Title Red shift in the absorption spectrum of phototropin LOV1 upon the formation of a semiquinone radical: reconstructing the orbital architecture /
Authors Kurle-Tucholski, Patrick ; Wiebeler, Christian ; Köhler, Lisa ; Qin, Ruonan ; Zhao, Ziyue ; Šimėnas, Mantas ; Pöppl, Andreas ; Matysik, Jörg
DOI 10.1021/acs.jpcb.4c00397
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Is Part of Journal of physical chemistry B.. Washington : American Chemical Society. 2024, vol. 128, iss. 18, p. 4344-4353.. ISSN 1520-6106. eISSN 1520-5207
Keywords [eng] absorption ; carbohydrates ; chemical calculations ; electron paramagnetic resonance spectroscopy ; quantum mechanics
Abstract [eng] Flavin mononucleotide (FMN) is a ubiquitous blue-light pigment due to its ability to drive one- and two-electron transfer reactions. In both light-oxygen-voltage (LOV) domains of phototropin from the green algae Chlamydomonas reinhardtii, FMN is noncovalently bound. In the LOV1 cysteine-to-serine mutant (C57S), light-induced electron transfer from a nearby tryptophan occurs, and a transient spin-correlated radical pair (SCRP) is formed. Within this photocycle, nuclear hyperpolarization is created by the solid-state photochemically induced dynamic nuclear polarization (photo-CIDNP) effect. In a side reaction, a stable protonated semiquinone radical (FMNH·) forms undergoing a significant bathochromic shift of the first electronic transition from 445 to 591 nm. The incorporation of phototropin LOV1-C57S into an amorphous trehalose matrix, stabilizing the radical, allows for application of various magnetic resonance experiments at ambient temperatures, which are combined with quantum-chemical calculations. As a result, the bathochromic shift of the first absorption band is explained by lifting the degeneracy of the molecular orbital energy levels for electrons with alpha and beta spins in FMNH· due to the additional electron.
Published Washington : American Chemical Society
Type Journal article
Language English
Publication date 2024
CC license CC license description