Spatial distributions and energy landscape of MinE protein dynamics via the biophysical spot tracking technique

The MinCDE protein system is known to dictate cytokinesis cell division in prokaryotes by spatial regulation of the Z-ring. The oscillatory dynamics of MinC and MinD depends on the presence of MinE, where the MinE protein dynamics acts as a topological specificity to the midcell. In this work, the Spot Tracking Technique is used to determine the biophysical quantities of MinE protein dynamics, namely, diffusive motion, velocity distribution, spatial distribution, and energy profile. An alternative quantity that indicates the potential of the mean force characteristic function is proposed to be an effective potential parameter to indicate the optimal energy to generate a stable spatial-temporal pattern formation of MinE proteins. The localization and distribution patterns along the cell length were well confirmed, while other quantitative information related to MinE cluster positions have been revealed. In addition, the effective potential was found to relate to the spring-like potential. The minimum region indicates the potential cluster depth that occurs near the midcell zone, which corresponds to the finding that the MinE cluster is mostly concentrated at midcell.