Metal-Assisted and Microwave-Accelerated Evaporative Crystallization: Proof-of-Principle Application to Proteins

Rapid crystallization of a model protein, i.e., lysozyme, on blank and silvered circular crystallization platforms with 21 sample capacity, using the metal-assisted and microwave-accelerated evaporative crystallization (MA-MAEC) technique is described. The effectiveness of the MA-MAEC technique for the crystallization of lysozyme was compared to the conventional crystallization technique (i.e., at room temperature without microwave heating) based on the following parameters: crystallization time, crystal size, crystal number, and crystal quality. Using silvered platforms, the growth of lysozyme crystals was concluded within 857 ± 31 min and 565 ± 64 min, at room temperature and using the MA-MAEC technique (microwave power level 1 or duty cycle of 3 s in a kitchen microwave oven), respectively. On blank platforms (silver is omitted), the growth of lysozyme crystals was concluded within 1190 ± 14 min and 955 ± 50 min, at room temperature and using microwave heating. The largest sizes of lysozyme crystals (200 ± 50 μm) were grown on silvered platforms and microwave heating at power level 1. In addition, superior intraplatform and interplatform repeatability of growth of lysozyme crystals was observed with silvered platforms and microwave heating at power level 1. Although the same well-defined tetragonal shapes of lysozyme crystals were observed at both room temperature and using the MA-MAEC technique, the quality of lysozyme crystals was found to slightly deteriorate with the use of microwave heating.