Scientific Tracks Abstracts: J Vaccines Vaccin
In Escherichia coli, the role of lacA, the third gene of the lactose operon, has remained an enigma. I suggest that its role is the consequence of the need for cells to have safety valves that protect them from the osmotic eff ect created by their permeases. Safety valves allow them to cope with the buildup of osmotic pressure under accidental transient conditions. Multidrug resistance (MDR) effl ux, thus named because of our anthropocentrism, is ubiquitous. Yet, the formation of simple leaks would result in futile infl ux/effl ux cycles. Versatile modifi cation enzymes with low sensitivity solve the problem if the modifi ed metabolite is the one exported by MDR permeases. Th is may account for the pervasive presence of acetyl transferases, such as LacA, associated to acetyl metabolite exporters. Th is scenario of constraints imposed by effi cient infl ux of metabolites provides us with a model that should be followed when constructing synthetic cells.