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Mar 26, 2014
Study of the Photoactive Yellow Protein receptor by femtosecond circular dichroism

Motions of the carbonyl group of the Photoactive Yellow Protein (PYP) chromophore have been investigated, for the first time, by femtosecond time-resolved circular dichroism (tr-CD) spectroscopy, in the near-ultraviolet spectral region. The quantitative analysis of the tr-CD signals shows that, upon excitation, the carbonyl group undergoes a fast (≪0.8 ps) and unidirectional flipping motion in the excited state with an angle of ca. 17−53°. For the subset of proteins that do not enter the photocycle, tr-CD spectroscopy provides strong evidence that the carbonyl group moves back to its initial position, leading to the formation of a nonreactive ground-state intermediate of trans conformation. The initial ground state is then restored within ca. 3 ps.




Lucille Mendonça, François Hache, Pascale Changenet-Barret, Pascal Plaza, Haik Chosrowjan, Seiji Taniguchi, and Yasushi Imamoto

J. Am. Chem. Soc., 2013, 135 (39), pp 14637–14643

DOI: 10.1021/ja404503q

#2337 - Last update : 10/11 2018


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