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BP: Fachverband Biologische Physik

BP 15: Single-Molecule Biophysics I

BP 15.5: Talk

Tuesday, March 15, 2011, 11:45–12:00, ZEU 250

Single-molecule spectroscopy on pigment proteins and bio-nano hybrids — •Marc Brecht¹, Robert Bittl², Jana Nieder², and Martin Hussels¹ — ¹Universität Tübingen Institut für Physikalische und Theoretische Chemie Auf der Morgenstelle 18 72076 Tübingen — ²FU Berlin Fachbereich Physik Arnimallee 14 14195 Berlin

I will present low temperature single-molecule fluorescence experiments on photosystem I (PSI) and PSI coupled to nano structures. The spectra show even at low temperature changes of the fluorescence emission during time like line hopping, anti-correlated intensity fluctuation or line broadening. Those changes are due to small conformational changes within the binding site of the pigments [1]. The influence of metal-nanostructures on the fluorescence properties of photosystem I, serving as an example for a multi-chromophore FRET-coupled system, will be shown [2]. Beside fluorescence-enhancement significant changes of the characteristic fluorescence emission from PSI were observed. These changes indicate altered energy transfer within the multi-chromophore assembly affecting the functionality of this protein complex. The observed spectral changes are discussed in a general framework of plasmonic interaction with multi-chromophore systems.

[1] Brecht, M. Radics, V. Nieder, J.B. and Bittl, R. (2009), PNAS, 106 (29):11857-11861 [2] Nieder, J.B. Bittl, R. Brecht, M. (2010) Angewandte Chemie,dx.doi.org/10.1002/anie.201002172