PDBsum entry 3msh

Protein binding

PDB id: 3msh

Contents

Protein chain

90 a.a. *

Ligands

GOL

IPA ×3

PO4

PG4

Waters ×68

* Residue conservation analysis

PDB id:

3msh

Name:

Protein binding

Title:

Crystal structure of hepatitis b x-interacting protein at high resolution

Structure:

Hepatitis b virus x-interacting protein. Chain: a. Synonym: hbv x-interacting protein, hbx-interacting protein. Engineered: yes

Source:

Homo sapiens. Human. Organism_taxid: 9606. Gene: hbxip, xip. Expressed in: escherichia coli. Expression_system_taxid: 469008.

Resolution:

1.51Å R-factor: 0.183 R-free: 0.212

Authors:

I.Garcia-Saez,D.Skoufias

Key ref:

I.Garcia-Saez et al. (2011). Structural characterization of HBXIP: the protein that interacts with the anti-apoptotic protein survivin and the oncogenic viral protein HBx. J Mol Biol, 405, 331-340. PubMed id: 21059355

Date:

29-Apr-10 Release date: 10-Nov-10

Protein chain

O43504  (LTOR5_HUMAN) -  Ragulator complex protein LAMTOR5 from Homo sapiens

Seq: 91 a.a.

Struc: 90 a.a.

J Mol Biol 405:331-340 (2011)

PubMed id: 21059355

Structural characterization of HBXIP: the protein that interacts with the anti-apoptotic protein survivin and the oncogenic viral protein HBx.

I.Garcia-Saez, F.B.Lacroix, D.Blot, F.Gabel, D.A.Skoufias.

ABSTRACT

Hepatitis B X-interacting protein (HBXIP) is a ubiquitous protein that was originally identified as a binding partner of the hepatitis B viral protein HBx. HBXIP is also thought to serve as an anti-apoptotic cofactor of survivin, promoting the suppression of pro-caspase-9 activation. Here were port the crystal structure of the shortest isoform of HBXIP (91 aa long,∼11 kDa) at 1.5 Å resolution. HBXIP crystal shows a monomer per asymmetric unit, with a profilin-like fold which is common to a super family of proteins, the Roadblock/LC7 domain family involved in protein-protein interactions. Based on this fold, we propose that HBXIP can form a dimer that can indeed be found in the crystal when symmetric molecules are generated around the asymmetric unit. This dimer shows an extended β-sheet area formed by 10 anti-parallel β-strands from both subunits. Another interesting aspect of the proposed HBXIP dimer interface is the presence of a small leucine zipper between the two α2 helices of each monomer. In solution, the scattering curve obtained by small-angle X-ray scattering for the sample used for crystallization indicates that the protein is dimeric form in solution. The fit between the experimental small angle X-ray scattering curve and the back calculated curves for two potential crystal dimers shows a significant preference for the Roadblock/LC7 fold dimer model. Moreover, the HBXIP crystal structure represents a step towards understanding the cellular role of HBXIP.