Rigid Rod-Shaped Polyols: Functional Nonpeptide Models for Transmembrane Proton Channels
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- 作者：Linnea A. Weiss ; Naomi Sakai ; Bereket Ghebremariam ; Chiyou Ni ; and Stefan Matile
- 刊名：Journal of the American Chemical Society
- 出版年：1997
- 出版时间：December 17, 1997
- 年：1997
- 卷：119
- 期：50
- 页码：12142 - 12149
- 全文大小：295K
- 年卷期：v.119,no.50(December 17, 1997)
- ISSN：1520-5126
文摘
The present study concerns the mode of action of a rigidrod-shaped polyol 1 and the correspondinghexamer 2. Proton flux mediated by 1 isshown to be strongly favored over metal cations and anions. Themodestselectivity for monovalent cations (Rb+ >Cs+ > K+ > Na+ 
Li+, Eisenman sequence II) is determined bythedehydration energy and is weakly influenced by the local electric(ionophoric) field. The induction of membranedefects was ruled out by the absence of dye leakage. Structuralstudies by circular dichroism and fluorescencespectroscopy imply that 1 aggregates in polar and nonpolarsolvents, but not in lipid bilayers. Furthermore, itisshown that a very small fraction of 1 adopts a monomerictransmembrane tunnel-like structure which accounts foractivity, while the remainder forms inactive self-assemblies. Theabove results suggest that 1 acts as afunctionalunimolecular proton wire which mimics the hydrogen-bonded chainmechanism found in bioenergetic systems.
Li+, Eisenman sequence II) is determined bythedehydration energy and is weakly influenced by the local electric(ionophoric) field. The induction of membranedefects was ruled out by the absence of dye leakage. Structuralstudies by circular dichroism and fluorescencespectroscopy imply that 1 aggregates in polar and nonpolarsolvents, but not in lipid bilayers. Furthermore, itisshown that a very small fraction of 1 adopts a monomerictransmembrane tunnel-like structure which accounts foractivity, while the remainder forms inactive self-assemblies. Theabove results suggest that 1 acts as afunctionalunimolecular proton wire which mimics the hydrogen-bonded chainmechanism found in bioenergetic systems.