Abstract
ABSTRACT: In the protein crystallization process, a growth unit has two possible molecular pathways it can follow from solution
to the crystal bulk, namely, the process of direct incorporation from solution or the process of surface diffusion preceded by surface
adsorption. We use real time in situ atomic force microscopy to monitor the molecular processes that govern the crystallization of
the protein triosephosphate isomerase. With this technique, we study the step edge dynamics on a molecular scale. We conclude that
step reorganization as a result of line diffusion has a negligible effect on step dynamics. Therefore, step displacements are attributed
to the exchange of growth units with the surrounding phases, i.e., the terrace and the solution. Triosephosphate isomerase (TIM)
tetramers are identified to be the dominating growth units. From the statistics of molecular attachment and detachment from the
step, we conclude that the incorporation of growth units occurs through surface diffusion. Additionally, in the tested supersaturation
range, normal growth is dominated by the two-dimensional nucleation of triangular islands. The step edges of these islands have
equal step formation energy.
to the crystal bulk, namely, the process of direct incorporation from solution or the process of surface diffusion preceded by surface
adsorption. We use real time in situ atomic force microscopy to monitor the molecular processes that govern the crystallization of
the protein triosephosphate isomerase. With this technique, we study the step edge dynamics on a molecular scale. We conclude that
step reorganization as a result of line diffusion has a negligible effect on step dynamics. Therefore, step displacements are attributed
to the exchange of growth units with the surrounding phases, i.e., the terrace and the solution. Triosephosphate isomerase (TIM)
tetramers are identified to be the dominating growth units. From the statistics of molecular attachment and detachment from the
step, we conclude that the incorporation of growth units occurs through surface diffusion. Additionally, in the tested supersaturation
range, normal growth is dominated by the two-dimensional nucleation of triangular islands. The step edges of these islands have
equal step formation energy.
| Original language | English |
|---|---|
| Pages (from-to) | 1173-1180 |
| Number of pages | 8 |
| Journal | Crystal Growth and Design |
| Volume | 8 |
| Publication status | Published - 2008 |
Keywords
- protein crystallization