Biological Assembly 1  

 3D View: Structure | Electron Density

Global Symmetry: Asymmetric - C1 
Global Stoichiometry: Monomer - A1 

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

Macromolecule Content

• Total Structure Weight: 57.81 kDa 
• Atom Count: 3373 
• Residue Count: 439 
• Unique protein chains: 2

3RZX

Mouse importin alpha-Ku70 NLS peptide complex

• DOI: 10.2210/pdb3RZX/pdb

• Classification: PROTEIN TRANSPORT
• Organism(s): Mus musculus, Homo sapiens
• Expression System: Escherichia coli
• Mutation(s): No 


• Deposited: 2011-05-12 Released: 2011-08-03 
• Deposition Author(s): Takeda, A.A.S., Fontes, M.R.M.

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Experimental Data Snapshot

• Method: X-RAY DIFFRACTION
• Resolution: 2.61 Å
• R-Value Free: 0.223 
• R-Value Work: 0.168 
• R-Value Observed: 0.170 

Literature

Structural basis of importin-alpha-mediated nuclear transport for Ku70 and Ku80.

Takeda, A.A., de Barros, A.C., Chang, C.W., Kobe, B., Fontes, M.R.

(2011) J Mol Biol 412: 226-234

• PubMed: 21806995 
• DOI: 10.1016/j.jmb.2011.07.038
• Structures With Same Primary Citation


• PubMed Abstract: 
  

Ku70 and Ku80 form a heterodimeric complex involved in multiple nuclear processes. This complex plays a key role in DNA repair due to its ability to bind DNA double-strand breaks and facilitate repair by the nonhomologous end-joining pathway. Ku70 and Ku80 have been proposed to contain bipartite and monopartite nuclear localization sequences (NLSs), respectively, that allow them to be translocated to the nucleus independently of each other via the classical importin-α (Impα)/importin-β-mediated nuclear import pathway. To determine the structural basis of the recognition of Ku70 and Ku80 proteins by Impα, we solved the crystal structures of the complexes of Impα with the peptides corresponding to the Ku70 and Ku80 NLSs. Our structural studies confirm the binding of the Ku80 NLS as a classical monopartite NLS but reveal an unexpected binding mode for Ku70 NLS with only one basic cluster bound to the receptor. Both Ku70 and Ku80 therefore contain monopartite NLSs, and sequences outside the basic cluster make favorable interactions with Impα, suggesting that this may be a general feature in monopartite NLSs. We show that the Ku70 NLS has a higher affinity for Impα than the Ku80 NLS, consistent with more extensive interactions in its N-terminal region. The prospect of nuclear import of Ku70 and Ku80 independently of each other provides a powerful regulatory mechanism for the function of the Ku70/Ku80 heterodimer and independent functions of the two proteins.

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Organizational Affiliation: 

Departamento de Física e Biofísica, Instituto de Biociências, Universidade Estadual Paulista, Botucatu, SP 18618-970, Brazil.

Macromolecules

Entity ID: 1
Molecule	Chains	Sequence Length	Organism	Details
Importin subunit alpha-2	A	510	Mus musculus	Mutation(s): 0  Gene Names: Kpna2, Rch1
Find proteins for P52293 (Mus musculus) Explore P52293  Go to UniProtKB:  P52293
NIH Common Fund Data Resources
IMPC  MGI:103561

Entity ID: 2
Molecule	Chains	Sequence Length	Organism	Details
Ku70 NLS peptide	B	22	Homo sapiens	Mutation(s): 0  Gene Names: XRCC6, G22P1 EC: 3.6.4 (UniProt), 4.2.99 (UniProt)
Find proteins for P12956 (Homo sapiens) Explore P12956  Go to UniProtKB:  P12956
NIH Common Fund Data Resources
PHAROS  P12956 GTEx  ENSG00000196419

Experimental Data & Validation

Experimental Data

• Method: X-RAY DIFFRACTION
• Resolution: 2.61 Å
• R-Value Free: 0.223 
• R-Value Work: 0.168 
• R-Value Observed: 0.170 
• Space Group: P 2₁ 2₁ 2₁

Unit Cell:

Length ( Å )	Angle ( ˚ )
a = 78.518	α = 90
b = 89.996	β = 90
c = 100.142	γ = 90

Software Package:

Software Name	Purpose
HKL-2000	data collection
AMoRE	phasing
REFMAC	refinement
HKL-2000	data reduction
HKL-2000	data scaling

Structure Validation

Entry History 

Deposition Data

• Deposited Date: 2011-05-12 
• Released Date: 2011-08-03 
Deposition Author(s): Takeda, A.A.S., Fontes, M.R.M.

Revision History 

• Version 1.0: 2011-08-03
  Type: Initial release
  
• Version 1.1: 2012-05-23
  Changes: Database references