Maeda Takuya, Saito Tomoya, Harb Omar S, Roos David S, Takeo Satoru, Suzuki Hiroko, Tsuboi Takafumi, Takeuchi Tsutomu, Asai Takashi
Department of Tropical Medicine and Parasitology, Keio University, Shinjuku-ku, Tokyo 160-8582, Japan.
Parasitol Int. 2009 Mar;58(1):101-5. doi: 10.1016/j.parint.2008.10.005. Epub 2008 Oct 31.
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.
I型和II型酶。I型酶具有典型的糖酵解特性,而II型酶参与脂肪酸II型生物合成,并且据预测其通过N端的靶向信号定位于顶质体。I型和II型同工型分别与刚地弓形虫的同工酶TgPyKI和TgPyKII具有相同的进化起源;然而,TgPyKII定位于线粒体和顶质体。因此,我们使用小麦胚无细胞表达系统制备了重组全长恶性疟原虫丙酮酸激酶II型蛋白,并获得了针对II型蛋白的特异性抗体。荧光显微镜分析显示,恶性疟原虫II型酶仅定位于顶质体,而不定位于线粒体。这些数据表明恶性疟原虫和刚地弓形虫丙酮酸激酶同工型在定位和代谢途径上存在差异。