Humboldt-Universität zu Berlin - Experimentelle Biophysik

A fully funded PhD scholarship with David is currently available, applications are welcome!

I am a Liebig-Fellow funded by the Funds of the German Chemical Industry (FCI), working with spectroscopic methods to investigate photoreceptor proteins. These proteins can sense light and regulate a plethora of different functions in cells, such as gene expression or the transport of ions across membranes. To understand and exploit how these complex molecular machines function on an atomistic level, spectroscopic techniques are among the most useful biophysical methods.

In my project, we investigate the light-activation in real time by applying a short laser pulse to a sample that mimics the natural excitation. The laser starts a reaction cascade in many molecules at one defined point in time that we can monitor with UV, visible, or infrared spectroscopy over orders of magnitude in time - a method we call pump-probe spectroscopy:

The molecular spectra are recorded as a function of time after the excitation pulse, and then analyzed with advanced mathematical models. This allows us to extract information about the different reaction steps such as the formation and breaking of covalent bonds or the transduction of an allosteric signal throug a protein. The main focus of the project is to understand the light-reaction of cyanobacteriochrome photoreceptors which have great potential for biotechnological applications such as optogenetic control or fluorescence imaging. Retinal proteins are also investigated in close collaboration with the groups of Peter Hegemann and Franz Bartl.

Recent Publications:

J. Ruf, P. Hamm and D. Buhrke. Needles in a Haystack: H-bonding in an Optogenetic Protein observed with Isotope Labeling and 2D-IR Spectroscopy. Phys Chem Chem Phys. 2021 5;23(17):10267-10273.

D. Buhrke. The impact of chromophore choice on the assembly kinetics and primary photochemistry of a red/green cyanobacteriochrome. Phys Chem Chem Phys. 2021 29;23(37):20867-20874.  

D. Buhrke, N. Michael, P. Hamm. Vibrational couplings between protein and cofactor in bacterial phytochrome Agp1 revealed by 2D-IR spectroscopy. PNAS 2022 119(31):e2206400119. 

J. Ruf, F. Bindschedler and D. Buhrke. The Molecular Mechanism of Light-induced Bond Formation and Breakage in the Cyanobacteriochrome TePixJ. Phys. Chem. Chem. Phys. 2023 25:6016-6024.