2v6v

From Proteopedia

Revision as of 13:31, 5 November 2007

THE STRUCTURE OF THE BEM1P PX DOMAIN

Overview

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 diverse PI, specificity of PX domains, we determined the crystal structure of the PX, domain from Bem1p, which has been reported to bind, phosphatidylinositol-4-phosphate (PtdIns4P). 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, PtdIns4P. The Bem1p PX domain contains a signature PI-binding site, optimized for PtdIns4P binding and also harbors a cationic membrane, binding surface. The membrane binding of Bem1p PX domain is initiated by, nonspecific electrostatic interactions between the cationic membrane, binding surface of the domain and anionic membrane surfaces, which is, followed by the membrane penetration of hydrophobic residues. Unlike other, PX domains, the Bem1p PX domain has significant intrinsic membrane, penetration activity in the absence of PtdIns4P ligand, suggesting that, the membrane penetration can occur before specific PtdIns4P and last after, the removal of PtdIns4P. Taken together, this structural and functional, study of the PtdIns4P-binding Bem1p PX domain provides new insight into, the diverse PI specificities and membrane binding mechanisms of PX, domains.

About this Structure

2V6V is a Single protein structure of sequence from Saccharomyces cerevisiae with DTT as ligand. Structure known Active Site: AC1. Full crystallographic information is available from OCA.

Reference

Structural and membrane binding analysis of the PX domain of Bem1p: Basis of phosphatidylinositol-4-phosphate specificity., Stahelin RV, Karathanassis D, Murray D, Williams RL, Cho W, J Biol Chem. 2007 Jun 20;. PMID:17581820

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