title: Experimental determination of water equilibration rates in the hanging drop method of protein crystallization.
abstract: 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.
authors.affiliation: Laboratoire de Biochimie, IBMC du CNRS, Strasbourg, France.
authors.forename: V
authors.initials: V
authors.lastname: Mikol
authors.forename: J L
authors.initials: JL
authors.lastname: Rodeau
authors.forename: R
authors.initials: R
authors.lastname: Giegé
mesh_terms: D055598:Chemical Phenomena; D011232:Chemical Precipitation; D002627:Chemistry, Physical; D003460:Crystallization; D007700:Kinetics; D008956:Models, Chemical; D009113:Muramidase; D011506:Proteins; D014867:Water
chemical_list: D011506:Proteins; D014867:Water; D009113:Muramidase