Protein dynamics at low temperatures

Abstract

The low temperature conformational dynamics of the heme type protein mesoporphyrin-IX-substituted horseradish peroxidase is investigated by spectral diffusion waiting time/ aging experiments. Spectral diffusion broadening is governed by a power law in time. There is a small but significant aging effect. It is assumed that the conformational dynamics of the protein which leads to the spectral broadening of the burnt-in holes is governed by a diffusion type equation. In this case the shape of the spectral diffusion kernel is Gaussian. This model is contrasted with spectral diffusion phenomena as described by the TLS-model ͑TLS, two level system͒.

Magnetic and optical anisotropy of Clostridium pasteurianum rubredoxin from optically detected electron paramagnetic resonance

“…Similar results have been reported for other systems on the basis of high resolution laser spectroscopy. [19][20][21] The orientation of the g-tensor could be identified by optically detected EPR: the EPR spectra correlate the optical anisotropy tensor with the g-tensor, clearly indicating that the optical symmetry axis is parallel to the direction of the largest g-value ͑the y-axis in the usual EPR notation͒. The analysis of the ODEPR spectra also gave improved values for the optical polarization of the charge transfer transitions in the 400-600 nm wavelength region.…”

Single Molecule Spectroscopy of the Green Fluorescent Protein: A Critical Assessment

“…If on the time scale of the experiment no heterogeneity between different molecules exists, then the values averaged over measurements of many individual molecules will yield the same results as a time averaged measurement of the emission of one molecule. While non-ergodic behavior must be assumed for proteins [24], its effects are usually not considered in the interpretation of room temperature single molecule measurements.…”

Fractional Brownian motions via random walk in the complex plane and via fractional derivative. Comparison and further results on their Fokker–Planck equations

“…This being the case, fractional Fokker-Planck equations (fFP-equation in the following) have been used to describe many phenomena such as, for instance, heat conduction and fluid flow in porous media, propagation of earthquake waves, diffusion and transport of drug molecules in biological tissues, relaxation in biopolymers, option prices in a market with frictions driven by the Black-Scholes equation, diffusion of protein [2,4,6,7,9,17,22,27,30,31]. Nevertheless, in most cases, the fPF-equations so considered are more or less introduced as formal generalizations of the classical FPequation, and their relation with fractional stochastic differential equations is not always completely clarified.…”