Heidelberg 2015 – scientific programme

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MO: Fachverband Molekülphysik

MO 18: Biomolecules

MO 18.1: Invited Talk

Thursday, March 26, 2015, 11:00–11:30, PH/SR106

cis-trans Isomerization, Ion-Pumps and pH-Sensor: From Molecular Interactions to Biological Function — •Rolf Diller¹, Patrick Singer¹, Miriam Colindres¹, Philipp Alt¹, Ekkehard Neuhaus², and Tilman Lamparter³ — ¹TU Kaiserslautern, Germany — ²TU Kaiserslautern, Germany — ³KIT, Karlsruhe, Germany

Light sensing and photosynthesis are only the most prominent examples for quite many extremely important phenomena in biology that rely on photochemical reactions. In spite of their realization by a relatively small number of chromophores the great functional diversity is facilitated by fine tuned reaction control via balanced chromophore protein interaction. Besides their versatility in biology these systems can be used and adapted for artificial applications in medicine and biological research. This requires the detailed understanding of molecular processes on time scales from femtoseconds to seconds.

Here we focus on photoinduced cis-trans isomerization as fundamental reaction in retinal binding proteins (ion pumps, light sensing) and in bilin binding phytochromes (light sensing). Femtosecond time resolved UV/Vis and infrared vibrational spectroscopy is used to explore electronic and structural dynamics of the cofactor-protein moiety. We report on the ultrafast interaction of the isomerizing retinal chromophore with a water cluster in Bacteriorhodospin and on the biliverdin binding phytochrome Agp2 from A. tumefaciens that has been suggested to serve as light-based pH-sensor and exhibits unusual properties involving isomerization of the deprotonated chromphore.