Hannover 2016 – wissenschaftliches Programm
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MO: Fachverband Molekülphysik
MO 11: Posters 2: Novelties in Molecular Physics: Femtosecond Spectroscopy, Quantum Control, Electronic Spectroscopy, Biomolecules and Photochemistry
MO 11.5: Poster
Dienstag, 1. März 2016, 16:30–19:00, Empore Lichthof
Photoinduced processes of bilins in solution and as protein-bound cofactor — •Daniel Muschol1, Maximilian Theiss1, Patrick Singer1, Nicole Frankenberg-Dinkel2, Tilman Lamparter3, and Rolf Diller1 — 1Dept. of Physics — 2Dept. of Biology, Univ. Kaiserslautern, 67663 Kaiserslautern, Germany — 3Botanical Inst., Karlsruhe Inst. of Techn., 76131 Karlsruhe, Germany
Bilins are linear tetrapyrrols with rich and divers photochemistry in solution, involving C-C single- and double-bond isomerization of one or several of the pyrrole-pyrrole methine bridges. When bound as cofactor to plant phytochrome proteins they serve as chromophores for a photoinduced signal cascade enabling red-light sensing and a variety of essential biological processes, such as seed germination, shade avoidance and photomorphogenesis. In the bound form protein-chromophor interaction restricts the potentially possible degrees of freedom and guides the excited electronic state dynamics along a complex reaction coordinate involving both chromophore as well as protein contributions, including H-bond networks and protein bound water molecules. For a better understanding of these mechanisms for molecular reaction control we study the primary photochemistry of the bilins biliverdin (BV), phycocyanobilin (PCB) and bilirubin (BR) in solution and of the BV-binding bathy-phytrochromes Agp2 (Agrobacterium fabrum) and PaBphP (Pseudomonas aeruginosa) employing fs transient absorption in the UV/Vis and mid-IR spectral region. In particular, Agp2 shows strongly pH dependent primary reaction kinetics suggesting excited state proton transfer processes.