This paper is part of the Proceedings of the 12th International Conference on Retinal Proteins held at Awaji Island, Hyogo, Japan on 4–8 June 2006.
Analysis of Light-Induced Conformational Changes of Natronomonas pharaonis Sensory Rhodopsin II by Time Resolved Electron Paramagnetic Resonance Spectroscopy†
Article first published online: 27 FEB 2007
Photochemistry and Photobiology
Volume 83, Issue 2, pages 263–272, March/April 2007
How to Cite
Bordignon, E., Klare, J. P., Holterhues, J., Martell, S., Krasnaberski, A., Engelhard, M. and Steinhoff, H.-J. (2007), Analysis of Light-Induced Conformational Changes of Natronomonas pharaonis Sensory Rhodopsin II by Time Resolved Electron Paramagnetic Resonance Spectroscopy. Photochemistry and Photobiology, 83: 263–272. doi: 10.1562/2006-07-05-RA-960
- Issue published online: 27 FEB 2007
- Article first published online: 27 FEB 2007
- Received 5 July 2006; accepted 29 August 2006; published online 7 September 2006
The nature and kinetics of the conformational changes leading to the activated state of NpSRII/NpHtrII157 were investigated by time-resolved electron paramagnetic resonance (TR-EPR) spectroscopy in combination with site-directed spin labeling (SDSL) on a series of spin labeled mutants of NpSRII. A structural rearrangement of the cytoplasmic moiety of NpSRII upon light activation was detected (helices B, C, F and G). The increase in distance between helices C and F in the M-trapped state of the complex observed in one double mutant is in line with the notion that an outward movement of helix F occurs upon receptor activation. The data obtained from the NpSRII/NpHtrII157 complex reconstituted in purple membrane lipids are compared with those obtained from the X-ray structure of the late M-state of the complex which shows some discrepancies. The results are discussed in the context also of other biophysical and EPR experimental evidences.