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Cheng M, Zhu F, Zhang S, Zhang X, Dhinakaran MK, Li H. A Funnel-Shaped Chloride Nanochannel Inspired By ClC Protein. NANO LETTERS 2021; 21:4086-4091. [PMID: 33885312 DOI: 10.1021/acs.nanolett.1c01055] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Chloride transport participates in a great variety of physiological activities, such as regulating electrical excitability and maintaining acid-base equilibrium. However, the high flux is the prerequisite to ensure the realization of the above functions. Actually, the high flux of ion transport is significant, not only for living things but also for practical applications. Herein, inspired by chloride channel (ClC) protein, a novel NH2-pillar[5]arene functionalized funnel-shaped nanochannel was designed and constructed. The introduction of functional molecules changed surface charge property and endowed the nanochannel with Cl- selectivity, which facilitated Cl- transport. Moreover, by adjusting the asymmetric degree of the nanochannel, the Cl- transport flux can be improved greatly. The successful construction of an artificial ion channel with high flux will be much useful for practical applications like microfluidic devices, sensors, and ion separation.
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Affiliation(s)
- Ming Cheng
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Fei Zhu
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Siyun Zhang
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Xingrou Zhang
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Manivannan Kalavathi Dhinakaran
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
| | - Haibing Li
- Key Laboratory of Pesticide and Chemical Biology (CCNU), Ministry of Education, College of Chemistry, Central China Normal University, Wuhan 430079, P. R. China
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2
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Zheng S, Jiang J, Lee A, Barboiu M. A Voltage‐Responsive Synthetic Cl−‐Channel Regulated by pH. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008393] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Shao‐Ping Zheng
- Lehn Institute of Functional Materials School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
- Institut Europeen des Membranes Adaptive Supramolecular Nanosystems Group University of Montpellier ENSCM-CNRS Place E. Bataillon CC047 34095 Montpellier France
| | - Ji‐Jun Jiang
- Lehn Institute of Functional Materials School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
| | - Arie Lee
- Institut Europeen des Membranes Adaptive Supramolecular Nanosystems Group University of Montpellier ENSCM-CNRS Place E. Bataillon CC047 34095 Montpellier France
| | - Mihail Barboiu
- Lehn Institute of Functional Materials School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
- Institut Europeen des Membranes Adaptive Supramolecular Nanosystems Group University of Montpellier ENSCM-CNRS Place E. Bataillon CC047 34095 Montpellier France
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3
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Zheng S, Jiang J, Lee A, Barboiu M. A Voltage‐Responsive Synthetic Cl−‐Channel Regulated by pH. Angew Chem Int Ed Engl 2020; 59:18920-18926. [DOI: 10.1002/anie.202008393] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 08/10/2020] [Indexed: 12/11/2022]
Affiliation(s)
- Shao‐Ping Zheng
- Lehn Institute of Functional Materials School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
- Institut Europeen des Membranes Adaptive Supramolecular Nanosystems Group University of Montpellier ENSCM-CNRS Place E. Bataillon CC047 34095 Montpellier France
| | - Ji‐Jun Jiang
- Lehn Institute of Functional Materials School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
| | - Arie Lee
- Institut Europeen des Membranes Adaptive Supramolecular Nanosystems Group University of Montpellier ENSCM-CNRS Place E. Bataillon CC047 34095 Montpellier France
| | - Mihail Barboiu
- Lehn Institute of Functional Materials School of Chemistry Sun Yat-Sen University Guangzhou 510275 China
- Institut Europeen des Membranes Adaptive Supramolecular Nanosystems Group University of Montpellier ENSCM-CNRS Place E. Bataillon CC047 34095 Montpellier France
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Cossu C, Fiore M, Baroni D, Capurro V, Caci E, Garcia-Valverde M, Quesada R, Moran O. Anion-Transport Mechanism of a Triazole-Bearing Derivative of Prodigiosine: A Candidate for Cystic Fibrosis Therapy. Front Pharmacol 2018; 9:852. [PMID: 30131695 PMCID: PMC6090297 DOI: 10.3389/fphar.2018.00852] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2018] [Accepted: 07/13/2018] [Indexed: 12/31/2022] Open
Abstract
Cystic fibrosis (CF) is a genetic lethal disease, originated from the defective function of the CFTR protein, a chloride and bicarbonate permeable transmembrane channel. CF mutations affect CFTR protein through a variety of molecular mechanisms which result in different functional defects. Current therapeutic approaches are targeted to specific groups of patients that share a common functional defect. We seek to develop an innovative therapeutic approach for the treatment of CF using anionophores, small molecules that facilitate the transmembrane transport of anions. We have characterized the anion transport mechanism of a synthetic molecule based on the structure of prodigiosine, a red pigment produced by bacteria. Anionophore-driven chloride efflux from large unilamellar vesicles is consistent with activity of an uniporter carrier that facilitates the transport of anions through lipid membranes down the electrochemical gradient. There are no evidences of transport coupling with protons. The selectivity sequence of the prodigiosin inspired EH160 ionophore is formate > acetate > nitrate > chloride > bicarbonate. Sulfate, phosphate, aspartate, isothionate, and gluconate are not significantly transported by these anionophores. Protonation at acidic pH is important for the transport capacity of the anionophore. This prodigiosin derived ionophore induces anion transport in living cells. Its low toxicity and capacity to transport chloride and bicarbonate, when applied at low concentration, constitute a promising starting point for the development of drug candidates for CF therapy.
