title: Global motions of the nuclear pore complex: insights from elastic network models.
abstract: The nuclear pore complex (NPC) is the gate to the nucleus. Recent determination of the configuration of proteins in the yeast NPC at approximately 5 nm resolution permits us to study the NPC global dynamics using coarse-grained structural models. We investigate these large-scale motions by using an extended elastic network model (ENM) formalism applied to several coarse-grained representations of the NPC. Two types of collective motions (global modes) are predicted by the ENMs to be intrinsically favored by the NPC architecture: global bending and extension/contraction from circular to elliptical shapes. These motions are shown to be robust against tested variations in the representation of the NPC, and are largely captured by a simple model of a toroid with axially varying mass density. We demonstrate that spoke multiplicity significantly affects the accessible number of symmetric low-energy modes of motion; the NPC-like toroidal structures composed of 8 spokes have access to highly cooperative symmetric motions that are inaccessible to toroids composed of 7 or 9 spokes. The analysis reveals modes of motion that may facilitate macromolecular transport through the NPC, consistent with previous experimental observations.
authors.affiliation: Department of Computational Biology, School of Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America.
authors.forename: Timothy R
authors.initials: TR
authors.lastname: Lezon
authors.forename: Andrej
authors.initials: A
authors.lastname: Sali
authors.forename: Ivet
authors.initials: I
authors.lastname: Bahar
mesh_terms: D021581:Active Transport, Cell Nucleus; D019295:Computational Biology / Q000379:methods*; D004548:Elasticity; D005656:Fungal Proteins / Q000737:chemistry / Q000378:metabolism; D008954:Models, Biological; D022022:Nuclear Pore / Q000737:chemistry* / Q000378:metabolism; D028861:Nuclear Pore Complex Proteins / Q000737:chemistry* / Q000378:metabolism; D015003:Yeasts
chemical_list: D005656:Fungal Proteins; D028861:Nuclear Pore Complex Proteins