Project A2

Surface protonation and conformational dynamics in cytochrome c oxidase and photoreceptors

Principal Investigator: Prof. Dr. Ulrike Alexiev (FU)

The A2 project aims at elucidating protonation dynamics in relation to protein conformational changes on different time and length scales in the redox-linked proton pump cytochrome c oxidase (CcO) and in two photoreceptors, channelrhodopsin (ChR) and phytochrome, using time-resolved fluorescence and fluorescence correlation methods. Polarization-resolved and time-correlated single photon counting (TCSPC) in two temporal dimensions gives access to local structural dynamics. Site-directed fluorescence labeling of cysteine residues allows mapping of the respective proteins to gain information on local protonation and structural dynamics.

Publications 2013 - 2017

Alexiev, U., and Farrens, D.L. (2014). Fluorescence spectroscopy of rhodopsins: Insights and approaches. Biochimica et Biophysica Acta (BBA) - Bioenergetics 1837, 694-709.

Kirchberg, K., Michel, H., and Alexiev, U. (2013). Exploring the entrance of proton pathways in cytochrome c oxidase from Paracoccus denitrificans: Surface charge, buffer capacity and redox-dependent polarity changes at the internal surface. Biochimica et Biophysica Acta (BBA) - Bioenergetics 1827, 276-284.

Richter, C., Schneider, C., Quick, M.T., Volz, P., Mahrwald, R., Hughes, J., Dick, B., Alexiev, U., and Ernsting, N.P. (2015). Dual-fluorescence pH probe for bio-labelling. Physical Chemistry Chemical Physics 17, 30590-30597.

Velazquez Escobar, F., Lang, C., Takiden, A., Schneider, C., Balke, J., Hughes, J., Alexiev, U., Hildebrandt, P., and Mroginski, M.A. (2017). Protonation-Dependent Structural Heterogeneity in the Chromophore Binding Site of Cyanobacterial Phytochrome Cph1. Journal of Physical Chemistry B 121, 47-57.

Volz, P., Boreham, A., Wolf, A., Kim, T.-Y., Balke, J., Frombach, J., Hadam, S., Afraz, Z., Rancan, F., Blume-Peytavi, U., Vogt, A., and Alexiev, U. (2015). Application of Single Molecule Fluorescence Microscopy to Characterize the Penetration of a Large Amphiphilic Molecule in the Stratum Corneum of Human Skin. International Journal of Molecular Sciences 16, 6960-6977.

Volz, P., Krause, N., Balke, J., Schneider, C., Walter, M., Schneider, F., Schlesinger, R., and Alexiev, U. (2016). Light and pH-induced changes in structure and accessibility of transmembrane helix B and its immediate environment in Channelrhodopsin-2. Journal of Biological Chemistry 291, 17382-17393.

Wolf, A., Schneider, C., Kim, T.Y., Kirchberg, K., Volz, P., and Alexiev, U. (2016). A simulation-guided fluorescence correlation spectroscopy tool to investigate to protonation dynamics of cytrochrome c oxidase. Physical Chemistry Chemical Physics 18, 12877-12885.