Abstract
The first part of this research was devoted to investigating the effect of alternate current (AC) using four different types of wave modes (pulse-wave) at 2 Hz on the crystal growth of lysozyme in solution. The best results, in terms of size and crystal quality, were obtained when protein crystals were grown under the influence of electric fields in a very specific wave mode (“breathing” wave), giving the highest resolution up to 1.34 Å in X-ray diffraction analysis compared with controls and with those crystals grown in gel. In the second part, we evaluated the effect of a strong magnetic field of 16.5 Tesla combined with radiofrequency pulses of 0.43 μs on the crystal growth in gels of tetragonal hen egg white (HEW) lysozyme. The lysozyme crystals grown, both in solution applying breathing-wave and in gel under the influence of this strong magnetic field with pulses of radio frequencies, produced the larger-in-size crystals and the highest resolution structures. Data processing and refinement statistics are very good in terms of the resolution, mosaicity and Wilson B factor obtained for each crystal. Besides, electron density maps show well-defined and distinctly separated atoms at several selected tryptophan residues for the crystal grown using the “breathing wave pulses”.
Highlights
The new trend in protein crystallography has been focused on finding new strategies to obtain crystals of different sizes for different bio-structural projects at very high resolution via X-ray diffraction, neutron diffraction, and recently using X-ray free electron lasers (XFEL)methods
There are other novel strategies and ad hoc devices that have been used in electric (DC & alternate current (AC)) [22,23,24,25,26,27,28,29,30] and ultrasonic fields [31] applied to protein crystallization techniques
The crystal growth cell used in these experiments for applying electric field (AC) in four types of wave modes was based on the batch method for proteins crystallization that we had previously published using direct current (DC), though with some modifications [16]
Summary
The new trend in protein crystallography has been focused on finding new strategies to obtain crystals of different sizes for different bio-structural projects at very high resolution via X-ray diffraction (powder and single-crystal), neutron diffraction, and recently using X-ray free electron lasers (XFEL)methods. Neutron crystallography is an emerging research area in which we can follow the details of precise mechanisms of chemical interactions and the new strategies for solving the structure of macromolecular complexes This is a powerful complementary technique for X-ray structural studies that explicitly determines the location and orientation of deuterium atoms in proteins [1,2,3,4,5]. The pioneering contributions about the use of electric fields applied to protein crystallization were proposed by Professor Christo Nanev and his group more than a decade ago [31,32,33] followed by a research on the kinetics of the process by Professor Aubry and his group [34,35]. These crystals would be suitable for high resolution
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
