Measurement and control of the crystal growth rate of tetragonal hen egg-white lysozyme imaged with an atomic force microscope

The step velocity of the tetragonal hen egg-white lysozyme (110)crystal pla ne toward the [001] direction could be controlled and measured accurately o n a nanometer scale using a specially designed sealed sample vessel on an a tomic force microscope. The effects of lysozyme and NaCl concentration on t he step velocity were also examined. The step velocity was a non-linear fun ction of supersaturation (sigma). The heights of steps and 2D islands corre sponded to a bimolecular layer and the dominant growth unit was estimated a s a tetramer. Crystal growth apparently stopped when the supersaturation wa s reduced to less than 0.69. (C) 2000 Elsevier Science B.V. All rights rese rved.