A Detailed View on the (Re)isomerization Dynamics in Microbial Rhodopsins Using Complementary Near-UV and IR Readouts
Marvin Asido1,2, Gerrit H U Lamm1, Jonas Lienert1
1Institute of Physical and Theoretical Chemistry, Goethe University Frankfurt, Max-von-Laue Straße 7, 60438, Frankfurt (Main), Germany.
Angewandte Chemie (International Ed. in English)
|November 11, 2024
Summary
Microbial rhodopsins use photoisomerization for function. Near-UV and mid-IR spectroscopy reveal retinal changes and ion interactions, detailing photocycle dynamics.
Area of Science:
- Biophysical Chemistry
- Spectroscopy
- Photochemistry
Background:
- Isomerization of retinal is central to microbial rhodopsin function.
- Understanding the dynamic interplay between protein structure and retinal relaxation is crucial.
- Chromophore-specific markers are needed for time-resolved spectral analysis.
Purpose of the Study:
- To investigate the dynamic interplay between protein structural changes and retinal thermal relaxation in microbial rhodopsins.
- To utilize near-UV and mid-IR spectroscopy for chromophore-specific probing.
- To analyze the photocycle dynamics of various microbial rhodopsin pumps (H+, Na+, Cl-).
Main Methods:
- Systematic time-resolved spectroscopic study.
- Utilized near-UV and mid-IR fingerprint regions.
- Investigated H+- (HsBR, (G)PR), Na+- (KR2, ErNaR), and Cl-- (NmHR) pumps.
Main Results:
- Near-UV spectroscopy effectively probes retinal configuration and transient ion binding.
- Mid-IR spectroscopy provides insights into the fingerprint region.
- Combined spectral analysis precisely describes retinal configurations throughout the photocycle.
Conclusions:
- The near-UV region is sensitive to retinal configuration and electrostatic environment, including ion binding.
- The combination of near-UV and mid-IR spectroscopy offers a powerful tool for detailed photocycle analysis.
- This approach allows precise, time-resolved characterization of chromophore-charge interactions and protein dynamics.
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