Ordering of Fractal Clusters in Crystallizing Lysozyme Solutions

Abstract

The cluster formation in nucleating hen egg white lysozyme−NaCl solutions was studied by simultaneous static and dynamic light scattering. Angular dependence measurements of the total scattered intensity and of the average cluster diffusion coefficient revealed the appearance of pronounced structure factor peaks at the initial nucleation stages. Such peaks are characteristic for the ordering often observed in highly concentrated colloidal suspensions. Free-energy minimizations of 4−60 particles, that adequately model the lysozyme monomer, were performed by using the effective interaction potentials described in previous work (Soumpasis; Georgalis Biophys. J. 1997, 72, 2770). Both experiment and computations show formation of clusters with fractal morphology, compatible with the findings of the present and previous works.