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Tsuda S, Komai Y, Fujiwara SI, Nishiyama Y. Cyclodextrin-Based [c2]Daisy Chain Rotaxane Insulating Two Diarylacetylene Cores. Chemistry 2021; 27:1966-1969. [PMID: 33089897 DOI: 10.1002/chem.202004505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Indexed: 11/10/2022]
Abstract
A [c2]daisy chain rotaxane with two diarylacetylene cores was efficiently synthesized in 53 % yield by capping a C2 -symmetric pseudo[2]rotaxane composed of two diarylacetylene-substituted permethylated α-cyclodextrins (PM α-CDs) with aniline stoppers. The maximum absorption wavelength of the [c2]daisy chain rotaxane remained almost unchanged in various solvents, unlike that of the stoppered monomer, indicating that the two independent diarylacetylene cores were insulated from the external environment by the PM α-CDs. Furthermore, the [c2]daisy chain rotaxane exhibited fluorescence emission derived from both diarylacetylene monomers and the excimer, which implies that the [c2]daisy chain structure can undergo contraction and extension. This is the first demonstration of a system in which excimer formation between two π-conjugated molecules within an isolated space can be controlled by the unique motion of a [c2]daisy chain rotaxane.
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Affiliation(s)
- Susumu Tsuda
- Department of Chemistry, Osaka Dental University, Hirakata, Osaka, 5731121, Japan
| | - Yoshitsugu Komai
- Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita, Osaka, 5648680, Japan
| | - Shin-Ichi Fujiwara
- Department of Chemistry, Osaka Dental University, Hirakata, Osaka, 5731121, Japan
| | - Yutaka Nishiyama
- Faculty of Chemistry, Materials and Bioengineering, Kansai University, Suita, Osaka, 5648680, Japan
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2
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Zheng M, Fyles TM. Properties of Liposomes Containing Natural and Synthetic Lipids Formed by Microfluidic Mixing. EUR J LIPID SCI TECH 2018. [DOI: 10.1002/ejlt.201700347] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Affiliation(s)
- Mengxiu Zheng
- Department of Chemistry; University of Victoria; 8205 Victoria BC Canada
| | - Thomas M. Fyles
- Department of Chemistry; University of Victoria; 8205 Victoria BC Canada
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3
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Mitchell GM, Hesketh A, Lombardi C, Ho C, Fyles TM. A membrane-spanning macrocyclic bolaamphiphile lipid mimic of archaeal lipids. CAN J CHEM 2017. [DOI: 10.1139/cjc-2016-0252] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The synthesis of a 72-membered macrocyclic tetraester bolaamphiphile is accomplished in six chemical steps from commercially available starting materials using copper-accelerated azide–alkyne coupling to close the macrocycle in high yield. Related diester amphiphiles and an acyclic tetraester bolaamphiphile were also prepared. The set of lipids bearing nitrophenyl phosphate head groups were incorporated into phospholipid vesicles but failed to undergo phosphate hydrolysis in basic conditions, undergoing efficient elimination in competition. The same lipid cores bearing phosphate-linked nitrobenzoxadiazole (NBD) head groups also incorporated into phospholipid vesicles and the NBD fluorescence was quenched with cobalt ions. The proportion of membrane-spanning bolaamphiphiles was determined from the ratio of cobalt quenching in the presence and in the absence of a detergent. The macrocyclic bolaamphiphile is incorporated into phospholipid vesicles such that 48 ± 4% of the NBD head groups are in the outer leaflet, consistent with a membrane-spanning orientation. The acyclic bolaamphiphile is incorporated with 75 ± 3% of the NBD head groups accessible to quencher in the absence of a detergent suggesting U-shaped incorporation in the outer leaflet of the bilayer membrane. In ring size and spanning ability, the macrocyclic bolaamphiphile mimics naturally occurring macrocyclic archaeal lipids.
