Temperature plays an important role in crystal formation. The higher the temperature, the faster the molecules in the crystalline solution move, allowing them to evaporate more quickly and form crystals. This means that crystals grow faster in warmer temperatures due to the liquid containing the dissolved material evaporating quickly. The probability of nucleation and crystal growth is greater when the system is pushed into the region of supersaturation.
To investigate the influence of temperature, crystallization plates with identical crystallization conditions are often stored at different temperatures. It was observed that placing the crystallization plate on ice, cooling the tank solution (to approximately 277 K) and using pre-cooled pipette tips had a positive effect on the crystal shape and reduced the formation of precipitates. For several typical crystals from each crystallization experiment, diffraction images were recorded to test resolution. In these experiments, crystal growth stopped again after 2 days and the crystals remained stable for several weeks to months.
For the crystals obtained in the first, second and third crystallization experiments, the 95th percentile resolution of all the reflections in the best image was 3.83, 3.64 and 3.27 A, respectively. It is clear that temperature has a significant impact on crystal formation. By pre-cooling components such as tips, solutions and trays, it is possible to reduce supersaturation levels and improve crystal quality. Additionally, cooling tank solutions and using pre-cooled pipette tips can also help to improve crystal shape and reduce spontaneous protein precipitation.
