PDBsum entry 2qmr

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Transport protein PDB id
Protein chains
835 a.a. *
* Residue conservation analysis
PDB id:
Name: Transport protein
Title: Karyopherin beta2/transportin
Structure: Transportin-1. Chain: a, b, c, d. Synonym: importin beta-2, karyopherin beta-2, m9 region interaction protein, mip. Engineered: yes
Source: Homo sapiens. Human. Organism_taxid: 9606. Gene: tnpo1, kpnb2, mip1, trn. Expressed in: escherichia coli bl21(de3). Expression_system_taxid: 469008.
3.00Å     R-factor:   0.262     R-free:   0.286
Authors: A.E.Cansizoglu,Y.M.Chook
Key ref:
A.E.Cansizoglu and Y.M.Chook (2007). Conformational heterogeneity of karyopherin beta2 is segmental. Structure, 15, 1431-1441. PubMed id: 17997969 DOI: 10.1016/j.str.2007.09.009
16-Jul-07     Release date:   30-Oct-07    
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Protein chains
Pfam   ArchSchema ?
Q92973  (TNPO1_HUMAN) -  Transportin-1
898 a.a.
835 a.a.
Key:    PfamA domain  Secondary structure  CATH domain

 Gene Ontology (GO) functional annotation 
  GO annot!
  Cellular component     cytoplasm   3 terms 
  Biological process     viral reproduction   8 terms 
  Biochemical function     protein binding     4 terms  


DOI no: 10.1016/j.str.2007.09.009 Structure 15:1431-1441 (2007)
PubMed id: 17997969  
Conformational heterogeneity of karyopherin beta2 is segmental.
A.E.Cansizoglu, Y.M.Chook.
Karyopherinbeta2 (Kap beta2) or transportin imports numerous RNA binding proteins into the nucleus. Kap beta2 binds substrates in the cytoplasm and targets them through the nuclear pore complex, where RanGTP dissociates them in the nucleus. Here we report the 3.0 A crystal structure of unliganded Kap beta2, which consists of a superhelix of 20 HEAT repeats. Together with previously reported structures of NLS and Ran complexes, this structure provides understanding of conformational heterogeneity that accompanies ligand binding. The Kap beta2 superhelix is divided into three major segments. Two of them (HEAT repeats 9-13 and 14-18), which constitute the substrate binding site, are rigid elements that rotate relative to each other about a flexible hinge. The third (HEAT repeats 1-8), which constitutes the Ran binding site, exhibits conformational changes throughout its length. An analogous segmental architecture is also observed in Importin beta, suggesting that it is functionally significant and may be conserved in other import karyopherins.
  Selected figure(s)  
Figure 3.
Figure 3. Hinge Motion in the C-Terminal Arch of Kapβ2
Stereo diagrams of the C-terminal arch (H9–H20) of chains A–D of unliganded Kapβ2 and substrate- and Ran-bound Kapβ2s superimposed at H9–H13 and drawn as spheres at the geometric center of each HEAT repeat. The hinge axes that rotate unliganded Kapβ2 with respect to substrate- and Ran-bound Kapβ2s are in pink and red, respectively.
Figure 4.
Figure 4. Conformational Change in the Kapβ2 N-Terminal Arch
(A) Ribbon diagram of the N-terminal arches of chains A (blue) and C (light blue) of unliganded Kapβ2, superimposed at H9–H13.
(B) Same as (A), except that chain A of unliganded Kapβ2 is superimposed on substrate-bound Kapβ2 (pink).
(C) Same as (A), except that chain A of Kapβ2 is superimposed on Ran-bound Kapβ2 (red). Ran is shown as a surface representation in gray and the H8 loop of the Ran complex is in yellow.
  The above figures are reprinted by permission from Cell Press: Structure (2007, 15, 1431-1441) copyright 2007.  
  Figures were selected by the author.  

Literature references that cite this PDB file's key reference

  PubMed id Reference
20826343 J.K.Forwood, A.Lange, U.Zachariae, M.Marfori, C.Preast, H.Grubmüller, M.Stewart, A.H.Corbett, and B.Kobe (2010).
Quantitative structural analysis of importin-β flexibility: paradigm for solenoid protein structures.
  Structure, 18, 1171-1183.
PDB code: 3nd2
18547523 U.Zachariae, and H.Grubmüller (2008).
Importin-beta: structural and dynamic determinants of a molecular spring.
  Structure, 16, 906-915.  
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