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Affiliation(s)
- Gavin M. Mitchell
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
| | - Amelia Hesketh
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
| | - Christie Lombardi
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
| | - Cally Ho
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
| | - Thomas M. Fyles
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
- Department of Chemistry, University of Victoria, Box 1700 STN CSC, Victoria, BC V8W 3V6, Canada
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4
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Membrane Assembly and Ion Transport Ability of a Fluorinated Nanopore. PLoS One 2016; 11:e0166587. [PMID: 27835700 PMCID: PMC5106009 DOI: 10.1371/journal.pone.0166587] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Accepted: 10/31/2016] [Indexed: 11/19/2022] Open
Abstract
A novel 21-residue peptide incorporating six fluorinated amino acids was prepared. It was designed to fold into an amphiphilic alpha helical structure of nanoscale length with one hydrophobic face and one fluorinated face. The formation of a fluorous interface serves as the main vector for the formation of a superstructure in a bilayer membrane. Fluorescence assays showed this ion channel's ability to facilitate the translocation of alkali metal ions through a phospholipid membrane, with selectivity for sodium ions. Computational studies showed that a tetramer structure is the most probable and stable supramolecular assembly for the active ion channel structure. The results illustrate the possibility of exploiting multiple Fδ-:M+ interactions for ion transport and using fluorous interfaces to create functional nanostructures.
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5
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Berry SN, Busschaert N, Frankling CL, Salter D, Gale PA. Aromatic isophthalamides aggregate in lipid bilayers: evidence for a cooperative transport mechanism. Org Biomol Chem 2016; 13:3136-43. [PMID: 25633557 DOI: 10.1039/c4ob02631d] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
The synthesis and anion transport properties of a series of transmembrane anion transporters based on an isophthalamide scaffold with phenyl, naphthyl or anthracenyl central rings are reported. Anion transport studies using POPC vesicles, showed that the compounds have Hill coefficients >1. This is indicative of higher order complex formation, evidence that leads us to suggest that the compounds are not functioning solely as mobile carriers but rather that a cooperative transport mechanism is being observed. Fluorescence spectroscopy was used to show that the compounds aggregate in the phospholipid bilayer, which provides evidence that these compounds function as a self-assembled anion-conducting aggregate.
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Affiliation(s)
- Stuart N Berry
- Chemistry, University of Southampton, Southampton, SO17 1BJ, UK.
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6
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Rodríguez-Vázquez N, Fuertes A, Amorín M, Granja JR. Bioinspired Artificial Sodium and Potassium Ion Channels. Met Ions Life Sci 2016; 16:485-556. [DOI: 10.1007/978-3-319-21756-7_14] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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7
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Basak D, Sridhar S, Bera AK, Madhavan N. Cation–halide transport through peptide pores containing aminopicolinic acid. Org Biomol Chem 2016; 14:4712-7. [DOI: 10.1039/c6ob00592f] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Aminopicolinic acid incorporated peptides form pores that promote cation–halide co-transport across lipid bilayers and do not show a closed state.
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Affiliation(s)
- Debajyoti Basak
- Department of Chemistry
- Indian institute of Technology
- Chennai 600036
- India
| | - Sucheta Sridhar
- Department of Biotechnology
- Indian institute of Technology
- Chennai 600036
- India
| | - Amal K. Bera
- Department of Biotechnology
- Indian institute of Technology
- Chennai 600036
- India
| | - Nandita Madhavan
- Department of Chemistry
- Indian institute of Technology
- Chennai 600036
- India
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8
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Werner S, Ebert H, Lechner BD, Lange F, Achilles A, Bärenwald R, Poppe S, Blume A, Saalwächter K, Tschierske C, Bacia K. Dendritic domains with hexagonal symmetry formed by x-shaped bolapolyphiles in lipid membranes. Chemistry 2015; 21:8840-50. [PMID: 25940233 PMCID: PMC4517157 DOI: 10.1002/chem.201405994] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Indexed: 12/22/2022]
Abstract
A novel class of bolapolyphile (BP) molecules are shown to integrate into phospholipid bilayers and self-assemble into unique sixfold symmetric domains of snowflake-like dendritic shapes. The BPs comprise three philicities: a lipophilic, rigid, π-π stacking core; two flexible lipophilic side chains; and two hydrophilic, hydrogen-bonding head groups. Confocal microscopy, differential scanning calorimetry, XRD, and solid-state NMR spectroscopy confirm BP-rich domains with transmembrane-oriented BPs and three to four lipid molecules per BP. Both species remain well organized even above the main 1,2-dipalmitoyl-sn-glycero-3-phosphocholine transition. The BP molecules only dissolve in the fluid membrane above 70 °C. Structural variations of the BP demonstrate that head-group hydrogen bonding is a prerequisite for domain formation. Independent of the head group, the BPs reduce membrane corrugation. In conclusion, the BPs form nanofilaments by π stacking of aromatic cores, which reduce membrane corrugation and possibly fuse into a hexagonal network in the dendritic domains.
