Preliminary results of fumarase structure determination by application of HVEM

Abstract

Glaeser and others have suggested that low-dose microscopy of thick, crystalline macromolecules might be more advantageously carried out at higher voltages. To investigate this, the HVEM has been constantly improved by redesign and modification of existing components in order to improve its reliability, stability, versatility, and ease of operation. This has been achieved by improvements in the camera, vacuum system, vibration reduction and installation of an image intensified TV camera with digital image memory; online PDP 11/23 computer for real time 2D FFT computations ; minimal exposure system ; digital fine control of focus, push button selection of five magnifications with independent control of C2; and design of a new cold stage for imaging of protein crystals. Further, a set of programs which provide for image analysis and processing, and synthesis of protein structures from electron micrographs of protein crystal arrays developed at Donner Laboratory, UC Berkeley, has now been implemented on a VAX 11/780 computer associated with the Astronony department at Madison.