CLASSICAL NUCLEATION THEORY APPLIED TO THE HETEROGENOUS NUCLEATION OF PROTEIN CRYSTALS

摘要

Crystallisation is commonly employed in the separation and purification of proteins. However, some proteins are very difficult to crystallise. The high degree of supersaturation typically required for protein crystallisation results in relatively fast crystal growth during which impurities are likely to be incorporated in the crystal. Previous research has shown that mineral substrates have reduced the time for nucleation, which indicates a reduction in the supersaturation required for nucleation. In addition, an increase in the purity of lysozyme crystals grown by vapor diffusion has been correlated with close lattice matching to mineral substrates. In this paper, classical nucleation theory is applied to help interpret results of experiments involving lysozyme and carefully selected mineral substrates. Preliminary results are presented studying the effect of the mineral’s surface chemistry as well as lattice matching on the induction time for nucleation investigated using video microscopy.