Study of the Dynamic Structure of Native and Hydrophobized Glucose Oxidase by Time-Domain Dielectric Spectroscopy

Abstract

The dynamic structures of native and hydrophobized (by covalent attachment of palmitoyl chains) glucose oxidase were studied by time-domain dielectric spectroscopy (TDDS). Analysis of the dipole correlation function for both types of the enzyme showed that the decay of the correlation function of the macromolecule motion can be presented as a sum of components corresponding to different kinds of protein motion: isotropic rotation of the protein molecule as a whole, anisotropic Brownian tumbling of subunits, and anisotropic intramolecular motion of polar groups and substructures. The slowest relaxation time was found to be longer for the modified enzyme than for the native enzyme. The dielectric strengths for all relaxation processes, as well as the dipole moment and the molecular volume, were also larger for the modified glucose oxidase. The observed differences between various types of the dipole motion for the native and modified glucose oxidase are discussed.

Relaxation dynamics of liposomes in an aqueous solution

“…First, characterizing the relaxation processes that appeared from the complex dielectric permittivity, curve-fitting procedures were carried out. It should be mentioned here that multiple relaxation processes were extracted from the complex dielectric spectrum by different groups [30][31][32] for different systems. We have applied the same method to extract the possible relaxation processes for the present system.…”