PfPDE1, a novel cGMP-specific phosphodiesterase from the human malaria parasite Plasmodium falciparum
PfPDE1, a novel cGMP-specific phosphodiesterase from the human malaria parasite Plasmodium falciparum
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DOI：
10.1042/bj20050425
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发表时间：
2005-11-15
影响因子：
4.1
通讯作者：
Omori, K
中科院分区：
文献类型：
--
作者：
Yuasa, K;Mi-Ichi, F;Omori, K
这是第一次报告的分子特征的一种新的环核苷酸PDE（磷酸二酯酶），分离自人类疟疾寄生虫恶性疟原虫，并指定PfPDE 1。PJPDE 1 cDNA编码一个884个氨基酸的蛋白质，包括6个假定的跨膜结构域的N-末端，其次是催化结构域。PJPDE 1基因是一个单拷贝基因，由两个外显子和一个170 bp的内含子组成。PfPDE 1转录本在寄生虫的无性血液阶段的环状形式中是丰富的。大肠杆菌产生的PfPDE 1的C-末端催化结构域特异性地水解cGMP，具有K.值为0.65 μ M。在测试的PDE抑制剂中，PDE 5抑制剂扎普司特是最有效的，其IC 50值为3.8 μ M。非特异性PDE抑制剂IBMX（3-异丁基-1甲基黄嘌呤）、茶碱和抗疟氯喹的IC 50值超过100 μ M。与胞质组分相比，从混合无性血液阶段的恶性疟原虫制备的膜组分显示出有效的cGMP水解活性。这种水解活性对扎普司特敏感，IC 50值为4.1 μ M，但对IBMX和茶碱不敏感。此外，体外抗疟活性测定证明扎普司特抑制无性血液寄生虫的生长，ED 50值为35 μ M。环核苷酸信号对这种寄生虫的细胞发育的影响以前已经讨论过。因此，这种酶被认为是一种新的潜在的治疗疟疾的目标。
This is the first report of molecular characterization of a novel cyclic nucleotide PDE (phosphodiesterase), isolated from the human malaria parasite Plasmodium falciparum and designated PfPDE1. PJPDE1 cDNA encodes an 884-amino-acid protein, including six putative transmembrane domains in the N-terminus followed by a catalytic domain. The PJPDE1 gene is a single-copy gene consisting of two exons and a 170 bp intron. PfPDE1 transcripts were abundant in the ring form of the asexual blood stages of the parasite. The C-terminal catalytic domain of PfPDE1, produced in Escherichia coli, specifically hydrolysed cGMP with a K. value of 0.65 mu M. Among the PDE inhibitors tested, a PDE5 inhibitor, zaprinast, was the most effective, having an IC50 value of 3.8 mu M. The non-specific PDE inhibitors IBMX (3-isobutyl-1 methylxanthine), theophylline and the antimalarial chloroquine had IC50 values of over 100 mu M. Membrane fractions prepared from P. falciparum at mixed asexual blood stages showed potent cGMP hydrolytic activity compared with cytosolic fractions. This hydrolytic activity was sensitive to zaprinast with an IC50 value of 4.1 mu M, but insensitive to IBMX and theophylline. Furthermore, an in vitro antimalarial activity assay demonstrated that zaprinast inhibited the growth of the asexual blood parasites, with an ED50 value of 35 mu M. The impact of cyclic nucleotide signalling on the cellular development of this parasite has previously been discussed. Thus this enzyme is suggested to be a novel potential target for the treatment of the disease malaria.