The structures of about 100 proteins have been determined since the 6 A structure of myoglobin was reported in 1958. The isomorphous replacement method was mainly used in order to determine the phase angle of each reflection, and the anomalous dispersion effect was also utilized in the recent analysis. The rotation function method and the direct method may be useful, when the molecule is rather large. The refinement procedures, real space ref inemet and energy refinement, were recently developed and were applied to several protein structures.
Development of electron interference microscope is reviewed in relation to the structure of the electron bi-prism, which is indispensable to the instrument. As one of many possible applications of the electron interference microscopy, measurement of mean inner potential is described.