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2BKU

Kap95p:RanGTP complex

Summary for 2BKU
Entry DOI10.2210/pdb2bku/pdb
DescriptorGTP-BINDING NUCLEAR PROTEIN RAN, IMPORTIN BETA-1 SUBUNIT, GUANOSINE-5'-TRIPHOSPHATE, ... (5 entities in total)
Functional Keywordsnuclear transport, importin-beta, rangtp, gtp binding, protein transport
Biological sourceCANIS FAMILIARIS (DOG)
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Cellular locationNucleus: P62825
Cytoplasm (By similarity): Q06142
Total number of polymer chains4
Total formula weight231484.72
Authors
Lee, S.J.,Matsuura, Y.,Liu, S.M.,Stewart, M. (deposition date: 2005-02-21, release date: 2005-05-04, Last modification date: 2023-12-13)
Primary citationLee, S.J.,Matsuura, Y.,Liu, S.M.,Stewart, M.
Structural Basis for Nuclear Import Complex Dissociation by Rangtp
Nature, 435:693-, 2005
Cited by
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
PDB entries with the same primary citation
Experimental method
X-RAY DIFFRACTION (2.7 Å)
Structure validation

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