scholarly journals Electron transfer flavoprotein domain II orientation monitored using double electron-electron resonance between an enzymatically reduced, native FAD cofactor, and spin labels

2011 ◽  
Vol 20 (3) ◽  
pp. 610-620 ◽  
Author(s):  
Michael A. Swanson ◽  
Velavan Kathirvelu ◽  
Tomas Majtan ◽  
Frank E. Frerman ◽  
Gareth R. Eaton ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Spin Labels ◽  
Electron Resonance ◽  
Electron Transfer Flavoprotein ◽  
Double Electron ◽  
Double Electron Electron Resonance

scholarly journals Strategies to identify and suppress crosstalk signals in double electron–electron resonance (DEER) experiments with gadolinium<sup>III</sup> and nitroxide spin-labeled compounds

2020 ◽  
Vol 1 (2) ◽  
pp. 285-299
Author(s):  
Markus Teucher ◽  
Mian Qi ◽  
Ninive Cati ◽  
Henrik Hintz ◽  
Adelheid Godt ◽  
...  
Keyword(s):  
Relaxation Times ◽  
Molecular Complexes ◽  
Spin Labels ◽  
Electron Resonance ◽  
Molecular Rulers ◽  
Distance Distributions ◽  
Double Electron ◽  
Biomolecular Complexes ◽  
Double Electron Electron Resonance ◽  
Intermolecular Distances

Abstract. Double electron–electron resonance (DEER) spectroscopy applied to orthogonally spin-labeled biomolecular complexes simplifies the assignment of intra- and intermolecular distances, thereby increasing the information content per sample. In fact, various spin labels can be addressed independently in DEER experiments due to spectroscopically nonoverlapping central transitions, distinct relaxation times, and/or transition moments; hence, they are referred to as spectroscopically orthogonal. Molecular complexes which are, for example, orthogonally spin-labeled with nitroxide (NO) and gadolinium (Gd) labels give access to three distinct DEER channels that are optimized to selectively probe NO–NO, NO–Gd, and Gd–Gd distances. Nevertheless, it has been previously recognized that crosstalk signals between individual DEER channels can occur, for example, when a Gd–Gd distance appears in a DEER channel optimized to detect NO–Gd distances. This is caused by residual spectral overlap between NO and Gd spins which, therefore, cannot be considered as perfectly orthogonal. Here, we present a systematic study on how to identify and suppress crosstalk signals that can appear in DEER experiments using mixtures of NO–NO, NO–Gd, and Gd–Gd molecular rulers characterized by distinct, nonoverlapping distance distributions. This study will help to correctly assign the distance peaks in homo- and heterocomplexes of biomolecules carrying not perfectly orthogonal spin labels.

scholarly journals Direct assignment of EPR spectra to structurally defined iron-sulfur clusters in complex I by double electron–electron resonance

2010 ◽  
Vol 107 (5) ◽  
pp. 1930-1935 ◽  
Author(s):  
Maxie M. Roessler ◽  
Martin S. King ◽  
Alan J. Robinson ◽  
Fraser A. Armstrong ◽  
Jeffrey Harmer ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Complex I ◽  
Proton Translocation ◽  
Flavin Mononucleotide ◽  
Detailed Knowledge ◽  
Electron Resonance ◽  
Nadh:Quinone Oxidoreductase ◽  
Iron Sulfur ◽  
Double Electron ◽  
Double Electron Electron Resonance

In oxidative phosphorylation, complex I (NADH:quinone oxidoreductase) couples electron transfer to proton translocation across an energy-transducing membrane. Complex I contains a flavin mononucleotide to oxidize NADH, and an unusually long series of iron-sulfur (FeS) clusters, in several subunits, to transfer the electrons to quinone. Understanding coupled electron transfer in complex I requires a detailed knowledge of the properties of individual clusters and of the cluster ensemble, and so it requires the correlation of spectroscopic and structural data: This has proved a challenging task. EPR studies on complex I from Bos taurus have established that EPR signals N1b, N2 and N3 arise, respectively, from the 2Fe cluster in the 75 kDa subunit, and from 4Fe clusters in the PSST and 51 kDa subunits (positions 2, 7, and 1 along the seven-cluster chain extending from the flavin). The other clusters have either evaded detection or definitive signal assignments have not been established. Here, we combine double electron-electron resonance (DEER) spectroscopy on B. taurus complex I with the structure of the hydrophilic domain of Thermus thermophilus complex I. By considering the magnetic moments of the clusters and the orientation selectivity of the DEER experiment explicitly, signal N4 is assigned to the first 4Fe cluster in the TYKY subunit (position 5), and N5 to the all-cysteine ligated 4Fe cluster in the 75 kDa subunit (position 3). The implications of our assignment for the mechanisms of electron transfer and energy transduction by complex I are discussed.

