Experimental determination of water equilibration rates in the hanging drop method of protein crystallization.
The hanging drop method for protein crystallization consists of equilibrating a water droplet containing the protein and a precipitant against a reservoir solution at a higher precipitant concentration. The time for water equilibration--which affects the kinetics of crystallization--to reach 90% of completion is shown to vary between about 25 h and more than 25 days, depending on experimental conditions. Experiments were performed with three of the most widely used precipitants (ammonium sulfate, polyethylene glycol, 2-methyl-2,4-pentanediol), combining various parameters expected to affect the rate of water evaporation. The most dramatic effects were obtained when varying temperature and initial drop volume. A simple empirical equation for estimating the kinetics of water equilibration under given crystallization conditions is proposed.
Mikol
V
V
Laboratoire de Biochimie, IBMC du CNRS, Strasbourg, France.
Rodeau
J L
JL
Giegé
R
R
D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D003460:Crystallization; D007700:Kinetics; D008956:Models, Chemical; D009113:Muramidase; D011506:Proteins; D014867:Water
D011506:Proteins; D014867:Water; D009113:Muramidase