Microscope for crystallization trials

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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.