Electron Microscopy of Thim Protein Crystals From Vapour Diffusion 'Hanging Drops' Provides Structural Information at Intermediate Resolution

摘要

Electron crystallography has emerged as a powerful method for the determination of molecular structures at intermediate to high spatial resolutions (3-20 A). Together with dircet imaging by high resolution electron micrscopy this techniqe provide an excellent tool for protein crystal analysis. However, application of these methods depends onthe availability of reltively lagrge (micrometre size), well-ordered and thin crystalline arrays of the protein molecules. One source of such crystals is that from vapour diffusion "hanging drops" which have been set up in order t grow crystals suitable for X-ray difraction. Crystals grown under these conditions are sometimes not suitable for X-ray analysis but when harvested onto an electron microscope grid prove to be sufficiently thin for analysis by electron microscopy.