Sadeghian, Keyarash and Bocola, Marco and Schuetz, Martin (2010) A QM/MM study on the fast photocycle of blue light using flavin photoreceptors in their light-adapted/active form. PHYSICAL CHEMISTRY CHEMICAL PHYSICS, 12 (31). pp. 8840-8846. ISSN 1463-9076, 1463-9084
Full text not available from this repository. (Request a copy)Abstract
Based on QM/MM calculations using a combination of time-dependent Hartree-Fock and coupled cluster response theory a mechanism is proposed for the photocycle of blue light using flavin (BLUF) domains in the signaling/light adapted conformation. In analogy to the dark-adapted form, a charge transfer state drives proton transfer from the highly conserved tyrosine residue to the flavin chromophore. The latter step is mediated by the adjacent glutamine residue, which, in the light adapted conformation, exists as its imidic tautomer. However, before the proton transfer is even halfway completed, a conical intersection seam between the charge transfer and ground state is reached. Two channels for the decay back to the initial light-adapted conformation are open, a rapid one leading directly through the funnel of the conical intersection, bypassing the formation of the biradical intermediate, and a slower one via the biradical intermediate. The mechanism as proposed here: (i) explains the very rapid photocycle; and (ii) confirms the concept of photoirreversibility, both of which have been experimentally observed for BLUF domains in their light-adapted conformations.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | DENSITY-FUNCTIONAL THEORY; INDUCED STRUCTURAL-CHANGES; TRANSFER EXCITED-STATES; SPECTROSCOPIC CHARACTERIZATION; PROTON-TRANSFER; FAD-PROTEIN; AB-INITIO; APPA; DOMAIN; RECEPTOR; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Chemistry and Pharmacy > Institut für Physikalische und Theoretische Chemie > Research Group Theoretical Chemistry > Prof. Dr. Martin Schütz |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 24 Aug 2020 08:00 |
| Last Modified: | 24 Aug 2020 08:00 |
| URI: | https://pred.uni-regensburg.de/id/eprint/25595 |
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