Macromolecular crystallization: basics and advanced methodologies

Abstract

For the first time, about 155 years ago and as a laboratory curiosity, German biologists observed the crystals of hemoglobin from worms and fishes. Since then, the crystallization of proteins, nucleic acids and big biological structures, like viruses, has been developed into a broad research field including several applications, for example in the drug discovery. This review is divided into four major sections. The first section addresses the specific physicochemical properties of biomolecular crystals accompanied by kinetics of supersaturation, nucleation and growth which are the three main steps required to achieve macromolecular crystals. Besides, various physical, chemical and biochemical parameters influencing the process of macromolecular crystallization are reviewed. The second part deals with classical approaches, such as vapor and batch diffusion methods, available to create macromolecular crystals. The third part overviews novel approaches including microgravity, cocrystallization, membrane-assisted crystallization and microfluidic array chips involved in more complicated techniques for growing macromolecular crystals and controlling their size and orientation. In the end, considering the very significant role of automation in providing biomolecules’ crystals in recent years, we provided a brief explanation about robotics and their importance in developing high-throughput crystallization. RDC-NMR and SAXS/WAXS hybrid methods with the aim of obtaining structural information of complex macromolecular assemblies are also discussed.