Fig. 1

Diagram of the proposed model for GR-GFP in E. coli BL21 (DE3). In the chemiosmotic coupling of E. coli, we hypothesized that the expression of Gloeobacter rhodopsin on the inner membrane could act as an additional source of proton gradient driven by light, thus promoting the proton motive force of ATP synthase. Also, the green fluorescence protein (GFP) was designed as a reporter gene for proper expression and folding of the fusion protein GF-GFP