Holzer, W. and Penzkofer, Alfons and Fuhrmann, M. and Hegemann, P. (2002) Spectroscopic characterization of flavin mononucleotide bound to the LOV1 domain of Phot1 from Chlamydomonas reinhardtii. PHOTOCHEMISTRY AND PHOTOBIOLOGY, 75 (5). pp. 479-487. ISSN 0031-8655
Full text not available from this repository. (Request a copy)Abstract
The absorption and emission behavior of flavin mononucleotide (FMN) in the light-, oxygen- and voItage-sensitive (LOV) domain LOV1 of the photoreceptor Phot1 from the green alga Chlanzydomonas reinhardtii was studied. The results from the wild-type (LOV1-NN'T) were compared with those from a mutant in which cysteine 57 was replaced by serine (LOV1-C57S), and with free FMN in aqueous solution. A fluorescence quantum yield of phi(F) = 0.30 and a fluorescence lifetime of tau(F) = 4.6 ns were determined for FMN in the mutant LOV1-C57S, whereas these quantities are reduced to about phi(F) = 0.17 and tau(F) = 2.9 ns for LOV1-WT, indicating an enhanced intersystem crossing in LOV1-WT because of the adjacent sulfur of C57. A single-exponential fluorescence decay was observed in picosecond laser time-resolved fluorescence measurements for both LOV1-WT and LOV1-C57S as expected for excited singlet state relaxation by intersystem crossing and internal conversion. An excitation intensity dependent fluorescence signal saturation was observed in steady-state fluorescence measurements for LOV1-WT, which is thought to be because of the formation of a long-lived intermediate flavin-C(4a)-cysteinyl adduct in the triplet state (few microseconds triplet lifetime, adduct lifetime around 150 s). No photobleaching was observed for LOV1-C57S, because no thiol group is present in the vicinity of FMN for an adduct formation.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | LIGHT PHOTORECEPTOR PHOTOTROPIN; BLUE-LIGHT; MOLECULAR LUMINESCENCE; HIGHER-PLANTS; ISOALLOXAZINES; ABSORPTION; BEHAVIOR; PULSES; NPH1; NPL1; |
| Subjects: | 500 Science > 530 Physics 500 Science > 570 Life sciences |
| Divisions: | Physics > Institute of Experimental and Applied Physics > Alumni or Retired Professors > Group Alfons Penzkofer Biology, Preclinical Medicine > Institut für Biochemie, Genetik und Mikrobiologie > Lehrstuhl für Biochemie I |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 27 Oct 2021 14:49 |
| Last Modified: | 27 Oct 2021 14:49 |
| URI: | https://pred.uni-regensburg.de/id/eprint/40358 |
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