Practices in Data Management to Significantly Reduce Costs in Cryo-EM

Structure determination by cryo-electron microscopy (cryo-EM) relies on imaging a specimen consisting of macromolecular complexes embedded in a thin layer of glassy ice. Data collected at the microscope consists of thousands of two-dimensional projection images (micrographs) each depicting tens to hundreds of individual macromolecules. Frozen hydrated biological specimens are composed of weakly scattering elements and because of their sensitivity to radiation need to be imaged under low electron doses. As a consequence, the signal to noise ratio (SNR) of the images is extremely low. To overcome this limitation, thousands of two-dimensional projection images of the complex of interest are computationally aligned and combined to obtain a three-dimensional density map.