Technical approaches of single particle analysis following electron microscopy to pre-screening biological candidates targeted on high resolution studies.

Electron microscopy is a successful application to structural studies in biological and material sciences. Last decades, state of the art technique, cryo-electron microscopy, has been solved detailed structures of many biological macromolecules at high resolution. Nevertheless, it is still regarded as a challenging approach with a low success rate and time-consuming process. Most problematic issue can be objects themselves adopting heterogeneous structures, not amenable to the high resolution studies. In this report, we introduce relatively quick techniques, combinations of single particle analysis and conventional electron microscopy, applicable to identify molecular states of target molecules at medium resolution. Introducing pre-screening techniques can be subjected to evaluation steps to choose best macromolecular candidate in prior cryo-electron microscopy. This report offer informative technical advances of the pre-screening techniques to those who are interested in structural biology on a basis of nano-, and bio-sciences.