Enhancing Protein Crystallization under a Magnetic Field

Abstract

High-quality crystals are essential to ensure high-resolution structural information. Protein crystals are controlled by many factors, such as pH, temperature, and the ion concentration of crystalline solutions. We previously reported the development of a device dedicated to protein crystallization. In the current study, we have further modified and improved our device. Exposure to external magnetic field leads to alignment of the crystal toward a preferred direction depending on the magnetization energy. Each material has different magnetic susceptibilities depending on the individual direction of their unit crystal cells. One of the strategies to acquire a large crystal entails controlling the nucleation rate. Furthermore, exposure of a crystal to a magnetic field may lead to new morphologies by affecting the crystal volume, shape, and quality.

Practical techniques for protein crystallization: additive assistance and external field intensification

“…Some researchers argued that the suspending microcrystals supported by magnetic field are oriented and thus attach on the growing mother crystals in the same direction, by which some stacking faults and dislocations can be prevented, exhibiting a slightly better resolution and lower mosaicity. 84 Pareja-Rivera et al utilized Fig. 5 Schematic diagram of the effect of magnetic field on protein crystallization.…”

“…Some researchers argued that the suspending microcrystals supported by magnetic field are oriented and thus attach on the growing mother crystals in the same direction, by which some stacking faults and dislocations can be prevented, exhibiting a slightly better resolution and lower mosaicity. 84 Pareja-Rivera et al utilized magnetic field for controlling the crystal size and orientation of lysozyme and glucose isomerase, 85 less crystals were obtained with larger size and higher diffraction quality (shown in Fig. 5(d)).…”

Heterogeneous Nucleation in Protein Crystallization

“…Experimental studies on protein crystallization using high magnetic fields showed that the number of crystal nuclei decreases, the magnetic orientation of microcrystals decreases, the crystal growth rate is relatively slow, and the crystal dissolution rate decreases when compared with those under normal gravity conditions outside the magnetic field [ 89 , 90 ]. Song et al developed a small and portable device using a 200 mT magnetic field, which improved the nucleation rate, ensured the growth of large single crystals in a short time, and promoted the crystallization of various proteins [ 91 ].…”

Recent progress on strategies for the enhancement of crystal growth process

“…18. Ryu 72 studied the effect of a magnetic field on the crystallization process of HEWL and enoyl acyl carrier protein reductase (ENR). They found that the protein solution exposed to the magnetic field could produce more crystals with larger sizes and more regular morphology.…”