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

Abstract

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.Communication pubs.acs.org/JACS

Controllable and Diversiform Topological Morphologies of Self‐Assembling Supra‐Amphiphiles with Aggregation‐Induced Emission Characteristics for Mimicking Light‐Harvesting Antenna

“…Supramolecular self‐assembly has captivated significant scientific interests not only for the purpose of fundamental studies, but also for performing as functional materials in an extensive range of applications. [ 1–4 ] The functions and properties of these self‐assembled aggregates are recognized to be intimately related to their topological morphologies, [ 5–11 ] which are undoubtedly lie on molecular arrangements at the supramolecular level. [ 12–14 ] Controlling self‐assembly conditions has been proven to be a powerful protocol to change the intramolecular interactions and molecular packing model, and thus regulate the supramolecular topological structure transformation.…”

Rational ion transport management mediated through membrane structures

“…Nanochannel‐structured membranes have already shown great application potential in sensing external ions, [ 159,308,309 ] molecules, [ 310–315 ] and stimuli. [ 45,241 ] For example, Wu et al.…”

“…Nanochannel-structured membranes have already shown great application potential in sensing external ions, [159,308,309] molecules, [310][311][312][313][314][315] and stimuli. [45,241] For example, Wu et al constructed nanochannels characterized by enhanced ion transport and selective detection of modified 5hydroxymethylcytosine in single-stranded DNA (i.e., DNA2-Bzim) through embedded short single-wall CNTs in a lipid bilayer (Figure 16E).…”

Crystal Packing‐Guided Construction of Hetero‐Oligomeric Peptidic Ensembles as Synthetic 3‐in‐1 Transporters

“…Nevertheless, over the past four decades of intensive research since the first report on the synthetic transporter in 1982, [11] study on the synthetic membrane transporters has overwhelmingly focused on transport of inorganic cations [12–37] or anions, [38–60] with much less on molecular species such as water [61–71] and glucose [72] . Specific to synthetic amino acid transporters, we are aware of only two artificial transporter systems based on a pillar[5]arene derivative by Hou in 2013 [73] or dynamic covalent bonds by Gale in 2015 [74] …”