Preparation of fragaceatoxin C (Fra C) nanopores

Abstract

Biological nanopores are an emerging class of biosensors with high-end precision owing to their reproducible fabrication at the nanometer scale. Most notably, nanopore-based DNA sequencing applications are currently being commercialized, while nanopore-based proteomics may become a reality in the near future. Although membrane proteins often prove to be difficult to purify, we describe a straightforward protocol for the preparation of Fragaceatoxin C (FraC) nanopores, which may have applications for DNA analysis and nanopore-based proteomics. Recombinantly expressed FraC nanopores are purified via two rounds of Ni-NTA affinity chromatography before and after oligomerization on sphingomyelin-containing liposomes. Starting from a plasmid vector containing the FraC gene, our method allows the production of purified nanopores within a week. Afterward, the FraC nanopores can be stored at +4 °C for several months, or frozen.