Sensing charges of the Ciona intestinalis voltage-sensing phosphatase.

摘要: Voltage control over enzymatic activity in voltage-sensitive phosphatases (VSPs) is conferred by a voltage-sensing domain (VSD) located the N terminus. These VSDs are constituted four putative transmembrane segments (S1 to S4) resembling those found voltage-gated ion channels. The fourth segment (S4) of VSD contains positive residues that likely function as elements. To study detail how these sense plasma membrane potential, we have focused on five arginines S4 Ciona intestinalis VSP (Ci-VSP). After implementing histidine scan, here show arginine-to-histidine mutants, namely R223H R232H, mediate voltage-dependent proton translocation across membrane, indicating transit through hydrophobic core Ci-VSP potential. observations indicate charges carried sensing charges. Furthermore, our results also electrical field VSPs narrow region separates extracellular and intracellular space constitutes energy barrier for charge crossing.