title: Pyruvate kinase type-II isozyme in Plasmodium falciparum localizes to the apicoplast.
abstract: Bioinformatics research on Plasmodium falciparum revealed two isoforms of pyruvate kinase: type-I and type-II enzymes. The type-I enzyme shows typical glycolytic properties, while type-II enzyme is involved in fatty acid type-II biosynthesis and has been predicted to localize to the apicoplast with the targeting signal in its N-terminus. The type-I and type-II isoforms have the same evolutionary origin as Toxoplasma gondii isozymes, TgPyKI and TgPyKII, respectively; however, TgPyKII localizes to both the mitochondrion and the apicoplast. Accordingly, we made a recombinant full length of P. falciparum pyruvate kinase type-II protein using a wheat germ cell-free expression system and obtained a specific antibody against the type-II protein. Fluorescent microscopic analysis revealed that P. falciparum type-II enzyme was localized only to the apicoplast, not to the mitochondrion. The data suggest differences in localization and metabolic pathways between P. falciparum and T. gondii pyruvate kinase isoforms.
authors.affiliation: Department of Tropical Medicine and Parasitology, Keio University, Shinjuku-ku, Tokyo 160-8582, Japan.
authors.forename: Takuya
authors.initials: T
authors.lastname: Maeda
authors.forename: Tomoya
authors.initials: T
authors.lastname: Saito
authors.forename: Omar S
authors.initials: OS
authors.lastname: Harb
authors.forename: David S
authors.initials: DS
authors.lastname: Roos
authors.forename: Satoru
authors.initials: S
authors.lastname: Takeo
authors.forename: Hiroko
authors.initials: H
authors.lastname: Suzuki
authors.forename: Takafumi
authors.initials: T
authors.lastname: Tsuboi
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Takeuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Asai
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D007527:Isoenzymes / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008856:Microscopy, Fluorescence; D008928:Mitochondria / Q000201:enzymology; D008969:Molecular Sequence Data; D010963:Plasmodium falciparum / Q000201:enzymology* / Q000235:genetics; D018087:Plastids / Q000201:enzymology*; D015800:Protozoan Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D011770:Pyruvate Kinase / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins; D017422:Sequence Analysis, DNA
chemical_list: D007527:Isoenzymes; D015800:Protozoan Proteins; D011994:Recombinant Proteins; D011770:Pyruvate Kinase