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Affiliation(s)
- Stefan Werner
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany) E-mail:
- ZIK HALOmem, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany)
| | - Helgard Ebert
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany) E-mail:
| | - Bob-Dan Lechner
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany) E-mail:
| | - Frank Lange
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany)
| | - Anja Achilles
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany)
| | - Ruth Bärenwald
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany)
| | - Silvio Poppe
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany) E-mail:
| | - Alfred Blume
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany) E-mail:
| | - Kay Saalwächter
- Institut für Physik - NMR, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany)
| | - Carsten Tschierske
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany) E-mail:
| | - Kirsten Bacia
- Institut für Chemie, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany) E-mail:
- ZIK HALOmem, Martin-Luther-Universität Halle-Wittenberg06120 Halle (Saale) (Germany)
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9
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Kandasamy YS, Cai J, Beler A, Sang MSJ, Andrews PD, Murphy RS. Photocontrol of ion permeation in lipid vesicles with amphiphilic dithienylethenes. Org Biomol Chem 2015; 13:2652-63. [DOI: 10.1039/c4ob02382j] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Asymmetrical amphiphilic dithienylethenes have been prepared and photocontrol of ion permeation was observed in lipid vesicles.
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Affiliation(s)
- Yamuna S. Kandasamy
- Department of Chemistry and Biochemistry
- Research and Innovation Centre
- University of Regina
- Regina
- Canada
| | - Jianxin Cai
- Department of Chemistry and Biochemistry
- Research and Innovation Centre
- University of Regina
- Regina
- Canada
| | - Alisha Beler
- Department of Chemistry and Biochemistry
- Research and Innovation Centre
- University of Regina
- Regina
- Canada
| | - M.-S. Jemeli Sang
- Department of Chemistry and Biochemistry
- Research and Innovation Centre
- University of Regina
- Regina
- Canada
| | - Patrick D. Andrews
- Department of Chemistry and Biochemistry
- Research and Innovation Centre
- University of Regina
- Regina
- Canada
| | - R. Scott Murphy
- Department of Chemistry and Biochemistry
- Research and Innovation Centre
- University of Regina
- Regina
- Canada
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10
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Muraoka T, Endo T, Tabata KV, Noji H, Nagatoishi S, Tsumoto K, Li R, Kinbara K. Reversible Ion Transportation Switch by a Ligand-Gated Synthetic Supramolecular Ion Channel. J Am Chem Soc 2014; 136:15584-95. [DOI: 10.1021/ja5070312] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Takahiro Muraoka
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1,
Katahira, Aoba-ku, Sendai 980-8577, Japan
- PRESTO, Japan Science and Technology Agency, 4-1-8, Honcho, Kawaguchi,
Saitama 332-0012, Japan
| | - Takahiro Endo
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1,
Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Kazuhito V. Tabata
- Department
of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku,
Tokyo 113-8656, Japan
| | - Hiroyuki Noji
- Department
of Applied Chemistry, School of Engineering, The University of Tokyo, Bunkyo-ku,
Tokyo 113-8656, Japan
| | - Satoru Nagatoishi
- Department
of Bioengineering, The University of Tokyo, Bunkyo-ku, Tokyo 108-8656, Japan
| | - Kouhei Tsumoto
- Department
of Bioengineering, The University of Tokyo, Bunkyo-ku, Tokyo 108-8656, Japan
- Department
of Chemistry and Biotechnology, The University of Tokyo, Bunkyo-ku, Tokyo 108-8656, Japan
- Institute
of Medical Science, The University of Tokyo, 4-6-1, Shirokanedai, Minato-ku, Tokyo 108-8639, Japan
| | - Rui Li
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1,
Katahira, Aoba-ku, Sendai 980-8577, Japan
| | - Kazushi Kinbara
- Institute
of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1,
Katahira, Aoba-ku, Sendai 980-8577, Japan
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11
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Abstract
Seventeen derivatives of α- and β-cyclodextrins were prepared from the cyclodextrin per-6-azide by "click" cyclization with terminal alkynes. Sixteen of these "half-channel" compounds showed significant activity as ion channels in planar bilayer members as assessed by the voltage-clamp technique. Activity ranged from persistent square-top openings to highly erratic conductance; mixed behaviours were evident in virtually all data recorded. Some of the erratic behaviours were shown to follow an apparent power-law distribution of open duration times. The activities observed for the suite were summarized using a model-free activity grid method which displays conductance, duration, and opening behaviour. The overall activity shows the clustering of conductance-duration indicating that activity arises from system properties rather that solely as a property of the compound. The activity grids also support an analysis of structure-activity relationships as they apply to the global behaviour of the compounds and reveal the complexity of a single structure change in controlling the distribution of concurrent conductance behaviours. Transient blockage of channel activity by the hydrophobic guest of the cyclodextrin (1-adamantyl carboxylate) is consistent with the formation of an end-to-end dimer channel among several other competing and interconverting structures.
