BIOCHEMICAL AND IMMUNOCHEMICAL CHARACTERIZATION OF A P-TYPE ATPASE FROM LEISHMANIA-DONOVANI PROMASTIGOTE PLASMA-MEMBRANE

An ATPase on the plasma membrane of Leishmania donovani has been characterized. An antiserum, generated against ATPase active bands from native gels, was specific for a 105 kDa protein in promastigotes. However, in plasma membrane preparations a 70 kDa protein is also recognized, suggesting proteolysis of the intact 105 kDa protein or the presence of a second similar ATPase, [gamma-P-32]ATP phosphorylates two proteins (105 kDa and 70 kDa) in promastigotes and plasma membranes. Both proteins form a transient phosphorylated intermediate, characteristic of a P-type ATPase. Immunostaining of permeabilized parasites shows diffuse staining of the surface of promastigotes and amastigotes, which is consistent with a plasma membrane protein. The antiserum immunoprecipitates a 70 kDa [C-14]DCCD binding protein from whole cells and plasma membranes of promastigotes. Furthermore, the antiserum immunoprecipitates a 105 kDa and 70 kDa protein which can be subsequently phosphorylated. These results indicate the presence of a 105 kDa P-type ATPase on the L. donovani plasma membrane which is similar to the mammalian and fungal cation pumps.