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Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Site-specific difference 2D-IR spectroscopy of bacteriorhodopsin.
Esben Ravn Andresen1, Peter Hamm
1Physikalisch-Chemisches Institut, Universitat Zurich, Winterthurerstrasse 190, 8057 Zurich, Switzerland.
The Journal of Physical Chemistry. B
|April 11, 2009
Summary
We extended difference Fourier transform infrared (FTIR) spectroscopy to 2D-IR spectroscopy. This method successfully isolated the all-trans retinal chromophore spectrum in bacteriorhodopsin, suppressing protein background noise.
Area of Science:
- Spectroscopy
- Biophysics
- Protein Dynamics
Background:
- Fourier transform infrared (FTIR) spectroscopy is a powerful tool for molecular analysis.
- 2D-IR spectroscopy provides detailed insights into molecular vibrations and dynamics.
- Bacteriorhodopsin is a crucial protein for studying light-driven proton pumping.
Purpose of the Study:
- To extend the principle of difference FTIR spectroscopy to difference 2D-IR spectroscopy.
- To measure the 2D-IR spectrum of the all-trans retinal chromophore within bacteriorhodopsin.
- To completely suppress the spectral background from the protein matrix.
Main Methods:
- Development and application of difference 2D-IR spectroscopy.
- Measurement of difference 2D-IR spectra of bacteriorhodopsin in its J- and K-intermediates.
- Comparison with static 2D-IR spectra of all-trans retinal protonated Schiff base.
Main Results:
- Successfully demonstrated the extension of difference spectroscopy to the 2D-IR domain.
- Obtained the 2D-IR spectrum of the all-trans retinal chromophore in bacteriorhodopsin.
- Achieved complete suppression of the protein background signal.
Conclusions:
- Difference 2D-IR spectroscopy is a viable technique for isolating chromophore spectra in complex systems.
- The method allows for detailed analysis of chromophore dynamics and interactions within proteins.
- Further models are discussed for interpreting the line shape of the difference 2D-IR spectrum.
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