Structural Analysis of Helminth mRNA Cap-Binding Proteins

描述（由申请人提供）：寄生蠕虫在世界许多地方仍然是一个重大的公共卫生问题。蠕虫感染超过20亿人，可降低儿童的身体和认知发育，导致相当高的发病率，并阻碍流行地区的社会经济发展。新的潜在药物靶点的鉴定和表征是必要的，因为已经确定了耐药性的例子。此外，开发更广谱的靶点和药物将是极其宝贵的。一个有趣的潜在靶点是寄生虫翻译起始因子eIF 4 E。eIF 4 E识别mRNA帽，是翻译中的关键和限速步骤。脊椎动物宿主eIF 4 E对单甲基鸟苷真核帽高度特异，并且这是脊椎动物mRNA上存在的唯一帽。相比之下，我们已经表明，蛔虫和EIF 4 Es的三甲基和单甲基鸟苷帽具有相似的亲和力。因此，寄生蠕虫eIF 4 E具有独特的能力，识别三甲基鸟苷（TMG）帽相比，其脊椎动物eIF 4 E对应物。寄生蠕虫中的许多mRNA具有TMG帽。大约10%（蛔虫）到90%（蛔虫）的蠕虫mRNA通过一种特殊类型的剪接获得TMG帽，称为剪接前导RNA反式剪接。反式剪接产生mRNA的成熟5'末端并将特化的TMG帽添加到蠕虫mRNA。寄生蠕虫的所有主要群体都表现出剪接的前导序列反式剪接。TMG帽的识别对于蠕虫mRNA的翻译是必需的，并且eIF 4 E在C中是必需的。优雅为了了解蠕虫eIF 4 E识别TMG帽的生化和生物物理基础，我们建议对与TMG帽m2，2，7 GpppG结合的蠕虫eIF 4 E进行X射线晶体学和NMR研究。来自这些研究的信息将提供深入了解寄生虫eIF 4 E与TMG-帽结合的关键相互作用和机制。这些信息将有助于指导合理的诱变研究，以进一步确定重要的eIF 4 E-TMG帽相互作用。总体而言，这些研究将确定TMG帽识别的关键特征，这可能使未来的研究能够设计特定的帽类似物，以靶向广泛的重要蠕虫感染中存在的eIF 4 E的独特底物结合属性。公共卫生相关性：寄生蠕虫在世界许多地方仍然是一个重大的公共卫生问题，并阻碍了流行地区的社会经济发展。我们将对一种重要的寄生虫蛋白eIF 4 E进行结构分析，该蛋白对mRNA帽具有独特的底物特异性，以评估该蛋白作为对抗寄生蠕虫的新型和新型疗法的潜在靶点。

DESCRIPTION (provided by applicant): Parasitic helminths remain a significant public health problem in many parts of the world. Helminths infect over 2 billion people, can decrease physical and cognitive development in children, lead to considerable morbidity, and hinder socioeconomic development in endemic areas. The identification and characterization of new potential drug targets is warranted as examples of drug resistance have been identified. In addition, the development of broader spectrum targets and drugs would be extremely valuable. One intriguing potential target is the parasite translation initiation factor eIF4E. eIF4E recognizes the mRNA cap and is a key and rate-limiting step in translation. Vertebrate host eIF4E is highly specific for a monomethylguanosine eukaryotic cap, and this is the only cap present on vertebrate mRNAs. In contrast, we have shown that Ascaris and schistosome eIF4Es have similar affinities for both the trimethyl- and monomethylguanosine caps. Thus, parasitic helminth eIF4Es have the unique ability to recognize trimethylguanosine (TMG) caps compared with their vertebrate eIF4E counterparts. Many mRNAs in parasitic helminths have a TMG cap. Approximately 10% (schistosomes) to 90% (Ascaris) of helminth mRNAs acquire a TMG cap through a special type of splicing known as spliced leader RNA trans-splicing. Trans-splicing generates the mature 5' ends of mRNAs and adds the specialized TMG cap to helminth mRNAs. All major groups of parasitic helminths exhibit spliced leader trans-splicing. Recognition of the TMG cap is essential for translation of helminth mRNAs and eIF4E is essential in C. elegans. To understand the biochemical and biophysical basis for helminth eIF4E recognition of the TMG cap, we propose to carry out X-ray crystallography and NMR studies on helminth eIF4E bound to the TMG cap, m2,2,7GpppG. Information from these studies will provide insight into the key interactions and mechanism of TMG-cap binding by parasite eIF4E. This information will help direct rational mutagenesis studies to further define important eIF4E-TMG cap interactions. Overall, these studies will identify key features of TMG cap recognition that may enable future studies directed at designing specific cap analogs to target the unique substrate binding attributes of eIF4E present in a broad spectrum of important helminth infections. PUBLIC HEALTH RELEVANCE: Parasitic helminths remain a significant public health problem in many parts of the world and hinder socioeconomic development in endemic areas. We will carry out structural analyses of an essential parasite protein, eIF4E, with unique substrate specificity for the mRNA cap to evaluate this protein as a potential target for new and novel therapeutics against parasitic helminths.