Host–Guest Complexes as Water-Soluble High-Performance DNP Polarizing Agents

Mao, Jiafei; Akhmetzyanov, Dmitry; Ouari, Olivier; Denysenkov, Vasyl; Corzilius, Björn; Plackmeyer, Jörn; Tordo, Paul; Prisner, Thomas F.; Glaubitz, Clemens

doi:10.1021/ja409840y

Cited by 35 publications

(33 citation statements)

References 49 publications

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“…The microwaves are directed directly at the rotating sample through a waveguide. Comparable enhancements on other membrane proteins using the same experimental setup but different polarizing agents have been reported from our group (Mao et al, 2013(Mao et al, , 2014Ong et al, 2013). 263 GHz vs. 400 MHz at 9.4 T).…”

Section: / 30supporting

confidence: 76%

The ABC exporter MsbA probed by solid state NMR – challenges and opportunities

Kaur

Lakatos

Spadaccini³

et al. 2015

Biological Chemistry

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ATP binding cassette (ABC) transporters form a superfamily of integral membrane proteins involved in translocation of substrates across the membrane driven by ATP hydrolysis. Despite available crystal structures and extensive biochemical data, many open questions regarding their transport mechanisms remain. Therefore, there is a need to explore spectroscopic techniques such as solid state NMR in order to bridge the gap between structural and mechanistic data. In this study, we investigate the feasibility of using Escherichia coli MsbA as a model ABC transporter for solid state NMR studies. We show that optimised solubilisation and reconstitution procedures enable preparing stable and homogenous protein samples. Depending on the duration of solubilisation, MsbA can be obtained in either an apo- or in a native lipid A bound form. Building onto these optimisations, the first promising MAS-NMR spectra with narrow lines have been recorded. However, further sensitivity improvements are required so that complex NMR experiments can be recorded within a reasonable amount of time. We therefore demonstrate the usability of paramagnetic doping for rapid data acquisition and explore dynamic nuclear polarisation as a method for general signal enhancement. Our results demonstrate that solid state NMR provides an opportunity to address important biological questions related to complex mechanisms of ABC transporters.

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Section: / 30supporting

confidence: 76%

The ABC exporter MsbA probed by solid state NMR – challenges and opportunities

Kaur

Lakatos

Spadaccini³

et al. 2015

Biological Chemistry

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“…Indeed, the outlook for surfactant encapsulated radical DNP on various chemical systems seems promising, with the recent paper by Mao et al using a similar approach with cyclodextrin. 41 Combined with the wide array of mono- and biradicals available, 17,18,20,21,40,42 this approach should offer effective methods to polarize important chemical systems opening up new scientific avenues.…”

Section: Resultsmentioning

confidence: 99%

High Field Dynamic Nuclear Polarization NMR with Surfactant Sheltered Biradicals

et al. 2014

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We illustrate the ability to place a water-insoluble biradical, bTbk, into a glycerol/water matrix with the assistance of a surfactant, sodium octyl sulfate (SOS). This surfactant approach enables a previously water insoluble biradical, bTbk, with favorable electron–electron dipolar coupling to be used for dynamic nuclear polarization (DNP) nuclear magnetic resonance (NMR) experiments in frozen, glassy, aqueous media. Nuclear Overhauser enhancement (NOE) and paramagnetic relaxation enhancement (PRE) experiments are conducted to determine the distribution of urea and several biradicals within the SOS macromolecular assembly. We also demonstrate that SOS assemblies are an effective approach by which mixed biradicals are created through an assembly process.

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“…This spawned a series of new nitroxide biradicals further optimized for CE DNP leading yet to higher enhancements. [20] [21] [22] [23] [24] [25] [26] …”

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confidence: 99%

Efficient Dynamic Nuclear Polarization at 800 MHz/527 GHz with Trityl‐Nitroxide Biradicals

et al. 2015

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Cross-effect (CE) dynamic nuclear polarization (DNP) is a rapidly developing technique that enhances the signal intensities in magic angle spinning (MAS) NMR spectra. We report CE DNP experiments at 211, 600 and 800 MHz using a new series of biradical polarizing agents referred to as TEMTriPols, in which a nitroxide (TEMPO) and a trityl radical are chemically tethered. The TEMTriPol molecule with the optimal performance yields a record 1H NMR signal enhancement of 65 at 800 MHz at a concentration of 10 mM in a glycerol/water solvent matrix. The CE DNP enhancement for the TEMTriPol biradicals does not decrease as the magnetic field is increased in the manner usually observed for bis-nitroxides. Instead, the relatively strong exchange interaction between the trityl and nitroxide moieties determines the magnetic field at which the optimum enhancement is observed.

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Host–Guest Complexes as Water-Soluble High-Performance DNP Polarizing Agents

Cited by 35 publications

References 49 publications

The ABC exporter MsbA probed by solid state NMR – challenges and opportunities

The ABC exporter MsbA probed by solid state NMR – challenges and opportunities

High Field Dynamic Nuclear Polarization NMR with Surfactant Sheltered Biradicals

Efficient Dynamic Nuclear Polarization at 800 MHz/527 GHz with Trityl‐Nitroxide Biradicals

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