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Affiliation(s)
- Claudia Cossu
- Istituto di Biofisica, Consiglio Nazionale Delle Ricerche, Genova, Italy
| | - Michele Fiore
- Istituto di Biofisica, Consiglio Nazionale Delle Ricerche, Genova, Italy
| | - Debora Baroni
- Istituto di Biofisica, Consiglio Nazionale Delle Ricerche, Genova, Italy
| | - Valeria Capurro
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | - Emanuela Caci
- U.O.C. Genetica Medica, Istituto Giannina Gaslini, Genova, Italy
| | | | - Roberto Quesada
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, Burgos, Spain
| | - Oscar Moran
- Istituto di Biofisica, Consiglio Nazionale Delle Ricerche, Genova, Italy
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Faggi E, Luis SV, Alfonso I. Sensing, Transport and Other Potential Biomedical Applications of Pseudopeptides. Curr Med Chem 2018; 26:4065-4097. [PMID: 29493442 DOI: 10.2174/0929867325666180301091040] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Revised: 01/17/2018] [Accepted: 01/20/2018] [Indexed: 11/22/2022]
Abstract
Pseudopeptides are privileged synthetic molecules built from the designed combination of peptide-like and abiotic artificial moieties. Consequently, they are benefited from the advantages of both families of chemical structures: modular synthesis, chemical and functional diversity, tailored three-dimensional structure, usually high stability in biological media and low non-specific toxicity. Accordingly, in the last years, these compounds have been used for different biomedical applications, ranging from bio-sensing, ion transport, the molecular recognition of biologically relevant species, drug delivery or gene transfection. This review highlights a selection of the most remarkable and recent advances in this field.
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Affiliation(s)
- Enrico Faggi
- Department of Biological Chemistry and Molecular Modelling, Institute of Advanced Chemistry of Catalonia, Consejo Superior de Investigaciones Cientificas, Barcelona, Spain
| | - Santiago V Luis
- Department of Inorganic and Organic Chemistry, Universitat Jaume I, Castellon, Spain
| | - Ignacio Alfonso
- Department of Biological Chemistry and Molecular Modelling, Institute of Advanced Chemistry of Catalonia, Consejo Superior de Investigaciones Cientificas, Barcelona, Spain
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6
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Efficient, non-toxic anion transport by synthetic carriers in cells and epithelia. Nat Chem 2015; 8:24-32. [PMID: 26673261 DOI: 10.1038/nchem.2384] [Citation(s) in RCA: 125] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2015] [Accepted: 09/24/2015] [Indexed: 12/12/2022]
Abstract
Transmembrane anion transporters (anionophores) have potential for new modes of biological activity, including therapeutic applications. In particular they might replace the activity of defective anion channels in conditions such as cystic fibrosis. However, data on the biological effects of anionophores are scarce, and it remains uncertain whether such molecules are fundamentally toxic. Here, we report a biological study of an extensive series of powerful anion carriers. Fifteen anionophores were assayed in single cells by monitoring anion transport in real time through fluorescence emission from halide-sensitive yellow fluorescent protein. A bis-(p-nitrophenyl)ureidodecalin shows especially promising activity, including deliverability, potency and persistence. Electrophysiological tests show strong effects in epithelia, close to those of natural anion channels. Toxicity assays yield negative results in three cell lines, suggesting that promotion of anion transport may not be deleterious to cells. We therefore conclude that synthetic anion carriers are realistic candidates for further investigation as treatments for cystic fibrosis.
