Enhancement of cation transport in synthetic hydraphile channels having covalently-linked headgroups

Shabany, Hossein; Gokel, George W.

doi:10.1039/b005436o

Cited by 23 publications

(21 citation statements)

References 12 publications

(9 reference statements)

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“…Of course, this is not a viable synthetic approach but such a tetramacrocyclic compound (19) was prepared [64]. When Na + transport was assessed by use of the NMR method, 19 showed a transport rate of 340 compared to 100 for dansyl channel 13.…”

Section: Formation Of a Tetramacrocyclic Channel Compoundmentioning

confidence: 99%

Coordination and transport of alkali metal cations through phospholipid bilayer membranes by hydraphile channels

Gokel

Daschbach

2008

Coordination Chemistry Reviews

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Hydraphiles are synthetic ionophores that were designed to mimic some properties of protein channels that conduct such cations as sodium. They use macrocyclic (crown) polyethers as amphiphilic headgroups and as entry and exit portals. Their overall length is controlled by covalent links between the two headgroups (distal macrocycles) and the "central relay" unit, typically also an azacrown. The hydraphiles insert in the bilayer membranes of synthetic phospholipid vesicles or vital cells and mediate the transport of cations. The hydraphiles were intended to be models but they are functional channels. Because they are symmetric, they are non-rectifying but they show open-close behavior characteristic of natural channels. Because they are non-rectifying, when they insert into a microbial membrane, they lead to a rapid change in osmotic balance that proves fatal to bacteria.

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Section: Formation Of a Tetramacrocyclic Channel Compoundmentioning

confidence: 99%

Coordination and transport of alkali metal cations through phospholipid bilayer membranes by hydraphile channels

Gokel

Daschbach

2008

Coordination Chemistry Reviews

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“…When the ∼(CH 2 ) 12 <bipip> (CH 2 ) 12 ∼ of 9 (dodecyl sidearms) is replaced by ∼(CH 2 ) 11 CO<bipip>CO(CH 2 ) 11 ∼ (10), the fractional Na + release drops only from 0.16 to 0.12. In contrast, an identical replacement in the benzyl-sidearmed series (13,14) leads to an increase in fractional Na + release from 0.12 to 0.44, a change of more than three-fold. It should also be noted that the change from 1 to 2 in the dodecyl-sidearmed series, in which ∼(CH 2 ) 12 <N18N>(CH 2 ) 12 ∼ (1) ∼ (CH 2 ) 11 CO<N18N>CO(CH 2 ) 11 ∼ (2) leads to a an increase in Na + fractional release from 0.20 to 0.48, or about at 2.4-fold increase.…”

Section: Sodium Cation Transport Mediated By Bipiperidyl Hydraphilesmentioning

confidence: 95%

“…When the central relay is diazacrown but the sidearms change from n-dodecyl (1) to benzyl (11), fractional Na + release increases from 0.20 to 0.27, or about 35%. When the sidearms are both benzyl and the central relay is changed from diazacrown (11) to bipiperidyl (13), the activity of the latter is only about half that of the former.…”

Section: Sodium Cation Transport Mediated By Bipiperidyl Hydraphilesmentioning

confidence: 99%

“…The synthesis of 17 and 18 required high dilution conditions because of the extremely large rings being formed. 13 Details of the preparation may be found in the experimental section. Scheme 2, the preparation of compounds 3 and 6, is shown at the right.…”

Section: Synthetic Access To Amidic Hydraphilesmentioning

confidence: 99%

“…1 H-NMR: 0.766 (6H, t), 1.145-1.319 (68H, m, 1.511 (8H, t), 2.199 (8H, t), 2.383 (4H, t), 2.673 (8H, t), 3.471-3.531 (64H, m). 13 116 mmol), DMAP (cat.) and Et 3 N (2 mL) in dry CH 2 Cl 2 (20 mL) was stirred at room temperature overnight.…”

Section: Sodium Cation Transport Measurementsmentioning

confidence: 99%

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Heterocyclic Amide Hydraphile Synthetic Cation Transporters

Wang¹,

Yamnitz²,

Gokel³

2007

HETEROCYCLES

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A family of hydraphile ionophores has been prepared in which various ∼CH 2 N∼ to ∼CON∼ replacements have been made to assess the effect on Na + transport through phospholipid bilayers. When the central relay (see graphical abstract) was a third macrocycle, symmetrical carbonyl for methylene replacements enhanced activity, but the presence of four or six amide residues diminished transport. When a pair of amides was incorporated into compounds having a 4,4′-bipiperidyl central relay, both significant increases and decreases were observed depending upon the amide positions. The presence of amides alters both the donor group type and strength and the conformation of the structural unit in which it occurs. These changes are shown to depend on the liposomes in which the Na + release studies were conducted. These changes are shown to affect the toxicity of the hydraphiles to E. coli.

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Supramolecular Chemistry

Cragg¹

2006

Kirk-Othmer Encyclopedia of Chemical Technology

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Supramolecular chemistry has its origins in the supermolecule, a term used by Nobel Laureate Jean‐Marie Lehn from the early 1970s when referring to a well‐defined chemical species comprising several components. The realization that supermolecules could in turn form larger molecular assemblies led to the shift in emphasis from super‐ to supramolecular in the literature to more accurately describe the complexity of systems involved. Supramolecular chemistry has since advanced to include complexes between molecules with complementary binding sites (molecular recognition), multicomponent complexes (supramolecular assemblies), the programmed interactions between large molecular assemblies (molecular tectonics), and even the directed assembly of three‐dimensional solids (crystal engineering). This article sets out the concepts and aims of supramolecular chemistry, illustrates some of the early development in the field, considers the synthesis and structures of individual supramolecular synthons as well as supramolecular assemblies, and concludes with an assessment of current and anticipated applications in materials science, medicine, the interface with biology, molecular computing, nanomaterials, and nanomachines.

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Enhancement of cation transport in synthetic hydraphile channels having covalently-linked headgroups

Abstract: A novel, pentamacrocyclic host molecule has been prepared in which four symmetry-equivalent diazacrown ethers lead to a dramatic enhancement in Na + transport, across a phospholipid bilayer, relative to open-chained analogs lacking the fourth crown.

Cited by 23 publications

References 12 publications

Coordination and transport of alkali metal cations through phospholipid bilayer membranes by hydraphile channels

Coordination and transport of alkali metal cations through phospholipid bilayer membranes by hydraphile channels

Heterocyclic Amide Hydraphile Synthetic Cation Transporters

Supramolecular Chemistry

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