Lysozyme Aggregation Studied by Light Scattering. I. Influence of Concentration and Nature of Electrolytes

Abstract

Static and dynamic light scattering have been employed to investigate the behaviour of lysozyme solutions when varying the concentration of (NH4)2SO 4 and NaC1 for screening the repulsive forces between the monomers. At the initial aggregation stages clusters, which can be classified as mass-fractals undergoing diffusion limitedlike aggregation, coexist with monomers or small lysozyme oligomers. The kinetics of fractal growth deliver observables that exhibit distinct tendencies when examined as a function of the concentration and nature of the electrolyte. The behaviour of the observables changes drastically above 0.84M (NH4)2SO 4 and 0.60M NaCl. Static light scattering revealed a progressive restructuring of the fractals to compact structures at the latter stages of the reaction. Based on the correlations between the various observables an attempt is made to predict the long-term fate of the nucleating solutions.

Light Scattering Studies of Hydration and Structural Transformations of Lysozyme

“…It follows from our measurements that for lysozyme in aqueous solution with zero concentration of ethanol the value of the hydrodynamic radius equals (1.856 ± 0.023) nm, which is in a good agreement with the results known from literature (e.g. 1.811 nm [22], 1.85 nm [25], 1.87 nm [24], 1.96 nm [27]). When the ethanol concentration reaches 9.91% (v/v), hydrodynamic radius increases up to (2.277 ± 0.020) nm.…”

Pre-assembled clusters distort crystal nucleation kinetics in supersaturated lysozyme solutions

“…Similar disagreement exists regarding the morphology and size of Biophysical Chemistry 129 (2007) 224 -234 http://www.elsevier.com/locate/biophyschem protein crystal nuclei. Using dynamic light scattering, Georgalis et al [22,23,42,46] reported large populations of amorphous lysozyme clusters in supersaturated solutions. Measurements by other investigators have not been able to confirm these findings [17,38,41].…”

Crystal nucleation as the ordering of multiple order parameters

“…In experiments, two-step pathways have been first considered in protein crystallization [82][83][84][85][86], most notably lysozyme, but were quickly observed also in colloidal systems [87,88]. Numerous examples of two-step crystallization from solutions has been reported in the last years, and several reviews have been written on the subject [89][90][91].…”