Frankfurt 2006 – wissenschaftliches Programm
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Q: Quantenoptik und Photonik
Q 60: Laserspektroskopie I
Q 60.6: Vortrag
Donnerstag, 16. März 2006, 12:25–12:40, HII
Absorption and Emission Spectroscopic Characterisation of Blue-light Receptor LOV1 - LOV2 Domain of Phot from Chlamydomonas reinhardtii — •Sang-Hun Song1, Bernhard Dick1, Peyman Zirak2, Alfons Penzkofer2, Tina Schiereis3, and Peter Hegemann3 — 1Institut für Physikalische und Theoretische Chemie, Universität Regensburg, 93053 Regensburg, Germany — 2Institut II - Experimentelle und Angewandte Physik, Universität Regensburg, Universitätstrasse 31, D-93053 Regensburg, Germany — 3Institut für Biologie, Experimentelle Biophysik, Humboldt-Universität zu Berlin, Invalidenstr.42, D-10115 Berlin, Germany
The combined wild-type LOV1 - LOV2 domain string with His-tag (abbreviated LOV1/2-His) of phot from the green alga Chlamydomonas reinhardtii is characterized by absorption and emission spectroscopy. Blue-light photo-excitation generates a non-fluorescent intermediate photoproduct (flavin-C(4a)-cysteinyl adduct with absorption peak at 390 nm). The fluorescence quantum yield of the dark adapted samples is approximately 0.15. After light exposure a bi-exponential absorption recovery is resolved with time constants of 30 s and 8.7 min. The quantum yield of photo-adduct formation is extracted from excitation intensity dependent absorption measurements. It changes from about 0.2 at low excitation intensity to about 0.1 at high excitation intensity. The behaviour of the combined wildtype LOV1 - LOV2 double domain is compared with the behaviour of the separate LOV1 and LOV2 domains.