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Coupling between overall rotational diffusion and domain motions in proteins and its effect on dielectric spectra
Author(s) -
Ryabov Yaroslav
Publication year - 2015
Publication title -
proteins: structure, function, and bioinformatics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.699
H-Index - 191
eISSN - 1097-0134
pISSN - 0887-3585
DOI - 10.1002/prot.24814
Subject(s) - rotational diffusion , dielectric , relaxation (psychology) , dipole , chemistry , frequency domain , molecular dynamics , spectral line , diffusion , nuclear magnetic resonance , coupling (piping) , time domain , chemical physics , computational chemistry , molecular physics , dispersion (optics) , work (physics) , domain (mathematical analysis) , molecule , physics , materials science , thermodynamics , quantum mechanics , computer science , mathematics , mathematical analysis , psychology , social psychology , organic chemistry , metallurgy , computer vision
In this work, we formulate a closed‐form solution of the model of a semirigid molecule for the case of fluctuating and reorienting molecular electric dipole moment. We illustrate with numeric calculations the impact of protein domain motions on dielectric spectra using the example of the 128 kDa protein dimer of Enzyme I. We demonstrate that the most drastic effect occurs for situations when the characteristic time of protein domain dynamics is comparable to the time of overall molecular rotational diffusion. We suggest that protein domain motions could be a possible explanation for the high‐frequency contribution that accompanies the major relaxation dispersion peak in the dielectric spectra of protein aqueous solutions. We propose that the presented computational methodology could be used for the simultaneous analysis of dielectric spectroscopy and nuclear magnetic resonance data. Proteins 2015; 83:1571–1581. © 2015 Wiley Periodicals, Inc.