Probing transmembrane domain connecting loops in 7TM receptors to understand function

我们的许多神经功能是通过存在于大脑中的受体蛋白（称为GPCR）控制的，因此，据估计，我们使用的所有药物中约有30%作用于这些受体，其中有800多种。GPCR控制的功能很多，一个受体可能参与许多反应。我们需要找出这些受体是如何工作的，据说这是当前结构生物学的主要挑战（Lagerstrom & Schioth，2008，Nature Reviews Drug Discovery，7，339-57）。为了帮助理解这一过程，由于最近的突破，现在有可能制造数量非常有限的GPCR，以便我们可以开始发现它们是如何工作的。我们已经能够用简单的E来表达其中的一些（少数）。大肠杆菌细胞和病毒细胞中的功能活性，使我们所做的任何工作与其在大脑中的功能有关。与许多这些受体一样，它们通过小分子的结合而被激活，尽管我们可以监测这种结合，但重要的方面是了解和研究蛋白质如何被激活，以及它如何将其信号发送给其他蛋白质并最终发送给细胞。缺失或难以获得的信息是对蛋白质的柔性或无序环的描述，这些环延伸到膜外并决定选择性和功能性信号传导。为了获得这些信息，我们将使用可以测量这些受体中纳米级（0.5- 8 nm +/- 0.01nm）距离的方法，以及灵活性的时间尺度（微秒-纳秒）。由于这种蛋白质通常位于膜中，它需要膜的一些脂质成分才能正常发挥作用，我们将在其发挥功能的自然环境中研究受体。来自这个尖端项目的所有信息将增加我们对它们如何工作的一般理解，并有助于未来的药物设计和疾病控制。

Many of our neurological functions are controlled through receptor proteins (called GPCRs) residing in the brain, and for this reason it has been estimated that about 30% of all drugs we use act on these receptors, of which there are more than 800. The functions controlled by GPCRs are numerous, and one receptor may be involved in many responses. We need to find out how these receptors work, and it has been said that this is the major challenge of current structural biology (Lagerstrom & Schioth, 2008, Nature Reviews Drug Discovery, 7, 339-57). To help in that process of understanding, and as a result of recent breakthroughs, it is now possible to make a very limited number of GPCRs so that we can start to discover how they function. We have been able to express some (a handful) of them in simple E. coli bacterial cells and in virus cells as functionally active to make any of the work we do relevant to its function in the brain. As with many of these receptors, they are activated by the binding of small molecules, and although we can monitor this binding, the important aspect is to understand and investigate how the protein is then activated and how it sends its signal to other proteins and then ultimately the cell. The information that is missing or difficult to obtain, is a description of the flexible or disordered loops of the proteins which extend beyond the membrane and determine selectivity and functional signalling. To obtain this information, we will use methods that can measure distances at the nanoscale (0.5-8nm +/- 0.01nm) in these receptors, as well as the time scale (in microseconds - nanoseconds) of the flexibility. Since this protein normally sits in a membrane, it needs some of the lipid components of the membrane to function properly, and we will investigate the receptor in its natural environment where it is functional. All the information from this cutting edge project will add to our general understanding of how they work, and help in future drug design and disease control when extended to other proteins.