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Affiliation(s)
- Jonathan K W Chui
- Department of Chemistry, University of Victoria, PO Box 3065, Victoria, BC, Canada V8W 3P6.
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12
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Lalgee LJ, Grierson L, Fairman RA, Jaggernauth GE, Schulte A, Benz R, Winterhalter M. Synthetic ion transporters: pore formation in bilayers via coupled activity of non-spanning cobalt-cage amphiphiles. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:1247-54. [PMID: 24508756 DOI: 10.1016/j.bbamem.2014.01.032] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2013] [Revised: 01/07/2014] [Accepted: 01/27/2014] [Indexed: 11/16/2022]
Abstract
Three amphiphilic cobalt-cage congeners bearing a diaza-crown bridge and varying alkyl chains (1:2:3; n = 12, 16, 18) have been assessed for their ion transport across planar lipid bilayer membranes. In symmetrical electrolyte solutions, a range of ion transport activity is provoked: 1 disrupts painted (fluid) bilayers in a detergent-like mode of action; 2 forms conducting "pores" in folded (rigid) membranes with long open lifetimes (>2 min) while 3 requires the larger auxiliary solvent volume and lower lateral stress of painted membranes to effect ion transport via long-lived pores. Hill analysis of the conductance variation with monomer concentration yields coefficients (2:3; n = 2.3, 1.9) in support of dimeric (n = 2) membrane-active structures, for which the derived "pore" radii are correlated with charge-density of the transported cations and their affinity for the crown moiety. A toroidal-pore model is invoked to account for the flux of guest ions through planar bilayer membranes without a fast-diffusing intermediary or direct membrane-spanning structure.
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Affiliation(s)
- Lorale J Lalgee
- The Department of Chemistry, The University of the West Indies, St. Augustine, Trinidad and Tobago.
| | - Lebert Grierson
- The Department of Chemistry, The University of the West Indies, St. Augustine, Trinidad and Tobago.
| | - Richard A Fairman
- The Department of Chemistry, The University of the West Indies, St. Augustine, Trinidad and Tobago.
| | - Gina E Jaggernauth
- The Department of Chemistry, The University of the West Indies, St. Augustine, Trinidad and Tobago.
| | - Albert Schulte
- The Department of Chemistry, The University of the West Indies, St. Augustine, Trinidad and Tobago.
| | - Roland Benz
- School of Engineering and Science, Jacobs University Bremen, Germany.
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13
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Abstract
A membrane transport system functions only when activated by a chemical fuel.
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Affiliation(s)
- A. K. Dambenieks
- Department of Chemistry
- University of Victoria
- Victoria, Canada V8W 3P6
| | - P. H. Q. Vu
- Department of Chemistry
- University of Victoria
- Victoria, Canada V8W 3P6
| | - T. M. Fyles
- Department of Chemistry
- University of Victoria
- Victoria, Canada V8W 3P6
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14
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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: 198] [Impact Index Per Article: 18.0] [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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15
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Kim Y, Li W, Shin S, Lee M. Development of toroidal nanostructures by self-assembly: rational designs and applications. Acc Chem Res 2013; 46:2888-97. [PMID: 24053785 DOI: 10.1021/ar400027c] [Citation(s) in RCA: 124] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Toroidal nanostructures are symmetrical ring-shaped structures with a central internal pore. Interestingly, in nature, many transmembrane proteins such as β-barrels and α-helical bundles have toroidal shapes. Because of this similarity, toroidal nanostructures can provide a template for the development of transmembrane channels. However, because of the lack of guiding principles for the construction of toroids, researchers have not widely studied the self-assembly of toroidal nanostructures as compared with the work on other supramolecular architectures. In this Account, we describe our recent efforts to construct toroidal nanostructures through the self-assembly of rationally designed building blocks. In one strategy for building these structures, we induce interfacial curvatures within the building blocks. When we laterally graft a bulky hydrophilic segment onto a p-oligophenyl rod or β-sheet peptides, the backbones of the self-assembled structures can bend in response to the steric effect of these large side groups, driving the p-oligophenyl rod or β-sheet peptides to form nanosized toriods. In another strategy, we can build toroids from bent-shaped building blocks by stacking the macrocycles. Aromatic segments with an internal angle of 120° can associate with each other in aqueous solution to form a hexameric macrocycle. Then these macrocycles can stack on top of each other via hydrophobic and π-π interactions and form highly uniform toroidal nanostructures. We provide many examples that illustrate these guiding principles for constructing toroidal nanostructures in aqueous solution. Efforts to create toroidal nanostructures through the self-assembly of elaborately designed molecular modules provide a fundamental approach toward the development of artificial transmembrane channels. Among the various toroids that we developed, a few nanostructures can insert into lipid membranes and allow limited transport in vesicles.
