2BKU

Kap95p:RanGTP complex

2BKU の概要

• エントリーDOI: 10.2210/pdb2bku/pdb
• 分子名称: GTP-BINDING NUCLEAR PROTEIN RAN, IMPORTIN BETA-1 SUBUNIT, GUANOSINE-5'-TRIPHOSPHATE, ... (5 entities in total)
• 機能のキーワード: nuclear transport, importin-beta, rangtp, gtp binding, protein transport
• 由来する生物種: CANIS FAMILIARIS (DOG); 詳細
• 細胞内の位置: Nucleus: P62825; Cytoplasm (By similarity): Q06142
• タンパク質・核酸の鎖数: 4
• 化学式量合計: 231484.72

構造登録者

Lee, S.J.,Matsuura, Y.,Liu, S.M.,Stewart, M. (登録日: 2005-02-21, 公開日: 2005-05-04, 最終更新日: 2023-12-13)

主引用文献

Lee, S.J.,Matsuura, Y.,Liu, S.M.,Stewart, M.
Structural Basis for Nuclear Import Complex Dissociation by Rangtp
Nature, 435:693-, 2005

PubMed Abstract: Nuclear protein import is mediated mainly by the transport factor importin-beta that binds cytoplasmic cargo, most often via the importin-alpha adaptor, and then transports it through nuclear pore complexes. This active transport is driven by disassembly of the import complex by nuclear RanGTP. The switch I and II loops of Ran change conformation with nucleotide state, and regulate its interactions with nuclear trafficking components. Importin-beta consists of 19 HEAT repeats that are based on a pair of antiparallel alpha-helices (referred to as the A- and B-helices). The HEAT repeats stack to yield two C-shaped arches, linked together to form a helicoidal molecule that has considerable conformational flexibility. Here we present the structure of full-length yeast importin-beta (Kap95p or karyopherin-beta) complexed with RanGTP, which provides a basis for understanding the crucial cargo-release step of nuclear import. We identify a key interaction site where the RanGTP switch I loop binds to the carboxy-terminal arch of Kap95p. This interaction produces a change in helicoidal pitch that locks Kap95p in a conformation that cannot bind importin-alpha or cargo. We suggest an allosteric mechanism for nuclear import complex disassembly by RanGTP.

PubMed: 15864302
DOI: 10.1038/NATURE03578

実験手法

X-RAY DIFFRACTION (2.7 Å)