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Updated: Oct 25, 2026

Realistic Membrane Modeling Using Complex Lipid Mixtures in Simulation Studies
Published on: September 1, 2023
Anisotropy of dipolar order relaxation rate in phospholipid bilayers
Gregory Furman1, Theodore Aptekarev1, Vladimir Sokolovsky1
1Physics Department, Ben Gurion University of the Negev, Beer Sheva, Israel.
Abstract:
The experimental NMR/MRI studies demonstrate the anisotropies of the second moment M2 and dipolar order relaxation rate R1D in myelin-like bilayers. In this paper, to analyze the anisotropy, we consider the dipole-dipole Hamiltonian averaged accounting for the restricted motion of hydrogen protons. The averaging of the Hamiltonian's spatial part enables the derivation of analytical expressions for the angular dependence of the second moment M2 and the relaxation rate R1D. Comparison of theoretical results and experimental data allowed us to determine the average orientation and standard deviation of the hydrogen pair of a CH₂ group within the phospholipid bilayer. Some differences in these parameters, estimated from angular dependences of the second moment and the relaxation rate, can be explained by using different methods to measure the moment and rate, as well as by the fact that the environment can influence transverse and spin-lattice relaxations differently. The correlation times of the fluctuating CH2 groups were estimated as 7.9×10-7s.
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