Molecular characterization of the ran-binding zinc finger domain of Nup153
Molecular characterization of the ran-binding zinc finger domain of Nup153
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DOI：
10.1074/jbc.m702715200
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发表时间：
2007-06-08
影响因子：
4.8
通讯作者：
Ullman, Katharine S.
中科院分区：
文献类型：
--
作者：
Higa, Meda M.;Alam, Steven L.;Ullman, Katharine S.
核孔复合体是细胞核和细胞质之间选择性交通的门户。为了了解孔的构建模块如何为转运受体和调节因子创建特定的对接位点，我们研究了高等真核生物核孔内存在多个副本的锌指模块。发现人 Nup153 的所有四个锌指均以 5 至 40 μM 范围内的解离常数结合小 GTPase Ran。此外，发现包含四个串联锌指的 Nup153 片段以相似的亲和力结合 Ran。 NMR 结构研究表明，代表性的 Nup153 锌指采用与之前表征的 Npl4 NZF 模块相同的锌带结构。 Ran 结合由位于两个锌配位环内的三氨基酸基序（Leu(13)/Val(14)/Asn(25)）介导。 Nup153 ZnF 以相似的亲和力结合 GDP 和 GTP 形式的 Ran，表明这种相互作用不受核苷酸依赖性构象转换的影响。总而言之，这些研究阐明了 Nup153 上的 Ran 结合界面，更广泛地说，提供了对该锌指结合模块的多功能性的深入了解。
The nuclear pore complex is the gateway for selective traffic between the nucleus and cytoplasm. To learn how building blocks of the pore can create specific docking sites for transport receptors and regulatory factors, we have studied a zinc finger module present in multiple copies within the nuclear pores of higher eukaryotes. All four zinc fingers of human Nup153 were found to bind the small GTPase Ran with dissociation constants ranging between 5 and 40 mu M. In addition a fragment of Nup153 encompassing the four tandem zinc fingers was found to bind Ran with similar affinity. NMR structural studies revealed that a representative Nup153 zinc finger adopts the same zinc ribbon structure as the previously characterized Npl4 NZF module. Ran binding was mediated by a three-amino acid motif (Leu(13)/Val(14)/Asn(25)) located within the two zinc coordination loops. Nup153 ZnFs bound GDP and GTP forms of Ran with similar affinities, indicating that this interaction is not influenced by a nucleotide-dependent conformational switch. Taken together, these studies elucidate the Ran-binding interface on Nup153 and, more broadly, provide insight into the versatility of this zinc finger binding module.