title: Voltage-induced gating of the mechanosensitive MscL ion channel reconstituted in a tethered lipid bilayer membrane.
abstract: The mechanosensitive (MS) ion channel is gated by changes in bilayer deformation. It is functional without the presence of any other proteins and gating of the channel has been successfully achieved using conventional patch clamping techniques where a voltage has been applied together with a pressure over the membrane. Here, we have for the first time analyzed the large conducting (MscL) channel in a supported membrane using only an external electrical field. This was made possible using a newly developed technique utilizing a tethered lipid bilayer membrane (tBLM), which is part of an engineered microelectronic array chip. Single ion channel activity characteristic for MscL was obtained, albeit with lower conductivity. The ion channel was gated using solely a transmembrane potential of 300 mV. Computations demonstrate that this amount of membrane potential induces a membrane tension of 12 dyn/cm, equivalent to that calculated to gate the channel in patch clamp from pressure-induced stretching of the bilayer. These results strengthen the supposition that the MscL ion channel gates in response to stress in the lipid membrane rather than pressure across it. Furthermore, these findings illustrate the possibility of using the MscL as a release valve for engineered membrane devices; one step closer to mimicking the true function of the living cell.
authors.affiliation: Department of Chemistry, University of Florida, Gainesville, FL, USA.
authors.forename: Martin
authors.initials: M
authors.lastname: Andersson
authors.forename: George
authors.initials: G
authors.lastname: Okeyo
authors.forename: Danyell
authors.initials: D
authors.lastname: Wilson
authors.forename: Henk
authors.initials: H
authors.lastname: Keizer
authors.forename: Paul
authors.initials: P
authors.lastname: Moe
authors.forename: Paul
authors.initials: P
authors.lastname: Blount
authors.forename: Daniel
authors.initials: D
authors.lastname: Fine
authors.forename: Ananth
authors.initials: A
authors.lastname: Dodabalapur
authors.forename: Randolph S
authors.initials: RS
authors.lastname: Duran
mesh_terms: D004553:Electric Conductivity; D029968:Escherichia coli Proteins / Q000737:chemistry / Q000502:physiology*; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry / Q000502:physiology*; D008051:Lipid Bilayers / Q000737:chemistry*; D040542:Mechanotransduction, Cellular / Q000502:physiology*; D011312:Pressure; D013314:Stress, Mechanical
chemical_list: D029968:Escherichia coli Proteins; D007473:Ion Channels; D008051:Lipid Bilayers; C086596:MscL protein, E coli