Electron Paramagnetic Resonance Spectroscopy on Flavin Cofactors in Blue-Light Receptors
Final Report Abstract
Paramagnetic states occur in all three classes of blue-light photoreceptors – light, oxygen, voltage (LOV) domains, blue-light using FAD (BLUF) sensory domains, and cryptochromes (CRY) as functional intermediates. In this project we have identified and characterized shortlived and metastable paramagnetic species in BLUF domains and CRY proteins using electron paramagnetic resonance (EPR) spectroscopy on isolated protein and under in cell conditions. On the isolated proteins we found in BLUF domains as well as in CRY proteins an astonishing variability of electron transfer pathways upon amino acid replacements. The in cell studies on CRY proteins provided important evidence for the assignment of the semireduced radical FAD state as the light-induced signaling state and allowed the distinction between plant CRY protein with the neutral FADH• and animal CRY proteins with the anionic FAD–• as light-induced intermediates, respectively.
Publications
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Cryptochrome blue-light photoreceptors are activated through interconversion of flavin redox states. Journal of Biological Chemistry 282 (2007) 9383-9391
J.-P. Bouly, E. Schleicher, M. Dionisio-Sese, F. Vandenbussche, D. Van Der Straeten, N. Bakrim, S. Meier, A. Batschauer, P. Galland, R. Bittl, M. Ahmad
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The Signaling State of Arabidopsis Cryptochrome 2 contains Flavin Semiquinone. Journal of Biological Chemistry 282 (2007) 14916-14922
R. Banerjee, E. Schleicher, S. Meier, R. Muñoz Viana, R. Pokorny, M. Ahmad, R. Bittl, A. Batschauer
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Human and Drosophila cryptochromes are light activated by flavin photoreduction in living cells. PLoS Biology 6 (2008) e160
N. Hoang, E. Schleicher, S. Kacprzak, J.P. Bouly, M. Picot, W. Wu, A. Berndt, E. Wolf, R. Bittl, M. Ahmad
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Direct observation of a photoinduced radical pair in a cryptochrome blue-light photoreceptor. Angewandte Chemie International Edition 48 (2009) 404-407
T. Biskup, E. Schleicher, A. Okafuji, G. Link, K. Hitomi, E.D. Getzoff, S. Weber
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Origin of light-induced spin-correlated radical pairs in cryptochrome. Journal of Physical Chemistry B 114 (2010) 14745–14754
S. Weber, T. Biskup, A. Okafuji, A. Marino, T. Berthold, G. Link, K. Hitomi, E.D. Getzoff, E. Schleicher, J.R. Norris
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The Electronic State of Flavoproteins: Investigations with Proton Electron–Nuclear Double Resonance. Applied Magnetic Resonance 37 (2010) 339-352
E. Schleicher, R. Wenzel, M. Ahmad, A. Batschauer, L.-O. Essen, K. Hitomi, E. D. Getzoff, R. Bittl, S. Weber, A. Okafuji
