The Role of Oil in Protein Crystallization - Molecules: Nucleation, Aggregation and Crystallization - page 129

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The Role of Oil in Protein Crystallization
Naomi E. Chayen*
The crystal growth of proteins is a complicated process which is dependent on
numerous factors. This chapter highlights the unique contribution of oil as a
major parameter in protein crystallization. Oils are used in screening to find
initial crystallization conditions as well as for optimizing crystallization
by control of nucleation and growth. A variety of techniques using oils is
described.
Keywords: Crystallogenesis; nucleation; protein crystallization; solubility;
vapour diffusion; microbatch; oil.
Introduction
Searching for crystallization conditions for a new protein or any macro-
molecule has been compared with looking for a “needle in a haystack.”
Once a condition which looks promising for crystallization is obtained,
conditions can generally be optimized by making variations to the param-
eters (precipitant, pH, temperature, etc.) involved. However, there is gen-
erally no indication that one is close to crystallization conditions until the
first crystals are obtained. Consequently, crystallization breaks down nat-
urally into two phases: screening, where one tries to obtain crystals of any
description, and optimization, where one tries to improve the size and dif-
fraction-quality of the crystals (Chayen et al ., 1996).
*Department of BioMolecular Medicine, Division of Surgery, Oncology, Reproductive
Biology and Anaesthetics, Faculty of Medicine, Imperial College London, Sir Alexander
Fleming Building, London SW7 2AZ, UK. E-mail: [e-mail].