TY - JOUR
T1 - Wetting of the Protein Active Site Leads to Non-Marcusian Reaction Kinetics
AU - Waskasi, Morteza M.
AU - Martin, Daniel R.
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 - 2018/11/21
Y1 - 2018/11/21
N2 - Enzymes exist in continuously fluctuating water bath dramatically affecting their function. Water not only forms the solvation shell but also penetrates into the protein interior. Changing the wetting pattern of the protein's active site in response to altering redox state initiates a highly nonlinear structural change and non-Gaussian electrostatic fluctuations at the active site. The free-energy surfaces of electron transfer are highly nonparabolic (non-Marcusian), as shown by atomistic molecular dynamics simulations of hydrated ferredoxin protein and by an analytical model in agreement with simulations. The reorganization energy of electron transfer passes through a spike marking equal probabilities of the wet and dry states of the active site. The activation thermodynamics affected by wetting leads to a non-Arrhenius, passing through a maximum, plot for the reaction rate vs the inverse temperature.
AB - Enzymes exist in continuously fluctuating water bath dramatically affecting their function. Water not only forms the solvation shell but also penetrates into the protein interior. Changing the wetting pattern of the protein's active site in response to altering redox state initiates a highly nonlinear structural change and non-Gaussian electrostatic fluctuations at the active site. The free-energy surfaces of electron transfer are highly nonparabolic (non-Marcusian), as shown by atomistic molecular dynamics simulations of hydrated ferredoxin protein and by an analytical model in agreement with simulations. The reorganization energy of electron transfer passes through a spike marking equal probabilities of the wet and dry states of the active site. The activation thermodynamics affected by wetting leads to a non-Arrhenius, passing through a maximum, plot for the reaction rate vs the inverse temperature.
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U2 - 10.1021/acs.jpcb.8b10376
DO - 10.1021/acs.jpcb.8b10376
M3 - Article
C2 - 30365331
AN - SCOPUS:85056705956
SN - 1520-6106
VL - 122
SP - 10490
EP - 10495
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 46
ER -