Berlin 2018 – wissenschaftliches Programm

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BP: Fachverband Biologische Physik

BP 15: Postersession III

BP 15.46: Poster

Dienstag, 13. März 2018, 14:00–16:00, Poster B

Photoinduced processes of free bilins in solution: fs TA absorption spectroscopy on phycocyanobilin and biliverdin IXα — •Maximilian Theiß¹, Tilman Lamparter², Maria Andrea Mroginski³, and Rolf Diller¹ — ¹TU Kaiserslautern, D-67663 Kaiserslautern — ²Karlsruhe Inst. of Techn., D-76131 Karlsruhe — ³TU Berlin, D-10623 Berlin

Bilins are linear tetrapyrrols with rich photochemistry in solution (1,2), involving C-C single- and double-bond isomerization of one or several of the pyrrole methine bridges. When bound to proteins they serve as chromophore in plant-phytochromes, bacterial sensor proteins and in optogenetic systems (3). In the bound form protein-chromophor interaction restricts the potentially possible degrees of freedom (4). For a better understanding of the underlying mechanisms we study the primary photochemistry of the bilins phycocyanobilin (PCB) and biliverdin IXα (BV) in solution, employing fs transient absorption in the UV/Vis and mid-IR spectral region, complemented by quantum chemical calculations. In particular, both bilins show conformational changes, PCB additionally indicates alteration of protonation state via photoexcitation, which is consistent with previous studies (5).

(1) Falk. (2012) The chemistry of linear oligopyrroles

and bile pigments (Vol. 1). SSBM

(2) Carreira-Blanco et al. (2016) PCCP. 18:7148-7155

(3) Gasser et al. (2014) PNAS. 111.24: 8803-8808.

(4) Singer et al. (2016) CPC. 17:1288-1297

(5) Dietzek et al. (2011) CPL. 515:163-169