Ion Channels Made from a Single Membrane-Spanning DNA Duplex.
Because of their hollow interior, transmembrane channels are capable of opening up pathways for ions across lipid membranes of living cells. Here, we demonstrate ion conduction induced by a single DNA duplex that lacks a hollow central channel. Decorated with six porpyrin-tags, our duplex is designed to span lipid membranes. Combining electrophysiology measurements with all-atom molecular dynamics simulations, we elucidate the microscopic conductance pathway. Ions flow at the DNA-lipid interface as the lipid head groups tilt toward the amphiphilic duplex forming a toroidal pore filled with water and ions. Ionic current traces produced by the DNA-lipid channel show well-defined insertion steps, closures, and gating similar to those observed for traditional protein channels or synthetic pores. Ionic conductances obtained through simulations and experiments are in excellent quantitative agreement. The conductance mechanism realized here with the smallest possible DNA-based ion channel offers a route to design a new class of synthetic ion channels with maximum simplicity.
Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, United Kingdom.
Kerstin
K
Göpfrich
Center for the Physics of Living Cells, Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801, United States.
Chen-Yu
CY
Li
School of Chemistry and Institute for Life Sciences, University of Southampton, Highfield , Southampton SO17 1BJ, United Kingdom.
Iwona
I
Mames
Jacobs University Bremen , 28759 Bremen, Germany.
Satya Prathyusha
SP
Bhamidimarri
Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, United Kingdom.
Maria
M
Ricci
Center for the Physics of Living Cells, Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801, United States.
Jejoong
J
Yoo
School of Chemistry and Institute for Life Sciences, University of Southampton, Highfield , Southampton SO17 1BJ, United Kingdom.
Adam
A
Mames
Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, United Kingdom.
Alexander
A
Ohmann
Jacobs University Bremen , 28759 Bremen, Germany.
Mathias
M
Winterhalter
School of Chemistry and Institute for Life Sciences, University of Southampton, Highfield , Southampton SO17 1BJ, United Kingdom.
Eugen
E
Stulz
Center for the Physics of Living Cells, Department of Physics, University of Illinois at Urbana-Champaign , 1110 West Green Street, Urbana, Illinois 61801, United States.
Aleksei
A
Aksimentiev
Cavendish Laboratory, University of Cambridge , Cambridge CB3 0HE, United Kingdom.
Ulrich F
UF
Keyser
D004247:DNA / Q000737:chemistry*; D015640:Ion Channel Gating; D007473:Ion Channels / Q000737:chemistry*; D017136:Ion Transport; D008051:Lipid Bilayers / Q000737:chemistry*; D056004:Molecular Dynamics Simulation
D007473:Ion Channels; D008051:Lipid Bilayers; D004247:DNA
DNA nanotechnology; lipid membrane; molecular dynamics; porphyrin; synthetic ion channel