4mhc | pdb_00004mhc
Crystal Structure of a Nucleoporin
Structural highlights
FunctionNU157_YEAST Functions as a component of the nuclear pore complex (NPC). NPC components, collectively referred to as nucleoporins (NUPs), can play the role of both NPC structural components and of docking or interaction partners for transiently associated nuclear transport factors.[1] Publication Abstract from PubMedAt the center of the nuclear pore complex (NPC) is a uniquely versatile central transport channel. Structural analyses of distinct segments ("protomers") of the three "channel" nucleoporins yielded a model for how this channel is constructed. Its principal feature is a midplane ring that can undergo regulated diameter changes of as much as an estimated 30 nm. To better understand how a family of "adaptor" nucleoporins-concentrically surrounding this channel-might cushion these huge structural changes, we determined the crystal structure of one adaptor nucleoporin, Nup157. Here, we show that a recombinant Saccharomyces cerevisiae Nup157 protomer, representing two-thirds of Nup157 (residues 70-893), folds into a seven-bladed beta-propeller followed by an alpha-helical domain, which together form a C-shaped architecture. Notably, the structure contains a large patch of positively charged residues, most of which are evolutionarily conserved. Consistent with this surface feature, we found that Nup15770-893 binds to nucleic acids, although in a sequence-independent manner. Nevertheless, this interaction supports a previously reported role of Nup157, and its paralogue Nup170, in chromatin organization. Based on its nucleic acid binding capacity, we propose a dual location and function of Nup157. Finally, modeling the remaining C-terminal portion of Nup157 shows that it projects as a superhelical stack from the compact C-shaped portion of the molecule. The predicted four hinge regions indicate an intrinsic flexibility of Nup157, which could contribute to structural plasticity within the NPC. Structure and nucleic acid binding activity of the nucleoporin Nup157.,Seo HS, Blus BJ, Jankovic NZ, Blobel G Proc Natl Acad Sci U S A. 2013 Oct 8;110(41):16450-16455. Epub 2013 Sep 23. PMID:24062435[2] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See AlsoReferences
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