| Autor: |
Maia RNA; Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany., Ehrenberg D; Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany., Oldemeyer S; Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany., Knieps-Grünhagen E; Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany., Krauss U; Institut für Molekulare Enzymtechnologie, Heinrich-Heine-Universität Düsseldorf, Forschungszentrum Jülich, D-52426 Jülich, Germany.; Institute of Bio- and Geosciences (IBG-1): Biotechnology, Forschungszentrum Jülich, D-52426 Jülich, Germany., Heberle J; Experimental Molecular Biophysics, Department of Physics, Freie Universität Berlin, Arnimallee 14, 14195 Berlin, Germany. |
| Abstrakt: |
LOV (light oxygen voltage) proteins are photosensors ubiquitous to all domains of life. A variant of the short LOV protein from Dinoroseobacter shibae (DsLOV) exhibits an exceptionally fast photocycle. We performed time-resolved molecular spectroscopy on DsLOV-M49S and characterized the formation of the thio-adduct state with a covalent bond between the reactive cysteine (C72) and C 4a of the FMN. By use of a tunable quantum cascade laser, the weak absorption change of the vibrational band of S-H stretching vibration of C57 was resolved with a time resolution of 10 ns. Deprotonation of C72 proceeded with a time constant of 12 μs which tallies the rise of the thio-adduct state. These results provide valuable information for the mechanistic interpretation of light-induced structural changes in LOV domains, which involves the choreographed sequence of proton transfers, changes in electron density distributions, spin alterations of the latter, and transient bond formation and breakage. Such molecular insight will help develop new optogenetic tools based on flavin photoreceptors. |
