Assembly of human ATP synthase

人 ATP 合酶的组装

• 批准号: MR/V009672/1
• 负责人: John Walker
• 金额: $ 107.24万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FV009672%2F1
• 关键词: Assembly; human; ATP; synthase

Energy from the food we ingest is broken down by oxidative processes in our bodies. The net effect is to generate potential energy in the form of a voltage across the inner membranes of the mitochondria. The mitochondria are the cellular power-houses that generate the fuel required to provide the energy for biological processes such as muscular action, thought processes and replicating DNA and proteins. The fuel is provided in the form of the molecule adenosine triphosphate, known simply as ATP. Every day, each one of us generates 50-60 kg of ATP in the mitochondria of our cells to sustain our bodily activities. The ATP is produced in the mitochondria by millions of copies of a tiny molecular machine with a rotary action known as ATP synthase. The mitochondria are surrounded by two biological membranes and the ATP synthases are embedded in the inner one, with their synthetic heads pointing towards the inside making them resemble tiny mushrooms. In the membrane embedded region of the ATP synthase, the voltage across the membrane makes a rotor turn at about 100-200 rotations every second. The rotor is attached to a robust stalk which penetrates into the catalytic head, and the rotation of the stalk recombines spent fuel elements to form new ATP which is released into the mitochondria. The head and a static structure are joined by a second protein linkage called the peripheral stalk, which is required to prevent the head and rotor turning together. From the mitochondrion, the ATP is distributed around the cell by transport processes and, after release of energy from ATP, the spent fuel in the form of the molecules adenosine diphosphate (ADP) and inorganic phosphate is brought back to the mitochondria to be recombined into new ATP molecules. The rotary machines are both complex and fragile. They need to be put together when the mitochondria are made, and replaced when they break down. They are made from 29 proteins of 18 different kinds. The instructions for making all but two of these proteins resides in the cellular nucleus, and these proteins are made outside the mitochondrion and then imported to the inside. Here they are assembled into the ATP synthases together with the two other proteins that are made inside the mitochondrion with instructions from a small DNA molecule that resides there. We are studying how these complicated machines are assembled. We have discovered that the proteins are first assembled into specific preformed modules and then joined together to make the complete machine, rather like the simpler components of a car are assembled into the engine, gear-box and other modules before being made into the complete vehicle. The ATP synthase modules correspond to the catalytic head, the membrane part of the rotor and the peripheral stalk. The assembly of the membrane part of the rotor and that catalytic head require other proteins that are not part of the finished machines to help in the assembly process. We are studying the properties of these factors, partly because human mutations in at least two of them leads to disease. Finally, the completed machines pair up, linked together in their membrane domains, with the heads at about 90 degrees to each other, and the pairs associate into long rows and help give the inner membranes of the mitochondria their characteristic invaginated appearance. We want to know more about how this happens.

我们摄入的食物中的能量被我们体内的氧化过程分解。净效应是以电压的形式在线粒体的内膜上产生势能。线粒体是细胞的能量库，可以产生为肌肉活动、思维过程以及DNA和蛋白质复制等生物过程提供能量所需的燃料。这种燃料以三磷酸腺苷分子的形式提供，简称ATP。每天，我们每个人在细胞的线粒体中产生50-60公斤的ATP，以维持我们的身体活动。线粒体中的ATP是由一个微小的分子机器的数百万个拷贝产生的，该分子机器具有旋转作用，称为ATP合成酶。线粒体被两层生物膜包围，ATP酶嵌入内层生物膜，它们的合成头指向内部，使它们看起来像小蘑菇。在ATP合成酶的膜嵌入区域，跨膜电压使转子每秒转动约100-200圈。转子连接到一个坚固的柄，该柄穿透到催化头中，并且柄的旋转重组乏燃料元件以形成新的ATP，该ATP被释放到线粒体中。头部和一个静止的结构是由第二个蛋白质连接称为外周柄，这是需要防止头部和转子一起转动。从线粒体开始，ATP通过运输过程分布在细胞周围，并且在ATP释放能量后，以分子二磷酸腺苷（ADP）和无机磷酸盐形式的废燃料被带回线粒体以重组成新的ATP分子。旋转机械既复杂又脆弱。当线粒体形成时，它们需要被放在一起，当它们分解时，它们需要被替换。它们由18种不同种类的29种蛋白质组成。制造这些蛋白质的指令除了两种之外都存在于细胞核中，这些蛋白质在细胞外被制造，然后被输入到细胞内。在这里，它们与其他两种蛋白质一起组装成ATP酶，这些蛋白质是在一个小的DNA分子的指导下在线粒体内产生的。我们正在研究这些复杂的机器是如何装配的。我们已经发现，蛋白质首先组装成特定的预制模块，然后连接在一起，使完整的机器，而不是像汽车的简单组件组装成发动机，变速箱和其他模块，然后才被制成完整的车辆。ATP合酶模块对应于催化头、转子的膜部分和外围柄。转子的膜部分和催化头的组装需要其他蛋白质来帮助组装过程，这些蛋白质不是成品机器的一部分。我们正在研究这些因子的特性，部分原因是其中至少两种因子的人类突变会导致疾病。最后，完成的机器配对，在它们的膜域中连接在一起，头部彼此成大约90度，成对的机器连接成长长的一排，帮助线粒体的内膜呈现出特征性的内陷外观。我们想知道更多关于这是如何发生的。