Electron imaging of crotoxin complex thin crystal at 3.5 A.

Crotoxin complex forms thin crystals which are suitable for electron crystallographic analysis. We have used a 100 kV electron microscope equipped with a superconducting lens to image this crystal embedded in glucose. Optical diffraction analysis of the micrographs show unambiguously a structural resolution of 3.9 A which has not been obtained with the conventional microscope at room temperature. A density map with a nominal resolution of 3.5 A has been synthesized from these images by computer processing techniques.