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Computational Modeling Reveals the Mechanism of Fluorescent State Recovery in the Reversibly Photoswitchable Protein Dreiklang

submitted on 24.07.2019 and posted on 26.07.2019 by Bella Grigorenko, Igor Polyakov, Anna I. Krylov, Alexander Nemukhin

The unique properties of the photoswitchable protein Dreiklang are attributed to a reversible hydration/dehydration reaction at the imidazolinone ring of the chromophore. Recovery of the fluorescent state, which is associated with a chemical reaction of chromophore dehydration, is an important part of the photocycle of this protein. Here we characterize the fluorescent (ON) and non-fluorescent (OFF) states of Dreiklang and simulate the thermal recovery reaction OFF → ON using computational approaches. By using molecular modeling methods including the quantum mechanics/molecular mechanics (QM/MM) technique, we characterize the structures and spectra of the ON- and OFF-states. The results are consistent with relevant experimental data. The computed reaction profile explains the observed recovery reaction and clarifies the mechanism of chemical transformations in the chromophore-containing pocket in Dreiklang.


Russian Science Foundation 17-13-01051

U.S. National Science Foundation CHE-1856342


Email Address of Submitting Author


Lomonosov Moscow State University


Russian Federation

ORCID For Submitting Author


Declaration of Conflict of Interest

No conflict of interest