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Ultrafast E to Z photoisomerization dynamics of the Cph1 phytochrome
Peter W Kim1, Jie Pan, Nathan C Rockwell
1Department of Chemistry, One Shields Ave, University of California, Davis, CA 95616, United States.
Abstract:
Femtosecond photodynamics of the reverse ( Pfr→ Pr) reaction of the red/far-red phytochrome Cph1 from Synechocystis were resolved with visible broadband transient absorption spectroscopy. Multi-phasic dynamics were resolved and separated via global target analysis into a fast-decaying (260 fs) excited-state population that bifurcates to generate the isomerized Lumi-F primary photoproduct and a non-isomerizing vibrationally excited ground state that relaxes back into the Pfr ground state on a 2.8-ps time scale. Relaxation on a 1-ms timescale results in the loss of red absorbing region, but not blue region, of Lumi-F, which indicates that formation of Pr occurs on slower timescales.
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