3AWF: Crystal Structure Of Pten-Like Domain Of Ci-Vsp (236-576)

Ciona intestinalis voltage-sensing phosphatase (Ci-VSP) has a transmembrane voltage sensor domain and a cytoplasmic region sharing similarity to the phosphatase and tensin homolog (PTEN). It dephosphorylates phosphatidylinositol 4,5-bisphosphate and phosphatidylinositol 3,4,5-trisphosphate upon membrane depolarization. The cytoplasmic region is composed of a phosphatase domain and a putative membrane interaction domain, C2. Here we determined the crystal structures of the Ci-VSP cytoplasmic region in three distinct constructs, wild-type (248-576), wild-type (236-576), and G365A mutant (248-576). The crystal structure of WT-236 and G365A-248 had the disulfide bond between the catalytic residue Cys-363 and the adjacent residue Cys-310. On the other hand, the disulfide bond was not present in the crystal structure of WT-248. These suggest the possibility that Ci-VSP is regulated by reactive oxygen species as found in PTEN. These structures also revealed that the conformation of the TI loop in the active site of the Ci-VSP cytoplasmic region was distinct from the corresponding region of PTEN; Ci-VSP has glutamic acid (Glu-411) in the TI loop, orienting toward the center of active site pocket. Mutation of Glu-411 led to acquirement of increased activity toward phosphatidylinositol 3,5-bisphosphate, suggesting that this site is required for determining substrate specificity. Our results provide the basic information of the enzymatic mechanism of Ci-VSP.
PDB ID: 3AWFDownload
MMDB ID: 90279
PDB Deposition Date: 2011/3/19
Updated in MMDB: 2011/12
Experimental Method:
x-ray diffraction
Resolution: 1.99  Å
Source Organism:
Similar Structures:
Biological Unit for 3AWF: monomeric; determined by author and by software (PISA)
Molecular Components in 3AWF
Label Count Molecule
Protein (1 molecule)
Voltage-sensor Containing Phosphatase
Molecule annotation
Chemicals (3 molecules)
* Click molecule labels to explore molecular sequence information.

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