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Updated: Aug 13, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Primary steps of the photoactive yellow protein: isolated chromophore dynamics and protein directed function
I-Ren Lee1, Wonchul Lee, Ahmed H Zewail
1Arthur Amos Noyes Laboratory of Chemical Physics, Laboratory for Molecular Sciences, California Institute of Technology, Pasadena, CA 91125, USA.
Abstract:
The cycle of the photoactive yellow protein (PYP) has been extensively studied, but the dynamics of the isolated chromophore responsible for transduction is unknown. Here, we present real-time observation of the dynamics of the negatively charged chromophore and detection of intermediates along the path of trans-to-cis isomerization using femtosecond mass selection/electron detachment techniques. The results show that the role of the protein environment is not in the first step of double-bond twisting (barrier crossing) but in directing efficient conversion to the cis-structure and in impeding radical formation within the protein.
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