I spent the day with Patrick Stewart. Not the actor, though both are from England. Patrick Shaw Stewart, to be more specific. He’s one of the founders of Douglas Instruments Ltd. and was here to show us the Oryx, a robot designed for automation of microseeding in crystallography. I had never done microseeding before, much less with a robot, so it was really exciting to experience.
In crystallography you have a tray which has several wells in it. In the bottom of these wells is a reservoir solution which contains a precipitant. In a hanging drop experiment, the wells are sealed by glass cover-slips (such as those for microscope slides), and a protein drop hangs from the bottom of the cover-slip. In a sitting drop experiment, the protein drop sits on a pedestal in the well, and the well is sealed with packaging tape or something similar. In both cases, the protein drop contains protein mixed with a small amount of reservoir solution, which causes the drop to have a lower concentration of precipitant than the reservoir solution in the bottom of the well. Water slowly leaves the protein drop to try to equalize the concentrations of precipitant in the bottom of the well and in the drop. Eventually protein crystals form in the drop. These crystals can diffract x-rays and the diffraction pattern can allow us to solve a structure of the protein. Check out Peter Nollert’s excellent blog on protein crystallography for more information.