Biological Assembly 1  

 3D View: Structure

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Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Hetero 2-mer - AB 

Biological assembly 1 assigned by authors and generated by PISA (software)

Macromolecule Content

• Total Structure Weight: 102707.26 
• Atom Count: 7185 
• Residue Count: 920 
• Unique protein chains: 2

1QGK

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

• DOI: 10.2210/pdb1QGK/pdb

• Classification: TRANSPORT RECEPTOR
• Organism(s): Homo sapiens
• Expression System: Escherichia coli


• Deposited: 1999-04-29 Released: 1999-05-24 
• Deposition Author(s): Cingolani, G., Petosa, C., Weis, K., Muller, C.W.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.5 Å
• R-Value Free: 0.273 
• R-Value Work: 0.221 

Literature

Structure of importin-beta bound to the IBB domain of importin-alpha.

Cingolani, G., Petosa, C., Weis, K., Muller, C.W.

(1999) Nature 399: 221-229

• PubMed: 10353244 
• DOI: 10.1038/20367
• Primary Citation of Related Structures:  
  1QGR


• 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.

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Organizational Affiliation: 

European Molecular Biology Laboratory, Grenoble Outstation, France.

Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
PROTEIN (IMPORTIN BETA SUBUNIT)	A	876	Homo sapiens	Mutation(s): 0  Gene Names: KPNB1 (NTF97)
Find proteins for Q14974 (Homo sapiens) Go to Gene View: KPNB1 Go to UniProtKB:  Q14974

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details
PROTEIN (IMPORTIN ALPHA-2 SUBUNIT)	B	44	Homo sapiens	Mutation(s): 0  Gene Names: KPNA2 (RCH1, SRP1)
Find proteins for P52292 (Homo sapiens) Go to Gene View: KPNA2 Go to UniProtKB:  P52292

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.5 Å
• R-Value Free: 0.273 
• R-Value Work: 0.221 
• Space Group: P 1 2₁ 1

Unit Cell:

Length (Å)	Angle (°)
a = 64.584	α = 90.00
b = 97.606	β = 91.13
c = 83.194	γ = 90.00

Software Package:

Software Name	Purpose
CNS	refinement
DENZO	data reduction
SCALEPACK	data scaling
SOLVE	phasing

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 1999-04-29 
• Released Date: 1999-05-24 
• Deposition Author(s): Cingolani, G., Petosa, C., Weis, K., Muller, C.W.

Revision History 

• Version 1.0: 1999-05-24
  Type: Initial release
• Version 1.1: 2008-04-26
  Type: Version format compliance
• Version 1.2: 2011-07-13
  Type: Version format compliance