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Main Title: Photoinduced reaction mechanisms in prototypical and bathy phytochromes
Author(s): Fernández López, María
Dahl, Margarethe
Velázquez Escobar, Francisco
Bonomi, Hernán Ruy
Kraskov, Anastasia
Michael, Norbert
Mroginski, Maria Andrea
Scheerer, Patrick
Hildebrandt, Peter
Type: Article
Abstract: Phytochromes, found in plants, fungi, and bacteria, exploit light as a source of information to control physiological processes via photoswitching between two states of different physiological activity, i.e. a red-absorbing Pr and a far-red-absorbing Pfr state. Depending on the relative stability in the dark, bacterial phytochromes are divided into prototypical and bathy phytochromes, where the stable state is Pr and Pfr, respectively. In this work we studied representatives of these groups (prototypical Agp1 and bathy Agp2 from Agrobacterium fabrum) together with the bathy-like phytochrome XccBphP from Xanthomonas campestris by resonance Raman and IR difference spectroscopy. In all three phytochromes, the photoinduced conversions display the same mechanistic pattern as reflected by the chromophore structures in the various intermediate states. We also observed in each case the secondary structure transition of the tongue, which is presumably crucial for the function of phytochrome. The three phytochromes differ in details of the chromophore conformation in the various intermediates and the energetic barrier of their respective decay reactions. The specific protein environment in the chromophore pocket, which is most likely the origin for these small differences, also controls the proton transfer processes concomitant to the photoconversions. These proton translocations, which are tightly coupled to the structural transition of the tongue, presumably proceed via the same mechanism along the Pr → Pfr conversion whereas the reverse Pfr → Pr photoconversion includes different proton transfer pathways. Finally, classification of phytochromes in prototypical and bathy (or bathy-like) phytochromes is discussed in terms of molecular structure and mechanistic properties.
Subject(s): bathy phytochromes
photoinduced reaction mechanisms
prototypical phytochromes
physiological processes
Issue Date: 4-May-2022
Date Available: 20-May-2022
Language Code: en
DDC Class: 540 Chemie und zugeordnete Wissenschaften
Sponsor/Funder: DFG, 221545957, SFB 1078: Proteinfunktion durch Protonierungsdynamik
TU Berlin, Open-Access-Mittel – 2022
Journal Title: Physical Chemistry, Chemical Physics
Publisher: Royal Society of Chemistry
Volume: 24
Issue: 19
Publisher DOI: 10.1039/D2CP00020B
Page Start: 11967
Page End: 11978
EISSN: 1463-9084
ISSN: 1463-9076
TU Affiliation(s): Fak. 2 Mathematik und Naturwissenschaften » Inst. Chemie » FG Modellierung biomolekularer Systeme
Appears in Collections:Technische Universität Berlin » Publications

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