Biomimetic Nanopores with Yeast Nucleoporins
A.B. Dwarkasing (TU Delft - Applied Sciences)
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Abstract
Nuclear pore complexes (NPC’s) facilitate the exchange of macromolecules between the cytoplasm and nucleus and act as a selective barrier for macromolecules in eukaryotes. Ongoing research suggests that the discriminatory function of the NPC is caused by nucleoporins rich in phenylalanine-glycine amino acids residue repeats (FG-regions) which fill the nuclear pore. To determine if the FG-domains are responsible for the selectivity of a NPC, in this research we will mimic a nuclear pore complex by coating a solid state nanopore with yeast FG-nup-NSP1. After coating a wild-type nucleoporin, to a solid-state nanopore, we find that a yeast importer protein kap95 was able to translocate through the nanopore. The dwell times were on the order of tens of milliseconds. An artificial control protein, tCherry, with the same size as kap95, was not able to pass the artificial NPC. By
coating a solid-state nanopore with mutated FG-nup-NSP1, where hydrophobic amino acid residues (F, I, L and V) were replaced with serine, we found that kap95 translocated with much lower translocation times, comparable to an uncoated nanopore, indicating less interaction with the mutated nucleoporins. Furthermore tCherry was also able to pass through the mimicked nuclear pore with mutated nucleoporins, making a very strong argument that FG-repeat regions in nucleoporins are responsible for the selectivity in NPC’s.