In the present work, we use complementary simulation tools as compared to Ref. to characterize the evolution of the system in the excited state. Namely, a combination of the cluster model and the QM/MM technique allowed us to explore the relief of the excited-state PES on the charge-transfer character, to find the relevant conical intersection points and to trace the evolution of the system on the way to the reaction product. Thus, the simulations described in the present work allow us to successfully complete the theoretical analysis and fully characterize the chain of transformations in Dreiklang after the illumination of its ON-state. In particular, the nature of the have been discovered . According to the author's suggestion, one of these proteins AausFP4 with the chromophore matured from the Ala65-Tyr66-Gly67 tripeptide shows a photochromic behavior similar to Dreiklang. Specifically, when expressed and/or stored in the dark, AausFP4