tetraethoxycarbonylmethoxy‐thiacalix[4]arene across the water/1,2‐dichloroethane interface was investigated by cyclic voltammetry. The dependence of the half‐wave transfer potential on the metal and ligand concentrations was used to formulate the stoichiometric ratio and to evaluate the association constants of the complexes formed between ionophore and metal ions. While the facilitated transfer of Li+ ion was not observed across the water/1,2‐dichloroethane interface, the facilitated transfers were observed by formation of 1 : 1 (metal:ionophore) complex for Na+, K+, and Rb+ ions except for Cs+ ion. In the case of Cs+ a 1 : 2 (metal:ionophore) complex was obtained from its special electrochemical response to the variation of ligand concentrations in the organic phase. The logarithms of the complex association constants, for facilitated transfer of Na+, K+, Rb+, and Cs+, were estimated as 6.52, 7.75, 7.91 (log β1°), and 8.36 (log β2°), respectively. 相似文献
19.
Zhanhu Sun Mihail Barboiu Yves‐Marie Legrand Eddy Petit Alexandru Rotaru 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2015,127(48):14681-14685
The bacterial KcsA channel conducts K+ cations at high rates while excluding Na+ cations. Herein, we report an artificial ion‐channel formed by H‐bonded stacks of crown‐ethers, where K+ cation conduction is highly preferred to Na+ cations. The macrocycles aligned along the central pore surround the K+ cations in a similar manner to the water around the hydrated cation, compensating for the energetic cost of their dehydration. In contrast, the Na+ cation does not fit the macrocyclic binding sites, so its dehydration is not completely compensated. The present highly K+‐selective macrocyclic channel may be regarded as a biomimetic of the KcsA channel. 相似文献
20.
Dr. Arundhati Roy Dr. Himanshu Joshi Ruijuan Ye Dr. Jie Shen Dr. Feng Chen Prof. Dr. Aleksei Aksimentiev Dr. Huaqiang Zeng 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(12):4836-4843
Reported herein is a series of pore-containing polymeric nanotubes based on a hydrogen-bonded hydrazide backbone. Nanotubes of suitable lengths, possessing a hollow cavity of about a 6.5 Å diameter, mediate highly efficient transport of diverse types of anions, rather than cations, across lipid membranes. The reported polymer channel, having an average molecular weight of 18.2 kDa and 3.6 nm in helical height, exhibits the highest anion-transport activities for iodide (EC50=0.042 μm or 0.028 mol % relative to lipid), whcih is transported 10 times more efficiently than chlorides (EC50=0.47 μm ). Notably, even in cholesterol-rich environment, iodide transport activity remains high with an EC50 of 0.37 μm . Molecular dynamics simulation studies confirm that the channel is highly selective for anions and that such anion selectivity arises from a positive electrostatic potential of the central lumen rendered by the interior-pointing methyl groups. 相似文献