title: A plant-like vacuolar H(+)-pyrophosphatase in Plasmodium falciparum.
abstract: Inorganic pyrophosphate promoted the acidification of a subcellular compartment in cell homogenates of Plasmodium falciparum trophozoites. The proton gradient driven by pyrophosphate was collapsed by addition of NH(4)Cl or the K(+)/H(+) exchanger nigericin and eliminated by the pyrophosphate analog aminomethylenediphosphonate. Pyrophosphatase activity was dependent upon K(+), and partially inhibited by Na(+). The presence of a plant-like vacuolar H(+)-translocating pyrophosphatase (V-H(+)-PPase) was confirmed using antibodies raised against conserved peptide sequences of the enzyme, which cross reacted with a protein band of 76.5 kDa. Immunofluorescence microscopy using these antibodies showed a general fluorescence over the whole parasites and intracellular bright spots suggesting a vesicular and plasma membrane localization. Together, these results indicate the presence in P. falciparum of a V-H(+)-PPase of similar characteristics to those of the enzyme from plants.
authors.affiliation: Laboratory of Molecular Parasitology, Department of Pathobiology, College of Veterinary Medicine, University of Illinois at Urbana-Champaign, 2001 S. Lincoln Avenue, Urbana, IL, USA.
authors.forename: S
authors.initials: S
authors.lastname: Luo
authors.forename: N
authors.initials: N
authors.lastname: Marchesini
authors.forename: S N
authors.initials: SN
authors.lastname: Moreno
authors.forename: R
authors.initials: R
authors.lastname: Docampo
mesh_terms: D000818:Animals; D015153:Blotting, Western; D006868:Hydrolysis; D043564:Inorganic Pyrophosphatase; D008856:Microscopy, Fluorescence; D010944:Plants / Q000201:enzymology; D010963:Plasmodium falciparum / Q000201:enzymology*; D011522:Protons; D011755:Pyrophosphatases / Q000378:metabolism*; D014617:Vacuoles / Q000201:enzymology*
chemical_list: D011522:Protons; D011755:Pyrophosphatases; D043564:Inorganic Pyrophosphatase