Molecular principles of translation termination

描述（由申请人提供）：所有生物中的翻译都是由核糖体进行的，核糖体是最古老和普遍保守的分子机器之一。终止是蛋白质合成的最后一步，它确保表达的蛋白质具有相应开放阅读框严格定义的长度。这个关键步骤应该是准确和有效的，以防止可能对细胞有毒的截短或过长的多肽产物的积累。虽然大多数翻译步骤和相应的核糖体外因子（如延伸因子）在细菌和真核生物之间高度保守，但翻译的终止却不是。在人类中，早产与许多遗传疾病有关。这些独特的特征使终止成为开发药物的一个有希望的目标。对细菌翻译终止的详细了解可以为我们开发抗菌药物提供工具。阐明真核终止的分子机制对于设计或寻找针对与过早终止相关的人类神经系统疾病的治疗方法是必要的。在这个提议中，我们将深入了解细菌和真核生物终止的分子机制。在目的1中，我们将确定细菌70S核糖体终止的中间构象步骤的晶体结构。这将为了解细菌释放因子RF1和RF2如何实现显著的准确性提供见解。在Aim 2中，我们将研究真核生物80S核糖体的终止。在这里，必需的I类释放因子eRF1和II类释放因子eRF3参与其中，它们在结构上不同于它们在细菌中的对应物。在Aim 3中，我们将探索针对早产引起的疾病的新治疗途径。我们研究的长期目标是获得涉及翻译的关键细胞过程的详细机制见解，并为治疗方法的开发做出贡献。

DESCRIPTION (provided by applicant): Translation in all organisms is performed by the ribosome, one of the most ancient and universally conserved molecular machines. Termination is the last step of protein synthesis, which ensures that expressed proteins have lengths strictly defined by the corresponding open reading frames. This critical step should be accurate and efficient to prevent accumulation of truncated or overly long polypeptide products that can be toxic to cell. Whereas most steps of translation and corresponding extraribosomal factors (e.g. elongation factors) are highly conserved between bacteria and eukaryotes, the termination of translation is not. In human, premature termination is associated with a large number of genetic diseases. These unique features place termination as a promising target for development of drugs. A detailed understanding of bacterial translation termination may provide us with tools to develop antibacterial drugs. Elucidation of the molecular mechanism of eukaryotic termination is necessary to design or search for therapeutics to target human neurological diseases linked to premature termination. In this proposal, we will gain insights into molecular mechanisms of termination in both bacteria and eukaryotes. In Aim 1, we will determine crystal structures of intermediate conformational steps of termination on the bacterial 70S ribosome. This will provide insights into how a remarkable accuracy is achieved by bacterial release factors RF1 and RF2. In Aim 2, we will study termination on the eukaryotic 80S ribosome. Here, essential class I release factor eRF1 and class II release factor eRF3 are involved, which are structurally distinct from their bacterial counterparts. In Aim 3, we will explore new therapeutic routes against diseases caused by premature termination. The long-term goals of our studies are to gain detailed mechanistic insights into key cellular processes involving translation, and to contribute to therapeutics development.