Cofactor metabolism and mitochondrial function in malaria parasites

疟原虫每年导致数亿例疟疾病例。无性繁殖期间 在红细胞的发育阶段，疟原虫从人血清中获取某些营养物质，同时 保留综合他人的能力。我们正在研究一种称为硫辛酸的必需酶辅因子及其 恶性疟原虫的代谢。我们的研究表明红细胞期寄生虫是 硫辛酸营养缺陷，尽管它们含有合成该辅因子的代谢途径。蛋白质在 顶质体细胞器依赖于硫辛酸的合成，而寄生虫线粒体中的蛋白质则依赖于硫辛酸的合成。 清除并且不能获得在顶质体中合成的硫辛酸。拟议的研究主要集中在两个方面 硫辛酸清除的各个方面，并采用生物化学、细胞生物学和遗传方法的组合。 我们的首要目标是定义硫辛酸依赖性蛋白的基本作用并确定其所需的因素 支持寄生虫线粒体中的这些活动。我们的第二个目标是探讨硫辛酸的机制 线粒体蛋白的摄取和附着，以了解该过程如何、何时以及为何进行 由氧化还原电位门控。这些研究将在硫辛酸附着酶和 他们的蛋白质底物。由于依赖于宿主营养素，这些蛋白质代表了一个脆弱的方面 可以在几个层面上针对寄生虫生物学。

Plasmodium parasites are responsible for hundreds of millions of malaria cases annually. During the asexual stages of development in red blood cells, malaria parasites acquire certain nutrients from human serum while retaining the ability to synthesize others. We are studying an essential enzyme cofactor called lipoate and its metabolism in Plasmodium falciparum. Our studies demonstrate that erythrocytic stage parasites are auxotrophic for lipoate, even though they contain a metabolic pathway to synthesize this cofactor. Proteins in the apicoplast organelle rely on lipoate synthesis while proteins in the parasite mitochondrion rely on scavenging and cannot obtain lipoate synthesized in the apicoplast. The proposed studies are focused on two aspects of lipoate scavenging and employ a combination of biochemical, cell biology and genetic approaches. Our first aim is to define the essentail roles of lipoate-dependent proteins and identify the factors required to support these activities in the parasite mitochondrion. Our second aim will probe the mechanism of lipoate uptake and attachment to mitochondrial proteins in order to understand how, when and why this process is gated by redox potential. These studies will forge a detailed link between the lipoate attachment enzymes and their protein substrates. By virtue of relying on a host nutrient, these proteins represent a vulnerable aspect of parasite biology which could be targeted at several levels.