Biophysical approach for studying the MinD protein dynamics and energy landscape: A novel use of the spot tracking technique

Abstract

The dynamics of MinD proteins have been acknowledged as playing a central role in accurate cell division. In our study, a spot tracking technique (STT) was applied to track motion and quantitatively characterize the dynamic behavior of MinD proteins on the level of particle cluster in Escherichia coli. We focused on the time and spatial distribution of MinD proteins. With the STT technique, the main quantitative results are twofold: (i) dynamic local and global pattern formations and (ii) energy landscape. The overall MinD cl uster motion is governed by two dynamical time scales, namely the (slow) trapping time (∼26 s) that appears at the cell poles, and the (fast) switching time (∼1-2 s) which emerges between the cell poles. MinD cluster motion at the polar zones performs subdiffusion. The energy landscape is found to be two wells and one barrier. These energy landscape results are to relate with the memory effect of GFP-MinD cluster motion, measuring the PSD exponent approximately 1.57 (α ∼ 0.57) corresponding to the estimated potential depth U 0 ∼ 1.75k B T. © EDP Sciences, 2011.