The sensor contains different domains: • ε subunit of the bacterial FoF1 ATPase from Bacillus spec. • superfolder circularly permutated GFP (cpsfGFP (reporter fluorophore) from Aequorea victoria) • LSSmApple (reference fluorophore) from Discosoma sp. and is constructed as: 1–39 N-Terminal 10xHis, T7tag, enterokinase site/XpressTag, 40–147 εFoF1-N-terminus of B. subtilis, 148–151 PASH Linker, 152–240 cpsfGFP-C-terminus, 241–243 GGT Linker, 244–478 LSSmApple, 479–481 GGS Linker, 482–625 cpsfGFP-N-terminus, 626–629 FNNP Linker, 630–708 εFoF1-N-terminus of B. PS3-C-terminus.