LASER MICHELSON INTERFEROMETRY INVESTIGATION OF PROTEIN CRYSTAL-GROWTH

Laser Michelson interferometry was applied to study the elementary gro wth mechanism of protein crystals. The results for the (101) face of t etragonal lysozyme show that for supersaturations sigma higher than 1. 6, growth proceeds by two-dimensional nucleation. However, at lower su persaturations growth is governed by dislocation sources. The observed non-linearity of the step velocity versus supersaturation dependence for supersaturations up to 1.2 is proved to be due to strong impurity effects. At sigma < 0.4 the crystal surface is covered with macrosteps . The effective step kinetic coefficient for the studied face is deter mined: beta = 2.8 x 10(-6) m/s. The applicability of general crystal g rowth principles and theories to protein crystallization is thus illus trated.