A New Way to Get Protein Crystal Structures

We present a method, ‘MicroED’, for structure determination by electron crystallography. It should be widely applicable to both soluble and membrane proteins as long as small, well-ordered crystals can be obtained. We have shown that diffraction data at atomic resolution can be collected and a structure determined from crystals that are up to 6 orders of magnitude smaller in volume than those typically used for X-ray crystallography. For difficult targets such as membrane proteins and multi-protein complexes, screening often produces microcrystals that require a great deal of optimization before reaching the size required for X-ray crystallography. Sometimes such size optimization becomes an impassable barrier. Electron diffraction of microcrystals as described here offers an alternative, allowing this roadblock to be bypassed and data to be collected directly from the initial crystallization hits. X-ray diffraction is, of course, the usual way to determine crystal structures. Electrons can do the same thing for you, but practically speaking, that's been hard to realize in a general sense. Protein crystals don't stand up very well to electron beams, particularly if you crank up the intensity in order to see lots of diffraction spots. Electrons interact strongly with atoms, which is nice, because you don't need as big a sample to get diffraction, but they interact so strongly that things start falling apart pretty quickly. You can collect more data by zapping more crysta...
Source: In the Pipeline - Category: Chemists Tags: Analytical Chemistry Source Type: blogs