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Title: Structural Analysis of the Carboxy Terminal PH Domain of Pleckstrin Bound to D-myo-Inositol 1,2,3,5,6-pentakisphosphate

Abstract

Pleckstrin homology (PH) domains are one of the most prevalent domains in the human proteome and represent the major phosphoinositide-binding module. These domains are often found in signaling proteins and function predominately by targeting their host proteins to the cell membrane. Inositol phosphates, which are structurally similar to phosphoinositides, are not only known to play a role as signaling molecules but are also capable of being bound by PH domains. In the work presented here it is shown that the addition of commercial myo-inositol hexakisphosphate (IP6) inhibited the binding of the carboxy terminal PH domain of pleckstrin (C-PH) to phosphatidylinositol 3, 4-bisphosphate with an IC50 of 7.5 {mu}M. In an attempt to characterize this binding structurally, C-PH was crystallized in the presence of IP6 and the structure was determined to 1.35 Angstroms . Examination of the resulting electron density unexpectedly revealed the bound ligand to be D-myo-inositol 1, 2,3, 5,6-pentakisphosphate. The discovery of D-myo-inositol 1, 2,3, 5,6-pentakisphosphate in the crystal structure suggests that the inhibitory effects observed in the binding studies may be due to this ligand rather than IP6. Analysis of the protein-ligand interaction demonstrated that this myo-inositol pentakisphosphate isomer interacts specifically with protein residues known to be involvedmore » in phosphoinositide binding. In addition to this, a structural alignment of other PH domains bound to inositol phosphates containing either four or five phosphate groups revealed that the majority of phosphate groups occupy conserved locations in the binding pockets of PH domains. These findings, taken together with other recently reported studies suggest that myo-inositol pentakisphosphates could act to regulate PH domain-phosphoinositide interactions by directly competing for binding, thus playing an important role as signaling molecules.« less

Authors:
; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
960077
Report Number(s):
BNL-83063-2009-JA
TRN: US201016%%1221
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: BMC Structural Biology; Journal Volume: 7
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALIGNMENT; CELL MEMBRANES; CRYSTAL STRUCTURE; ELECTRON DENSITY; INOSITOL; ISOMERS; PHOSPHATES; PROTEINS; RESIDUES; national synchrotron light source

Citation Formats

Jackson,S., Zhang, Y., Haslam, R., and Junop, M.. Structural Analysis of the Carboxy Terminal PH Domain of Pleckstrin Bound to D-myo-Inositol 1,2,3,5,6-pentakisphosphate. United States: N. p., 2007. Web. doi:10.1186/1472-6807-7-80.
Jackson,S., Zhang, Y., Haslam, R., & Junop, M.. Structural Analysis of the Carboxy Terminal PH Domain of Pleckstrin Bound to D-myo-Inositol 1,2,3,5,6-pentakisphosphate. United States. doi:10.1186/1472-6807-7-80.
Jackson,S., Zhang, Y., Haslam, R., and Junop, M.. Mon . "Structural Analysis of the Carboxy Terminal PH Domain of Pleckstrin Bound to D-myo-Inositol 1,2,3,5,6-pentakisphosphate". United States. doi:10.1186/1472-6807-7-80.
@article{osti_960077,
title = {Structural Analysis of the Carboxy Terminal PH Domain of Pleckstrin Bound to D-myo-Inositol 1,2,3,5,6-pentakisphosphate},
author = {Jackson,S. and Zhang, Y. and Haslam, R. and Junop, M.},
abstractNote = {Pleckstrin homology (PH) domains are one of the most prevalent domains in the human proteome and represent the major phosphoinositide-binding module. These domains are often found in signaling proteins and function predominately by targeting their host proteins to the cell membrane. Inositol phosphates, which are structurally similar to phosphoinositides, are not only known to play a role as signaling molecules but are also capable of being bound by PH domains. In the work presented here it is shown that the addition of commercial myo-inositol hexakisphosphate (IP6) inhibited the binding of the carboxy terminal PH domain of pleckstrin (C-PH) to phosphatidylinositol 3, 4-bisphosphate with an IC50 of 7.5 {mu}M. In an attempt to characterize this binding structurally, C-PH was crystallized in the presence of IP6 and the structure was determined to 1.35 Angstroms . Examination of the resulting electron density unexpectedly revealed the bound ligand to be D-myo-inositol 1, 2,3, 5,6-pentakisphosphate. The discovery of D-myo-inositol 1, 2,3, 5,6-pentakisphosphate in the crystal structure suggests that the inhibitory effects observed in the binding studies may be due to this ligand rather than IP6. Analysis of the protein-ligand interaction demonstrated that this myo-inositol pentakisphosphate isomer interacts specifically with protein residues known to be involved in phosphoinositide binding. In addition to this, a structural alignment of other PH domains bound to inositol phosphates containing either four or five phosphate groups revealed that the majority of phosphate groups occupy conserved locations in the binding pockets of PH domains. These findings, taken together with other recently reported studies suggest that myo-inositol pentakisphosphates could act to regulate PH domain-phosphoinositide interactions by directly competing for binding, thus playing an important role as signaling molecules.},
doi = {10.1186/1472-6807-7-80},
journal = {BMC Structural Biology},
number = ,
volume = 7,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}