Tuning the properties of nitroxide spin labels for use in electron paramagnetic resonance spectroscopy through chemical modification of the nitroxide framework

Haugland, Marius M.; Anderson, Edward A.; Lovett, Janet E.

doi:10.1039/9781782629436-00001

Cited by 23 publications

(37 citation statements)

References 18 publications

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“…Experimental DEER spectra were then obtained by attaching spin labels at the equivalent sites on E. coli SecYEG, and measuring the inter-nitroxide distance (Martin et al, 1998; Jeschke, 2012; Haugland et al, 2016; Jeschke et al, 2006; Todd et al, 1989) for SecYEG alone; with SecA and ADP; and with SecA and the non-hydrolysable ATP analogue AMPPNP. The results reveal a strong nucleotide-dependent effect on channel conformation (Figure 5E–F and Figure 5—figure supplement 2).…”

Section: Resultsmentioning

confidence: 99%

ATP-induced asymmetric pre-protein folding as a driver of protein translocation through the Sec machinery

Corey

Ahdash

Shah

et al. 2019

eLife

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Transport of proteins across membranes is a fundamental process, achieved in every cell by the ‘Sec’ translocon. In prokaryotes, SecYEG associates with the motor ATPase SecA to carry out translocation for pre-protein secretion. Previously, we proposed a Brownian ratchet model for transport, whereby the free energy of ATP-turnover favours the directional diffusion of the polypeptide (Allen et al., 2016). Here, we show that ATP enhances this process by modulating secondary structure formation within the translocating protein. A combination of molecular simulation with hydrogendeuterium-exchange mass spectrometry and electron paramagnetic resonance spectroscopy reveal an asymmetry across the membrane: ATP-induced conformational changes in the cytosolic cavity promote unfolded pre-protein structure, while the exterior cavity favours its formation. This ability to exploit structure within a pre-protein is an unexplored area of protein transport, which may apply to other protein transporters, such as those of the endoplasmic reticulum and mitochondria.

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Section: Resultsmentioning

confidence: 99%

ATP-induced asymmetric pre-protein folding as a driver of protein translocation through the Sec machinery

Corey

Ahdash

Shah

et al. 2019

eLife

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“…Figure 2 shows the chemical structure of some nitroxide-based spin-label probes used for EPR spectroscopic studies of membrane proteins [13,27,[42][43][44][45][46][47][48][49][50]. The spin-label probes in Figure 2 are incorporated using site-directed mutagenesis.…”

Section: Nitroxide Based Spin Labeling Eprmentioning

confidence: 99%

Electron Paramagnetic Resonance as a Tool for Studying Membrane Proteins

Sahu

Lorigan

2020

Biomolecules

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Membrane proteins possess a variety of functions essential to the survival of organisms. However, due to their inherent hydrophobic nature, it is extremely difficult to probe the structure and dynamic properties of membrane proteins using traditional biophysical techniques, particularly in their native environments. Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling (SDSL) is a very powerful and rapidly growing biophysical technique to study pertinent structural and dynamic properties of membrane proteins with no size restrictions. In this review, we will briefly discuss the most commonly used EPR techniques and their recent applications for answering structure and conformational dynamics related questions of important membrane protein systems.

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“…This change in line-shape of the EPR spectrum relative to the diffusional case arises from as lower tumbling rate which can be ac onsequence of the impaired mobility of the TEMPO moiety upon STEMPO immobilization. [38] Figure 2f highlights the results from the FE-EPR investigation. C-mesoITO j STEMPO samples were poised at aparticular potential, using athree-electrode setup,and then flash-frozen to allow for low-temperature EPR characterization.…”

Section: Angewandte Chemiementioning

confidence: 99%

A Precious‐Metal‐Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO₂‐to‐Syngas Conversion

et al. 2020

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Electrolyzers combining CO2 reduction (CO2R) with organic substrate oxidation can produce fuel and chemical feedstocks with a relatively low energy requirement when compared to systems that source electrons from water oxidation. Here, we report an anodic hybrid assembly based on a (2,2,6,6‐tetramethylpiperidin‐1‐yl)oxyl (TEMPO) electrocatalyst modified with a silatrane‐anchor (STEMPO), which is covalently immobilized on a mesoporous indium tin oxide (mesoITO) scaffold for efficient alcohol oxidation (AlcOx). This molecular anode was subsequently combined with a cathode consisting of a polymeric cobalt phthalocyanine on carbon nanotubes to construct a hybrid, precious‐metal‐free coupled AlcOx–CO2R electrolyzer. After three‐hour electrolysis, glycerol is selectively oxidized to glyceraldehyde with a turnover number (TON) of ≈1000 and Faradaic efficiency (FE) of 83 %. The cathode generated a stoichiometric amount of syngas with a CO:H2 ratio of 1.25±0.25 and an overall cobalt‐based TON of 894 with a FE of 82 %. This prototype device inspires the design and implementation of nonconventional strategies for coupling CO2R to less energy demanding, and value‐added, oxidative chemistry.

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Tuning the properties of nitroxide spin labels for use in electron paramagnetic resonance spectroscopy through chemical modification of the nitroxide framework

Cited by 23 publications

References 18 publications

ATP-induced asymmetric pre-protein folding as a driver of protein translocation through the Sec machinery

ATP-induced asymmetric pre-protein folding as a driver of protein translocation through the Sec machinery

Electron Paramagnetic Resonance as a Tool for Studying Membrane Proteins

A Precious‐Metal‐Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO₂‐to‐Syngas Conversion

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Tuning the properties of nitroxide spin labels for use in electron paramagnetic resonance spectroscopy through chemical modification of the nitroxide framework

Cited by 23 publications

References 18 publications

ATP-induced asymmetric pre-protein folding as a driver of protein translocation through the Sec machinery

ATP-induced asymmetric pre-protein folding as a driver of protein translocation through the Sec machinery

Electron Paramagnetic Resonance as a Tool for Studying Membrane Proteins

A Precious‐Metal‐Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO2‐to‐Syngas Conversion

Contact Info

Product

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About

A Precious‐Metal‐Free Hybrid Electrolyzer for Alcohol Oxidation Coupled to CO₂‐to‐Syngas Conversion