Synthesis and Ion Channel Formation of Novel Cyclic Peptides Containing a Non-natural Amino Acid

Ishida, Hideyuki; Donowaki, Kiyoshi; Inoue, Yoshihisa; Qi, Zhi; Sokabe, Masahiro

doi:10.1246/cl.1997.953

Cited by 13 publications

(11 citation statements)

References 6 publications

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“…Using the same strategy, Ishida and co-workers reported ion channels formed by compounds of type 2, described as ''cyclic peptides containing an non-natural amino acid'' (3-amino-5-N-acylbenzoic acid). 36,37 Each of the individual elements were modified systematically: ring size (hexa-to deca-peptide), length of alkyl chain (10, 16, 18 carbons total), and amino acid side-chain on the macrocycle. Regular openings were observed for all of the compounds, and these openings were amenable to blocking by Ca 2+ ions.…”

Section: Circular Topology/macrocycle-basedmentioning

confidence: 99%

Ionic conductance of synthetic channels: analysis, lessons, and recommendations

2012

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Synthetic ion channels have been known for nearly three decades, but it is only in the past decade that analysis of the currents these ionic conductors carry has become a standard technique. A broad range of structural types have been explored and these reports have produced a very diverse collection of ion channel conductance behaviours. In this critical review we describe a notational method to extract salient information from reported ion channel experiments. We use an activity grid to represent quantitative information on conductance and opening duration with a five-level colour code to represent qualitative information on the nature of the conductance-time profile. Analysis of the cumulative dataset suggests that the reported conductance data can reflect the structural features of the compounds prepared, but does also reflect the energetic landscape of the bilayer membrane in which synthetic ion channels function (143 references).

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Section: Circular Topology/macrocycle-basedmentioning

confidence: 99%

Ionic conductance of synthetic channels: analysis, lessons, and recommendations

2012

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“…Based on this simple structural model the structure and function of the channel could be correlated. The peptide ring, with its rigid structure (Ishida et al, 1997) on one hand, provides a cavity for the entering of water and permeant ions into the pore and, with its hydrophilic feature on the other hand, forms the channel entrance at the membranewater interface and gives the binding site for ions. Consequently, the acyl chains line across the membrane form an ion-conducting pathway.…”

Section: Structural Modelmentioning

confidence: 99%

“…One way to do so is to take advantage of the simpler structure of the artificial ion channel to build a model channel system. Such model channels have been paid great attention (Sokabe et al, 1997) and developed by means of several different strategies: by employing the channel-forming antibiotics, such as the gramicidin channel (see Andersen and Koeppe, 1992 for review); by mimicking the sequence of the pore region of known channel proteins (Oiki et al, 1988a,b); or by de novo design (Lear et al, 1988;Kobuke et al, 1992;Tanaka et al, 1995;Ishida et al, 1997).…”

Section: Introductionmentioning

confidence: 99%

“…A primary purpose of the present work is to construct a structure model of a channel that can correlate with its function. To achieve this aim, a channel formed from cyclo(-Ala-Aba(C 16 )-) 4 (AC164), a cyclic octa-peptide consisting of four alternate L-alanine (Ala) and NЈ-acylated 3-aminobenzoic acid (Aba) moieties (Ishida et al, 1997), was studied in bilayer membranes. The function and structure of the channel to provide a conduction pathway for permeant ions was studied by electrophysiological experiments.…”

Section: Introductionmentioning

confidence: 99%

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Structure-Function Study on a de Novo Synthetic Hydrophobic Ion Channel

Sokabe

Donowaki

et al. 1999

Biophysical Journal

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Ion conduction properties of a de novo synthesized channel, formed from cyclic octa-peptides consisting of four alternate L-alanine (Ala) and N'-acylated 3-aminobenzoic acid (Aba) moieties, were studied in bilayer membranes. The single-channel conductance was 9 pS in symmetrical 500 mM KCl. The channel favored permeation of cations over anions with a permeability ratio (PCl-/PK+) of 0.15. The selectivity sequence among monovalent cations based on permeability ratio (PX+/PK+) fell into an order: NH4+(1.4) > Cs+(1. 1) >/= K+(1.0) > Na+(0.4) >> Li+(0). The conductance-activity relationship of the channel in K+ solutions followed simple Michaelis-Menten kinetics with a half-maximal saturating activity of 8 mM and a maximal conductance of 9 pS. The permeability ratio PNa+/PK+ remained constant ( approximately 0.40) under biionic concentrations from 10 to 500 mM. These results suggests that the channel is a one-ion channel. The pore diameter probed by a set of organic cations was approximately 6 A. The single-channel current was blocked by Ca2+ in a dose-dependent manner that followed a single-site titration curve with a voltage-dependent dissociation constant of 0.6 mM at 100 mV. The electric distance of the binding site for Ca2+ was 0.07 from both entrances of the channel, indicating the presence of two symmetrical binding sites in each vicinity of the channel entrance. Correlations between conduction properties and structural aspects of the channel are discussed in terms of a three-barrier and two-binding-site (3B2S) model of Eyring rate theory. All available structural information supported an idea that the channel was formed from a tail-to-tail associated dimer of the molecule, the pore of which was lined with hydrophobic acyl chains. This is the first report to have made a systematic analysis of ion permeation through a hydrophobic pore.

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“…[33][34][35] UV-vis titration experiments in DMSO indicated that the disodium salt of 4-nitrophenyl phosphate forms 1 : 1 complexes with the receptors [K a = 1.2 Â 10 6 M À1 for cyclo-(Ala-Aba) 3 (4)]. Additional evidence for the binding mode was obtained by 1 H NMR spectroscopy, which indicates that 4 has C 3 -symmetry that is maintained on binding the phosphoester.…”

Section: Simple Cyclic Peptidesmentioning

confidence: 98%

Anion recognition by cyclic peptides

Elmes

Jolliffe

2015

Chem. Commun.

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Anion binding selectivity can often be controlled by judicious arrangement of recognition moieties around an anion of interest. Indeed, nature takes advantage of large peptides/proteins to provide highly efficient and selective anion receptors using a small number of amino acid building blocks placed in a precise arrangement. Cyclic peptides are ideal synthetic scaffolds to position binding residues in a similarly preorganised manner as their synthetic versatility and rigidified structure allows precise control over their size and shape. This review summarises the recent use of such cyclic peptide scaffolds as receptors for various anionic species.

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Synthesis and Ion Channel Formation of Novel Cyclic Peptides Containing a Non-natural Amino Acid

Cited by 13 publications

References 6 publications

Ionic conductance of synthetic channels: analysis, lessons, and recommendations

Ionic conductance of synthetic channels: analysis, lessons, and recommendations

Structure-Function Study on a de Novo Synthetic Hydrophobic Ion Channel

Anion recognition by cyclic peptides

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