Structure and nucleic acid binding activity of the nucleoporin Nup157.
Proc Natl Acad Sci U S A
; 110(41): 16450-5, 2013 Oct 08.
Article
em En
| MEDLINE
| ID: mdl-24062435
At 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 ß-propeller followed by an α-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 Nup157(70-893) 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.
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Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Conformação Proteica
/
Ácidos Nucleicos
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Modelos Moleculares
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Complexo de Proteínas Formadoras de Poros Nucleares
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Proteínas de Saccharomyces cerevisiae
Tipo de estudo:
Prognostic_studies
Idioma:
En
Revista:
Proc Natl Acad Sci U S A
Ano de publicação:
2013
Tipo de documento:
Article