Proton-Coupled Electron Transfer Constitutes the Photoactivation Mechanism of the Plant Photoreceptor UVR8
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- 作者：Tilo Mathes ; Monika Heilmann ; Anjali Pandit ; Jingyi Zhu ; Janneke Ravensbergen ; Miroslav Kloz ; Yinan Fu ; Brian O. Smith ; John M. Christie ; Gareth I. Jenkins ; John T. M. Kennis
- 刊名：Journal of the American Chemical Society
- 出版年：2015
- 出版时间：July 1, 2015
- 年：2015
- 卷：137
- 期：25
- 页码：8113-8120
- 全文大小：491K
- ISSN：1520-5126
文摘
UVR8 is a novel UV-B photoreceptor that regulates a range of plant responses and is already used as a versatile optogenetic tool. Instead of an exogenous chromophore, UVR8 uniquely employs tryptophan side chains to accomplish UV-B photoreception. UV-B absorption by homodimeric UVR8 induces monomerization and hence signaling, but the underlying photodynamic mechanisms are not known. Here, by using a combination of time-resolved fluorescence and absorption spectroscopy from femto- to microseconds, we provide the first experimental evidence for the UVR8 molecular signaling mechanism. The results indicate that tryptophan residues at the dimer interface engage in photoinduced proton coupled electron transfer reactions that induce monomerization.