Abstract

Despite recent advances in electron cryomicroscopy (cryo-EM) and the atomic resolution afforded by modern aberration corrected electron optics, the structures of many proteins and macromolecular complexes cannot be determined by cryo-EM because the individual protein molecules move during electron irradiation. This blurs the images so they cannot be aligned with each other to calculate a 3D density map. I will discuss the types of physical movement at various length scales that occur in biological specimen during high-energy electron irradiation, and show how reducing this movement leads to improved micrographs and density maps. Our approach to the problem combines detailed study of the physical origins of specimen movement with re-engineering the specimen support to reduce this movement to below the resolution limit of the microscope. Further, I will discuss protein-surface interactions in the context of electron microscopy, which are critical to the successful determination of protein structures. The study, and ultimately the control of protein interactions with tailored surfaces designed for cryo-EM, may represent an important opportunity for the use of a near-field microscope.