Rosette Nanotube Porins as Ion Selective Transporters and Single-Molecule Sensors

Prabhat Tripathi, Liang Shuai, Himanshu Joshi, Hirohito Yamazaki, William H. Fowle, Aleksei Aksimentiev, Hicham Fenniri, Meni Wanunu

Research output: Contribution to journalArticlepeer-review


Rosette nanotubes (RNTs) are a class of materials formed by molecular self-assembly of a fused guanine-cytosine base (G∧C base). An important feature of these self-assembled nanotubes is their precise atomic structure, intriguing for rational design and optimization as synthetic transmembrane porins. Here, we present experimental observations of ion transport across 1.1 nm inner diameter RNT porins (RNTPs) of various lengths in the range 5-200 nm. In a typical experiment, custom lipophilic RNTPs were first inserted into lipid vesicles; the vesicles then spontaneously fused with a planar lipid bilayer, which produced stepwise increases of ion current across the bilayer. Our measurements in 1 M KCl solution indicate ion transport rates of ∼50 ions s-1 V-1 m, which for short channels amounts to conductance values of ∼1 nS, commensurate with naturally occurring toxin channels such as α-hemolysin. Measurements of interaction times of α-cyclodextrin with RNTPs reveal two distinct unbinding time scales, which suggest that interactions of either face of α-cyclodextrin with the RNTP face are differentiable, backed with all-atom molecular dynamics simulations. Our results highlight the potential of RNTPs as self-assembled nonproteinaceous single-molecule sensors and selective nanofilters with tunable functionality through chemistry.

Original languageEnglish (US)
Pages (from-to)1680-1685
Number of pages6
JournalJournal of the American Chemical Society
Issue number4
StatePublished - Jan 29 2020

ASJC Scopus subject areas

  • General Chemistry
  • Biochemistry
  • Catalysis
  • Colloid and Surface Chemistry


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