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Dual photoisomerization on distinct potential energy surfaces in a UV-absorbing rhodopsin
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SYSNO ASEP 0536453 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Dual photoisomerization on distinct potential energy surfaces in a UV-absorbing rhodopsin Author(s) Hontani, Y. (NL)
Broser, M. (DE)
Luck, M. (DE)
Weissenborn, J. (NL)
Kloz, Miroslav (FZU-D) ORCID
Hegemann, P. (DE)
Kennis, J.T.M. (NL)Number of authors 7 Source Title Journal of the American Chemical Society. - : American Chemical Society - ISSN 0002-7863
Roč. 142, č. 26 (2020), s. 11464-11473Number of pages 10 s. Language eng - English Country US - United States Keywords resolution optical spectroscopy ; stretching Raman lines ; all-trans ; resonance raman ; electronic excitations ; ultraviolet vision ; Schiff-bases ; femtosecond Subject RIV BO - Biophysics OECD category Biophysics Method of publishing Open access Institutional support FZU-D - RVO:68378271 UT WOS 000547329800018 EID SCOPUS 85087468750 DOI 10.1021/jacs.0c03229 Annotation UV-absorbing rhodopsins are essential for UV vision and sensing in all kingdoms of life. Unlike the well-known visible-absorbing rhodopsins, which bind a protonated retinal Schiff base for light absorption, UV-absorbing rhodopsins bind an unprotonated retinal Schiff base. Thus far, the photoreaction dynamics and mechanisms of UV-absorbing rhodopsins have remained essentially unknown. Here, we report the complete excited- and ground-state dynamics of the UV form of histidine kinase rhodopsin 1 (HKR1) from eukaryotic algae, using femtosecond stimulated Raman spectroscopy (FSRS) and transient absorption spectroscopy, covering time scales from femtoseconds to milliseconds. We found that energy-level ordering is inverted with respect to visible-absorbing rhodopsins, with an optically forbidden low-lying S-1 excited state that has Ag- symmetry and a higher-lying UV-absorbing S-2 state of Bu+ symmetry. UV-photoexcitation to the S-2 state elicits a unique dual-isomerization reaction: first, C13=C14 cis-trans isomerization occurs during S-2-S-1 evolution in <100 fs. This very fast reaction features the remarkable property that the newly formed isomer appears in the excited state rather than in the ground state. Second, C15=N16 anti-syn isomerization occurs on the S-1-S-0 evolution to the ground state in 4.8 ps. We detected two ground-state unprotonated retinal photoproducts, 13-trans/15-anti (all-trans) and 13-cis/15-syn, after relaxation to the ground state. These isomers become protonated in 58 mu s and 3.2 ms, respectively, resulting in formation of the blue-absorbing form of HKR1. Our results constitute a benchmark of UV-induced photochemistry of animal and microbial rhodopsins. Workplace Institute of Physics Contact Kristina Potocká, potocka@fzu.cz, Tel.: 220 318 579 Year of Publishing 2021 Electronic address http://hdl.handle.net/11104/0314228
Number of the records: 1