Database Accession: DI1110009
Name: Importin alpha - nucleoplasmin NLS complex
PDB ID: 1ejy
Experimental method: X-ray (2.90 Å)
Source organism: Xenopus laevis / Mus musculus
Proof of disorder:
Kd: 2.70×10-09 M
Primary publication of the structure:
Fontes MR, Teh T, Kobe B
Structural basis of recognition of monopartite and bipartite nuclear localization sequences by mammalian importin-alpha.
(2000) J. Mol. Biol. 297: 1183-94
Importin-alpha is the nuclear import receptor that recognizes cargo proteins which contain classical monopartite and bipartite nuclear localization sequences (NLSs), and facilitates their transport into the nucleus. To determine the structural basis of the recognition of the two classes of NLSs by mammalian importin-alpha, we co-crystallized an N-terminally truncated mouse receptor protein with peptides corresponding to the monopartite NLS from the simian virus 40 (SV40) large T-antigen, and the bipartite NLS from nucleoplasmin. We show that the monopartite SV40 large T-antigen NLS binds to two binding sites on the receptor, similar to what was observed in yeast importin-alpha. The nucleoplasmin NLS-importin-alpha complex shows, for the first time, the mode of binding of bipartite NLSs to the receptor. The two basic clusters in the NLS occupy the two binding sites used by the monopartite NLS, while the sequence linking the two basic clusters is poorly ordered, consistent with its tolerance to mutations. The structures explain the structural basis for binding of diverse NLSs to the sole receptor protein.
Molecular function: not assigned
Biological process: not assigned
Entry contents: 2 distinct polypeptide molecules
Chains: N, I
Notes: No modifications of the original PDB file.
Source organism: Xenopus laevis
Length: 16 residues
Sequence:Sequence according to PDB SEQRESKRPAATKKAGQAKKKK
UniProtKB AC: P05221 (positions: 155-170)Coverage: 8%
UniRef90 AC: UniRef90_P05221 (positions: 155-170)
Name: Importin subunit alpha-1
Source organism: Mus musculus
Length: 426 residues
Sequence:Sequence according to PDB SEQRESGTVNWSVEDIVKGINSNNLESQLQATQAARKLLSREKQPPIDNIIRAGLIPKFVSFLGKTDCSPIQFESAWALTNIASGTSEQTKAVVDGGAIPAFISLLASPHAHISEQAVWALGNIAGDGSAFRDLVIKHGAIDPLLALLAVPDLSTLACGYLRNLTWTLSNLCRNKNPAPPLDAVEQILPTLVRLLHHNDPEVLADSCWAISYLTDGPNERIEMVVKKGVVPQLVKLLGATELPIVTPALRAIGNIVTGTDEQTQKVIDAGALAVFPSLLTNPKTNIQKEATWTMSNITAGRQDQIQQVVNHGLVPFLVGVLSKADFKTQKEAAWAITNYTSGGTVEQIVYLVHCGIIEPLMNLLSAKDTKIIQVILDAISNIFQAAEKLGETEKLSIMIEECGGLDKIEALQRHENESVYKASLNLIEKYFS
UniProtKB AC: P52293 (positions: 72-497)Coverage: 80.5%
UniRef90 AC: UniRef90_P52293 (positions: 72-497)
The 120-200 region described in DisProt entry DP00217 cover 100% of the sequence present in the structure. The protein region involved in the interaction contains a known functional linear motif (TRG_NLS_Bipartite_1).
The armadillo repeat domain involved in the interaction is known to adopt a stable structure in isolation (see Pfam domain PF00514). A solved monomeric structure of the domain is represented by PDB ID 1ial.