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new approaches for fresh perspectives on quinol/quinone oxidoreductases

对醌/醌氧化还原酶的新视角的新方法

基本信息

批准号：
BB/G009228/1
负责人：
Julea Butt
金额：
$ 42.74万
依托单位：
University of East Anglia
依托单位国家：
英国
项目类别：
Research Grant
财政年份：
2009
资助国家：
英国
起止时间：
2009 至无数据
项目状态：
已结题

来源：
https://gtr.ukri.org/projects?ref=BB%2FG009228%2F1
关键词：
new approaches fresh perspectives quinol

项目摘要

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.

所有的活细胞都被一层薄膜包围着，这层薄膜将细胞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。这些细胞器也被细胞膜与细胞的其余部分分开。这些薄膜含有许多蛋白质，这些蛋白质可以积极地运输化合物，如营养物质和盐，特别是穿过薄膜。因此，许多化合物的浓度在膜的内部与外部是不同的。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，比如光合作用和新陈代谢。其中一些蛋白质利用细胞“燃烧”糖和脂肪时形成的电子释放的能量，积极地“泵”质子穿过细胞膜。这些电子不能在细胞内自由流动，而是附着在“漂浮”在细胞膜上的小分子上。这些分子被称为醌或辅酶q。这项提议旨在开发一种新的工具，我们可以用它来研究位于膜上并与醌发生反应的蛋白质。为什么我们想要更多地了解这些蛋白质？这些蛋白质参与了许多重要的反应。例如，在细菌中，它们负责所有涉及氮和二氧化碳的反应，因此控制这些元素如何在我们的大气中循环。在人类中，类似的蛋白质参与了糖和脂肪的燃烧以及能量的产生；这些蛋白质一旦出现问题，我们就会生病。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。当我们在实验室中研究蛋白质和醌的结构和功能时，它们通常是从膜中取出的，因此这些蛋白质和醌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，在本提案中，我们的目标是开发一种新的工具，可以在膜的自然环境中研究膜蛋白和醌。为了实现这一目标，我们将首先在固体表面放置一个通常接受或向醌类化合物提供电子的“膜蛋白”。这种固体具有导电性（就像金属线一样），我们将仔细控制其表面的特性，这样就可以使电子进出蛋白质。然后我们在蛋白质上面放一层膜，这层膜将含有醌类。如果一切都像我们想象的那样进行，蛋白质就会给醌或从醌中获得电子。由于电子的传递只不过是电流，我们可以非常精确地测量这些电子从表面传递到蛋白质和进入醌（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，我们将进一步了解它们在天然膜内的功能。