%0 Journal Article %J J. Phys. Chem. B %D 2021 %T Functional-State Dependence of Picosecond Protein Dynamics %A George, D. K. %A Chen, J. Y. %A He, Yunfen %A Knab, J. R. %A Markelz, A. G. %X

We examine temperature-dependent picosecond dynamics of two benchmarking proteins lysozyme and cytochrome c using temperature-dependent terahertz permittivity measurements. We find that a double Arrhenius temperature dependence with activation energies E1 ∼ 0.1 kJ/mol and E2 ∼ 10 kJ/mol fits the folded and ligand-free state response. The higher activation energy is consistent with the so-called protein dynamical transition associated with beta relaxations at the solvent–protein interface. The lower activation energy is consistent with correlated structural motions. When the structure is removed by denaturing, the lower-activation-energy process is no longer present. Additionally, the lower-activation-energy process is diminished with ligand binding but not for changes in the internal oxidation state. We suggest that the lower-energy activation process is associated with collective structural motions that are no longer accessible with denaturing or binding.

%B J. Phys. Chem. B %V 125 %P 11134-11140 %G eng %N 40 %& 11134 %R 10.1021/acs.jpcb.1c05018 %0 Journal Article %J arXiv:1105.4425 %D 2012 %T Functional State Dependence of Picosecond Protein Dynamics %A Chen, J. Y. %A George, D. K. %A He, Y. %A Knab, J. R. %A Markelz, A.G. %B arXiv:1105.4425 %G eng %U http://arxiv.org/0054394