The human body is composed of a large number of proteins, each performing a task essential to the proper functioning of the body. Thus, to fully understand how the body works we must know the functions of all our bodily proteins. Knowledge of a protein s structure is often necessary to determine the protein s function. For this purpose x-ray diffraction is used, which requires the proteins to be present in their crystalline form. At present, the actual process of crystallization is poorly understood and crystallographers are forced to follow a set of recipes based on past experience and intuition.
Protein crystallization is the rate limiting step in the determination of a protein s structure.
Only 4000 structures of the approximately 50,000 human proteins have been solved. The aim of this project is to remove this very bottleneck in protein structure determination. The first step is the mapping of phase diagrams of various proteins as a function of temperature, ionic strength, and added polymer. The phase diagram of a typical protein with short range attraction has a metastable liquid-liquid line underlying a liquid crystal boundary referred to as a liquidus line. The theory predicts that if one can push the liquid-liquid phase up through the liquidus line, the nucleation rate of proteins would increase dramatically due to a decrease in the free energy of the nucleation barrier in the vicinity of the critical point.