Affiliation: | a LCM3B, Groupe Biocristallographie, Université Henri Poincaré Nancy I, BP 239, 54506 Vandoeuvre lès Nancy Cedex, France b LMCP, Université Pierre et Marie Curie, Case 115, 4 Place Jussieu, 75252 Paris Cedex 05, France c LURE, Baiment 209D, Université Paris Sud, 91405 Orsay Cedex, France |
Abstract: | An external electric field affects the crystallization of proteins when applied under some conditions of temperature, pH, and precipitating agent composition. As suggested in the theoretical part of this paper, it produces large protein concentration gradients inside the mother liquor leading to a local supersaturation area in the crystallization solution. Such an experiment has been used for the first time on the crystallization of a protein. The effects of an external electric field on the crystallization of hen egg-white lysozyme at 293 K, pH 4.5, and two NaCl concentrations (0.6–0.7 M) have been investigated using the vapor diffusion method. The application of electric field results in a smaller number of crystals with larger size. The crystals grew at the droplet surface, near the cathode. The nucleation rate is drastically reduced and this experimental method could be used to control the number of crystals in the droplet. |