Spatially filtered images of B. subtilisα-amylase crystals

SUMMARY Microcrystals of B. subtilis α‐amylase have been negatively stained and examined by electron microscopy. The micrographs were then subjected to spatial filtering and averaging using a Fourier transform procedure programmed for a mini computer. From these ‘enhanced’ images refined crystallographic parameters were obtained and a model for the packing of the asymmetric units within the crystal was derived. In addition, these parameters...