1btn
From Proteopedia
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STRUCTURE OF THE BINDING SITE FOR INOSITOL PHOSPHATES IN A PH DOMAIN
Overview
Phosphatidylinositol bisphosphate has been found to bind specifically to, pleckstrin homology (PH) domains that are commonly present in signalling, proteins but also found in cytoskeleton. We have studied the complexes of, the beta-spectrin PH domain and soluble inositol phosphates using both, circular dichroism and nuclear magnetic resonance spectroscopy, and X-ray, crystallography. The specific binding site is located in the centre of a, positively charged surface patch of the domain. The presence of, 4,5-bisphosphate group on the inositol ring is critical for binding. In, the crystal structure that has been determined at 2.0 A resolution, inositol-1,4,5-trisphosphate is bound with salt bridges and hydrogen bonds, through these phosphate groups whereas the 1-phosphate group is mostly, solvent-exposed and the inositol ring has virtually no interactions with, the protein. We propose a model in which PH domains are involved in, reversible anchoring of proteins to membranes via their specific binding, to phosphoinositides. They could also participate in a response to a, second messenger such as inositol trisphosphate, organizing cross-roads in, cellular signalling.
About this Structure
1BTN is a Single protein structure of sequence from Mus musculus with I3P as ligand. Full crystallographic information is available from OCA.
Reference
Structure of the binding site for inositol phosphates in a PH domain., Hyvonen M, Macias MJ, Nilges M, Oschkinat H, Saraste M, Wilmanns M, EMBO J. 1995 Oct 2;14(19):4676-85. PMID:7588597
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