Optical Diffraction and Spatial Filtering of Electron Micrographs of Biological Materials

摘要

Optical diffraction and spatial filtering methods have been used to determine the characteristics of periodic structures in many biological materials. The head shell of bacteriophage T4 was chosen for this study, since aberrations in the assembly of the shell due to mutation or changes in growth conditions lead to the formation of a variety of elongated tubular head forms. The lattice parameters of structures assembled at elevated growth temperatures by normal, wild-type T4 and by a mutant (regA) were analyzed using optical diffraction patterns obtained from electron micrographs. Spatial filtering procedures were used for the reconstruction of one-sided images to determine the characteristics of the head structures assembled under different growth conditions. (ERA citation 06:008206)