BioNanopore · Biomimetic nanopore for a mechanistic study of the nuclear pore complex

Compartmentalization of the eukaryotic genome into a nucleus necessitates nuclear import and export to achieve basic cellular processes. The nuclear pore complex (NPC) is a large (60 - 125 MDa) macromolecular structure in eukaryotic cells, where it spans the nuclear membrane and serves as the gatekeeper of nucleocytoplasmic transport. While water, ions, and small molecules can freely diffuse through the NPC, macromolecules larger than 25 - 40 kDa cannot pass the NPC’s permeability barrier unless ferried by specific transport proteins called nuclear transport receptors (NTRs). While the structural arrangement and biochemistry of the complex have been largely worked out, the underlying mechanism of the pore’s transport and selectivity remains poorly understood. Mechanistic studies of the NPC have been largely carried out in vivo because in vitro reconstitution of the complex is not possible. Here, I propose to develop a biomimetic NPC-like system based on solid-state nanopore technology to conduct a real-time, single-molecule investigation into the mechanism of NPC transport and selectivity. Both electrical detection and a novel optical-electrical method will be used to monitor the translocation of individual substrates through a single biomimetic pore. The biomimetic approach proposed here will provide a significant step forward in experimentally studying the NPC, by affording an in vitro system that will allow for rigorous testing of key NPC proteins and their mechanistic role in transport and selectivity. This work will be carried out in the laboratory of Professor Cees Dekker, who is a world leader in nanofabrication and the application of solid-state nanopores to biology. My expertise in single-molecule biophysics, fluorescence microscopy, and biochemistry is well suited to complement the resources of the Dekker lab to collectively meet the interdisciplinary demands of this innovative effort.