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Light‐induced switching of HAMP domain conformation and dynamics revealed by time‐resolved EPR spectroscopy
Author(s) -
Klose Daniel,
Voskoboynikova Natalia,
Orban-Glass Ioan,
Rickert Christian,
Engelhard Martin,
Klare Johann P.,
Steinhoff Heinz-Jürgen
Publication year - 2014
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/j.febslet.2014.09.012
Subject(s) - hamp , phototaxis , hamp domain , electron paramagnetic resonance , biophysics , conformational change , spectroscopy , chemistry , coiled coil , site directed spin labeling , time domain , transient (computer programming) , dynamics (music) , nuclear magnetic resonance , physics , biology , binding domain , computer science , biochemistry , binding site , hepcidin , botany , quantum mechanics , immunology , inflammation , acoustics , computer vision , operating system
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 Np SRII/ Np HtrII. We characterize the kinetic coupling of Np HtrII to Np SRII 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.