Crystallization, Structural Determination and Structure Modeling Sample Preparation

Protein Sample Requirements for Crystallization Trials

• Pure protein as assessed by SDS-PAGE.
• Homogeneous.
• A reproducible source of several milligrams of the pure protein.
• The protein should be at an optimal concentration, in the range of 10-40mg/ml, as determined in a precrystallization trial by the crystallization unit. The salt concentration should be as low as possible, the buffer concentration should be 20-50mM, at a pH close to neutral, and potassium should be avoided if possible.
• For each of 96 crystallization conditions (one plate regardless of the crystallization method used) 25μl of protein is needed. 150μl of protein is needed for initial screening.