Structure and function of ClpXP

ClpXP的结构和功能

• 批准号: 10373109
• 负责人: Robert T Sauer
• 金额: $ 38.78万
• 依托单位: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
• 依托单位国家: 美国
• 财政年份: 2021
• 资助国家: 美国
• 起止时间: 2021-04-01 至 2026-03-31
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/10373109
• 关键词: ATP Hydrolysis; ATP phosphohydrolase; ATP-Dependent Proteases; Address; Antibiotics; Basic Science; Biochemical; Biotechnology; C-terminal; Cell physiology; Cells; Coupled; Defect; Disease; Ensure; Enzymes; Escherichia coli; Family; Goals; Growth; Health Promotion; Infertility; Light; Mammals; Mechanics; Medicine; Mitochondria; Molecular; Mycobacterium tuberculosis; N-terminal; Pathogenesis; Peptide Hydrolases; Play; Positioning Attribute; Proteins; Role; Specificity; Structure; Time; Work; experimental study; hearing impairment; heme biosynthesis; polypeptide; prevent; protein degradation; protein folding

Project Summary AAA+ proteases remove toxic proteins and regulate many other important cellular processes that promote health and prevent disease. At the same time, protein degradation must be carefully regulated. AAA+ proteases assemble into multi-subunit structures with an internal proteolytic chamber, accessible through narrow channels that exclude natively folded proteins. This mechanism protects most proteins from unintended degradation and requires specific substrates to be recognized, unfolded, and then translocated into the degradation chamber. In the AAA+ ClpXP protease, for example, a ring hexamer of ClpX uses the energy of ATP hydrolysis to unfold specific target proteins and translocate them into ClpP for degradation. ClpXP is one of the best-characterized AAA+ proteases and is a paradigm for other ATP- dependent proteases and AAA+ remodeling machines. These ATP-fueled enzymes perform a wide variety of mechanical remodeling, transport, and regulatory tasks in the cell. In mammals, loss of mitochondrial ClpP results in infertility, hearing loss, and growth defects, whereas mitochondrial ClpX plays an important role in heme biosynthesis. Bacterial ClpXP can promote pathogenesis and is a validated antibiotic target in M. tuberculosis. Substantial progress has been made in understanding the general biochemical and structural features of E. coli ClpXP and other AAA+ enzymes but important and fundamental questions concerning the molecular mechanisms of these machines remain. For example, it is not known how ClpX identifies many classes of N-terminal and C-terminal degrons, whether ClpX rotates with respect to ClpP during normal function, whether proofreading helps ensure degradation specificity, how multiple substrate chains can be simultaneously translocated through the ClpX channel, what the detailed and interacts with polypeptide substrates during mechanical unfolding, whether ATP hydrolysis can occur at multiple positions in the spiral ClpX ring or only at one or a few special positions, and how the detailed ATPase cycle is coupled to mechanical work. The experiments described in this proposal will address these questions and provide a conceptual framework applicable to studies of the entire superfamily of AAA+ machines.

项目摘要 AAA+蛋白酶清除有毒蛋白质并调节许多其他重要的细胞过程 促进健康和预防疾病。与此同时，蛋白质降解必须 仔细监管。AAA+蛋白酶组装成多亚基结构， 蛋白水解室，可通过排除天然折叠蛋白的狭窄通道进入。 这种机制保护大多数蛋白质免于意外降解，并需要特定的 将待识别的衬底展开，然后转移到降解室中。在 AAA+ ClpXP蛋白酶，例如ClpX的环状六聚体，使用ATP的能量 水解解折叠特异性靶蛋白，并将其转位到ClpP中进行降解。 ClpXP是最具特征的AAA+蛋白酶之一，是其他ATP- 依赖蛋白酶和AAA+重塑机器。这些以ATP为燃料的酶 细胞中各种各样的机械重塑、运输和调节任务。在哺乳动物中， 线粒体ClpP的缺失导致不育、听力损失和生长缺陷，而 线粒体ClpX在血红素生物合成中起重要作用。细菌ClpXP可以促进 致病机制，是M.结核实质性进展 对E.大肠杆菌ClpXP 和其他AAA+酶，但重要的和基本的问题， 这些机器的机械结构仍然存在。例如，不知道ClpX如何识别许多 N-末端和C-末端降解决定子的类别，ClpX是否相对于ClpP旋转 在正常功能期间，校正是否有助于确保降解特异性，如何 多个底物链可以同时通过ClpX通道移位， 在机械解折叠过程中， ATP水解可以发生在螺旋ClpX环中的多个位置或仅发生在一个或几个位置 特殊的位置，以及详细的ATP酶循环如何与机械功相结合。的 本提案中描述的实验将解决这些问题，并提供一个概念性的 该框架适用于整个AAA+机器超家族的研究。