new approaches for fresh perspectives on quinol/quinone oxidoreductases

所有的活细胞都被一层薄膜所包围，这层薄膜将这些细胞的内部与周围环境隔离开来。在更高级的生物体中，细胞器位于细胞内，具有特定的功能。此外，这些细胞器通过膜与细胞的其余部分分开（区室化）。这些薄膜含有许多蛋白质，它们可以积极地运输化合物，如营养物质和盐，特别是穿过膜。因此，许多化合物的浓度在膜的内部与外部相比是不同的。这些梯度在生物学中起着至关重要的作用，细胞中的许多反应都依赖于它们，如光合作用和新陈代谢。这些蛋白质中的一些利用细胞“燃烧”糖和脂肪时形成的电子释放的能量主动地“泵”质子穿过细胞膜。这些电子不能在细胞中自由流动，而是附着在细胞膜上的小分子上。这些分子被称为醌或辅酶Q。该提案旨在开发一种新的工具，用于研究位于膜上并与醌反应的蛋白质。为什么我们要更多地了解这些蛋白质？这些蛋白质参与许多重要的反应。例如，在细菌中，它们负责所有涉及氮气和二氧化碳的反应，因此控制这些元素在我们大气中的循环。在人类中，类似的蛋白质参与糖和脂肪的燃烧以及能量的产生;这些蛋白质的任何问题都会使我们生病。最后，醌类本身是“抗氧化剂”，可以带走所谓的“自由基”，而自由基被认为在疾病和衰老中起着重要作用。当我们在实验室研究蛋白质和醌类化合物的结构和功能时，它们通常被带出细胞膜，因此这些蛋白质和醌类化合物的环境发生了很大的变化。这样做是因为膜不溶于水，我们的大多数实验都是在水中进行的;因此我们需要把膜拿走。然而，在这项提案中，我们的目标是开发一种新的工具，允许研究膜蛋白和醌在其自然环境中，膜。为了实现这一目标，我们将首先在固体表面上放置一种通常接受或给予醌电子的“膜蛋白”。这种固体是导电的（就像金属线一样），我们将仔细控制表面的性质，这样就可以向蛋白质提供电子或从蛋白质获取电子。然后我们将在蛋白质上放置一个膜，这个膜将包含醌。如果一切都像我们想象的那样工作，蛋白质将向醌类提供电子或从醌类获得电子。由于电子的转移只不过是电流，我们可以非常准确地测量这些电子从表面传递到蛋白质并进入醌（或相反）的速度。一旦这个系统完成，我们就可以使用这些表面来“询问”这些膜蛋白，它们在细胞中遇到的几乎相同的膜环境。通过研究这些蛋白质，我们将更多地了解它们在天然膜内的功能。

All living cells are surrounded by a thin membrane that shields and separates the inside of these cells from their surroundings. In more advanced organisms, organelles are located inside the cell with specific functions. Also these organelles are separated (compartmentalised) from the rest of the cell by membranes. These thin membranes contain many proteins that actively transport compounds, like nutrients and salt, specifically across the membrane. Consequently, the concentration of many compounds is different on the inside of the membrane compared to the outside. These gradients play a crucial role in biology and many reactions in the cell are dependent on them, like photosynthesis and metabolism. Some of these proteins actively 'pump' protons across the membrane using energy that is released from electrons that are formed when sugars and fats are 'burned' by the cell. These electrons do not flow freely in the cell, but are attached to small molecules which 'float' in the membranes of the cell. These molecules are called quinones or co-enzyme Q. This proposal aims to develop a new tool with which we can study the proteins that are located in the membrane and react with quinones. Why do we want to learn more about these proteins? These proteins are involved in many important reactions. For instance, in bacteria they are responsible for all reactions involving nitrogen and carbon dioxide and therefore control how these elements are recycled in our atmosphere. In humans, similar proteins are involved in the burning of sugars and fat and the production of energy; Any problems with these proteins and we become ill. Finally, quinones themselves are 'anti-oxidants' and known to take away so-called 'radicals' which are thought to play an important role in diseases and aging. When we study the structure and function of proteins and quinones in the lab, they are normally taken out of the membrane and thus the environment of these proteins and quinones is changed a great deal. This is done because membranes do not dissolve in water and most of our experiments are performed in water; we thus need to take the membrane away. However, in this proposal we aim to develop a new tool that allows the study of membrane proteins and the quinone in their natural environment, the membrane. For this to be achieved, we will first place a 'membrane protein' that normally receives or gives electrons to the quinones on a solid surface. This solid is conducting (like metal wires) and we will carefully control the properties of the surface so that it will be possible to give or take electrons to or from the protein. We will then place a membrane on top of the proteins and this membrane will contain quinones. If everything works as we think it will, the protein will give or take electrons to or from the quinones. As the transfer of electrons is nothing more than electrical current, we can measure very accurately how fast these electrons are passed from the surface to the proteins and into the quinones (or the other way around). Once this system is complete, we can use these surfaces to 'interrogate' these membrane proteins in almost the same membrane environment they encounter in the cell. By studying these proteins we will thus learn more about how they function inside their natural membrane.