2QNA

Crystal structure of human Importin-beta (127-876) in complex with the IBB-domain of Snurportin1 (1-65)

Summary for 2QNA

• Entry DOI: 10.2210/pdb2qna/pdb
• Descriptor: Importin subunit beta-1, Snurportin-1, SULFATE ION, ... (4 entities in total)
• Functional Keywords: nuclear transport, import of spliceosomal subunits, protein-protein interaction, heat-repeat protein, host-virus interaction, nucleus, protein transport, rna-binding, transport protein
• Biological source: Homo sapiens (human); More
• Cellular location: Cytoplasm : Q14974; Nucleus : O95149
• Total number of polymer chains: 2
• Total formula weight: 92437.16

Authors

Wohlwend, D.,Strasser, A.,Dickmanns, A.,Ficner, R. (deposition date: 2007-07-18, release date: 2008-04-08, Last modification date: 2024-02-21)

Primary citation

Wohlwend, D.,Strasser, A.,Dickmanns, A.,Ficner, R.
Structural basis for RanGTP independent entry of spliceosomal U snRNPs into the nucleus.
J.Mol.Biol., 374:1129-1138, 2007

PubMed Abstract: The nuclear import of assembled spliceosomal subunits, the uridine-rich small nuclear ribonucleoprotein particles (U snRNPs), is mediated by a nuclear import receptor adaptor couple of importin beta (Imp beta) and snurportin1 (SPN1). In contrast to any other characterized active nuclear import, the Imp beta/SPN1/U snRNP complex does not require RanGTP for the terminal release from the nuclear basket of the nuclear pore complex (NPC). The crystal structure of Imp beta (127-876) in complex with the Imp beta-binding (IBB) domain of SPN1 (1-65) at 2.8-A resolution reveals that Imp beta adopts an open conformation, which is unique for a functional Imp beta/cargo complex, and rather surprisingly, it resembles the conformation of the Imp beta/RanGTP complex. As binding of RanGTP to Imp beta usually triggers the release of import complexes from the NPC, we propose that by already mimicking a conformation similar to Imp beta/RanGTP the independent dissociation of Imp beta/SPN1 from the nuclear basket is energetically aided.

PubMed: 18028944
DOI: 10.1016/j.jmb.2007.09.065

Experimental method

X-RAY DIFFRACTION (2.84 Å)