Crystal structure of the metazoan Nup62•Nup58•Nup54 nucleoporin complex

Abstract

Nuclear pore complexes (NPCs) conduct nucleocytoplasmic transport and gain transport selectivity through nucleoporin FG domains. Here, we report a structural analysis of the FG Nup62.58.54 complex, which is a crucial component of the transport system. It comprises a .13 nanometer-long trimerization interface with an unusual 2W3Fcoil, a canonical heterotrimeric coiled coil, and a kink that enforces a compact six-helix bundle. Nup54 also contains a ferredoxin-like domain.We further identified a heterotrimeric Nup93-binding module for NPC anchorage.The quaternary structure alternations in the Nup62 complex, which were previously proposed to trigger a general gating of the NPC, are incompatible with the trimer structure.We suggest that the highly elongated Nup62 complex projects barrier-forming FG repeats far into the centralNPCchannel, supporting a barrier that guards the entire cross section.