ABSTRACT - We created nanometer-scale transmembrane channels in lipid bilayers by means of self-assembled DNA-based nanostructures. Scaffolded DNA origami was used to create a stem that penetrated and spanned a lipid membrane, as well as a barrel-shaped cap that adhered to the membrane, in part via 26 cholesterol moieties. In single-channel electrophysiological measurements, we found similarities to the response of natural ion channels, such as conductances on the order of 1 nanosiemens and channel gating. More pronounced gating was seen for mutations in which a single DNA strand of the stem protruded into the channel. Single-molecule translocation experiments show that the synthetic channels can be used to discriminate single DNA molecules.
TEM image of multiple DNA channels attached to a small lipid vesicle. This image relates to a paper that appeared in the Nov. 16, 2012, issue of Science, published by AAAS. The paper, by Martin Langecker at Technische Universität München in Garching, Germany, and colleagues was titled, "Synthetic Lipid Membrane Channels Formed by Designed DNA Nanostructures." Credit: Image courtesy of Technische Universität München
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