General Information

Database Accession: DI1110009

Name: Importin alpha - nucleoplasmin NLS complex

PDB ID: 1ejy PDB

Experimental method: X-ray (2.90 Å)

Source organism: Xenopus laevis / Mus musculus

Proof of disorder: Confirmed

Kd: 2.70×10-09 M PubMed

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

PMID: 10764582 PubMed


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.

Function and Biology Annotations from the GeneOntology database. Only terms that fit at least two of the interacting proteins are shown.

Molecular function: not assigned

Biological process: not assigned

Cellular component:

nucleoplasm That part of the nuclear content other than the chromosomes or the nucleolus. GeneOntology

Structure Summary Structural annotations of the participating protein chains.

Entry contents: 2 distinct polypeptide molecules

Chains: N, I

Notes: No modifications of the original PDB file.

Chain N

Name: Nucleoplasmin Disordered Confirmed

Source organism: Xenopus laevis

Length: 16 residues

Sequence:Sequence according to PDB SEQRESKRPAATKKAGQAKKKK

UniProtKB AC: P05221 (positions: 155-170) UniProt Coverage: 8%

UniRef90 AC: UniRef90_P05221 (positions: 155-170) UniRef90

Chain I

Name: Importin subunit alpha-1 Ordered

Source organism: Mus musculus

Length: 426 residues


UniProtKB AC: P52293 (positions: 72-497) UniProt Coverage: 80.5%

UniRef90 AC: UniRef90_P52293 (positions: 72-497) UniRef90

Evidence Evidence demonstrating that the participating proteins are unstructured prior to the interaction and their folding is coupled to binding.

Chain N: Disordered Confirmed

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).

Chain I: Ordered

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.

Related Structure(s) Structures from the PDB that contain the same number of proteins, and the proteins from the two structures show a sufficient degree of pairwise similarity, i.e. they belong to the same UniRef90 cluster (the full proteins exhibit at least 90% sequence identity) and convey roughly the same region to their respective interactions (the two regions from the two proteins share a minimum of 70% overlap).

There is 1 related structure in the Protein Data Bank:

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