Figure 1.
THz time-domain signals of GP2 at 15, 263 and 294 K.
Figure 2.
Absorption coefficient of HER2/nue for 0.1-1.5 THz at temperatures between 15 K and 294 K.
Figure 3.
The frequency dependence of the absorption coefficient for GP2 solution at temperatures 15-294 K.
The temperatures along the intersection curve give the calculated TD for each frequency, the inset shows this for 0.56 THz.
Figure 4.
The calculated dynamical temperature TD as a function of frequency.
A linear best fit is also shown (red solid line).
Figure 5.
Cole-Cole plot for GP2 solution at different temperatures.
The upper box indicates the distribution of the dielectric constant of the protein above TD, the lower box shows the different distribution when the temperature is below TD.
Table 1.
Dielectric parameters of GP2 at temperatures below TD found by fitting the data to Equation 2.
Figure 6.
Cole-Cole plot for temperatures 15, 80, 150 and 200 K.
Lines are fitted by the Cole-Davison model and have a skewed arc distribution.
Table 2.
Dielectric parameters of GP2 at temperatures above TD found by fitting the data to Equation 7.
Figure 7.
Cole-Cole plot for temperature at 263, 273, 283 and 294 K.
Lines are fitted by CDRA model considering the resonance response. Note the semicircular arc distribution.
Figure 8.
Schematic diagrams to illustrate the molecular processes above and below TD.
(a) Both slow (τ1) and fast (τ2) dynamical processes were present in the protein solution when the temperature is above TD. The slow process is from the resonance absorption of the hydrated protein; the fast process was caused by the rearrangement of hydrogen bonding within the peripheral water. (b) Only one slow relaxation process τCD was identified at temperatures below TD.
Figure 9.
The temperature dependence of the fitted relaxation times τCD and τ1 plotted using ln(τ) vs. T0/T scale (T0 = 15 K).
The corresponding fits to the Arrhenius law crossover at 211.3 K. The inset shows the temperature dependence of the fast and slow relaxation times for temperatures above TD.