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Evans NH, Beer PD. Advances in anion supramolecular chemistry: from recognition to chemical applications. Angew Chem Int Ed Engl 2014; 53:11716-54. [PMID: 25204549 DOI: 10.1002/anie.201309937] [Citation(s) in RCA: 434] [Impact Index Per Article: 39.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2013] [Indexed: 12/11/2022]
Abstract
Since the start of this millennium, remarkable progress in the binding and sensing of anions has been taking place, driven in part by discoveries in the use of hydrogen bonding, as well as the previously under-exploited anion-π interactions and halogen bonding. However, anion supramolecular chemistry has developed substantially beyond anion recognition, and now encompasses a diverse range of disciplines. Dramatic advance has been made in the anion-templated synthesis of macrocycles and interlocked molecular architectures, while the study of transmembrane anion transporters has flourished from almost nothing into a rapidly maturing field of research. The supramolecular chemistry of anions has also found real practical use in a variety of applications such as catalysis, ion extraction, and the use of anions as stimuli for responsive chemical systems.
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Affiliation(s)
- Nicholas H Evans
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB (UK).
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8
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Evans NH, Beer PD. Supramolekulare Chemie von Anionen: von der Erkennung zur chemischen Anwendung. Angew Chem Int Ed Engl 2014. [DOI: 10.1002/ange.201309937] [Citation(s) in RCA: 83] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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9
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Milano D, Benedetti B, Boccalon M, Brugnara A, Iengo E, Tecilla P. Anion transport across phospholipid membranes mediated by a diphosphine–Pd(ii) complex. Chem Commun (Camb) 2014; 50:9157-60. [DOI: 10.1039/c4cc02881c] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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10
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Gokel GW, Negin S. Synthetic ion channels: from pores to biological applications. Acc Chem Res 2013; 46:2824-33. [PMID: 23738778 DOI: 10.1021/ar400026x] [Citation(s) in RCA: 208] [Impact Index Per Article: 17.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
In this Account, we describe the development of several diverse families of synthetic, membrane-active amphiphiles that form pores and facilitate transport within membrane bilayers. For the most part, the compounds are amphiphiles that insert into the bilayer and form pores either on their own or by self-assembly. The first family of synthetic ion channels prepared in our lab, the hydraphiles, used crown ethers as head groups and as a polar central element. In a range of biophysical studies, we showed that the hydraphiles formed unimolecular pores that spanned the bilayer. They mediated the transport of Na(+) and K(+) but were blocked by Ag(+). The hydraphiles are nonrectifying and disrupt ion homeostasis. As a result, these synthetic ion channels are toxic to various bacteria and yeast, a feature that has been used therapeutically in direct injection chemotherapy. We also developed a family of amphiphilic heptapeptide ion transporters that selected Cl(-) >10-fold over K(+) and showed voltage dependent gating. The formed pores were approximately dimeric, and variations in the N- and C-terminal anchor chains and the acids affected transport rates. Surprisingly, the longer N-terminal anchor chains led to less transport but greater Cl(-) selectivity. A proline residue, which is present in the ClC protein channel's conductance pore, proved to be critical for Cl(-) transport selectivity. Pyrogallol[4]arenes are macrocycles formed by acid-catalyzed condensation of four 1,2,3- trihydroxybenzenes with four aldehydes. The combination of 12 hydroxyl groups on one face of the macrocycle and four pendant alkyl chains conferred considerable amphiphilicity to these compounds. The pyrogallol[4]arenes inserted into bilayer membranes and conducted ions. Based on our experimental evidence, the ions passed through a self-assembled pore comprising four or five amphiphiles rather than passing through the central opening of a single macrocycle. Pyrogallol[4]arenes constructed with branched chains are also amphiphilic and active in membranes. The pyrogallol[4]arene with 3-pentyl sidechains formed a unique nanotube assembly and functioned as an ion channel in bilayer membranes. Finally, we showed that dianilides of either isophthalic or dipicolinic acids, compounds which have been extensively studied as anion binders, can self-assemble to form pores within bilayers. We called these dianilides tris-arenes and have shown that they readily bind to phosphate anions. These structures also mediated the transport of DNA plasmids through vital bilayer membranes in the bacterium Escherichia coli and in the yeast Saccharomyces cerevisiae . This transformation or transfection process occurred readily and without any apparent toxicity or mutagenicity.
