Oral Presentation 2014 International Biophysics Congress

CryoEM and CryoET studies of protein structure and dynamics (#24)

Steven Ludtke 1
  1. Baylor College of Medicine, Houston, TX, USA

In recent years, new technology has led to a significant increase in CryoEM structures at resolutions approaching those of X-ray crystallography (3-4 Å). Membrane proteins are generally much more difficult structural targets than their soluble counterparts, but their structures have also been improved significantly in recent years. An important advantage of these methods is the ability to study proteins in a time snapshot of their native or near-native conditions. Now that the underlying imaging technology is no longer the limiting factor, it has become clear that most proteins will encounter an inherent resolution limit related to their flexibility in the solution environment. While this can be frustrating from a traditional resolution-driven structural perspective, it is also a tremendous opportunity because it means the population dynamics of large molecules and assemblies can be directly studied. Similar improvements to CryoET (tomography) are now beginning to offer the ultimate goal in protein structure: direct imaging of macromolecular complexes within the cell. While the resolution of single particle CryoET remains substantially worse than traditional single particle CryoEM, it has also seen significant improvements due to the development of direct detectors and phase plates. These improvements now permit visualizing complexes and emergent phenomena with less than one third the mass previously possible, paving the way for visualizing many complex assemblies as they exist within the cell.