Amphiphiles modify the properties of detergent solutions used in crystallization of membrane proteins.

The effect of the amphiphile heptanetriol on the properties of solutions containing several detergents commonly used for crystallization of membrane proteins was characterized. The critical micelle concentration was found to be relatively unchanged by the presence of the amphiphile. In contrast, the addition of heptanetriol to solutions containing both detergent and polyethylene glycol exhibited significant shifts in the clouding behavior, with the largest shifts being for lauryl dimethylamine oxide. These results suggest that conditions favorable for crystallization of integral membrane proteins can be inferred from the properties of the detergents and amphiphiles.