Berlin 2012 – scientific programme

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BP: Fachverband Biologische Physik

BP 7: Posters: Proteins

BP 7.9: Poster

Monday, March 26, 2012, 17:30–19:30, Poster A

Ab initio Molecular Dynamics & NMR Spectra of Phycocyanobilin in the α-C-Phycocyanin binding pocket — •Hossam Elgabarty and Daniel Sebastiani — Freie Universität Berlin Fachbereich Physik Arnimallee 14 14195 Berlin

Biliproteins are ubiquitous photoreceptors. On exposure to red light the bound bilin chromophore exhibits a very quick photoisomerization within a few picoseconds [1]. Interactions between the bilin and its binding pocket play a crucial role in this process. We have performed ab-initio QM/MM molecular dynamics simulations of phycocyanobilin bound to the C-subunit of α-C-phycocyanin. Our results provide insight into the nature of the local interactions around the chromophore. Calculations of ¹⁴N and ¹H NMR shifts are in good agreement with experimental spectra and demonstrate that the chromophore is stably protonated in acccord with experimental findings [2]. Our results pave the way to further investigation of the photocycle by exploiting the sensitivity of NMR spectra to local environment [3].

1. Ulijasz, A. T., Vierstra, R. D. Curr. Opin. Plant Biol., 14, 498-506. (2011)
2. Hahn, J., Kühne, R., Schmieder, P. ChemBioChem, 8, 2249-55. (2007)
3. Elgabarty, H., Röben, M., Schmieder, P., Sebastiani, D. (Submitted)