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Updated: Apr 23, 2026

Proton Transfer and Protein Conformation Dynamics in Photosensitive Proteins by Time-resolved Step-scan Fourier-transform Infrared Spectroscopy
Published on: June 27, 2014
Light-induced switching of HAMP domain conformation and dynamics revealed by time-resolved EPR spectroscopy
Daniel Klose1, Natalia Voskoboynikova1, Ioan Orban-Glass1
1Department of Physics, University of Osnabrück, Barbarastr. 7, 49076 Osnabrück, Germany.
Abstract:
HAMP domains are widely abundant signaling modules. The putative mechanism of their function comprises switching between two distinct states. To unravel these conformational transitions, we apply site-directed spin labeling and time-resolved EPR spectroscopy to the phototactic receptor/transducer complex NpSRII/NpHtrII. We characterize the kinetic coupling of NpHtrII to NpSRII along with the activation period of the transducer and follow the transient conformational signal. The observed transient shift towards a more compact state of the HAMP domain upon light-activation agrees with structure-based calculations. It thereby validates the two modeled signaling states and integrates the domain's dynamics into the current model.
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