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Affiliation(s)
- Yongju Kim
- State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Wen Li
- State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
| | - Suyong Shin
- Department of Chemistry, Seoul National University, Seoul 151-747, Korea
| | - Myongsoo Lee
- State Key Lab of Supramolecular Structure and Materials, College of Chemistry, Jilin University, Changchun 130012, China
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16
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Fyles TM. How do amphiphiles form ion-conducting channels in membranes? Lessons from linear oligoesters. Acc Chem Res 2013; 46:2847-55. [PMID: 23586980 DOI: 10.1021/ar4000295] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
The X-ray crystal structures of biological ion channels are exquisitely complex, but not all natural products capable of forming ion-conducting channels are equally elaborate. Examples such as the peptides gramicidin or alamethicin or the polyene antibiotics amphotericin and nystatin clearly form well-defined channels without requiring a massive protein superstructure. These molecules form the starting point for a supramolecular chemistry challenge: how to create synthetic compounds and systems that catalyze the translocation of ionic species across bilayer membranes mimicking naturally occurring channels. Over the past three decades, supramolecular chemists have developed numerous examples of systems with transport rates and efficiencies that rival natural channels. As the field developed, researchers discovered many compounds that are functional for ion transport but bear very little resemblance to any imagined architectures of ion channels. We and others have followed these lead compounds extensively in a quest to focus on the mechanisms such simple compounds use to achieve their function. These compounds show all the hallmarks of ion channels including high activity, ion specificity, regular time-dependent conductance changes, and in some cases higher-order phenomena such as voltage-dependent activity. In this Account, we summarize experimental evidence derived from an extensive class of oligoester bolaamphiphiles that illustrates how amphiphilic molecules can form ion-conducting channels in membranes. Examination of increasingly simple compounds over the past two decades has shifted the focus away from biological paradigms towards alternative modes for transmembrane ion transport. We have developed new tools to move beyond simple on-off channel openings to complex bursts of high activity. From the perspective of flux, the highly conducting bursts clearly move ions more efficiently than simple on-off openings. High and sustained conductance, whatever its structural origin, has direct applications in amplification of chemical signals or membrane-disrupting biological activity. These results ensure that simple transporters will continue to fascinate and puzzle for a long time to come.
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Affiliation(s)
- Thomas M. Fyles
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
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17
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A rigid macrocyclic bis-malonate for the regioselective preparation of trans-1 and trans-3 fullerene bis-adducts. Tetrahedron Lett 2013. [DOI: 10.1016/j.tetlet.2013.04.024] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Moszynski JM, Fyles TM. Mechanism of Ion Transport by Fluorescent Oligoester Channels. J Am Chem Soc 2012; 134:15937-45. [DOI: 10.1021/ja306596m] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Joanne M. Moszynski
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
| | - Thomas M. Fyles
- Department of Chemistry, University of Victoria, Victoria, British Columbia V8P 5C2, Canada
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Chui JKW, Fyles TM. Ionic conductance of synthetic channels: analysis, lessons, and recommendations. Chem Soc Rev 2012; 41:148-75. [DOI: 10.1039/c1cs15099e] [Citation(s) in RCA: 141] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Affiliation(s)
- Kathleen Genge
- a Department of Chemistry , University of Victoria , Victoria , BC , V8W 3V6 , Canada
| | - Joanne M. Moszynski
- a Department of Chemistry , University of Victoria , Victoria , BC , V8W 3V6 , Canada
| | - Matthew Thompson
- a Department of Chemistry , University of Victoria , Victoria , BC , V8W 3V6 , Canada
| | - Thomas M. Fyles
- a Department of Chemistry , University of Victoria , Victoria , BC , V8W 3V6 , Canada
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Moszynski JM, Fyles TM. Synthesis and ion transport activity of oligoesters containing an environment-sensitive fluorophore. Org Biomol Chem 2011; 9:7468-75. [DOI: 10.1039/c1ob06047c] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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