Single - particle cryoelectron microscopy (cryoEM) is now able to provide structures of macromolecular assemblies to resolutions approaching 3 Å, sufficient to allow the polypeptide chain fold to be traced in a number of cases. (cen.xraycrystals.org)
As an introduction to electron microscopy I can highly recommend Transmission Electron Microscopy by Ludwig Reimer and Helmut Kohl and Three - Dimensional Electron Microscopy of Macromolecular Assemblies: Visualization of Biological Molecules in Their Native State by Joachim Frank. (ulrikeboehm.org)
(Collaborative Computational Project, Number 4) a collection of programs and associated data and software libraries used for macromolecular structure determination by X-ray crystallography. (sbgrid.org)