Protein crystals are typically prepared by creating a supersaturated solution of the protein under controlled conditions.
Preparing protein crystals involves forming a supersaturated solution of the protein. This means dissolving the protein in a liquid medium at a concentration higher than its solubility limit under specific conditions.
To achieve this supersaturated state and induce crystallization, scientists add precipitants to the protein solution. Common examples of these precipitants mentioned in the reference include ammonium sulfate and polyethylene glycol. These substances help to reduce the solubility of the protein, forcing it out of solution in an organized, crystalline form rather than precipitating randomly.
Furthermore, this crystallization process can serve as an ultimate purification step. Since the resulting protein crystals are made up of a repeating array of a single protein molecule, the process effectively excludes impurities, leading to a highly pure sample.
