title: In situ, Reversible Gating of a Mechanosensitive Ion Channel through Protein-Lipid Interactions.
abstract: Understanding the functioning of ion channels, as well as utilizing their properties for biochemical applications requires control over channel activity. Herein we report a reversible control over the functioning of a mechanosensitive ion channel by interfering with its interaction with the lipid bilayer. The mechanosensitive channel of large conductance fromEscherichia coliis reconstituted into liposomes and activated to its different sub-open states by titrating lysophosphatidylcholine (LPC) into the lipid bilayer. Activated channels are closed back by the removal of LPC out of the membrane by bovine serum albumin (BSA). Electron paramagnetic resonance spectra showed the LPC-dose-dependent gradual opening of the channel pore in the form of incrementally increasing spin label mobility and decreasing spin-spin interaction. A method to reversibly open and close mechanosensitive channels to distinct sub-open conformations during their journey from the closed to the fully open state enables detailed structural studies to follow the conformational changes during channel functioning. The ability of BSA to revert the action of LPC opens new perspectives for the functional studies of other membrane proteins that are known to be activated by LPC.
authors.affiliation: Department of Biochemistry, University of Groningen Groningen, Netherlands.
authors.forename: Anna
authors.initials: A
authors.lastname: Dimitrova
authors.affiliation: Department of Biochemistry, University of Groningen Groningen, Netherlands.
authors.forename: Martin
authors.initials: M
authors.lastname: Walko
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University Leiden, Netherlands.
authors.forename: Maryam
authors.initials: M
authors.lastname: Hashemi Shabestari
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University Leiden, Netherlands.
authors.forename: Pravin
authors.initials: P
authors.lastname: Kumar
authors.affiliation: Huygens-Kamerlingh Onnes Laboratory, Department of Physics, Leiden University Leiden, Netherlands.
authors.forename: Martina
authors.initials: M
authors.lastname: Huber
authors.affiliation: Neuroscience Department, University of Groningen, University Medical Center Groningen Groningen, Netherlands.
authors.forename: Armagan
authors.initials: A
authors.lastname: Kocer
keywords: MscL; bovine serum albumin; electron spin resonance spectroscopy; lysophosphatidylcholines; mechanosensation; reversible gating