Protein Structure Analysis and Validation with X-Ray Crystallography.

X-ray crystallography is the main technique for the determination of protein structures. About 85% of all protein structures known to date have been elucidated using X-ray crystallography. Knowledge of the three-dimensional structure of proteins can be used in various applications in biotechnology, biomedicine, drug design , and basic research and as a validation tool for protein modifications and ligand binding. Moreover, the requirement for pure, homogeneous, and stable protein solutions in crystallizations makes X-ray crystallography beneficial in other fields of protein research as well. Here, we describe the technique of X-ray protein crystallography and the steps involved for a successful three-dimensional crystal structure determination.