CTF DETERMINATION OF IMAGES OF ICE-EMBEDDED SINGLE PARTICLES USING A GRAPHICS INTERFACE

We implement a graphical user interface in an X-window/UNIX environmen t to compute and display the incoherently averaged Fourier transforms of electron images of single particles embedded in ice and the simulat ed contrast transfer function with or without envelope functions. This interface provides an easy and efficient operation for the determinat ion of defocus value and the evaluation of the extent of Fourier ampli tude falloff. This computational procedure is crucial for prescreening image data and performing image correction of contrast transfer funct ion in high-resolution three-dimensional reconstruction of single part icles. (C) 1996 Academic Press, Inc.