Project B5

Spectroscopic investigations of proton transfer processes and hydrogen-bonded networks in bacterial phytochromes and channelrhodopsins

Principal Investigator: Prof. Dr. Franz Bartl (Charité)

The B5-project approaches an improved mechanistic understanding of the photocycle and the associated protonation dynamics of both channelrhodopsins and bacterial phytochromes. Difference spectroscopy in the infrared and the UV-visible range is directly combined in advanced static and time-resolved experiments with millisecond resolution at room and low temperatures. In wild-type and genetically modified proteins, the role of specific side chains for proton transfer processes occurring during the photocycle is investigated. In a collaborative effort, an understanding of the interplay between proton transfer processes and structural changes of the photoreceptors which are crucial for protein function is approached.

Publications 2013 - 2017

Kazmin, R., Rose, A., Szczepek, M., Elgeti, M., Ritter, E., Piechnick, R., Hofmann, K.P., Scheerer, P., Hildebrand, P.W., and Bartl, F.J. (2015). The Activation Pathway of Human Rhodopsin in Comparison to Bovine Rhodopsin. Journal of Biological Chemistry 290, 20117-20127.

Krause, B.S., Grimm, C., Kaufmann, J.C.D., Schneider, F., Sakmar, T.P., Bartl, F.J., and Hegemann, P. (2017). Complex Photochemistry within the Green-Absorbing Channelrhodopsin ReaChR. Biophysical Journal 112, 1166-1175.

Kuhne, J., Eisenhauer, K., Ritter, E., Hegemann, P., Gerwert, K., and Bartl, F. (2015). Early Formation of the Ion-Conducting Pore in Channelrhodopsin-2. Angewandte Chemie International Edition 54, 4953-4957.

Pyta, K., Przybylski, P., and Bartl, F. (2015). Regioselective Long-Range Proton Transfer in New Rifamycin Antibiotics: A Process in which Crown Ethers Act as Stronger Br circle divide nsted Bases than Amines. ChemPhysChem 16, 938-942.

Ritter, E., Piwowarski, P., Hegemann, P., and Bartl, F.J. (2013). Light-dark Adaptation of Channelrhodopsin C128T Mutant. Journal of Biological Chemistry 288, 10451-10458.

Salewski, J., Escobar, F.V., Kaminski, S., von Stetten, D., Keidel, A., Rippers, Y., Michael, N., Scheerer, P., Piwowarski, P., Bartl, F., Frankenberg-Dinkel, N., Ringsdorf, S., Gaertner, W., Lamparter, T., Mroginski, M.A., and Hildebrandt, P. (2013). Structure of the Biliverdin Cofactor in the Pfr State of Bathy and Prototypical Phytochromes. Journal of Biological Chemistry 288, 16800-16814.

Szczepek, M., Beyriere, F., Hofmann, K.P., Elgeti, M., Kazmin, R., Rose, A., Bartl, F.J., von Stetten, D., Heck, M., Sommer, M.E., Hildebrand, P.W., and Scheerer, P. (2014). Crystal structure of a common GPCR-binding interface for G protein and arrestin. Nature Communications 5, 4801.

Takiden, A., Velazquez-Escobar, F., Dragelj, J., Woelke, A.L., Knapp E.-W., Piwowarski, P., Bartl, F., Hildebrandt, P., and Mroginski, M.A. (2017). Structural and Vibrational Characterization of the Chromophore Binding Site of Bacterial Phytochrome Agp1. Photochemistry and Photobiology 93, 713-723.

Velazquez Escobar, F., Piwowarski, P., Salewski, J., Michael, N., Fernandez Lopez, M., Rupp, A., Muhammad Qureshi, B., Scheerer, P., Bartl, F., Frankenberg-Dinkel, N., Siebert, F., Mroginski, M.A., and Hildebrandt, P. (2015). A protonation-coupled feedback mechanism controls the signalling process in bathy phytochromes. Nature Chemistry 7, 423-430. [Link to news section.]