Association of nuclear pore FG-repeat domains to NTF2 import and export complexes.

Transport into and out of the nucleus is regulated by the nuclear pore complex. Vital to this regulation are nuclear pore proteins with FG sequence repeats, which have been shown to be crucial for cell viability and which interact with nuclear transport receptors. Here we use molecular dynamics simulations to investigate the binding of FG-repeat peptides to the surface of NTF2, the Ran importer. The simulations, covering over 254 ns, agree with previous X-ray, mutational, NMR, and computational data in identifying four binding spots. They also serve to provide an all-atom view of binding at each spot, whereas FG-repeat binding has been only directly observed at a single spot. Furthermore, the simulations identify two novel binding spots in addition to the four others. All six binding spots broadly form a stripe across the surface of NTF2. The resulting regularity and proximity of binding spots on the surface may be necessary for identification of the transport receptor by the FG-repeats in the nuclear pore complex and for the successful transit of NTF2 through the pore.