Functional EPR Spectroscopy and Imaging of Nitroxides

Khramtsov, Valery V.

doi:10.1007/978-1-4020-6466-1_10

Cited by 5 publications

(3 citation statements)

References 102 publications

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“…They can also be highly functionalised, specifically tailoring the spin label to its intended environment [78]; recent advances include the spin labelling of graphene with aryl radical diazonium tetrafluoroborate salts [79]. Imidizolines 23 have been developed to give a largely pH dependent EPR spectrum, and are commonly used as pH probes, and for in-cell pH imaging [80].…”

Section: Nitroxidesmentioning

confidence: 99%

New Developments in Spin Labels for Pulsed Dipolar EPR

et al. 2014

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Spin labelling is a chemical technique that enables the integration of a molecule containing an unpaired electron into another framework for study. Given the need to understand the structure, dynamics, and conformational changes of biomacromolecules, spin labelling provides a relatively non-intrusive technique and has certain advantages over X-ray crystallography; which requires high quality crystals. The technique relies on the design of binding probes that target a functional group, for example, the thiol group of a cysteine residue within a protein. The unpaired electron is typically supplied through a nitroxide radical and sterically shielded to preserve stability. Pulsed electron paramagnetic resonance (EPR) techniques allow small magnetic couplings to be measured (e.g., <50 MHz) providing information on single label probes or the dipolar coupling between multiple labels. In particular, distances between spin labels pairs can be derived which has led to many protein/enzymes and nucleotides being studied. Here, we summarise recent examples of spin labels used for pulse EPR that serve to illustrate the contribution of chemistry to advancing discoveries in this field.

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Section: Nitroxidesmentioning

confidence: 99%

New Developments in Spin Labels for Pulsed Dipolar EPR

et al. 2014

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“…Barley is one of the most widespread grain crops in the world [9][10][11]. Its grain is widely used for fodder, food and technical purposes [12][13][14]. Considering the national economic importance of this crop, barley requires considerable attention and a careful technological approach.…”

Section: Introductionmentioning

confidence: 99%

Dynamics of the content of nutrients in winter barley plants depending on the variety, sowing dates and plant growth regulators

Zaiets¹,

Onufran²,

Fundirat³

et al. 2022

UBSRAS

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The problem of increasing the production of winter barley grain on irrigated lands can be solved thanks to the improvement of the varietal composition, optimization of sowing dates and improvement of the nutrition system, in particular through the use of drugs with growth-regulating properties. Taking into account the important biological role of growth regulators in the plant nutrition system, the aim was to determine the influence of Gummifield Forte brix, MIR and PROLIS on the content of nitrogen, phosphorus and potassium in the main phases of plant development of different varieties of winter barley at optimal and late sowing dates. The research was conducted at the Institute of Irrigated Agriculture (now the Institute of Climate-Oriented Agriculture) of the National Academy of Sciences according to methodological recommendations for conducting field tests under irrigation conditions. In the above-ground mass of plants, straw and grain, the total content was determined: nitrogen – according to Kjeldahl, phosphorus – according to Murphy-Reilly, potassium – using a flame photometer. It was determined that on the irrigated lands of the South of Ukraine, the use of growth regulators Gumifield Forte brix, MIR and PROLIS had a significant effect on the accumulation of the main nutrients (especially nitrogen) by plants and winter barley grains. The highest content of basic nutrients in plants was at the early stages of development (spring tillering), after which their amount decreased until the end of the growing season of the crop. The maximum nitrogen content of 2.02% on dry matter on the Dev'iatyi val variety and 1.85% on the Academichnyi variety was provided by the use of Gummifield Forte Brix.Among the varieties, the Dev'iatyi val, on average, accumulated nitrogen in the grain for sowing on October 1 and 20 by 9.1 and 9.5 percentage points more than Akademichnyi, according to the plant growth regulator factor. Thanks to the treatment of winter barley seeds with plant growth regulators Gumifield Forte Brix and PROLIS and sowing the crop at the optimal time, it is possible to increase the nitrogen content in plants and grain by 6.0-15.1 and 9.3-22.5 percentage points, respectively, which will have a positive effect on grain formation and its quality. In further studies, it is necessary to optimize the application doses of mineral fertilizers using new multi-component growth regulators of winter barley plants under irrigation conditions in the South of Ukraine

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“…The imidazoline and imidazolidine nitroxide radicals (NRs) are the most commonly used pH-sensitive EPR probes [19]. Figure 1 shows 4-amino-2,2,5,5-tetramethyl-3-imidazoline-1-yloxy (ATI) [20], a commonly used imidazolidine NR. The protonation of the N-3 atom of ATI leads to a decrease in unpaired electron density at the N-1 atom and is manifested in the EPR spectrum as a decrease in the hyperfine coupling constant.…”

Section: Introductionmentioning

confidence: 99%

Spectral modeling for accelerated pH spectroscopy using EPR

Ahmad

Potter

Khramtsov

2012

Journal of Magnetic Resonance

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A data modeling and processing method for electron paramagnetic resonance (EPR)-based pH spectroscopy is presented. The proposed method models the EPR spectrum of a pH-sensitive probe in both protonated and unprotonated forms. Under slow-exchange conditions, the EPR spectrum of a sample with an unknown pH value can be accurately represented by a weighted sum of the two models, with the pH value completely determined by their relative weights. Unlike traditional pH spectroscopy, which relies on locating resonance peaks, the proposed modeling-based approach utilizes the information from the entire scan and hence leads to more accurate estimation of pH for a given acquisition time. By employing the proposed methodology, we expect a reduction in the pH estimation error by more than a factor of three, which represents an order of magnitude reduction in acquisition time compared to the traditional method.

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Functional EPR Spectroscopy and Imaging of Nitroxides

Cited by 5 publications

References 102 publications

New Developments in Spin Labels for Pulsed Dipolar EPR

New Developments in Spin Labels for Pulsed Dipolar EPR

Dynamics of the content of nutrients in winter barley plants depending on the variety, sowing dates and plant growth regulators

Spectral modeling for accelerated pH spectroscopy using EPR

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