@article {178, title = {Polarized Water Wires under Confinement in Chiral Channels}, journal = {The Journal of Physical Chemistry B}, volume = {119}, year = {2015}, month = {Jul-16-2015}, pages = {8707 - 8717}, abstract = {
Abstract Image

The alignment of water molecules along chiral pores may activate proton/ion conduction along dipolar hydrophilic pathways. Here we show that a simple synthetic \“T-channel\” forms a directional pore with its carbonyl moieties solvated by chiral helical water wires. Atom-scale simulations and experimental crystallographic assays reveal a dynamical structure of water and electrolyte solutions (alkali metal chlorides) confined in these organic T-channels. Oscillations in the dipole orientation, which correspond to alternative ordering (dipole up\–dipole down) of the water molecules with a period of about 4.2 \Å (imposed by the distance between two successive carbonyl groups) are observed. When ions are added to the system, despite the strong Coulombic water/ion interaction, confined water remains significantly ordered in the T-channel and still exhibits surface-induced polarization. Cation permeation can be achieved through alternated hydration\–dehydration occurring along strongly oriented water wires. The T-channel, which exhibits chirality with strong water orientation, provides an opportunity to unravel novel water-channel systems that share many interesting properties of biomolecular systems.

}, issn = {1520-6106}, doi = {10.1021/acs.jpcb.5b03322}, author = {Barboiu, Mihail and Pierre-Andre Cazade and Le Duc, Yann and Yves-Marie Legrand and Arie Van Der Lee and Benoit A. Coasne} } @article {107, title = {An artificial primitive mimic of the Gramicidin-A channel}, journal = {Nature Communications}, volume = {5}, year = {2014}, month = {Jun-26-2014}, type = {Article}, abstract = {

Gramicidin A (gA) is the simplest known natural channel, and important progress in improving conduction activity has previously been obtained with modified natural gAs. However, simple artificial systems mimicking the gA functions are unknown. Here we show that gA can be mimicked using a simple synthetic triazole or {\textquoteleft}T-channel\&$\#$39; forming compound (TCT), having similar constitutional functions as the natural gAs. As in gA channels, the carbonyl moieties of the TCT, which point toward the T-channel core and surround the transport direction, are solvated by water. The net-dipolar alignment of water molecules along the chiral pore surfaces influences the conduction of protons/ions, envisioned to diffuse along dipolar hydrophilic pathways. Theoretical simulations and experimental assays reveal that the conduction through the T-channel, similar to that in gA, presents proton/water conduction, cation/anion selectivity and large open channel-conductance states. T-channels-associating supramolecular chirality with dipolar water alignment-represent an artificial primitive mimic of gA.

Molecular structures and crystal packing.

Molecular simulations of water molecules and ions confined within T-channel.

Bilayer membrane transport experiments.

Single channel conductance of T-channels under {\textquoteleft}early stage{\textquoteright} conductance records.

}, issn = {2041-1723}, doi = {10.1038/ncomms5142}, author = {Barboiu, Mihail and Le Duc, Yann and Gilles, Arnaud and Pierre-Andre Cazade and Michau, Mathieu and Yves-Marie Legrand and Arie Van Der Lee and Benoit A. Coasne and Parvizi, Paria and Post, Joshua and Fyles, Thomas} }