1QGK

STRUCTURE OF IMPORTIN BETA BOUND TO THE IBB DOMAIN OF IMPORTIN ALPHA

Summary for 1QGK

• Entry DOI: 10.2210/pdb1qgk/pdb
• Descriptor: PROTEIN (IMPORTIN BETA SUBUNIT), PROTEIN (IMPORTIN ALPHA-2 SUBUNIT) (3 entities in total)
• Functional Keywords: transport receptor, nuclear import, heat motif, nls-binding
• Biological source: Homo sapiens (human); More
• Cellular location: Cytoplasm: Q14974 P52292
• Total number of polymer chains: 2
• Total formula weight: 102707.26

Authors

Cingolani, G.,Petosa, C.,Weis, K.,Muller, C.W. (deposition date: 1999-04-29, release date: 1999-05-24, Last modification date: 2023-12-27)

Primary citation

Cingolani, G.,Petosa, C.,Weis, K.,Muller, C.W.
Structure of importin-beta bound to the IBB domain of importin-alpha.
Nature, 399:221-229, 1999

PubMed Abstract: Cytosolic proteins bearing a classical nuclear localization signal enter the nucleus bound to a heterodimer of importin-alpha and importin-beta (also called karyopherin-alpha and -beta). The formation of this heterodimer involves the importin-beta-binding (IBB) domain of importin-alpha, a highly basic amino-terminal region of roughly 40 amino-acid residues. Here we report the crystal structure of human importin-beta bound to the IBB domain of importin-alpha, determined at 2.5 A and 2.3 A resolution in two crystal forms. Importin-beta consists of 19 tandemly repeated HEAT motifs and wraps intimately around the IBB domain. The association involves two separate regions of importin-beta, recognizing structurally distinct parts of the IBB domain: an amino-terminal extended moiety and a carboxy-terminal helix. The structure indicates that significant conformational changes occur when importin-beta binds or releases the IBB domain domain and suggests how dissociation of the importin-alpha/beta heterodimer may be achieved upon nuclear entry.

PubMed: 10353244
DOI: 10.1038/20367

Experimental method

X-RAY DIFFRACTION (2.5 Å)