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Affiliation(s)
- George W. Gokel
- Departments of †Chemistry & Biochemistry and ‡Biology, §Center for Nanoscience, University of Missouri—St. Louis, St. Louis, Missouri 63121, United States
| | - Saeedeh Negin
- Departments of †Chemistry & Biochemistry and ‡Biology, §Center for Nanoscience, University of Missouri—St. Louis, St. Louis, Missouri 63121, United States
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11
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Bukovnik U, Sala-Rabanal M, Francis S, Frazier SJ, Schultz BD, Nichols CG, Tomich JM. Effect of diaminopropionic acid (Dap) on the biophysical properties of a modified synthetic channel-forming peptide. Mol Pharm 2013; 10:3959-66. [PMID: 24010543 DOI: 10.1021/mp4002377] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Channel replacement therapy, based on synthetic channel-forming peptides (CFPs) with the ability to supersede defective endogenous ion channels, is a novel treatment modality that may augment existing interventions against multiple diseases. Previously, we derived CFPs from the second transmembrane segment of the α-subunit of the glycine receptor, M2GlyR, which forms chloride-selective channels in its native form. The best candidate, NK4-M2GlyR T19R, S22W (p22-T19R, S22W), was water-soluble, incorporated into cell membranes and was nonimmunogenic, but lacked the structural properties for high conductance and anion selectivity when assembled into a pore. Further studies suggested that the threonine residues at positions 13, 17, and 20 line the pore of assembled p22-T19R, S22W, and here we used 2,3-diaminopropionic acid (Dap) substitutions to introduce positive charges to the pore-lining interface of the predicted p22-T19R, S22W channel. Dap-substituted p22-T19R, S22W peptides retained the α-helical secondary structure characteristic of their parent peptide, and induced short-circuit transepithelial currents when exposed to the apical membrane of Madin-Darby canine kidney (MDCK) cells; the sequences containing multiple Dap-substituted residues induced larger currents than the peptides with single or no Dap substitutions. To gain further insights into the effects of Dap residues on the properties of the putative pore, we performed two-electrode voltage clamp electrophysiology on Xenopus oocytes exposed to p22-T19R, S22W or its Dap-modified analogues. We observed that Dap-substituted peptides also induced significantly larger voltage-dependent currents than the parent compound, but there was no apparent change in reversal potential upon replacement of external Na+, Cl- or K+, indicating that these currents remained nonselective. These results suggest that the introduction of positively charged side chains in predicted pore-lining residues does not improve anion-to-cation selectivity, but results in higher conductance, perhaps due to higher oligomerization numbers.
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Affiliation(s)
- Urska Bukovnik
- Department of Biochemistry and ⊥Department of Anatomy and Physiology, Kansas State University , Manhattan, Kansas 66506, United States
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12
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Licen S, Bagnacani V, Baldini L, Casnati A, Sansone F, Giannetto M, Pengo P, Tecilla P. Anion transport across phospholipid bilayers promoted by a guanidinium calix[4]arene conjugate. Supramol Chem 2013. [DOI: 10.1080/10610278.2013.824576] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Sabina Licen
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Giorgieri 1, 34127 Trieste, Italy
| | - Valentina Bagnacani
- Department of Chemistry, University of Parma, Parco Area delle Scienze 17/a, 43124 Parma, Italy
| | - Laura Baldini
- Department of Chemistry, University of Parma, Parco Area delle Scienze 17/a, 43124 Parma, Italy
| | - Alessandro Casnati
- Department of Chemistry, University of Parma, Parco Area delle Scienze 17/a, 43124 Parma, Italy
| | - Francesco Sansone
- Department of Chemistry, University of Parma, Parco Area delle Scienze 17/a, 43124 Parma, Italy
| | - Marco Giannetto
- Department of Chemistry, University of Parma, Parco Area delle Scienze 17/a, 43124 Parma, Italy
| | - Paolo Pengo
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Giorgieri 1, 34127 Trieste, Italy
| | - Paolo Tecilla
- Department of Chemical and Pharmaceutical Sciences, University of Trieste, Via Giorgieri 1, 34127 Trieste, Italy
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Busschaert N, Gale PA. Niedermolekulare transmembranäre Anionentransporter für biologische Anwendungen. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201207535] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
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Busschaert N, Gale PA. Small-Molecule Lipid-Bilayer Anion Transporters for Biological Applications. Angew Chem Int Ed Engl 2013; 52:1374-82. [DOI: 10.1002/anie.201207535] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2012] [Indexed: 12/20/2022]
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Alfonso I, Quesada R. Biological activity of synthetic ionophores: ion transporters as prospective drugs? Chem Sci 2013. [DOI: 10.1039/c3sc50882j] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
