The Structural Layers of the Nuclear Pore Complex

The human nuclear pore complex (hNPC) is a 110 MDa structure of ∼30 different proteins that occur in multiple copies. Proteins that compose the hNPC are themselves built into subcomplexes, which are arranged with eight-fold rotational symmetry to build the overall assembly. The three-dimensional structure of purified subcomplex was determined by single particle electron microscopy. By crosslinking of subcomplexes engaged within the hNPC and the subsequent identification of crosslinked peptides by crosslinking mass spectrometry (XL-MS), we uncover their dynamic interacting layers of the NPC. These data, along with a high resolution structure of the hNPC were integrated to determine how the layers of the NPC come together forming reticulated rings of the hNPC. Our approach to elucidate NPC structure integrates biochemistry and several structural biology techniques that span length scales and may be widely applied to the study of large, complex molecular organizations and will contribute to the field of structural biology as a whole. We used molecular modeling combined with XL-MS and cryo-electron tomography to obtain a composite structure. This architectural map explains the vast majority of the electron density of the scaffold.