2019 Volume 44 Issue 3 Pages 115-118
We present the aggregation effects of the precipitant chloride salts with different cations, namely KCl, MgCl2 and CaCl2, on hen egg-white lysozyme (HEWL) crystallization, characterized by forward static light scattering at small angles. The pre-crystalline HEWL solutions with the chloride salts exhibit non-integer power-law profiles of forward light scatterings, indicating formation of fractal aggregates. The fractal aggregates with a closely packed structure were formed in the solutions with the chloride salts under crystallization conditions. The crystallization ability ranking of the cations almost agrees with the Hofmeister series. CaCl2 presented the slowest crystal growth of HEWL, owing to the weakest effect of aggregation on HEWL among the chloride salts studied.