MS04-05 - Micro Electron Diffraction is a Quick and Versatile Tool for Structure Determination of Macromolecules and Small Molecules

Alevtyna Yakushevska (Thermo Fisher Scientific)

X-ray crystallography experiments require large, well-ordered protein crystals for diffraction data collection.  Growing protein crystals  is  difficult,  requires  a  lot  of  time  and  effort  and  it  is sometimes even impossible. However, crystallization experiments quite often produce plenty of microcrystals which are too small for conventional X-ray diffraction experiments. Moreover, large protein  crystals  are  frequently  imperfect  and  often  suffer  from  different  defects  like  high mosaicity. Small  crystals  are  usually  not  affected  by  such  defects  and  may  yield  better  quality data. These kind of small crystals could be used for high-resolution structure determination by electron microscopy methods.

Cryo-transmission  electron  microscope  (cryo-TEM)anddiffraction  are  increasingly  powerful methods  for  the  analysis  of  biological  structures  at  near  atomic  resolution.However,  the  very strong interaction of electrons with matter limits the thickness of specimens that can be analyzed at  high  resolution,  by  the  current  implementations  of  these  methods,  to a  few hundreds of nanometers.To  efficiently  collect  MicroED  data,  software  automation,  dedicated  hardware components and customized optical setting can be installed on a cryo-TEM. Combined with the intrinsic microscope performance, we show that data collection is now fully automated and can be realized in a matter of minutes.