共查询到20条相似文献,搜索用时 15 毫秒
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《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2017,129(25):7292-7296
Chirality is an intriguing and intrinsic feature of life and is highly associated with many significant biological processes. However, whether it influences the translocation behavior of proteins remains unclear. Herein, based on biomimetic strategies, we made chiral nanopores modified with cysteine enantiomers, and studied the chirality gating effects on protein transport. The results show that protein is preferentially transported through nanopores modified with l ‐cysteine because of chiral interaction, indicating chirality strongly influences protein transport process. This study presents a new method for better understanding the role of chirality in selective protein transport processes and provides a convenient approach for studying protein chiral separation and targeted treatments. 相似文献
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多相手性催化是合成手性化合物的有效途径之一,开发高活性、高选择性的多相手性催化剂并应用于不对称催化反应是兼具基础科学和应用科学背景的重要研究方向. 本文综述了近年来具有代表性的固体表面上、纳米孔道内以及手性乳液体系中的多相手性催化研究进展,着重对本实验室近年来在该领域中的探索研究进行了介绍,涉及的重要手性催化反应包括氢化、氢转移、氢甲酰化、环氧化、环氧化物水解动力学拆分、Aldol反应和Diels-Alder反应等. 我们的研究表明,手性修饰纳米粒子催化剂上的手性氢化反应可以获得95% ee以上的手性选择性以及高达 20 000 h-1 的TOF, 手性氢甲酰化反应得到90% ee的手性选择性;在手性催化剂组装的乳液体系中,催化不对称Aldol反应获得高达99% ee的手性选择性,催化活性得到显著提升,乳液氢转移反应的TOF可达3×105 h-1;在纳米孔中多个手性环氧化反应的例子显示出孔道效应能够显著提高手性选择性,并发现在纳米反应器中的环氧化物水解动力学拆分反应显示出催化剂协同活化效应,使催化反应的活性大幅度提高. 本文还讨论了表面、界面上以及孔道中的催化剂组装、孔道限阈以及多中心协同效应等因素对多相手性催化反应性能的影响. 相似文献
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Chemical Modification of Proteins at Cysteine: Opportunities in Chemistry and Biology 总被引:1,自引:0,他引:1
Justin M. Chalker Gonçalo J. L. Bernardes Dr. Yuya A. Lin Benjamin G. Davis Prof. 《化学:亚洲杂志》2009,4(5):630-640
Cys‐tematic modification : Cysteine is a versatile amino acid for selective chemical modification of proteins. Both chemical and biological innovations made possible by cysteine modification are highlighted in this Focus Review.
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Dr. Tiandi Zhuang Prof. Lukas K. Tamm 《Angewandte Chemie (International ed. in English)》2014,53(23):5897-5902
Protein nanopores have attracted much interest for nucleic acid sequencing, chemical sensing, and protein folding at the single molecule level. The outer membrane protein OmpG from E. coli stands out because it forms a nanopore from a single polypeptide chain. This property allows the separate engineering of each of the seven extracellular loops that control access to the pore. The longest of these loops, loop 6, has been recognized as the main gating loop that closes the pore at low pH values and opens it at high pH values. A method was devised to pin each of the loops to the embedding membrane and measure the single‐pore conductances of the resulting constructs. The electrophysiological and complementary NMR measurements show that the pinning of individual loops alters the structure and dynamics of neighboring and distant loops in a correlated fashion. Pinning loop 6 generates a constitutively open pore and patterns of concerted loop motions control access to the OmpG nanopore. 相似文献
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Soma Papp Gyula Jágerszki Prof. Róbert E. Gyurcsányi 《Angewandte Chemie (International ed. in English)》2018,57(17):4752-4755
