Turbidity as a useful optical parameter to predict protein crystallization by dynamic light scattering

The aggregation behavior of several proteins in solution including the human apolipoproteins A-II and C-III, as well as concanavalin A, thaumatin, lysozyme and mexicain, is discussed based on dynamic light scattering techniques. According to our results, the estimation of parameters such as the geometrical factor (H) and turbidity (τ) under different environmental conditions, is a useful approach in order to elucidate if protein aggregation is carried out by either nucleation or random mechanisms. We conclude that dynamic light scattering, an accurate and non-destructive technique, can be used to determine either protein precrystallization parameters or crystallization conditions when both H and r are taken into account. (C) 2000 Elsevier Science B.V.