Der Einfluss von Reibung auf Proteindynamik
Final Report Abstract
The project aimed at revealing molecular components and interaction mechanisms that introduce friction in protein dynamics. We employed single-molecule fluorescence spectroscopy to monitor photoinduced electron transfer and fluorophore dimerization as quenching mechanism on nanometer length scales reporting on peptide conformational dynamics. By temporal analysis based on fluorescence fluctuation analysis using fluorescence correlation spectroscopy (PET-FCS) we identified the contributing fluctuation mechanisms also in high viscosity solutions, including rotational and translational diffusion, quenching interactions, and photophysical processes like intersystem crossing, redox reactions and irreversible photodestruction. We identified a small and previously unknown photophysical effect for ATTO655 (that is absent for the structurally similar MR121) in sucrose solutions. This effect is independent of any PET-quenching interactions, dependent on excitation intensity and solvent viscosity, and occurs on a time scale about an order of magnitude faster than the intersystem crossing transition. Progress was made in data analysis of FCS data indicating interdependences and influences on viscosity-dependent measurements.
Publications
- Dimer formation of organic fluorophores reports on biomolecular dynamics under denaturing conditions. Physical Chemistry Chemical Physics 2011, 13, 12874-12882
Bollmann, S.; Löllmann, M.; Sauer, M.; Doose, S.
- Analysis of homodimeric avian and human galectins by two methods based on fluorescence spectroscopy: Different structural alterations upon oxidation and ligand binding. Biochimie 2012, 94, 2649-2655
Göhler, A.; Buechner, C.; Andre, S.; Doose, S.; Kaltner, H.; Gabius, H.-J.
(See online at https://doi.org/10.1016/j.biochi.2012.08.001) - Dissertation, Structural dynamics of oligopeptides determined by fluorescence quenching of organic dyes, Fakultät für Physik, Universität Würzburg, 20.12.2013
Stefan Bollmann
- Systematic evaluation of fluorescence correlation spectroscopy data analysis on the nanosecond time scale. Physical Chemistry Chemical Physics 2013, 15, 10435-10445
Steger, K.; Bollmann, S.; Noe, F.; Doose, S.
(See online at https://doi.org/10.1039/c3cp50644d) - Reporters of protein conformation: photophysics of fluorescent dyes and applications to studying protein dynamics, Chapter in “Single Molecule Studies of Protein Folding” edited by J. Clarke, R. Best, A. Borgia, Wiley-VCH, 2017
S. Doose, M. Sauer
