Single Particle Cryo-Electron Microscopy (cryo-EM) Single particle EM is a versatile technique to extract structural information of macromolecules by averaging a large number of molecules without growing crystals. Given the recent advances in the instrumentation and computation, 3D structures of macromolecular assemblies at as low as 200 kDa could be resolved to 20 - 3 Å resolution. This powerful technique could reveal different conformations of a macromolecule in multiple functional states.
Cryo-Electron Tomography (cryo-ET) Electron tomography is to obtain a 3D structure by reconstructing series of tilt images acquired of a single object. The technique has extensive applications to visualize cellular structures or pleomorphic assemblies, such as HIV and influenza viruses. The resolution of the reconstruction could be further improved by averaging multiple sub-tomographic volumes containing structures of interest.
Mass Spectrometry Mass spectrometry is a valuable technique to determine the mass of the molecule at high accuracy and sensitivity. Coupled with chemical cross-linking and hydrogen/deuterium exchange techniques, it provides residue or peptide specific information regarding protein-protein interactions, conformational changes and structural dynamics.