PDBsum entry 4xrk

Transport protein

PDB id: 4xrk

Contents

Protein chain

832 a.a.

PDB id:

4xrk

Name:

Transport protein

Title:

Crystal structure of importin beta in a polyethylene glycol condition

Structure:

Importin beta. Chain: a. Engineered: yes

Source:

Chaetomium thermophilum. Organism_taxid: 759272. Strain: dsm 1495 / cbs 144.50 / imi 039719. Gene: ctht_0012280. Expressed in: escherichia coli. Expression_system_taxid: 562.

Resolution:

3.25Å R-factor: 0.291 R-free: 0.317

Authors:

M.J.Tauchert,P.Neumann,R.Ficner,A.Dickmanns

Key ref:

M.J.Tauchert et al. (2016). Impact of the crystallization condition on importin-β conformation. Acta Crystallogr D Struct Biol, 72, 705-717. PubMed id: 27303791 DOI: 10.1107/S2059798316004940

Date:

21-Jan-15 Release date: 27-Jan-16

Protein chain

G0S143  (G0S143_CHATD) -  Importin N-terminal domain-containing protein from Chaetomium thermophilum (strain DSM 1495 / CBS 144.50 / IMI 039719)

Seq: 877 a.a.

Struc: 832 a.a.

Enzyme reactions

• Enzyme class: E.C.?

DOI no: 10.1107/S2059798316004940

Acta Crystallogr D Struct Biol 72:705-717 (2016)

PubMed id: 27303791

Impact of the crystallization condition on importin-β conformation.

M.J.Tauchert, C.Hémonnot, P.Neumann, S.Köster, R.Ficner, A.Dickmanns.

ABSTRACT

In eukaryotic cells, the exchange of macromolecules between the nucleus and cytoplasm is highly selective and requires specialized soluble transport factors. Many of them belong to the importin-β superfamily, the members of which share an overall superhelical structure owing to the tandem arrangement of a specific motif, the HEAT repeat. This structural organization leads to great intrinsic flexibility, which in turn is a prerequisite for the interaction with a variety of proteins and for its transport function. During the passage from the aqueous cytosol into the nucleus, the receptor passes the gated channel of the nuclear pore complex filled with a protein meshwork of unknown organization, which seems to be highly selective owing to the presence of FG-repeats, which are peptides with hydrophobic patches. Here, the structural changes of free importin-β from a single organism, crystallized in polar (salt) or apolar (PEG) buffer conditions, are reported. This allowed analysis of the structural changes, which are attributable to the surrounding milieu and are not affected by bound interaction partners. The importin-β structures obtained exhibit significant conformational changes and suggest an influence of the polarity of the environment, resulting in an extended conformation in the PEG condition. The significance of this observation is supported by SAXS experiments and the analysis of other crystal structures of importin-β deposited in the Protein Data Bank.