1IQ1

CRYSTAL STRUCTURE OF THE IMPORTIN-ALPHA(44-54)-IMPORTIN-ALPHA(70-529) COMPLEX


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.209 

wwPDB Validation 3D Report Full Report


This is version 1.2 of the entry. See complete history

Literature

Biophysical characterization of interactions involving importin-alpha during nuclear import.

Catimel, B.Teh, T.Fontes, M.R.Jennings, I.G.Jans, D.A.Howlett, G.J.Nice, E.C.Kobe, B.

(2001) J.Biol.Chem. 276: 34189-34198

  • DOI: 10.1074/jbc.M103531200

  • PubMed Abstract: 
  • Proteins containing the classical nuclear localization sequences (NLSs) are imported into the nucleus by the importin-alpha/beta heterodimer. Importin-alpha contains the NLS binding site, whereas importin-beta mediates the translocation through the n ...

    Proteins containing the classical nuclear localization sequences (NLSs) are imported into the nucleus by the importin-alpha/beta heterodimer. Importin-alpha contains the NLS binding site, whereas importin-beta mediates the translocation through the nuclear pore. We characterized the interactions involving importin-alpha during nuclear import using a combination of biophysical techniques (biosensor, crystallography, sedimentation equilibrium, electrophoresis, and circular dichroism). Importin-alpha is shown to exist in a monomeric autoinhibited state (association with NLSs undetectable by biosensor). Association with importin-beta (stoichiometry, 1:1; K(D) = 1.1 x 10(-8) m) increases the affinity for NLSs; the importin-alpha/beta complex binds representative monopartite NLS (simian virus 40 large T-antigen) and bipartite NLS (nucleoplasmin) with affinities (K(D) = 3.5 x 10(-8) m and 4.8 x 10(-8) m, respectively) comparable with those of a truncated importin-alpha lacking the autoinhibitory domain (T-antigen NLS, K(D) = 1.7 x 10(-8) m; nucleoplasmin NLS, K(D) = 1.4 x 10(-8) m). The autoinhibitory domain (as a separate peptide) binds the truncated importin-alpha, and the crystal structure of the complex resembles the structure of full-length importin-alpha. Our results support the model of regulation of nuclear import mediated by the intrasteric autoregulatory sequence of importin-alpha and provide a quantitative description of the binding and regulatory steps during nuclear import.


    Organizational Affiliation

    Ludwig Institute for Cancer Research, Royal Melbourne Hospital, Victoria 3050, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
IMPORTIN ALPHA-2 SUBUNIT
A, B
11Mus musculusGene Names: Kpna2 (Rch1)
Find proteins for P52293 (Mus musculus)
Go to UniProtKB:  P52293
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
IMPORTIN ALPHA-2 SUBUNIT
C
460Mus musculusGene Names: Kpna2 (Rch1)
Find proteins for P52293 (Mus musculus)
Go to UniProtKB:  P52293
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.8 Å
  • R-Value Free: 0.248 
  • R-Value Work: 0.209 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 78.939α = 90.00
b = 89.623β = 90.00
c = 100.372γ = 90.00
Software Package:
Software NamePurpose
CNSrefinement
DENZOdata reduction
SCALEPACKdata scaling
CNSphasing

Structure Validation

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Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2001-11-14
    Type: Initial release
  • Version 1.1: 2008-04-27
    Type: Version format compliance
  • Version 1.2: 2011-07-13
    Type: Version format compliance