Electron spin echo detection of stochastic molecular librations: Non-cooperative motions on solid surface

Golysheva, Elena A.; Samoilova, Rimma I.; Zotti, Marta De; Toniolo, Claudio; Formaggio, Fernando; Dzuba, Sergei A.

doi:10.1016/j.jmr.2019.106621

Cited by 5 publications

(7 citation statements)

References 47 publications

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“…Therefore, with the help of experimental data obtained in the present work, we substantiate structural grounds for the observed L(T) anomalies in IL glasses. tails around spin probe, which was earlier proposed in the literature [35,44,78,79], as well as in our previous studies [53,54].…”

Section: Resultssupporting

confidence: 81%

“…Despite TAM being much larger that the N1 radical and having drastically different structure and shape, the L(T) curves were found very similar using both probes, implying that the relaxation (and thus L(T)) is truly dictated by the librations of glassy environment. Interestingly, in recent works of Dzuba and colleagues, similar L(T) shapes with a clear maximum were obtained for tumbling radicals attached to the surface (i.e., not in glassy media)[79]. The observation of such saturation near room temperature was explained by violating the applicability of Redfield relaxation theory, when (α 2 )τ c becomes large due…”

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confidence: 74%

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Validation of Structural Grounds for Anomalous Molecular Mobility in Ionic Liquid Glasses

et al. 2021

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Ionic liquid (IL) glasses have recently drawn much interest as unusual media with unique physicochemical properties. In particular, anomalous suppression of molecular mobility in imidazolium IL glasses vs. increasing temperature was evidenced by pulse Electron Paramagnetic Resonance (EPR) spectroscopy. Although such behavior has been proven to originate from dynamics of alkyl chains of IL cations, the role of electron spin relaxation induced by surrounding protons still remains unclear. In this work we synthesized two deuterated imidazolium-based ILs to reduce electron–nuclear couplings between radical probe and alkyl chains of IL, and investigated molecular mobility in these glasses. The obtained trends were found closely similar for deuterated and protonated analogs, thus excluding the relaxation-induced artifacts and reliably demonstrating structural grounds of the observed anomalies in heterogeneous IL glasses.

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Section: Resultssupporting

confidence: 81%

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confidence: 74%

Validation of Structural Grounds for Anomalous Molecular Mobility in Ionic Liquid Glasses

et al. 2021

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“…We have to note here that these two starting temperatures, 130 and 100 K, seem to be quite a general property of ESE-detected stochastic molecular motions in biological systems [ 54 , 55 ]. Some evidence exists that at 130 K motions appear because of bending of the molecular structure while at 100 K the source of motions could be torsional oscillations [ 55 ].…”

Section: Discussionmentioning

confidence: 99%

“…Some evidence exists that at 130 K motions appear because of bending of the molecular structure while at 100 K the source of motions could be torsional oscillations [ 55 ]. In all the cases, stochastic molecular librations in biological systems develop because of cooperative effects [ 54 , 55 ].…”

Section: Discussionmentioning

confidence: 99%

Evidence for an Ordering Transition near 120 K in an Intrinsically Disordered Protein, Casein

2021

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Intrinsically disordered proteins (IDPs) are proteins that possess large unstructured regions. Their importance is increasingly recognized in biology but their characterization remains a challenging task. We employed field swept Electron Spin Echoes in pulsed EPR to investigate low-temperature stochastic molecular librations in a spin-labeled IDP, casein (the main protein of milk). For comparison, a spin-labeled globular protein, hen egg white lysozyme, is also investigated. For casein these motions were found to start at 100 K while for lysozyme only above 130 K, which was ascribed to a denser and more ordered molecular packing in lysozyme. However, above 120 K, the motions in casein were found to depend on temperature much slower than those in lysozyme. This abrupt change in casein was assigned to an ordering transition in which peptide residues rearrange making the molecular packing more rigid and/or more cohesive. The found features of molecular motions in these two proteins turned out to be very similar to those known for gel-phase lipid bilayers composed of conformationally ordered and conformationally disordered lipids. This analogy with a simpler molecular system may appear helpful for elucidation properties of molecular packing in IDPs.

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“…Pulsed EPR allows the detection of stochastic molecular librations – low-amplitude stochastic orientational molecular motions. 32–35 (This type of motion is also called “quasi-librations”. 36 ) Stochastic molecular librations are present in molecular systems of different origins.…”

Section: Introductionmentioning

confidence: 99%

Structural properties of supercooled deep eutectic solvents: choline chloride–thiourea compared to reline

Golysheva

Maslennikova

Baranov

et al. 2022

Phys. Chem. Chem. Phys.

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Electron spin echo detection of stochastic molecular librations: Non-cooperative motions on solid surface

Cited by 5 publications

References 47 publications

Validation of Structural Grounds for Anomalous Molecular Mobility in Ionic Liquid Glasses

Validation of Structural Grounds for Anomalous Molecular Mobility in Ionic Liquid Glasses

Evidence for an Ordering Transition near 120 K in an Intrinsically Disordered Protein, Casein

Structural properties of supercooled deep eutectic solvents: choline chloride–thiourea compared to reline

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