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Template:STRUCTURE 2rea

Crystal structures of C2ALPHA-PI3 kinase PX-domain domain indicate conformational change associated with ligand binding.

Overview

ABSTRACT: BACKGROUND: PX domains have specialized protein structures involved in binding of phosphoinositides (PIs). Through binding to the various PIs PX domains provide site-specific membrane signals to modulate the intracellular localisation and biological activity of effector proteins. Several crystal structures of these domains are now available from a variety of proteins. All PX domains contain a canonical core structure with main differences exhibited within the loop regions forming the phosphoinositide binding pockets. It is within these areas that the molecular basis for ligand specificity originates. RESULTS: We now report two new structures of PI3K-C2 PX domain that crystallised in a P3121 space group. The two structures, refined to 2.1 A and 2.5 A, exhibit significantly different conformations of the phosphoinositide-binding loops. Unexpectedly, in one of the structures, we have detected a putative-ligand trapped in the binding site during the process of protein purification and crystallisation. CONCLUSIONS: The two structures reported here provide a more complete description of the phosphoinositide binding region compared to the previously reported 2.6 A crystal structure of human PI3K-C2 PX where this region was highly disordered. The structures enabled us to further analyse PI specificity and to postulate that the observed conformational change could be related to ligand-binding.

About this Structure

2REA is a Single protein structure of sequence from Homo sapiens. Full crystallographic information is available from OCA.

Reference

Crystal structures of PI3K-C2alpha PX domain indicate conformational change associated with ligand binding., Parkinson GN, Vines D, Driscoll PC, Djordjevic S, BMC Struct Biol. 2008 Feb 29;8(1):13. PMID:18312637 Page seeded by OCA on Sun May 4 16:44:08 2008