THE INFLUENCE OF TEMPERATURE ON THE DYNAMICS OF PROTEIN PRECRYSTALLIZATION CLUSTERS, STUDIED BY PHOTON-CORRELATION SPECTROSCOPY

Hen-egg white lysozyme was used for studying the influence of temperature on crystallization. The reaction was initiated at variable temperatures, covering the range between 5-50-degrees-C, and was monitored with photon correlation spectroscopy. When aggregation was induced by addition of NaCl, the clusters formed exhibited diffusion limited aggregation behavior and crystals appeared in less than two days. In contrast, (NH4)2SO4 induced aggregation took place mostly in the cross-over regime. In this case, solutions either remained transparent and void of crystals or formed gels within a few weeks. In both cases the kinetics could be dynamically scaled into master curves indicating that the precrystallization formed aggregates are fractals resulting from different collision processes.