Regensburg 2010 – scientific programme

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DF: Fachverband Dielektrische Festkörper

DF 9: Focus Session: Structural dynamics in photoexcited molecules

DF 9.4: Topical Talk

Wednesday, March 24, 2010, 11:20–11:40, H11

Light induced conformational changes of retinal proteins — •Heinz-Jürgen Steinhoff — Universität Osnabrück, Osnabrück, Germany

Since the discovery of the light driven proton pump bacteriorhodopsin, the scope of microbial rhodopsins has been considerably extended in view of their functional properties as pumps, sensors, and channels. The structures of these membrane proteins are related, and, as we have shown by electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling, light induced isomerisation of the retinal chromophore initiates similar conformational changes in the protein scaffold of bacteriorhopodsin and sensory rhodopsin SRII. The light receptor SRII, in complex with the receptor specific transducer, HtrII, is responsible for the negative phototaxis of halobacteria. The talk focuses on time resolved EPR detection of light induced conformational changes of SRII, which reveals unique conformational rearrangements and uncovers the mechanism of the signal transfer from SRII to the associated transducer HtrII.