We report the synthesis and analytical application of the first Cu2+‐selective synthetic ion channel based on peptide‐modified gold nanopores. A Cu2+‐binding peptide motif (Gly‐Gly‐His) along with two additional functional thiol derivatives inferring cation‐permselectivity and hydrophobicity was self‐assembled on the surface of gold nanoporous membranes comprising of about 5 nm diameter pores. These membranes were used to construct ion‐selective electrodes (ISEs) with extraordinary Cu2+ selectivities, approaching six orders of magnitude over certain ions. Since all constituents are immobilized to a supporting nanoporous membrane, their leaching, that is a ubiquitous problem of conventional ionophore‐based ISEs was effectively suppressed. 相似文献
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Małgorzat Kozbia Marek Pietraszkiewicz Oksana Pietraszkiewicz 《Journal of inclusion phenomena and macrocyclic chemistry》1998,30(1):69-77
A chiral crown ether incorporating a methyl -d-mannopyranoside unit displayed pronounced enantioselection of amino acids in partition liquid chromatography experiments involving solvent systems of limited miscibility: water–ethanol–2,2,4-trimethylpentane. The same system has been used for amino acid transport across a liquid membrane containing the crown ether, and in liquid–liquid extraction experiments. Remarkable enantioselection has been noted for amino acids in all the processes studied. 相似文献
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以氧氟沙星、扑尔敏、特布它林和普萘洛尔为手性药物,分别采用羟丙基-β环糊精(HP--βCD)、羟丙基-β-环糊精结合羧甲基-β-环糊精(HP--βCD/CM--βCD)作手性拆分试剂,考察环糊精浓度和pH对手性选择性的影响。结果发现环糊精提供手性相互作用,而pH强烈地影响这种相互作用。以HP--βCD/CM-β-CD组成的双环糊精系统能更好地优化手性选择性,而通过调节pH可以获得需要的分离选择性、迁移次序。 相似文献
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The recovery of ammonium from urine requires distinguishing and excluding sodium and potassium. A polymer inclusion membrane selective for ammonium is developed using an ionophore based on pyrazole substituted benzene. The interactions of the components are studied, as well as their effect on transport and selectivity. Spectroscopic and thermogravimetric measurements show no extensive physical interactions of the components, and that the plasticizer reduces the intermolecular forces (rigidity) of the membrane. The ionophore turns the membrane more rigid, although it increases its swelling degree and therefore the affinity of cations. A ratio of plasticizer (DEHP) and polymer (PVC) of 1:3 in mass gives the highest ammonium flux. Tested contents of ionophore (2 and 5 wt%) show that the higher the content of the ionophore, the fastest the flux is (7.5 × 10−3 mmol cm−2 h−1). Selectivity of NH4+ over Na+ and over K+ is reduced from 13.07 to 9.33 and from 14.15 to 9.57 correspondingly.
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两类新型含硫手性大环配体的合成 总被引:6,自引:1,他引:5
以L-半胱氨酸为手性源,合成了两类新型含硫手性大环配体,并进行了结构表征.L-半胱氨酸与二溴化合物反应生成双氨基酸,转变为双氨基酸酯后与双酰氯在高度稀释和无水条件下进行关环反应,制得环上含硫的手性大环配体3a-3e.L-半胱氨酸经苄基化和硼烷还原后与对应的双对甲苯磺酸酯偶联生成手性二胺4f-4h,最后与2,6-吡啶二甲酰氯关环,制得侧臂含硫的手性大环配体5f-5h. 相似文献
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具有pH值可调聚电解质(Polyelectrolyte,PE)刷的合成纳米孔的仿生离子通道在纳米尺度下离子、流体和生物粒子的主动运输控制方面具有重大应用潜力. 离子选择性是纳流体设备中离子传输的重要现象,具有很大的现实意义和实用价值. 本文提出了施加压力控制纳米孔中离子选择度的方法,综合研究了溶液pH值、浓度、外加电压和压力对离子选择度的影响. 仿真结果表明,离子选择度对压力的刺激是敏感的,且不像电压对离子选择度的影响会受到溶液pH值和浓度的制约,且方向不定,速度不可控;压力对离子选择度的影响不受溶液性质制约,并且灵活可控. 该结果对设计带pH值可调聚电解质刷的纳米孔有重要的启发作用. 相似文献
