Investigations into Protein Crystallization in the Presence of a Strong Magnetic Field

Abstract

A new strategy is proposed for batch crystallization of proteins in solution-growth or gel-growth by using the batch method inside capillary tubes applying magnetic fields. Four proteins with differing proportions of R-helices and β-sheets and crystallized in five different crystallographic space groups are studied, allowing an analysis of the anisotropy of the diamagnetic susceptibility of the peptide bond as well as the polarity of the space groups in the presence of a strong magnetic field of 11.75 T. The crystal quality is shown to be improved by using a strong magnetic field to orient protein molecules, and gel-growth (high concentrations of agar) to control the transport phenomena as well as crystal growth. Some advantages to increase the crystal quality for crystals from marginal conditions for X-ray diffraction, and disadvantages of the use of solution-and gel-growth (low concentration of agar) in magnetic fields, and their plausible applications to high resolution X-ray crystallography are discussed.

Crystal Growth in Gels from the Mechanisms of Crystal Growth to Control of Polymorphism: New Trends on Theoretical and Experimental Aspects

“…Additionally, strong magnetic fields increase the viscosity of supersaturated solutions by reducing the convective transport phenomenon and thus modifying the diffusion phenomenon during biomacromolecules crystal nucleation and growth. A sufficient reduction of the convection could mimic microgravity conditions, therefore resulting in higher quality crystals [103][104][105][106].…”

Crystallization in Gels

“…Other types of gel applications are, for instance, polyacrylamide gels used as dialysis membranes [124][125][126]. Agarose gels have been used to control the transport processes in microgravity experiments for protein crystallization [14] and for the orientation of crystals in the presence of strong magnetic fields [50,127], as well as to grow membrane proteins [128,129] to crystallize biomacromolecular complexes, such as the Toll receptor of Drosophila melanogaster to obtain Liesegang-like patterns [45]. Agarose gels have been used to control the transport processes in microgravity experiments for protein crystallization [14] and for the orientation of crystals in the presence of strong magnetic fields [50,127], as well as to grow membrane proteins [128,129] to crystallize biomacromolecular complexes, such as the Toll receptor of Drosophila melanogaster to obtain Liesegang-like patterns [45].…”

Practical Physics Behind Growing Crystals of Biological Macromolecules

“…To overcome this problem and because primary nucleation is a stochastic phenomenon, seeding techniques are often used. However, some authors recently proposed unusual approaches using external fields to control crystallization from metastable solutions, for instance magnetic [28][29][30][31][32][33], [34][35][36][37][38][39][40][41] or electromagnetic [42][43][44][45][46][47][48][49][50][51]. Moreover, spatial and temporal location of nucleation can also be reached by confining the nucleation volume [52].…”