Schleicher, E. and Kowalczyk, R. M. and Kay, C. W. M. and Hegemann, Peter and Bacher, A. and Fischer, M. and Bittl, R. and Richter, G. and Weber, Stefan (2004) On the reaction mechanism of adduct formation in LOV domains of the plant blue-light receptor phototropin. JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 126 (35). pp. 11067-11076. ISSN 0002-7863,
Full text not available from this repository. (Request a copy)Abstract
The blue-light sensitive photoreceptor, phototropin, is a flavoprotein which regulates the phototropism response of higher plants. The photoinduced triplet state and the photoreactivity of the flavin-mononuclectide (FMN) cofactor in two LOV domains of Avena sativa, Adiantum capillus-veneris, and Chlamydomonas reinhardtii phototropin have been studied by time-resolved electron paramagnetic resonance (EPR) and UV-vis spectroscopy at low temperatures (T less than or equal to 80 K). Differences in the electronic structure of the FMN as reflected by altered zero-field splitting parameters of the triplet state could be correlated with changes in the amino acid composition of the binding pocket in wild-type LOV1 and LOV2 as well as in mutant LOV domains. Even at cryogenic temperatures, time-resolved EPR experiments indicate photoreactivity of the wild-type LOV domains, which was further characterized by UV-vis spectroscopy. Wild-type LOV1 and LOV2 were found to form an adduct between the FMN cofactor and the functional cysteine with a yield of 22% and 68%, respectively. The absorption maximum of the low-temperature photoproduct of wild-type LOV2 is red-shifted by about 15 nm as compared with the FMN C(4a)-cysteinyl adduct formed at room temperature. In light of these observations, we discuss a radical-pair reaction mechanism for the primary photoreaction in LOV domains.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | ELECTRON-PARAMAGNETIC-RESONANCE; ALGA CHLAMYDOMONAS-REINHARDTII; FLAVIN MONONUCLEOTIDE; TRIPLET-STATE; ARABIDOPSIS NPH1; FLASH-PHOTOLYSIS; PHOTORECEPTOR PHOTOTROPIN; CHLOROPLAST RELOCATION; ADIANTUM PHYTOCHROME3; STRUCTURAL-CHANGES; |
| Subjects: | 500 Science > 540 Chemistry & allied sciences |
| Divisions: | Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Biochemie I |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 28 Jun 2021 10:07 |
| Last Modified: | 28 Jun 2021 10:07 |
| URI: | https://pred.uni-regensburg.de/id/eprint/37193 |
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