Ultrafast photoconversion dynamics of the knotless phytochrome SynCph2

  • The family of phytochrome photoreceptors contains proteins with different domain architectures and spectral properties. Knotless phytochromes are one of the three main subgroups classified by their distinct lack of the PAS domain in their photosensory core module, which is in contrast to the canonical PAS-GAF-PHY array. Despite intensive research on the ultrafast photodynamics of phytochromes, little is known about the primary kinetics in knotless phytochromes. Here, we present the ultrafast Pr ⇆ Pfr photodynamics of SynCph2, the best-known knotless phytochrome. Our results show that the excited state lifetime of Pr* (~200 ps) is similar to bacteriophytochromes, but much longer than in most canonical phytochromes. We assign the slow Pr* kinetics to relaxation processes of the chromophore-binding pocket that controls the bilin chromophore’s isomerization step. The Pfr photoconversion dynamics starts with a faster excited state relaxation than in canonical phytochromes, but, despite the differences in the respective domain architectures, proceeds via similar ground state intermediate steps up to Meta-F. Based on our observations, we propose that the kinetic features and overall dynamics of the ultrafast photoreaction are determined to a great extent by the geometrical context (i.e., available space and flexibility) within the binding pocket, while the general reaction steps following the photoexcitation are most likely conserved among the red/far-red phytochromes.

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Author:Tobias Fischer, Luuk J. G. W. van Wilderen, Petra Gnau, Jens BredenbeckORCiD, Lars-Oliver Essen, Josef WachtveitlORCiDGND, Chavdar SlavovORCiDGND
URN:urn:nbn:de:hebis:30:3-633944
DOI:https://doi.org/10.3390/ijms221910690
ISSN:1422-0067
Parent Title (English):International journal of molecular sciences
Publisher:Molecular Diversity Preservation International
Place of publication:Basel
Document Type:Article
Language:English
Date of Publication (online):2021/10/02
Date of first Publication:2021/10/02
Publishing Institution:Universitätsbibliothek Johann Christian Senckenberg
Release Date:2022/01/25
Tag:photochemistry; photoisomerization; phytochromes; tetrapyrrole-binding photoreceptors; time-resolved spectroscopy
Volume:22
Issue:19, art. 10690
Page Number:15
First Page:1
Last Page:15
Note:
This research was funded by the Deutsche Forschungsgemeinschaft (WA 1850/4-3, ES152/21). J.B. thanks the Alexander von Humboldt Foundation for a Sofia Kovalevskaja Award and the Deutsche Forschungsgemeinschaft for funding (No. INST 161/722-1 FUGG).
HeBIS-PPN:490981690
Institutes:Biochemie, Chemie und Pharmazie
Dewey Decimal Classification:5 Naturwissenschaften und Mathematik / 54 Chemie / 540 Chemie und zugeordnete Wissenschaften
5 Naturwissenschaften und Mathematik / 57 Biowissenschaften; Biologie / 570 Biowissenschaften; Biologie
Sammlungen:Universitätspublikationen
Open-Access-Publikationsfonds:Biochemie, Chemie und Pharmazie
Licence (German):License LogoCreative Commons - Namensnennung 4.0