Microscope for crystallization trials

我们实验室有兴趣了解细菌如何利用蛋白质来摄取必需的和稀缺的营养铁。例如，致病菌需要铁元素才能在被感染的宿主体内存活。如果这些细菌不能从环境中获得足够的铁，它们就会饿死。为了获得铁，细菌制造一种叫做铁载体的分子，这种分子分泌到环境中来清除铁。大约有12种蛋白质在大肠杆菌中被鉴定为合成和分泌铁载体所必需的。我们的研究包括表征这些蛋白质以及它们如何相互作用。我们认为，它们的作用以一种类似网络的方式协调，以确保铁载体的有效合成和分泌。我们将描述参与铁载体生物合成和分泌的蛋白质的三维结构。为了做到这一点，我们将纯化蛋白质并尝试使它们结晶。然后我们可以用x射线通过测量x射线被晶体衍射的方式来确定蛋白质的结构。由于蛋白质晶体非常小（一般在10-500微米大小），我们需要使用强大的显微镜来监测我们的晶体在实验室的生长。我们还需要一个设备，将平面偏振光通过晶体，因为蛋白质晶体暴露在偏振光下会改变颜色。这将使我们能够评估蛋白质晶体的质量。最后，一个数字摄影记录系统将使我们能够监测我们的结晶试验的进展。

Our laboratory is interested in learning how bacteria use proteins to uptake the essential and scarce nutrient iron. Pathogenic bacteria, for example, require iron for survival in infected hosts. If these bacteria cannot obtain enough iron from their environment, they will starve. To obtain iron, bacteria make molecules called siderophores, which are secreted into the environment to scavenge iron. About a dozen proteins have been identified in the bacterium E. coli as being necessary to synthesize and secrete siderophores. Our research involves characterizing these proteins and how they interact with each other. We believe that their action is coordinated in a network-like arrangement to make sure that siderophores are efficiently synthesized and secreted. We will characterize the three-dimensional structures of proteins involved in siderophore biosynthesis and secretion. To do this, we will purify the proteins and attempt to crystallize them. We can then use X-rays to determine the structures of the proteins by measuring how the X-rays are diffracted by the crystal. Since protein crystals are very small (generally 10-500 microns in size), we need to use a powerful microscope to monitor the growth of our crystals in the laboratory. We also need a device that will plane-polarize light through the crystal since protein crystals change colour when exposed to polarized light. This will allow us to assess the qualities of our protein crystals. Finally, a digital photodocumentation system will allow us to monitor the progress of our crystallization trials.