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Martí I, Rubio J, Bolte M, Burguete MI, Vicent C, Quesada R, Alfonso I, Luis SV. Tuning Chloride Binding, Encapsulation, and Transport by Peripheral Substitution of Pseudopeptidic Tripodal Small Cages. Chemistry 2012; 18:16728-41. [DOI: 10.1002/chem.201202182] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2012] [Indexed: 11/05/2022]
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Gokel GW, Negin S. Synthetic membrane active amphiphiles. Adv Drug Deliv Rev 2012; 64:784-96. [PMID: 22306202 DOI: 10.1016/j.addr.2012.01.011] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2011] [Revised: 01/18/2012] [Accepted: 01/19/2012] [Indexed: 11/18/2022]
Abstract
During the past several decades, various synthetic organic compounds that form pores in bilayer membranes have been prepared and studied. These membrane active amphiphiles have also proved to be useful in affecting the transport of molecules into or through the bilayer. This article discusses the evolution of these compounds and exemplifies recent applications such as enhancement of antimicrobial activity.
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Affiliation(s)
- George W Gokel
- Center for Nanoscience, Department of Chemistry & Biochemistry, University of Missouri - Saint Louis, Saint Louis, MO 63121, USA.
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Díaz de Greñu B, Iglesias Hernández P, Espona M, Quiñonero D, Light ME, Torroba T, Pérez-Tomás R, Quesada R. Synthetic prodiginine obatoclax (GX15-070) and related analogues: anion binding, transmembrane transport, and cytotoxicity properties. Chemistry 2011; 17:14074-83. [PMID: 22069220 DOI: 10.1002/chem.201101547] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2011] [Indexed: 11/06/2022]
Abstract
Synthetic prodiginine obatoclax shows promise as a potential anticancer drug. This compound promotes apoptosis of cancer cells, although the mechanism of action is unclear. To date, only the inhibition of BCL-2 proteins has been proposed as a mechanism of action. To gain insight into other possible modes of action, we have studied the anion-binding properties of obatoclax and related analogues in solution, in the solid state, and by means of density functional theory calculations. These compounds are well suited to interact with anions such as chloride and bicarbonate. The anion-transport properties of the compounds synthesized were assayed in model phospholipid liposomes by using a chloride-selective-electrode technique and (13)C NMR spectroscopy. The results demonstrated that these compounds are efficient anion exchangers that promote chloride, bicarbonate, and nitrate transport through lipid bilayers at very low concentrations. In vitro studies on small-cell lung carcinoma cell line GLC4 showed that active ionophores are able to discharge pH gradients in living cells and the cytotoxicity of these compounds correlates well with ionophoric activity.
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Affiliation(s)
- Borja Díaz de Greñu
- Departamento de Química, Facultad de Ciencias, Universidad de Burgos, 09001 Burgos, Spain
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Bukovnik U, Gao J, Cook GA, Shank LP, Seabra MB, Schultz BD, Iwamoto T, Chen J, Tomich JM. Structural and biophysical properties of a synthetic channel-forming peptide: designing a clinically relevant anion selective pore. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1818:1039-48. [PMID: 21835162 DOI: 10.1016/j.bbamem.2011.07.037] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2011] [Accepted: 07/25/2011] [Indexed: 12/15/2022]
Abstract
The design, synthesis, modeling and in vitro testing of channel-forming peptides derived from the cys-loop superfamily of ligand-gated ion channels are part of an ongoing research focus. Over 300 different sequences have been prepared based on the M2 transmembrane segment of the spinal cord glycine receptor α-subunit. A number of these sequences are water-soluble monomers that readily insert into biological membranes where they undergo supramolecular assembly, yielding channels with a range of selectivities and conductances. Selection of a sequence for further modifications to yield an optimal lead compound came down to a few key biophysical properties: low solution concentrations that yield channel activity, greater ensemble conductance, and enhanced ion selectivity. The sequence NK(4)-M2GlyR T19R, S22W (KKKKPARVGLGITTVLTMRTQW) addressed these criteria. The structure of this peptide has been analyzed by solution NMR as a monomer in detergent micelles, simulated as five-helix bundles in a membrane environment, modified by cysteine-scanning and studied for insertion efficiency in liposomes of selected lipid compositions. Taken together, these results define the structural and key biophysical properties of this sequence in a membrane. This model provides an initial scaffold from which rational substitutions can be proposed and tested to modulate anion selectivity. This article is part of a Special Issue entitled: Protein Folding in Membranes.
