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Channels from DNA
Artificial transmembrane channels are of interest for applications, such as sensing and modifying cell signaling. Langecker et al. (p. 932; see the Perspective by Strano) used α-hemolysin as a model for creating a nanostructure with DNA origami that, when inserted into a lipid bilayer membrane, acted as a membrane channel. Ion channel responses were similar to those measured for natural ion channels, and channels that protruded further into the membrane exhibited greater gating responses. The channels were used to detect single-DNA molecules.
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.