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Transient 2D IR Spectroscopy and Multiscale Simulations Reveal Vibrational Couplings in the Cyanobacteriochrome Slr1393-g3


Buhrke, David; Lahav, Yigal; Rao, Aditya; Ruf, Jeannette; Schapiro, Igor; Hamm, Peter (2023). Transient 2D IR Spectroscopy and Multiscale Simulations Reveal Vibrational Couplings in the Cyanobacteriochrome Slr1393-g3. Chemistry, 145(29):15766-15775.

Abstract

Cyanobacteriochromes are bistable photoreceptor proteins with desirable photochemical properties for biotechnological applications, such as optogenetics or fluorescence microscopy. Here, we investigate Slr1393-g3, a cyanobacteriochrome that reversibly photoswitches between a red-absorbing (Pr) and green-absorbing (Pg) form. We applied advanced IR spectroscopic methods to track the sequence of intermediates during the photocycle over many orders of magnitude in time. In the conversion from Pg to Pr, we have revealed a new intermediate with distinct spectroscopic features in the IR, which precedes Pr formation using transient IR spectroscopy. In addition, stationary and transient 2D IR experiments measured the vibrational couplings between different groups of the chromophore and the protein in these intermediate states, as well as their structural disorder. Anharmonic QM/MM calculations predict spectra in good agreement with experimental 2D IR spectra of the initial and final states of the photocycle. They facilitate the assignment of the IR spectra that serve as a basis for the interpretation of the spectroscopic results and suggest structural changes of the intermediates along the photocycle.

Abstract

Cyanobacteriochromes are bistable photoreceptor proteins with desirable photochemical properties for biotechnological applications, such as optogenetics or fluorescence microscopy. Here, we investigate Slr1393-g3, a cyanobacteriochrome that reversibly photoswitches between a red-absorbing (Pr) and green-absorbing (Pg) form. We applied advanced IR spectroscopic methods to track the sequence of intermediates during the photocycle over many orders of magnitude in time. In the conversion from Pg to Pr, we have revealed a new intermediate with distinct spectroscopic features in the IR, which precedes Pr formation using transient IR spectroscopy. In addition, stationary and transient 2D IR experiments measured the vibrational couplings between different groups of the chromophore and the protein in these intermediate states, as well as their structural disorder. Anharmonic QM/MM calculations predict spectra in good agreement with experimental 2D IR spectra of the initial and final states of the photocycle. They facilitate the assignment of the IR spectra that serve as a basis for the interpretation of the spectroscopic results and suggest structural changes of the intermediates along the photocycle.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:07 Faculty of Science > Department of Chemistry
Dewey Decimal Classification:540 Chemistry
Scopus Subject Areas:Physical Sciences > Catalysis
Physical Sciences > General Chemistry
Life Sciences > Biochemistry
Physical Sciences > Colloid and Surface Chemistry
Uncontrolled Keywords:Colloid and Surface Chemistry, Biochemistry, General Chemistry, Catalysis
Language:English
Date:14 July 2023
Deposited On:18 Feb 2024 15:30
Last Modified:30 Jun 2024 01:37
Publisher:Wiley-Blackwell Publishing, Inc.
ISSN:0947-6539
OA Status:Closed
Publisher DOI:https://doi.org/10.1021/jacs.3c00896
PubMed ID:37450891
Project Information:
  • : FunderSNSF
  • : Grant ID213507
  • : Project TitleLinking time-resolved structures and signal transduction within multi-domain photosensors