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Affiliation(s)
- U Bukovnik
- Department of Biochemistry, Kansas State University, Manhattan, KS 66506, USA
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Smith BA, Daschbach MM, Gammon ST, Xiao S, Chapman SE, Hudson C, Suckow M, Piwnica-Worms D, Gokel GW, Leevy WM. In vivo cell death mediated by synthetic ion channels. Chem Commun (Camb) 2011; 47:7977-9. [PMID: 21681307 DOI: 10.1039/c1cc12933c] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Synthetic ion channel hydraphiles, which are known to infiltrate membranes and disrupt ion homeostasis, were tested as direct injection toxins in live mice as potential schlerotic agents. The study uses a near-IR dye to image and evaluate the success of the approach.
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Affiliation(s)
- Bryan A Smith
- Department of Chemistry and Biochemistry, University of Notre Dame, Notre Dame, IN 46556, USA
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21
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Matile S, Vargas Jentzsch A, Montenegro J, Fin A. Recent synthetic transport systems. Chem Soc Rev 2011; 40:2453-74. [PMID: 21390363 DOI: 10.1039/c0cs00209g] [Citation(s) in RCA: 297] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
This critical review covers progress with synthetic transport systems, particularly ion channels and pores, between January 2006 and December 2009 in a comprehensive manner. This is the third part of a series launched in the year 2000, covering a rich collection of structural and functional motifs that should appeal to a broad audience of non-specialists, including to organic, biological, supramolecular and polymer chemists. Impressive breakthroughs have been achieved over the past four years in part because of a fruitful expansion toward new types of interactions, including metal-organic, π-π, aromatic electron donor-acceptor, anion-π or anion-macrodipole interactions as well as dynamic covalent bonds (169 references).
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Affiliation(s)
- Stefan Matile
- Department of Organic Chemistry, University of Geneva, Geneva, Switzerland.
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Haynes CJE, Gale PA. Transmembrane anion transport by synthetic systems. Chem Commun (Camb) 2011; 47:8203-9. [DOI: 10.1039/c1cc12061a] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Clare JP, Statnikov A, Lynch V, Sargent AL, Sibert JW. “Wurster-Type” Ureas as Redox-Active Receptors for Anions. J Org Chem 2009; 74:6637-46. [DOI: 10.1021/jo9011392] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- John P. Clare
- Department of Chemistry, The University of Texas at Dallas, Richardson, Texas 75080
| | - Anna Statnikov
- Department of Chemistry, The University of Texas at Dallas, Richardson, Texas 75080
| | - Vincent Lynch
- Department of Chemistry, The University of Texas at Austin, Austin, Texas 78712
| | - Andrew L. Sargent
- Department of Chemistry, East Carolina University, Greenville, North Carolina 27858
| | - John W. Sibert
- Department of Chemistry, The University of Texas at Dallas, Richardson, Texas 75080
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Licen S, Coppola C, D'Onofrio J, Montesarchio D, Tecilla P. CyPLOS: a new family of synthetic ionophores. Org Biomol Chem 2009; 7:1060-3. [DOI: 10.1039/b820906e] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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Elliott EK, Daschbach MM, Gokel GW. Aggregation behavior and dynamics of synthetic amphiphiles that self-assemble to anion transporters. Chemistry 2008; 14:5871-9. [PMID: 18481801 DOI: 10.1002/chem.200800148] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The amphiphilic heptapeptides-referred to as synthetic anion transporters (SATs)-mediate chloride transport in planar lipid bilayer membranes, synthetic liposomes, and mammalian cells. The SATs described have the general formula R1(2)NCOCH2OCH2CO-(Gly)3-Pro-(Gly)3-OR2. Substitution at R1 and R2 with various aliphatic or aromatic groups alters the ability of SATs to transport chloride through a phospholipid bilayer membrane. Despite extensive structure-activity relationship studies concerning Cl(-)-mediated transport by SATs, relatively little was known about the mechanism of insertion and pore-formation in the membrane. In the current study, the mechanistic behavior of SATs was investigated in aqueous solution and at the air-water interface. In the latter case, Langmuir trough studies and Brewster angle microscopy (BAM) revealed the extent of monolayer stability and organization for SATs. Dynamic light scattering and transmission electron microscopy (TEM) confirmed these results and defined the aggregation behavior of SATs in solution. SAT derivatives that showed low chloride transport activity organized into stable monolayers at the air-water interface, while more active SATs formed less stable monolayers. The relationship between intermolecular organization of SATs and pore-formation in the membrane is discussed along with its implications for chloride transport.
