EPR spectroscopy of complex biological iron–sulfur systems

Hagen, Wilfred R.

doi:10.1007/s00775-018-1543-y

Cited by 34 publications

(28 citation statements)

References 63 publications

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“…This series of papers is a landmark for both NMR of paramagnetic systems and for Fe-S proteins. Only 1 year earlier, the first interpretation of the NMR spectra of paramagnetic proteins appeared for cytochrome c (Kowalsky, 1965;McDonald et al, 1969;Wüthrich, 1969), and very few articles were available on paramagnetic NMR spectra of transition metal complexes (Holm et al, 1966;La Mar and Sacconi, 1968;Sacconi and Bertini, 1966). The first NMR spectra of non-heme metalloproteins showed everyone the huge potential of NMR spectroscopy, capable of combining on the one hand the information on the electronic structure of the paramagnetic center and, on the other hand, its unique ability to identify individual hydrogen atoms within the protein framework.…”

Section: Introductionmentioning

confidence: 99%

The long-standing relationship between paramagnetic NMR and iron–sulfur proteins: the mitoNEET example. An old method for new stories or the other way around?

et al. 2021

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Abstract. Paramagnetic NMR spectroscopy and iron–sulfur (Fe–S) proteins have maintained a synergic relationship for decades. Indeed, the hyperfine shifts with their temperature dependencies and the relaxation rates of nuclei of cluster-bound residues have been extensively used as a fingerprint of the type and of the oxidation state of the Fe–S cluster within the protein frame. The identification of NMR signals from residues surrounding the metal cofactor is crucial for understanding the structure–function relationship in Fe–S proteins, but it is generally impaired in standard NMR experiments by paramagnetic relaxation enhancement due to the presence of the paramagnetic cluster(s). On the other hand, the availability of systems of different sizes and stabilities has, over the years, stimulated NMR spectroscopists to exploit iron–sulfur proteins as paradigmatic cases to develop experiments, models, and protocols. Here, the cluster-binding properties of human mitoNEET have been investigated by 1D and 2D 1H diamagnetic and paramagnetic NMR, in its oxidized and reduced states. The NMR spectra of both oxidation states of mitoNEET appeared to be significantly different from those reported for previously investigated [Fe2S2]2+/+ proteins. The protocol we have developed in this work conjugates spectroscopic information arising from “classical” paramagnetic NMR with an extended mapping of the signals of residues around the cluster which can be taken, even before the sequence-specific assignment is accomplished, as a fingerprint of the protein region constituting the functional site of the protein. We show how the combined use of 1D NOE experiments, 13C direct-detected experiments, and double- and triple-resonance experiments tailored using R1- and/or R2-based filters significantly reduces the “blind” sphere of the protein around the paramagnetic cluster. This approach provided a detailed description of the unique electronic properties of mitoNEET, which are responsible for its biological function. Indeed, the NMR properties suggested that the specific electronic structure of the cluster possibly drives the functional properties of different [Fe2S2] proteins.

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Section: Introductionmentioning

confidence: 99%

The long-standing relationship between paramagnetic NMR and iron–sulfur proteins: the mitoNEET example. An old method for new stories or the other way around?

et al. 2021

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“…Nevertheless, clear values for g eff -mid and A -mid are obtained. A g eff value of 4.8 suggests that the g -mid and A -mid are for the | ± 1/2〉 state from the rhombogram [9]. …”

Section: Resultsmentioning

confidence: 99%

Better Resolution of High-Spin Cobalt Hyperfine at Low Frequency: Co-Doped Ba(Zn1/3Ta2/3)O3 as a Model Complex

Antholine

Zhang

Gonzales

et al. 2018

IJMS

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Low-frequency electron paramagnetic resonance (EPR) is used to extract the EPR parameter A-mid and support the approximate X-band value of g-mid for Ba(CoyZn1/3−yTa2/3)O3. Although the cobalt hyperfine structure for the |±1/2〉 state is often unresolved at X-band or S-band, it is resolved in measurements on this compound. This allows for detailed analysis of the molecular orbital for the |±1/2〉 state, which is often the ground state. Moreover, this work shows that the EPR parameters for Co substituted into Zn compounds give important insight into the properties of zinc binding sites.

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“…Reduced forms are detectable by electron paramagnetic resonance (EPR) (S = ½ for most of the ETC clusters). The EPR signals provided a useful tool to determine reduction in the mitochondrial membrane in the 1960s (reviewed in [10]), and EPR continues to be used to examine the various proportions of oxidized and reduced carriers (their redox status) in complex systems [11].…”

Section: Cofactor Structures and Redox Potentialsmentioning

confidence: 99%

Electron carriers and energy conservation in mitochondrial respiration

Ramsay

2019

ChemTexts

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The chemical system for the transformation of energy in eukaryotic mitochondria has engaged researchers for almost a century. This summary of four lectures on the electron transport system in mitochondria is an introduction to the mammalian electron transport chain for those unfamiliar with mitochondrial oxidative phosphorylation. It gives references chosen to reflect the history of the field and to highlight some of the recent advances in bioenergetics. The electron transport chain converts the energy that is released as electrons are passed to carriers of progressively higher redox potential into a proton gradient across the membrane that drives adenosine triphosphate (ATP) synthesis. The electron carriers include flavins, iron-sulfur centers, heme groups, and copper to divide the redox change from reduced nicotinamide adenine dinucleotide (NADH) at −320 mV to oxygen at +800 mV into steps that allow conversion and conservation of the energy released in three major complexes (Complexes I, III, and IV) by moving protons across the mitochondrial inner membrane. The three processes of proton pumping are now known after the successful determination of the structures of the large membrane protein complexes involved. Mitochondria and their proteins play roles not only in the production of ATP but also in cell survival, for which energy supply is the key.

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EPR spectroscopy of complex biological iron–sulfur systems

Cited by 34 publications

References 63 publications

The long-standing relationship between paramagnetic NMR and iron–sulfur proteins: the mitoNEET example. An old method for new stories or the other way around?

The long-standing relationship between paramagnetic NMR and iron–sulfur proteins: the mitoNEET example. An old method for new stories or the other way around?

Better Resolution of High-Spin Cobalt Hyperfine at Low Frequency: Co-Doped Ba(Zn1/3Ta2/3)O3 as a Model Complex

Electron carriers and energy conservation in mitochondrial respiration

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