TY - JOUR
T1 - Dielectrophoresis of proteins in solution
AU - Heyden, Matthias
AU - Matyushov, Dmitry V.
N1 - Funding Information:
This research was supported by the National Science Foundation (CHE-1800243, D.V.M.). D.V.M. greatly enjoyed discussing dielectrophoresis with Ronald Pethig. The authors acknowledge Research Computing at Arizona State University for providing high performance computing resources that have contributed to the research results reported in this paper.
Publisher Copyright:
© 2020 American Chemical Society
PY - 2020/12/24
Y1 - 2020/12/24
N2 - A nonionic particle placed in the gradient of an electric field experiences the dielectrophoretic force which scales linearly with the gradient of the electric field squared. The proportionality constant is the dielectrophoretic susceptibility, that is, a linear transport coefficient. For proteins in solution, it is mostly affected by the following two parameters: the squared dipole moment and the cavity susceptibility accounting for cross-correlations of the protein dipole with the hydration shell (protein-water Kirkwood factor). Both of these parameters enter the dielectric increment of the solution which fully specifies the dielectrophoretic susceptibility. The link between these two measurable properties is proven here to hold using molecular dynamics simulations of solvated proteins. The dielectrophoretic susceptibility for proteins is in the range of 104, significantly exceeding traditional estimates limiting it to values below unity. Part of this large magnitude of the dielectrophoretic response is the cavity susceptibility of the protein-water interface, which significantly exceeds dielectric estimates. The study analyzes local fields inside the protein in terms of the reaction-field and directing-field components. We find that the local field exceeds the external field by a substantial factor described by the local field susceptibility. The electric field produced by water inside the protein is retarded by 3-4 orders of magnitude compared to the bulk.
AB - A nonionic particle placed in the gradient of an electric field experiences the dielectrophoretic force which scales linearly with the gradient of the electric field squared. The proportionality constant is the dielectrophoretic susceptibility, that is, a linear transport coefficient. For proteins in solution, it is mostly affected by the following two parameters: the squared dipole moment and the cavity susceptibility accounting for cross-correlations of the protein dipole with the hydration shell (protein-water Kirkwood factor). Both of these parameters enter the dielectric increment of the solution which fully specifies the dielectrophoretic susceptibility. The link between these two measurable properties is proven here to hold using molecular dynamics simulations of solvated proteins. The dielectrophoretic susceptibility for proteins is in the range of 104, significantly exceeding traditional estimates limiting it to values below unity. Part of this large magnitude of the dielectrophoretic response is the cavity susceptibility of the protein-water interface, which significantly exceeds dielectric estimates. The study analyzes local fields inside the protein in terms of the reaction-field and directing-field components. We find that the local field exceeds the external field by a substantial factor described by the local field susceptibility. The electric field produced by water inside the protein is retarded by 3-4 orders of magnitude compared to the bulk.
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U2 - 10.1021/acs.jpcb.0c09007
DO - 10.1021/acs.jpcb.0c09007
M3 - Article
C2 - 33307704
AN - SCOPUS:85098783957
SN - 1520-6106
VL - 124
SP - 11634
EP - 11647
JO - Journal of Physical Chemistry B
JF - Journal of Physical Chemistry B
IS - 51
ER -