Computational & Biochemical Studies of the Malarial Blood Stage Invasion Complex

描述（由申请人提供）：虽然存在有效的疟疾治疗方法，但寄生虫对这些药物的耐药性正在迅速增长，迫切需要建立新的机制来防治这种疾病。最近的几项研究表明，寄生虫的运动和侵袭机制代表了一个有希望的药物发现的新靶点。为了促进未来针对疟疾运动和侵袭机制的药物发现项目，本提案旨在使用跨学科的方法来阐明恶性疟原虫merozoites中表达的部分复合物的结构特征-这种寄生虫的侵袭性血液阶段，是脑型疟疾和大多数疟疾死亡的病原体。与其他顶复合体原生动物一样，疟原虫采用一种不依赖纤毛或鞭毛的依赖基质的滑行运动机制。滑翔和宿主细胞入侵是寄生虫的重要功能，并且越来越多地被发现是由位于生物体质膜下的肌动蛋白/肌球蛋白运动驱动的。肌凝蛋白通过强力取代肌动蛋白而产生运动。在疟原虫的分裂子中，这种力通过肌动蛋白结合、糖酵解酶、醛缩酶传递到MTRAP， MTRAP是一种具有粘附结构域的I型跨膜分子，能够与宿主细胞表面相互作用。这种寄生虫利用这种力量主动侵入人体红细胞。本课题旨在通过体外对mtrap -醛缩酶复合体的生化表征和mtrap -醛缩酶界面在硅上的三维分辨率，阐明恶性疟原虫子体中mtrap -醛缩酶相互作用的结构特征。位点定向突变、同源性建模和计算对接的结合将用于识别和可视化两种蛋白质之间的关键接触。由此获得的mtap -醛缩酶相互作用结构基础的详细图谱，将为今后合理设计抗疟疾药物提供平台。公共卫生相关性：疟疾影响着全世界数亿人——使他们遭受贫血、剧烈疼痛、发烧的折磨，在严重的情况下，还会导致脑血管闭塞、器官损伤和死亡。本文提出的研究为全球传染病的计算生物学和生物化学提供了一个理想的培训机会，同时增加了疟疾生物学关键方面的现有知识，并促进了新型、安全、有效的抗疟疾药物的设计。

DESCRIPTION (provided by applicant): While effective treatments for malaria exist, parasite resistance to these drugs is growing rapidly, and there is a critical need for new mechanisms to combat this disease. Several recent studies indicate that the motile and invasive machinery of the parasite represents a promising new target for drug discovery. In order to facilitate future drug discovery projects targeting the malarial motor and invasion machinery, this proposal aims to use an interdisciplinary approach to elucidate the structural features of a part of this complex expressed in Plasmodium falciparum merozoites - the invasive blood stage of this parasite, andthe causative agent of cerebral malaria and the majority of malarial mortality. Plasmodia, like other apicomplexan protozoa, employ a mechanism of substrate-dependent gliding motility that does not depend on cilia or flagella. Gliding and host cell invasion are crucial parasite functions and increasingly appear to be driven by an actin/myosin motor located beneath the organism's plasma membrane. Myosin generates movement by forcefully displacing actin. In Plasmodium merozoites, this force is transmitted - viatheactin-binding, glycolytic enzyme, aldolase - to MTRAP, a type I trans-membrane molecule bearing adhesive domains capable of interacting with host-cell surfaces. The parasite uses this force to actively invade human red blood cells. This proposal aims to elucidate the structural features of the MTRAP-aldolase interaction in Plasmodium falciparum merozoites via the biochemical characterization of this complex in vitro and the three-dimensional resolution of the MTRAP-aldolase interface in silico. A combination of site-directed mutagenesis, homology modeling, and computational docking will be used to identify and visualize key contacts between the two proteins. The detailed picture of the structural basis for the MTRAP-aldolase interaction thus obtained will serve as the platform for the future rational design of anti-malarial agents. PUBLIC HEALTH RELEVANCE: Malarial disease affects hundreds of millions of people worldwide - afflicting them with anemia, excruciating pain, fever, and in severe cases, cerebral blood vessel occlusion, organ damage, and death. The research proposed here serves as an ideal training opportunity in computational biology and the biochemistry of a global infectious disease, while simultaneously increasing the current knowledge of a key aspect of malarial biology, and facilitating the design of novel, safe, and effective anti-malarial agents.