Protein farnesyltransferase and protein prenylation in Plasmodium falciparum
Protein farnesyltransferase and protein prenylation in Plasmodium falciparum
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DOI：
10.1074/jbc.m202860200
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发表时间：
2002-11-01
影响因子：
4.8
通讯作者：
Allen, CM
中科院分区：
文献类型：
--
作者：
Chakrabarti, D;Da Silva, T;Allen, CM
比较疟疾寄生虫和哺乳动物蛋白戊烯基转移酶及其细胞底物对于确定这种酶作为开发抗疟疾药物的靶标很重要。用19个羧基末端氨基酸不同的七肽作为部分纯化的恶性疟原虫蛋白法尼基转移酶的替代底物。只有NRSCAIM和NRSCAIQ作为底物，其中NRSCAIM最好。多肽类化合物FTI-276和GGTI-287对转移酶有抑制作用，其IC50值分别为1和32 nm。恶性疟原虫感染的红细胞与[H-3]法尼醇标记的50和22-28 kDa蛋白质孵育，而[H-3]香叶醇标记的只有22-28 kDa的蛋白质。50 kDa的蛋白质被证明是法尼化的，而22-28 kDa的蛋白质是香叶基香叶化的，与标记的戊烯醇无关。蛋白质标记被5um FTI-277或GGTI-298抑制50%以上。同样浓度的抑制剂还可以抑制寄生虫从环期开始的生长50%，减少Prenyl特异性抗体检测到的Prenylated蛋白的表达，并抑制滋养体阶段以外的寄生虫分化。此外，还证实了恶性疟原虫蛋白的分化特异性预烯基化。蛋白质标记主要在滋养体到裂殖体和裂殖体到环的转变过程中检测到。这些结果显示了恶性疟原虫蛋白质预烯基化的独特性质：与哺乳动物酶相比，肽底物的法尼基转移酶的特异性有限，使用法尼醇标记蛋白质上的法尼基和香叶基的能力，分化特异性的蛋白质预烯基化，以及模拟肽的异丙烯基转移酶抑制剂阻止寄生虫分化的能力。
Comparison of the malaria parasite and mammalian protein prenyltransferases and their cellular substrates is important for establishing this enzyme as a target for developing antimalarial agents. Nineteen heptapeptides differing only in their carboxyl-terminal amino acid were tested as alternative substrates of partially purified Plasmodium falciparum protein farnesyltransferase. Only NRSCAIM and NRSCAIQ serve as substrates, with NRSCAIM being the best. Peptidomimetics, FTI-276 and GGTI-287, inhibit the transferase with IC50 values of 1 and 32 nm, respectively. Incubation of P. falciparum-infected erythrocytes with [H-3]farnesol labels 50- and 22-28-kDa proteins, whereas [H-3]geranylgeraniol labels only 22-28-kDa proteins. The 50-kDa protein is shown to be farnesylated, whereas the 22-28-kDa proteins are geranylgeranylated, irrespective of the labeling prenol. Protein labeling is inhibited more than 50% by either 5 mum FTI-277 or GGTI-298. The same concentration of inhibitors also inhibits parasite growth from the ring stage by 50%, decreases expression of prenylated proteins as measured with prenyl-specific antibody, and inhibits parasite differentiation beyond the trophozoite stage. Furthermore, differentiation specific prenylation of P. falciparum proteins is demonstrated. Protein labeling is detected predominantly during the trophozoite to schizont and schizont to ring transitions. These results demonstrate unique properties of protein prenylation in P. falciparum: a limited specificity of the farnesyltransferase for peptide substrates compared with mammalian enzymes, the ability to use farnesol to label both farnesyl and geranylgeranyl moieties on proteins, differentiation specific protein prenylation, and the ability of peptidomimetic prenyltransferase inhibitors to block parasite differentiation.