Electron Paramagnetic Resonance Spectra Simulation Directly from Molecular Dynamics Trajectories of a Liquid Crystal with a Doped Paramagnetic Spin Probe

Abstract

'Electron paramagnetic resonance spectra simulation directly from molecular dynamics trajectories of a liquid crystal with a doped paramagnetic spin probe.', Physical review letters., 102 (1). 013005. Use policyThe full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that:• a full bibliographic reference is made to the original source • a link is made to the metadata record in DRO • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders.Please consult the full DRO policy for further details.

Prediction of EPR Spectra of Liquid Crystals with Doped Spin Probes from Fully Atomistic Molecular Dynamics Simulations: Exploring Molecular Order and Dynamics at the Phase Transition

“…[6] Nitroxide spin probes can be readily introduced into LCs to probe the order and dynamics of mesogens in different phases. [4,7] Scheme 1 shows an example of a cholesteric nitroxide SP typically used for calamitic (rod-shaped) LCs. The nitroxide radical is chemically relatively stable and has an EPR spectrum consisting of an almost isotropic g tensor (g xx = 2.0088, g yy = 2.0061, g zz = 2.0027) [4] with anisotropic hyperfine coupling (A tensor: A xx = 5.9 G, A yy = 5.9 G, A zz = 31.7 G) [4] to a single 14 N nuclear spin I = 1 that gives a three derivative shape line spectrum at the X-band.…”

“…[4,7] Scheme 1 shows an example of a cholesteric nitroxide SP typically used for calamitic (rod-shaped) LCs. The nitroxide radical is chemically relatively stable and has an EPR spectrum consisting of an almost isotropic g tensor (g xx = 2.0088, g yy = 2.0061, g zz = 2.0027) [4] with anisotropic hyperfine coupling (A tensor: A xx = 5.9 G, A yy = 5.9 G, A zz = 31.7 G) [4] to a single 14 N nuclear spin I = 1 that gives a three derivative shape line spectrum at the X-band. The three lines w(t) m = (g zz (W(t))bB+A zz (W(t)m)/" h are the functions of the calculated MD trajectory W(t) where A zz and g zz are effective g and hyperfine coupling constants calculated by using the principle values for g and A according to the previously described procedure.…”

A combined EPR and MD simulation study of a nitroxyl spin label with restricted internal mobility sensitive to protein dynamics

“…These methods have been successfully applied to soft matter systems doped with nitroxide spin probes (40,41) and MTSL spin labelled proteins (4,26,28,32,38). In order to probe motions of both R1 and Rn in two different protein environments and to predict and analyse the relevant EPR spectra we have performed fully atomistic MD simualtions of all four cases of spin labelled Mb.…”

EPR spectroscopy and molecular dynamics modelling: a combined approach to study liquid crystals

“…This approach has paved the way for the first-time prediction of motional EPR spectra directly and completely from MD trajectories of actual molecular structures. It has been successfully applied to proteins [29,30], DNA [31], lipid bilayers [32] and also LCs [33][34][35]. A computer code developed by the author [27,28], which includes both options, namely the propagation of the trajectories along the entire sampling time and the use of truncated trajectories combined with autocorrelation function method, has been employed for the simulation of EPR spectra of LC systems reported in this review.…”

“…Our MD-EPR simulation methodology has been applied for the first time to 5CB LC system doped with CSL probe using truncated MD trajectories with autocorrelation function-based method (Equations 5-6 and 12) [33]. A hybrid MD simulation model was used where the spin probe was represented at FA level and the host LCs molecules were treated at a CG level.…”