At the end, we comment on the importance of proton wires for biophysical properties of GFP-like proteins . Here, we draw an attention to the wires shown in Figs. . Besides the already mentioned wire connecting structures with the neutral and ionic forms of Chro, the wires connect the structures with the protonated and deprotonated forms of Glu222. We discussed above only the structures with the protonated side chain of Glu222 in the initial ON-state of the protein. Although this protonation state of Glu222 is supported by previous works , we cannot exclude the occurrence of the deprotonated Glu222 in some protein conformations. Wire-1 shown in Fig. may serve as a low-barrier proton translocation pathway from Oε1(Glu222) to Nδ(His145). Considering this scenario, we repeated SA-CASSCF calculations similar to those illustrated in Fig. , starting from the structure with the deprotonated (negatively charged) Glu222.