1O7K: Human P47 PX Domain Complex With Sulphates

p47(phox) is a key cytosolic subunit required for activation of phagocyte NADPH oxidase. The X-ray structure of the p47(phox) PX domain revealed two distinct basic pockets on the membrane-binding surface, each occupied by a sulfate. These two pockets have different specificities: one preferentially binds phosphatidylinositol 3,4-bisphosphate [PtdIns(3,4)P(2)] and is analogous to the phophatidylinositol 3-phosphate (PtdIns3P)-binding pocket of p40(phox), while the other binds anionic phospholipids such as phosphatidic acid (PtdOH) or phosphatidylserine. The preference of this second site for PtdOH may be related to previously observed activation of NADPH oxidase by PtdOH. Simultaneous occupancy of the two phospholipid-binding pockets radically increases membrane affinity. Strikingly, measurements for full-length p47(phox) show that membrane interaction by the PX domain is masked by an intramolecular association with the C-terminal SH3 domain (C-SH3). Either a site-specific mutation in C-SH3 (W263R) or a mimic of the phosphorylated form of p47(phox) [Ser(303, 304, 328, 359, 370)Glu] cause a transition from a closed to an open conformation that binds membranes with a greater affinity than the isolated PX domain.
PDB ID: 1O7KDownload
MMDB ID: 21318
PDB Deposition Date: 2002/11/7
Updated in MMDB: 2002/12 
Experimental Method:
x-ray diffraction
Resolution: 2  Å
Source Organism:
Similar Structures:
Biological Unit for 1O7K: trimeric; determined by author and by software (PQS)
Molecular Components in 1O7K
Label Count Molecule
Proteins (3 molecules)
Neutrophil Cytosol Factor 1
Molecule annotation
Chemicals (7 molecules)
* Click molecule labels to explore molecular sequence information.

Citing MMDB