Quantitative Crystal Structure Analysis In The Electron Microscope

Electron crystallography is a term which has emerged in the past few years to describe the quantitative structure analysis of microcrystalline preparations in the electron microscope. The field represents the confluence of two techniques, i.e. the ultramicroscopic capabilities of the electron microscope coupled with analytical techniques long in use by X-ray crystallographers. In the area of organic materials, the most visible success of the technique to date has been in the structure analysis of thin protein microcrystals typically to ca20 Å resolution but sometimes out to e.g. 7 Å and, in this field, there has been considerable effort by an increasing number of laboratories.Although the electron crystallography of small organic molecules and linear polymers has a much longer history than the application to globular proteins, one cannot cite an overwhelming enthusiasm for this technique, despite its promise as a probe for molecules which are not easily crystallized to sample sizes useful for single crystal X-ray diffraction measurements.