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You L, Li R, Gokel GW. Anion transport properties of amine and amide-sidechained peptides are affected by charge and phospholipid composition. Org Biomol Chem 2008; 6:2914-23. [PMID: 18688484 PMCID: PMC3124115 DOI: 10.1039/b800530c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Four synthetic anion transporters (SATs) having the general formula (n-C(18)H(37))(2)N-COCH(2)OCH(2)CO-(Gly)(3)Pro-Lys(epsilon-N-R)-(Gly)(2)-O-n-C(7)H(15) were prepared and studied. The group R was Cbz, H (TFA salt), t-Boc, and dansyl in peptides 1, 2, 3, and 4 respectively. The glutamine analog (GGGPQAG sequence) was also included. A dansyl-substituted fluorescent SAT was used to probe peptide insertion; the dansyl sidechain resides in an environment near the bilayer's midpolar regime. When the lysine sidechain was free or protected amine, little effect was noted on final Cl(-) transport rate in DOPC : DOPA (7 : 3) liposomes. This stands in contrast to the significant retardation of transport previously observed when a negative glutamate residue was present in the peptide sequence. It was also found that Cl(-) release from liposomes depended on the phospholipid composition of the vesicles. Chloride transport diminished significantly for the free lysine containing SAT, 2, when the lipid was altered from DOPC : DOPA to pure DOPC. Amide-sidechained SATs 1 and 5 showed a relatively small decrease in Cl(-) transport. The effect of lipid composition on Cl(-) transport was explained by differences in electrostatic interaction between amino acid sidechain and lipid headgroup, which was modeled by computation.
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Affiliation(s)
- Lei You
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - Ruiqiong Li
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
| | - George W. Gokel
- Department of Chemistry, Washington University, St. Louis, MO 63130, USA
- Departments of Chemistry & Biochemistry and Biology, Center for Nanoscience, University of Missouri-Saint Louis, One University Boulevard, Saint Louis, MO 63121, USA
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You L, Ferdani R, Li R, Kramer JP, Winter REK, Gokel GW. Carboxylate anion diminishes chloride transport through a synthetic, self-assembled transmembrane pore. Chemistry 2008; 14:382-96. [PMID: 17924596 PMCID: PMC2711533 DOI: 10.1002/chem.200701071] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Six amphiphilic heptapeptides with the structure (C18H37)2NCOCH2OCH2CO-(Gly)3-Pro-(Gly)n-(Glx)-(Gly)m-O(CH2)6CH3, in which Glx represents glutamic acid or its benzyl ester and n+m=2, have been studied. In addition, the glutamate residue in the GGGPGGE sequence was esterified by fluorescent 1-pyrenemethanol. These compounds insert into phospholipid bilayers and form anion-conducting pores. Hill plots based on carboxyfluorescein release indicate that the pores are at least dimeric. Studies that involved ion-selective electrode techniques showed that transport of chloride varied with the position of glutamate within the peptide chain and whether glutamic acid was present as the free acid or its benzyl ester. Chloride transport activity was significantly higher for the glutamate esters than for free carboxylates irrespective of the glutamate position. Activity was highest when the glutamate residue in approximately (Gly)3-Pro-(Xxx)3 approximately was closest to the C terminus of the peptide. A fluorescent pyrene residue was introduced to probe the aggregation state of the amphiphile. The selectivity of the pore for Cl(-) over K+ was maintained even when the carboxylate anion was present within it. Complexation of Cl(-) by the ionophoric peptides was confirmed by negative ion mass spectrometry. Planar bilayer voltage clamp experiments confirmed that pores with more than one conductance state may form in these dynamic, self-assembled pores.
