Spectral Diffusion Experiment with a Denatured Protein

Abstract

Spectral diffusion broadening of cytochrome c carrying the free-base analogue of heme is investigated in its unfolded state and compared with the corresponding broadening in the native state. Spectral diffusion is much larger in the unfolded state, in comparison to the native state. Interestingly, the time law that governs spectral diffusion changes as the aging time increases, from a power-law behavior in the native state to an apparent logarithmic behavior in the unfolded state.

Spectroscopy of proteins at low temperature. Part I: Experiments with molecular ensembles

“…7 shows the respective experiments. The protein investigated is free base cytochrome c (H 2 -Cc) [88]. Fig.…”

Parameters of the Protein Energy Landscapes of Several Light-Harvesting Complexes Probed via Spectral Hole Growth Kinetics Measurements

“…Nevertheless, waiting and aging time SHB experiments still continued to be employed to study low-temperature dynamics of other proteins. − Both SHB and single-molecule spectroscopy have been applied in the research on low-temperature dynamics and energy barrier distributions of glasses and polymers. − In particular, hole growth kinetics (HGK) measurements have been employed in refs and − . (In HGK measurements, the evolution of absorption in resonance with the burning laser frequency is followed while the burning occurs.)…”

Physics of Proteins at Low Temperature

“…The aging effect of spectral holes observed in native proteins 26,28 is anomalously weak compared to the expectations of the standard TLS model. In the standard TLS model, spectral hole broadening is associated with the dynamics of TLS having energies comparable with the thermal energy and higher.…”

“…The most remarkable observation, however, concerns the dramatic change of the time evolution of the hole width beyond aging times of about 100 h: The power law changes to a seemingly logarithmic time behavior (at least in the experimental time window) as is immediately obvious from the straight line representation in the lin-log plot. 26 Note that since a power law is exponential in ln(t), the change is really dramatic. In Fig.2c we compare the data for Gl/W with data for TH.…”