PROTEIN CRYSTALLIZATION WITH AND WITHOUT PRECIPITANTS

Crystals for X-ray structure analysis can be obtained from supersatura ted protein solutions using the vapour-diffusion technique. Added elec trolytes can act as competitors for water in the droplets as well as t o reduce the activity of water and decrease the water vaporization rat e. The water vaporization rate is critical for the protein crystalliza tion process. It is a function of the type of electrolyte used and can be altered when testing the influence of various electrolytes on prot ein crystallization. Here we present a new approach to controlling the water vaporization rate using a vacuum pump to lower the pressure dur ing the crystallization process. The successful application of the met hod for crystallization of adrenodoxin is described.