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Affiliation(s)
- Lei You
- Department of Chemistry, Washington University, 1 Brookings Drive, St. Louis, MO 63130, USA
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Gale PA, García-Garrido SE, Garric J. Anion receptors based on organic frameworks: highlights from 2005 and 2006. Chem Soc Rev 2008; 37:151-90. [DOI: 10.1039/b715825d] [Citation(s) in RCA: 715] [Impact Index Per Article: 42.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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Wesolowski R, Sommer A, Arndt HD, Koert U, Reiss P, Wimmers S, Strauss O. Functional studies of synthetic gramicidin hybrid ion channels in CHO cells. Chembiochem 2007; 8:513-20. [PMID: 17300127 DOI: 10.1002/cbic.200600384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The function of a gramicidin hybrid ion channel in living Chinese hamster ovary (CHO) cells was investigated by the patch clamp method. The synthetic ion channel 1 consists of two cyclohexyl ether amino acids that link two mini-gramicidin strands. With 1 at a concentration of 1.0 microM, an increase in the whole-cell membrane conductance was observed after 1.37 min. The conductance showed larger currents when Cs(+) was used as charge carrier than when Na(+) and K(+) were used. In single-channel recordings with Cs(+) as charge carrier, the substance showed comparable single-channel amplitudes in the membrane of living cells and artificial black lipid bilayers. In addition to functioning as a cation channel, compound 1 appeared to be a water channel. Exposure of the CHO cells to an extracellular hypoosmotic solution did not substantially change the cell volume. Extracellular hypoosmotic conditions in the presence of 1 increased the cell size to 146.5 % that of the control. Thus, the synthetic hybrid channel 1 can function as a cation channel with some Cs(+) specificity, and as a water channel in CHO cells.
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Affiliation(s)
- Ryszard Wesolowski
- Experimentelle Ophthalmologie, Klinik und Poliklinik für Augenheilkunde, Universitätsklinikum Hamburg-Eppendorf, Martinistrasse 52, 20246 Hamburg, Germany
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Abstract
Amphiphilic peptides typically consist of a peptide portion that may be 5-25 (or more) amino acids in length. The hydrophobic portion may be a single fatty acid residue, but can also be more elaborate. The main focus of this article lies on the family of synthetic anion binders (SATs) of the general structure (R(1))(2)N-COCH(2)OCH(2)CO-(Aaa)(n)-OR(3). The most-common R(1) group is the octadecyl (C(18)H(37)) group. The most studied peptide sequence in this family is (Gly)(3)-Pro-(Gly)(3), although different sequences (and longer and shorter peptides) have been prepared as well. The C-terminal ester residue providing the most effective anion release from liposomes is heptyl (C(7)H(15)), although many others have been examined. The compound (C(18)H(37))(2)N-COCH(2)OCH(2)CO-(Gly)(3)-Pro-(Gly)(3)-OBn (Bn=benzyl) was found to mediate Cl(-) transport in mouse epithelial cells.
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Affiliation(s)
- Carl R Yamnitz
- Department of Chemistry, Washington University, Saint Louis, MO 63130, USA
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Abstract
It is 25 years since the first report of a synthetic ion channel transporter. Today, dozens of molecular and supramolecular designs have been developed to facilitate ion and small molecule transport across a bilayer membrane. Presented here is a concise summary of the advances made over the past four years. The transporters are grouped into three mechanistic classes: mobile carrier, monomeric channel, and self-assembled pore. Common building blocks are crown ethers, steroids, cyclodextrins, peptides, curcubiturils, and calixarenes. The eventual goal is to produce functional supramolecular devices such as sensors, enzyme assays, and lead candidates for pharmaceutical development.
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Affiliation(s)
- Beth A McNally
- Department of Chemistry and Biochemistry, University of Notre Dame, 251 Nieuwland Science Hall, Notre Dame, IN 46556, USA
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Abstract
The compelling chemical goal of modeling protein channel behavior has led to synthetic compounds that are true ion channels. Although they largely lack the selectivity and sophistication of highly evolved proteins, they successfully perform a variety of biological functions. This tutorial review describes these novel structures and their activity in living systems. Different channel structures show antibacterial to anticancer activity when tested against a variety of cell types.
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Affiliation(s)
- George W Gokel
- Department of Chemistry, University of Missouri, Saint Louis, MO 63121, USA.
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Pajewski R, Pajewska J, Li R, Daschbach MM, Fowler EA, Gokel GW. The effect of midpolar regime mimics on anion transport mediated by amphiphilic heptapeptides. NEW J CHEM 2007. [DOI: 10.1039/b705179b] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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