Rationalizing Overhauser DNP of nitroxide radicals in water through MD simulations

Sezer, Deniz (2013) Rationalizing Overhauser DNP of nitroxide radicals in water through MD simulations. (Accepted/In Press)

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Abstract

The recently introduced methodology (Sezer, Phys. Chem. Chem. Phys., 2013, 15, 526) for calculating dynamic nuclear polarization (DNP) coupling factors through synergistic use of molecular dynamics (MD) simulations and the analytical model of diffusing hard spheres with spins at their centers (HSCS) is applied to several nitroxides in water. Computations with one TEMPONE and one TEMPOL in water agree with experiments at 0.35 T and 3.4 T, respectively. At 9.2 T the predicted coupling factors are larger by about 50% than the experimental numbers obtained with 1M TEMPOL solution. MD simulations at this elevated concentration reveal nanoscopic TEMPOL clusters and qualitatively explain the lower experimental values. Comparing the dynamics from the MD simulations with that of the HSCS model, the assumption of centered spins is shown to be too limiting even for small molecules like TEMPOL and water. Using the available extension of the HSCS model to off-centered spins, the current procedure for analyzing hydration water dynamics from Overhauser DNP measurements on spin-labeled proteins is revisited.
Item Type: Article
Subjects: Q Science > QD Chemistry
Q Science > QC Physics
Divisions: Faculty of Engineering and Natural Sciences > Basic Sciences > Chemistry
Faculty of Engineering and Natural Sciences > Basic Sciences > Physics
Faculty of Engineering and Natural Sciences
Depositing User: Deniz Sezer
Date Deposited: 16 Jan 2014 11:50
Last Modified: 01 Aug 2019 12:22
URI: https://research.sabanciuniv.edu/id/eprint/22520

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