Time-Resolved and Pulse EPR Study of Triplet States of Alkylketones in β-Cyclodextrin

Krumkacheva, Olesya A.; Tanabe, Mana; Yamauchi, Seigo; Fedin, Matvey V.; Marque, Sylvain R. A.; Bagryanskaya, Elena G.

doi:10.1007/s00723-011-0289-2

Cited by 9 publications

(8 citation statements)

References 42 publications

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“…11 Bagryanskaya and coworkers reported the measurement of electron spin relaxation time T 2 ≈ T m ≈ 1. was longer by a factor of 3−4 compared to that of benzophenone in toluene. 12 We envision a novel supramolecular approach, taking advantage of host−guest molecular recognition, to lengthen the T m of spin-labeled proteins and decrease conformational mobility. Binding of β-CD to spin labels at solvent exposed sites of a protein would increase T m , and this may facilitate long-distance DEER measurements at near physiological temperatures.…”

Section: ■ Introductionmentioning

confidence: 99%

“…In addition, adamantane and its derivatives complex strongly to β-cyclodextrin (β-CD) with large association constants, K a ≈ 10 3 – 10 6 M –1 . Bagryanskaya and coworkers reported the measurement of electron spin relaxation time T 2 ≈ T m ≈ 1.2 μs for triplet excited state benzophenone encapsulated inside methylated β-CD in water/glycerol at 30 K. Notably, this T m was longer by a factor of 3–4 compared to that of benzophenone in toluene …”

Section: Introductionmentioning

confidence: 99%

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Supramolecular Approach to Electron Paramagnetic Resonance Distance Measurement of Spin-Labeled Proteins

et al. 2020

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We demonstrate a host–guest molecular recognition approach to advance double electron–electron resonance (DEER) distance measurements of spin-labeled proteins. We synthesized an iodoacetamide derivative of 2,6-diazaadamantane nitroxide (DZD) spin label that could be doubly incorporated into T4 Lysozyme (T4L) by site-directed spin labeling with efficiency up to 50% per cysteine. The rigidity of the fused ring structure and absence of mobile methyl groups increase the spin echo dephasing time (T m) at temperatures above 80 K. This enables DEER measurements of distances >4 nm in DZD-labeled T4L in glycerol/water at temperatures up to 150 K with increased sensitivity compared to that of a common spin label such as MTSL. Addition of β-cyclodextrin reduces the rotational correlation time of the label, slightly increases T m, and most importantly, narrows (and slightly lengthens) the interspin distance distributions. The distance distributions are in good agreement with simulated distance distributions obtained by rotamer libraries. These results provide a foundation for developing supramolecular recognition to facilitate long-distance DEER measurements at near physiological temperatures.

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Section: ■ Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Supramolecular Approach to Electron Paramagnetic Resonance Distance Measurement of Spin-Labeled Proteins

et al. 2020

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“…The longitudinal (T 1 ) and transverse (T 2 ) relaxation times have been reported to depend on the orientation of the molecules relative to the magnetic field 41 . We studied this dependence in our system.…”

Section: Resonance Spectrum and Condition Selectingmentioning

confidence: 99%

Coherent manipulation and quantum phase interference in a fullerene-based electron triplet molecular qutrit

et al. 2021

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High-spin magnetic molecules are promising candidates for quantum information processing because their intrinsic multiplicity facilitates information storage and computational operations. However, due to the absence of suitable sublevel splittings, their susceptibility to environmental disturbances and limitation from the selection rule, the arbitrary control of the quantum state of a molecular electron multiplet has not been realized. Here, we exploit the photoexcited triplet of C70 as a molecular electron spin qutrit with pulsed electron paramagnetic resonance. We prepared the system into 3-level superposition states characteristic of a qutrit and validated them by the tomography of their density matrices. To further elucidate the coherence of the operation and the nature of the system as a qutrit, we demonstrated the quantum phase interference in the superposition. The interference pattern is further interpreted as a map of possible evolution paths in the space of phase factors, representing the quantum nature of the 3-level system.

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“…Supramolecular design of new functional systems is one of the perspective fields in current chemistry, biology, and nanotechnology. − The applications of such supramolecular complexes can be broadened by the development of new synthetic approaches where the properties of well-known host molecules are enhanced by the new functions of molecules attached to them. − Recently a series of new compounds based on cyclodextrins (CDs) has been developed owing to the high efficiency of supramolecular complex formation of CD with many hydrophobic molecules. − One of the new directions of research in this field is the synthesis of CDs covalently bound to nitroxides (NCDs). − These systems can be considered as potential probes to study supramolecular assemblies of CDs with biomolecules, as reduction agents in aqueous solutions, as polarizing agents for DNP signal enhancement in NMR studies of proteins, and as efficient and selective fluorescence quenchers . Moreover, complex formation of cyclodextrins with spin traps is used to increase the lifetimes of spin adducts formed in reactions with short-lived radicals (superoxide, − thyil, etc.…”

Section: Introductionmentioning

confidence: 99%

“…10−15 These systems can be considered as potential probes to study supramolecular assemblies of CDs with biomolecules, 14 as reduction agents in aqueous solutions, as polarizing agents for DNP signal enhancement in NMR studies of proteins, 16 and as efficient and selective fluorescence quenchers. 17 Moreover, complex formation of cyclodextrins with spin traps is used to increase the lifetimes of spin adducts formed in reactions with shortlived radicals (superoxide, 18−23 thyil, 12 etc. ).…”

Section: ■ Introductionmentioning

confidence: 99%

Structural Equilibrium in New Nitroxide-Capped Cyclodextrins: CW and Pulse EPR Study

et al. 2013

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Design of the new spin-labeled cyclodextrins can significantly extend the functionality of nitroxides. A series of new complexes based on fully methylated cyclodextrin (TRIMEB) covalently bound to the piperidine, pyrroline, pyrrolidine, and pH-sensitive imidazoline type nitroxides has been synthesized and studied using pulse and continuous wave electron paramagnetic resonance (EPR). The influence of the radical and linker properties on the structure of complexes formed has been investigated. Using the electron spin echo envelope modulation technique, we have analyzed quantitatively the accessibility of radicals to solvent molecules in studied complexes depending on the structure and length of the linkers. In all studied systems we observed different types of equilibria between conformations with radical fragment being outside the TRIMEB cavity and radical fragment capping the cavity of TRIMEB. The observed guest-induced shift of equilibrium toward the complex with radical capping TRIMEB cavity was explained by a change of macrocyclic configuration of TRIMEB. Complex with the -NH-CO- linker has been found most perspective for the applications requiring close location of nitroxide to the inclusion complex of TRIMEB. Using continuous wave EPR, we have shown that the pH-sensitive radical covalently bound to TRIMEB maintains its pH-sensitivity, but this complexation does not reduce radical reduction rate in the reaction with ascorbic acid.

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Time-Resolved and Pulse EPR Study of Triplet States of Alkylketones in β-Cyclodextrin

Cited by 9 publications

References 42 publications

Supramolecular Approach to Electron Paramagnetic Resonance Distance Measurement of Spin-Labeled Proteins

Supramolecular Approach to Electron Paramagnetic Resonance Distance Measurement of Spin-Labeled Proteins

Coherent manipulation and quantum phase interference in a fullerene-based electron triplet molecular qutrit

Structural Equilibrium in New Nitroxide-Capped Cyclodextrins: CW and Pulse EPR Study

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