2V6V image
Deposition Date 2007-07-21
Release Date 2007-07-31
Last Version Date 2024-11-20
Entry Detail
PDB ID:
2V6V
Keywords:
Title:
The structure of the Bem1p PX domain
Biological Source:
Source Organism:
Host Organism:
Method Details:
Experimental Method:
Resolution:
1.50 Å
R-Value Free:
0.25
R-Value Work:
0.22
R-Value Observed:
0.22
Space Group:
P 21 21 21
Macromolecular Entities
Polymer Type:polypeptide(L)
Molecule:BUD EMERGENCE PROTEIN 1
Gene (Uniprot):BEM1
Chain IDs:A, B
Chain Length:156
Number of Molecules:2
Biological Source:SACCHAROMYCES CEREVISIAE
Modified Residue
Compound ID Chain ID Parent Comp ID Details 2D Image
MSE A MET SELENOMETHIONINE
Ligand Molecules
Primary Citation
Structural and Membrane Binding Analysis of the Phox Homology Domain of Bem1P: Basis of Phosphatidylinositol 4-Phosphate Specificity.
J.Biol.Chem. 282 25737 ? (2007)
PMID: 17581820 DOI: 10.1074/JBC.M702861200

Abstact

Phox homology (PX) domains, which have been identified in a variety of proteins involved in cell signaling and membrane trafficking, have been shown to interact with phosphoinositides (PIs) with different affinities and specificities. To elucidate the structural origin of the diverse PI specificity of PX domains, we determined the crystal structure of the PX domain from Bem1p that has been reported to bind phosphatidylinositol 4-phosphate (PtdIns(4)P). We also measured the membrane binding properties of the PX domain and its mutants by surface plasmon resonance and monolayer techniques and calculated the electrostatic potentials for the PX domain in the absence and presence of bound PtdIns(4)P. The Bem1p PX domain contains a signature PI-binding site optimized for PtdIns(4)P binding and also harbors basic and hydrophobic residues on the membrane-binding surface. The membrane binding of the Bem1p PX domain is initiated by nonspecific electrostatic interactions between the cationic membrane-binding surface of the domain and anionic membrane surfaces, followed by the membrane penetration of hydrophobic residues. Unlike other PX domains, the Bem1p PX domain has high intrinsic membrane penetrating activity in the absence of PtdIns(4)P, suggesting that the partial membrane penetration may occur before specific PtdIns(4)P binding and last after the removal of PtdIns(4)P under certain conditions. This structural and functional study of the PtdIns(4)P-binding Bem1p PX domain provides new insight into the diverse PI specificities and membrane-binding mechanisms of PX domains.

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Primary Citation of related structures