Fig. 4
From: An evolutionary optimization of a rhodopsin-based phototrophic metabolism in Escherichia coli
Light-driven proton pumping in the E. coli strains expressing GR. The ancestral E. coli cells expressing GR and ET5 evolved from the ancestral cells were suspended in an unbuffered saline solution, and proton pumping was estimated by measuring the pH decrease after 60-s illumination. Bar graph represents the proton pumping as mean ± SD from at least three measurements, and the line-scattered graph indicates the pH traces during the measurement (Closed bar/circle ancestral strain, Open bar/circle ET5)