ZB 10 - Soft Condensed Matter (R. Holyst)

Movement of proteins in an environment crowded by surfactant micelles: Anomalous versus normal diffusion

Author(s): Szymanski, J and Patkowski, A and Gapinski, J and Wilk, A and Holyst, R
Title: Movement of proteins in an environment crowded by surfactant micelles: Anomalous versus normal diffusion
Abstract: Small proteins move in crowded cell compartments by anomalous diffusion. many of them, e.g., the endoplasmic reticulum, the proteins move lipid membranes in the aqueous lumen. Molecular crowding in offers a systematic way to study anomalous and normal diffusion in well controlled environment not accessible in vivo. We prepared a environment in vitro consisting of hexaethylene glycol ether (C12E6) nonionic surfactant and water and observed diffusion between elongated micelles. We have fitted the data in fluorescence correlation spectroscopy using an anomalous model and a two-component normal diffusion model. For a small of surfactant (below 4 wt \%) the data can be fitted by normal diffusion. For larger concentrations the normal fit gave two components: one very slow and one fast. The of the slow component grows with C12E6 concentration. The of diffusion coefficients (slow to fast) is on the order of 0.1 all concentrations of surfactant in the solution. The fast diffusion due to free proteins while the slow one is due to the protein-micelle The protein-micelle interaction is weak since even in a concentrated solution (35\% of C12E6) the amplitude of the slow is only 10\%, despite the fact that the average distance between micelles is the same as the size of the protein. The anomalous model gave the anomality index (< r2(t)> similar to t(alpha)),
Pages: 7367-7373
Journal: JOURNAL OF PHYSICAL CHEMISTRY B
Volume: 110
ID: ISI:000236772900045
Year: 2006
DOI: 10.1021/jp055626w