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Yanan Jiang Wenjie Ma Yujuan Qiao Yifei Xue Jiahao Lu Jun Gao Nannan Liu Fei Wu Ping Yu Lei Jiang Lanqun Mao 《Angewandte Chemie (International ed. in English)》2020,59(31):12795-12799
Biological ion channels and ion pumps with sub‐nanometer sizes modulate ion transport in response to external stimuli. Realizing such functions with sub‐nanometer solid‐state nanopores has been an important topic with wide practical applications. Herein, we demonstrate a biomimetic photoresponsive ion channel and photodriven ion pump using a porphyrin‐based metal–organic framework membrane with pore sizes comparable to hydrated ions. We show that the molecular‐size pores enable precise and robust optoelectronic ion transport modulation in a broad range of concentrations, unparalleled with conventional solid‐state nanopores. Upon decoration with platinum nanoparticles to form a Schottky barrier photodiode, photovoltage across the membrane is generated with “uphill” ion transport from low concentration to high concentration. These results may spark applications in energy conversion, ion sieving, and artificial photosynthesis. 相似文献
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采用高效液相色谱法,在自制的纤维素-三(3,5-二甲基苯基氨基甲酸酯)(ATEO-OD)、纤维素-三(4-甲基苯基氨基甲酸酯)(ATEO-OG)和纤维素-三(4-甲基苯基甲酸酯)(ATEO-OJ)3种手性柱上对16种不同结构的手性化合物进行了拆分和比较.试验结果表明:16个手性样品在这3种手性固定相上分别获得了不同程度的拆分,A TEO-OD对所分析样品具有更好的手性识别能力,ATEO-OG和ATEO-OJ的手性识别能力相当. 相似文献
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吸附蛋白质固定相电色谱手性分离的研究 总被引:4,自引:1,他引:4
将牛血清白蛋白 (BSA)吸附于强阴离子交换固定相 (SAX)上用于电色谱手性分离。当SAX吸附BSA后 ,电渗淌度仅仅下降 2 6 3% ,而电渗流的方向没有改变。在该系统中电渗流的方向和阴离子的电泳方向一致 ,因而克服了一般蛋白质固定相不能分离酸性对映体的缺点。 1种中性对映体安息香和 4种阴离子性对映体色氨酸、华法令、非诺洛芬、酮基布洛芬获得了成功分离。当流动相含体积分数为 7%的乙腈时 ,死时间和D 色氨酸、L 色氨酸的迁移时间的相对标准偏差分别为 0 90 % ,0 87%和 0 96 % (n =2 1) ,说明该体系有很好的重现性。 相似文献
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Biomimetic Synthesis of Shaped and Chiral Silica Entities Templated by Organic Objective Materials 下载免费PDF全文
Prof. Ren‐Hua Jin Dr. Dong‐Dong Yao Dr. Rumi Levi 《Chemistry (Weinheim an der Bergstrasse, Germany)》2014,20(24):7196-7214
Organic molecules with accompanying self‐organization have been a great subject in chemistry, material science and nanotechnology in the past two decades. One of the most important roles of organized organic molecules is the capability of templating complexly structured inorganic materials. The focus of this Minireview is on nanostructured silica with divergent morphologies and/or integrated chirality directed by organic templates of self‐assembled polyamine/polypeptides/block copolymers, chiral organogels, self‐organized chiral amphiphiles and chiral crystalline complexes, etc., by biomimetic silicification and conventional sol–gel reaction. Among them, biosilica (diatoms and sponges)‐inspired biomimetic silicifications are particularly highlighted. 相似文献
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Selective Permeability of Uranyl Peroxide Nanocages to Different Alkali Ions: Influences from Surface Pores and Hydration Shells 下载免费PDF全文
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