LAUSR

Crystals are required to determine three-dimensional structures of proteins and other bio-molecules via X-ray diffraction. This is the prime cause for the keen interest in protein crystallization. Recently published experimental and theoretical studies on protein crystal nucleation and growth are reviewed, and the prospects of protein-based crystalline pharmaceuticals mass-production are considered. A new insight into protein crystal nucleation is presented from a physical perspective. It refers to modeling nuclei number density as a definite (curved) surface where each point has two coordinates, supersaturation and time. In doing so, theoretical S-shaped dependences of nuclei number densities on both supersaturation and time are found. These dependences are confirmed experimentally by plotting insulin crystal nucleation data. Growth of protein crystals of narrow size distribution is monitored to establish crystal polydispersity cause. Ostwald ripening is considered as a post-growth stage of the crystallization process.