What Ion Flow along Ion Channels Can Tell us about Their Functional Activity
The functional activity of channel-forming peptides and proteins is most directly verified by monitoring the flow of physiologically relevant inorganic ions, such as Na+, K+ and Cl−, along the ion channels. Electrical current measurements across bilayer lipid membranes (BLMs) interposed between two...
| Main Authors: | , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2016-12-01
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| Series: | Membranes |
| Subjects: | |
| Online Access: | http://www.mdpi.com/2077-0375/6/4/53 |
| _version_ | 1827845943144218624 |
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| author | Lucia Becucci Rolando Guidelli |
| author_facet | Lucia Becucci Rolando Guidelli |
| author_sort | Lucia Becucci |
| collection | DOAJ |
| description | The functional activity of channel-forming peptides and proteins is most directly verified by monitoring the flow of physiologically relevant inorganic ions, such as Na+, K+ and Cl−, along the ion channels. Electrical current measurements across bilayer lipid membranes (BLMs) interposed between two aqueous solutions have been widely employed to this end and are still extensively used. However, a major drawback of BLMs is their fragility, high sensitivity toward vibrations and mechanical shocks, and low resistance to electric fields. To overcome this problem, metal-supported tethered BLMs (tBLMs) have been devised, where the BLM is anchored to the metal via a hydrophilic spacer that replaces and mimics the water phase on the metal side. However, only mercury-supported tBLMs can measure and regulate the flow of the above inorganic ions, thanks to mercury liquid state and high hydrogen overpotential. This review summarizes the main results achieved by BLMs incorporating voltage-gated channel-forming peptides, interpreting them on the basis of a kinetic mechanism of nucleation and growth. Hg-supported tBLMs are then described, and their potential for the investigation of voltage-gated and ohmic channels is illustrated by the use of different electrochemical techniques. |
| first_indexed | 2024-03-12T09:06:38Z |
| format | Article |
| id | doaj.art-56eb39bc6dcc4cf1ba5462071d589f6b |
| institution | Directory Open Access Journal |
| issn | 2077-0375 |
| language | English |
| last_indexed | 2024-03-12T09:06:38Z |
| publishDate | 2016-12-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Membranes |
| spelling | doaj.art-56eb39bc6dcc4cf1ba5462071d589f6b2023-09-02T15:16:09ZengMDPI AGMembranes2077-03752016-12-01645310.3390/membranes6040053membranes6040053What Ion Flow along Ion Channels Can Tell us about Their Functional ActivityLucia Becucci0Rolando Guidelli1Department of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia, 3, Sesto Fiorentino 50019, ItalyDepartment of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia, 3, Sesto Fiorentino 50019, ItalyThe functional activity of channel-forming peptides and proteins is most directly verified by monitoring the flow of physiologically relevant inorganic ions, such as Na+, K+ and Cl−, along the ion channels. Electrical current measurements across bilayer lipid membranes (BLMs) interposed between two aqueous solutions have been widely employed to this end and are still extensively used. However, a major drawback of BLMs is their fragility, high sensitivity toward vibrations and mechanical shocks, and low resistance to electric fields. To overcome this problem, metal-supported tethered BLMs (tBLMs) have been devised, where the BLM is anchored to the metal via a hydrophilic spacer that replaces and mimics the water phase on the metal side. However, only mercury-supported tBLMs can measure and regulate the flow of the above inorganic ions, thanks to mercury liquid state and high hydrogen overpotential. This review summarizes the main results achieved by BLMs incorporating voltage-gated channel-forming peptides, interpreting them on the basis of a kinetic mechanism of nucleation and growth. Hg-supported tBLMs are then described, and their potential for the investigation of voltage-gated and ohmic channels is illustrated by the use of different electrochemical techniques.http://www.mdpi.com/2077-0375/6/4/53bilayer lipid membranetethered bilayer lipid membranevoltage-gated ion channelohmic ion channelgramicidinmelittinalamethicin |
| spellingShingle | Lucia Becucci Rolando Guidelli What Ion Flow along Ion Channels Can Tell us about Their Functional Activity Membranes bilayer lipid membrane tethered bilayer lipid membrane voltage-gated ion channel ohmic ion channel gramicidin melittin alamethicin |
| title | What Ion Flow along Ion Channels Can Tell us about Their Functional Activity |
| title_full | What Ion Flow along Ion Channels Can Tell us about Their Functional Activity |
| title_fullStr | What Ion Flow along Ion Channels Can Tell us about Their Functional Activity |
| title_full_unstemmed | What Ion Flow along Ion Channels Can Tell us about Their Functional Activity |
| title_short | What Ion Flow along Ion Channels Can Tell us about Their Functional Activity |
| title_sort | what ion flow along ion channels can tell us about their functional activity |
| topic | bilayer lipid membrane tethered bilayer lipid membrane voltage-gated ion channel ohmic ion channel gramicidin melittin alamethicin |
| url | http://www.mdpi.com/2077-0375/6/4/53 |
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