Large-Conductance Transmembrane Porin Made from DNA Origami

Abstract

DNA nanotechnology allows for the creation of three-dimensional structures at nanometer scale. Here, we use DNA to build the largest synthetic pore in a lipid membrane to date, approaching the dimensions of the nuclear pore complex and increasing the pore-area and the conductance 10-fold compared to previous man-made channels. In our design, 19 cholesterol tags anchor a megadalton funnel-shaped DNA origami porin in a lipid bilayer membrane. Confocal imaging and ionic current recordings reveal spontaneous insertion of the DNA porin into the lipid membrane, creating a transmembrane pore of tens of nanosiemens conductance. All-atom molecular dynamics simulations characterize the conductance mechanism at the atomic level and independently confirm the DNA porins’ large ionic conductance.

Stability and dynamics of membrane-spanning DNA nanopores

“…Therefore, there is unlikely to be significant ion ‘leakage' possible around the edges of the pore. It is interesting to compare this with a recent study of a large conductance DNA ‘porin'59 for which simulations suggest ca. 20% of the ionic current may flow around the outside of the channel.…”

“…This demonstration of modularity of pore function and membrane stability will guide design of next-generation DNA nanopores with tailored gating and ion selectivity properties. Such designs will benefit from our understanding of both simple DNA nanopores, as in the current study, and, for example, of more complex DNA origami `porins'59.…”

Porphyrin-Assisted Docking of a Thermophage Portal Protein into Lipid Bilayers: Nanopore Engineering and Characterization

“…The calculations of local densities and ion fluxed were performed on a 50 × 50 × 76 cubic grid using a previously described method. 55,59,114 …”

Nanopore Sensing

“…(d–f) Reproduced from Gopfrich, K.; Li, C.-Y. ; Ricci, M.; Bhamidimarri, S. P.; Yoo, J.; Gyenes, B.; Ohmann, A.; Winterhalter, M.; Aksimentiev, A.; Keyser, U. F. ACS Nano 2016 10 , 8207–8214 (ref 85). Copyright 2016 American Chemical Society.…”