4OIH

Importin Alpha in Complex with the Bipartite NLS of Prp20


Experimental Data Snapshot

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.168 

wwPDB Validation 3D Report Full Report


This is version 1.0 of the entry. See complete history

Literature

Structural Characterisation of the Nuclear Import Receptor Importin Alpha in Complex with the Bipartite NLS of Prp20

Roman, N.Christie, M.Swarbrick, C.M.D.Kobe, B.Forwood, J.K.

(2013) Plos One 8: e82038-e82038

  • DOI: 10.1371/journal.pone.0082038

  • PubMed Abstract: 
  • The translocation of macromolecules into the nucleus is a fundamental eukaryotic process, regulating gene expression, cell division and differentiation, but which is impaired in a range of significant diseases including cancer and viral infection. Th ...

    The translocation of macromolecules into the nucleus is a fundamental eukaryotic process, regulating gene expression, cell division and differentiation, but which is impaired in a range of significant diseases including cancer and viral infection. The import of proteins into the nucleus is generally initiated by a specific, high affinity interaction between nuclear localisation signals (NLSs) and nuclear import receptors in the cytoplasm, and terminated through the disassembly of these complexes in the nucleus. For classical NLSs (cNLSs), this import is mediated by the importin-α (IMPα) adaptor protein, which in turn binds to IMPβ to mediate translocation of nuclear cargo across the nuclear envelope. The interaction and disassembly of import receptor:cargo complexes is reliant on the differential localisation of nucleotide bound Ran across the envelope, maintained in its low affinity, GDP-bound form in the cytoplasm, and its high affinity, GTP-bound form in the nucleus. This in turn is maintained by the differential localisation of Ran regulating proteins, with RanGAP in the cytoplasm maintaining Ran in its GDP-bound form, and RanGEF (Prp20 in yeast) in the nucleus maintaining Ran in its GTP-bound form. Here, we describe the 2.1 Å resolution x-ray crystal structure of IMPα in complex with the NLS of Prp20. We observe 1,091 Å(2) of buried surface area mediated by an extensive array of contacts involving residues on armadillo repeats 2-7, utilising both the major and minor NLS binding sites of IMPα to contact bipartite NLS clusters (17)RAKKMSK(23) and (3)KR(4), respectively. One notable feature of the major site is the insertion of Prp20NLS Ala(18) between the P0 and P1 NLS sites, noted in only a few classical bipartite NLSs. This study provides a detailed account of the binding mechanism enabling Prp20 interaction with the nuclear import receptor, and additional new information for the interaction between IMPα and cargo.


    Organizational Affiliation

    School of Biomedical Sciences, Charles Sturt University, Wagga Wagga, New South Wales, Australia.




Macromolecules

Find similar proteins by: Sequence  |  Structure

Entity ID: 1
MoleculeChainsSequence LengthOrganismDetails
Importin subunit alpha-1
A
460Mus musculusMutation(s): 0 
Gene Names: Kpna2 (Rch1)
Find proteins for P52293 (Mus musculus)
Go to UniProtKB:  P52293
Entity ID: 2
MoleculeChainsSequence LengthOrganismDetails
Guanine nucleotide exchange factor SRM1
B
27Saccharomyces cerevisiae (strain ATCC 204508 / S288c)Mutation(s): 0 
Gene Names: SRM1 (MTR1, PRP20)
Find proteins for P21827 (Saccharomyces cerevisiae (strain ATCC 204508 / S288c))
Go to UniProtKB:  P21827
Experimental Data & Validation

Experimental Data

  • Method: X-RAY DIFFRACTION
  • Resolution: 2.1 Å
  • R-Value Free: 0.201 
  • R-Value Work: 0.168 
  • Space Group: P 21 21 21
Unit Cell:
Length (Å)Angle (°)
a = 78.910α = 90.00
b = 89.920β = 90.00
c = 99.700γ = 90.00
Software Package:
Software NamePurpose
MOSFLMdata reduction
SCALAdata scaling
REFMACrefinement
Blu-Icedata collection
PHASERphasing

Structure Validation

View Full Validation Report or Ramachandran Plots



Entry History 

Deposition Data

Revision History 

  • Version 1.0: 2014-02-19
    Type: Initial release