Crystallization of Proteins: Principles and Methods - Molecules: Nucleation, Aggregation and Crystallization - page 118

phase diagram (Fig. 1). Although all methods aim at bringing the macro-
molecular solution to a supersaturated state, the means by which this is
achieved varies in each of these techniques.
The main techniques for protein crystallization include:
Batch crystallization
This is the oldest method used for crystallizing proteins. The sample is
directly mixed with the precipitant creating a homogeneous crystallization
medium requiring no equilibration with a reservoir as the supersaturation
is immediately reached (Fig. 2).
Over the years this method has been modified and is now carried out
using microlitre amounts of the protein in either glass capillaries or in
micro droplets under oil (Fig. 3).
Figure 4 shows protein crystals grown under oil.
Fig. 2. Macromolecular crystals grown using the oldest method of protein crystalliza-
tion, the batch method using millilitre volumes, where the samples are directly mixed with
each other.