Conformational equilibrium of MinE regulates the allowable concentration ranges of a protein wave for cell division.

The Min system for determining the cell division position at the center in bacteria has a unique character that uses a protein wave (Min wave) emerged by its components (MinD and MinE). The Min wave emerges under the coupling of chemical reactions and molecular diffusions of MinDE and appears when the concentration of MinD and MinE are similar. However, the nanoscale mechanism to determine their concentration ranges remained elusive. In this study, by using artificial cells as a mimic of cells, we showed that the dominant MinE conformations determine the allowable concentration ranges for Min wave emergence. Furthermore, the deletion of the membrane-binding region of MinE indicated that the region is essential for limiting the concentration ranges narrower. These findings illustrate a parameter tuning mechanism underlying complex molecular systems at nanoscale for spatiotemporal regulation in living cells, and show a possibility that regulation of the equilibrium among molecular conformations can work as a switch for cell division.