1QBK
STRUCTURE OF THE KARYOPHERIN BETA2-RAN GPPNHP NUCLEAR TRANSPORT COMPLEX
Summary for 1QBK
| Entry DOI | 10.2210/pdb1qbk/pdb |
| Descriptor | KARYOPHERIN BETA2, RAN, MAGNESIUM ION, ... (4 entities in total) |
| Functional Keywords | heat repeats, nuclear transport protein complex |
| Biological source | Homo sapiens (human) More |
| Cellular location | Cytoplasm: Q92973 Nucleus : P62826 |
| Total number of polymer chains | 2 |
| Total formula weight | 127665.20 |
| Authors | Chook, Y.M.,Blobel, G. (deposition date: 1999-04-23, release date: 1999-06-01, Last modification date: 2024-10-30) |
| Primary citation | Chook, Y.M.,Blobel, G. Structure of the nuclear transport complex karyopherin-beta2-Ran x GppNHp. Nature, 399:230-237, 1999 Cited by PubMed Abstract: Transport factors in the karyopherin-beta (also called importin-beta) family mediate the movement of macromolecules in nuclear-cytoplasmic transport pathways. Karyopherin-beta2 (transportin) binds a cognate import substrate and targets it to the nuclear pore complex. In the nucleus, Ran x GTP binds karyopherin-beta2 and dissociates the substrate. Here we present the 3.0 A structure of the karyopherin-beta2-Ran x GppNHp complex where GppNHp is a non-hydrolysable GTP analogue. Karyopherin-beta2 contains eighteen HEAT repeats arranged into two continuous orthogonal arches. Ran is clamped in the amino-terminal arch and substrate-binding activity is mapped to the carboxy-terminal arch. A large loop in HEAT repeat 7 spans both arches. Interactions of the loop with Ran and the C-terminal arch implicate it in GTPase-mediated dissociation of the import-substrate. Ran x GppNHp in the complex shows extensive structural rearrangement, compared to Ran GDP, in regions contacting karyopherin-beta2. This provides a structural basis for the specificity of the karyopherin-beta family for the GTP-bound state of Ran, as well as a rationale for interactions of the karyopherin-Ran complex with the regulatory proteins ranGAP, ranGEF and ranBP1. PubMed: 10353245DOI: 10.1038/20375 PDB entries with the same primary citation |
| Experimental method | X-RAY DIFFRACTION (3 Å) |
Structure validation
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