TY - JOUR
T1 - Termination of Biological Function at Low Temperatures
T2 - Glass or Structural Transition?
AU - Seyedi, Salman
AU - Matyushov, Dmitry
N1 - Funding Information:
This research was supported by the National Science Foundation (CHE-1800243). CPU time was provided by the National Science Foundation through XSEDE resources (TG-MCB080071).
PY - 2018/5/3
Y1 - 2018/5/3
N2 - Energy of life is produced by electron transfer in energy chains of respiration or photosynthesis. A small input of free energy available to biology puts significant restrictions on how much free energy can be lost in each electron-transfer reaction. We advocate the view that breaking ergodicity, leading to violation of the fluctuation-dissipation theorem (FDT), is how proteins achieve high reaction rates without sacrificing the reaction free energy. Here we show that a significant level of nonergodicity, represented by a large extent of the configurational temperature over the kinetic temperature, is maintained in the entire physiological range for the cytochrome c electron transfer protein. The protein returns to the state consistent with the FDT below the crossover temperature close to the temperature of the protein glass transition. This crossover leads to a sharp increase in the activation barrier of electron transfer and is displayed by a kink in the Arrhenius plot for the reaction rate constant.
AB - Energy of life is produced by electron transfer in energy chains of respiration or photosynthesis. A small input of free energy available to biology puts significant restrictions on how much free energy can be lost in each electron-transfer reaction. We advocate the view that breaking ergodicity, leading to violation of the fluctuation-dissipation theorem (FDT), is how proteins achieve high reaction rates without sacrificing the reaction free energy. Here we show that a significant level of nonergodicity, represented by a large extent of the configurational temperature over the kinetic temperature, is maintained in the entire physiological range for the cytochrome c electron transfer protein. The protein returns to the state consistent with the FDT below the crossover temperature close to the temperature of the protein glass transition. This crossover leads to a sharp increase in the activation barrier of electron transfer and is displayed by a kink in the Arrhenius plot for the reaction rate constant.
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U2 - 10.1021/acs.jpclett.8b00537
DO - 10.1021/acs.jpclett.8b00537
M3 - Article
C2 - 29669418
AN - SCOPUS:85046545510
SN - 1948-7185
VL - 9
SP - 2359
EP - 2366
JO - Journal of Physical Chemistry Letters
JF - Journal of Physical Chemistry Letters
IS - 9
ER -