Functional reconstitution of plasma membrane H+ -ATPase from mungbean (Vigna radiata L.) hypocotyls in liposomes prepared with various molecular species of phospholipids

Functional reconstitution of plasma membrane H+ -ATPase from mungbean (Vigna radiata L.) hypocotyls in liposomes prepared with various molecular species of phospholipids

1991

A:PS

The activity of solubilized plasma membrane ATPase is affected by the nature of exogenously added molecular species of phospholipids. To examine the role of the polar head group and of the molecular species of phospholipids in H+ -pumping, the ATPase solubilized from plasma membranes of mungbean (Vigna radiata L.) hypocotyls was reconstituted in liposomes prepared with a variety of phospholipids. The extent of activation of solubilized plasma membrane ATPase due to the addition of 1-palmitoyl 2-oleoyl-phospholipids (PO-phospholipids) and asolectin decreased in the following order: POPS > POPC >= asolectin >= POPG > POPE > POPA. H+ -pumping into proteoliposomes reconstituted with asolectin and plasma membrane ATPase was demonstrated by quinacrine fluorescence quenching in the presence of ATP-MgSO4. H+ -pumping was inhibited by VO4 and gramicidin D. When plasma membrane ATPase was reconstituted in liposomes prepared with various PO-phospholipids, the ability of PO-phospholipids to support H+ -pumping into the proteoliposomes decreased in the following orer: POPG >= POPS > asolectin >= POPC. POPE and POPA failed to support any H+ -pumping. A remarkably high rate of H+ -pumping was observed in proteoliposomes prepared with 1-saturated 2-unsaturated fatty acids, such as POPC, but H+ -pumping could hardly be detected in proteoliposomes prepared with 1-, 2-unsaturated or 1-, 2-saturated fatty acids, such as PSPC or DLPC. ATPase activity in proteoliposomes was dependent on the species of PO-phospholipids used for reconstitution and decreased in the following orer: POPS > POPG >POPC >= asolectin > POPA > POPE. DLPC which includes a 1-, 2-unsaturated fatty acic supported only markedly depressed activity. Both H+ -pumping and the affected by the polar head group and composition of the fatty acyl chain of phospholipids used to prepare liposomes for reconstitution of the ATPase. [AS]

v.32(8):1219-1225, PLANT AND CELL PHYSIOLOGY

Research > Published Articles