scholarly journals Interaction of triarylmethyl radicals with DNA termini revealed by orientation-selective W-band double electron–electron resonance spectroscopy

2016 ◽  
Vol 18 (42) ◽  
pp. 29549-29554 ◽  
Author(s):  
Matvey V. Fedin ◽  
Georgiy Yu. Shevelev ◽  
Dmitrii V. Pyshnyi ◽  
Victor M. Tormyshev ◽  
Gunnar Jeschke ◽  
...  
Keyword(s):  
Experimental Evidence ◽  
Spin Labels ◽  
Resonance Spectroscopy ◽  
Specific Interactions ◽  
Distance Measurements ◽  
Electron Resonance ◽  
W Band ◽  
Double Electron ◽  
Double Electron Electron Resonance ◽  
Triarylmethyl Radicals

We report the first experimental evidence of specific interactions between DNAs and triarylmethyl spin labels, crucial for EPR distance measurements.

Distance measurements between manganese(ii) and nitroxide spin-labels by DEER determine a binding site of Mn2+ in the HP92 loop of ribosomal RNA

2015 ◽  
Vol 17 (23) ◽  
pp. 15098-15102 ◽  
Author(s):  
Ilia Kaminker ◽  
Morgan Bye ◽  
Natanel Mendelman ◽  
Kristmann Gislason ◽  
Snorri Th. Sigurdsson ◽  
...  
Keyword(s):  
Binding Site ◽  
Ribosomal Rna ◽  
Spin Labels ◽  
Distance Measurements ◽  
Electron Resonance ◽  
W Band ◽  
Double Electron ◽  
Nitroxide Spin Labels ◽  
Double Electron Electron Resonance

W-band (95 GHz) double electron–electron resonance (DEER) distance measurements between Mn2+ and nitroxide spin labels were used to determine the location of a Mn2+ binding site within an RNA molecule.

Direct Observation of Chain Lengths and Conformations in Oligofluorene Distributions from Controlled Polymerization by Double Electron-Electron Resonance

2019 ◽  
Author(s):  
Dennis Bücker ◽  
Annika Sickinger ◽  
Julian D. Ruiz Perez ◽  
Manuel Oestringer ◽  
Stefan Mecking ◽  
...  
Keyword(s):  
Chain Length ◽  
Length Distribution ◽  
Catalyst System ◽  
Chain Conformation ◽  
Controlled Polymerization ◽  
Chain Length Distribution ◽  
Electron Resonance ◽  
Double Electron ◽  
The Individual ◽  
Double Electron Electron Resonance

Synthetic polymers are mixtures of different length chains, and their chain length and chain conformation is often experimentally characterized by ensemble averages. We demonstrate that Double-Electron-Electron-Resonance (DEER) spectroscopy can reveal the chain length distribution, and chain conformation and flexibility of the individual n-mers in oligo-(9,9-dioctylfluorene) from controlled Suzuki-Miyaura Coupling Polymerization (cSMCP). The required spin-labeled chain ends were introduced efficiently via a TEMPO-substituted initiator and chain terminating agent, respectively, with an in situ catalyst system. Individual precise chain length oligomers as reference materials were obtained by a stepwise approach. Chain length distribution, chain conformation and flexibility can also be accessed within poly(fluorene) nanoparticles.

In-Cell Double Electron–Electron Resonance at Nanomolar Protein Concentrations

2021 ◽  
pp. 3679-3684
Author(s):  
Svetlana Kucher ◽  
Christina Elsner ◽  
Mariya Safonova ◽  
Stefano Maffini ◽  
Enrica Bordignon
Keyword(s):  
Electron Resonance ◽  
Double Electron ◽  
Double Electron Electron Resonance

Distance Determination in Proteins insideXenopus laevisOocytes by Double Electron−Electron Resonance Experiments

2010 ◽  
Vol 132 (24) ◽  
pp. 8228-8229 ◽  
Author(s):  
Ryuji Igarashi ◽  
Tomomi Sakai ◽  
Hideyuki Hara ◽  
Takeshi Tenno ◽  
Toshiaki Tanaka ◽  
...  
Keyword(s):  
Distance Determination ◽  
Electron Resonance ◽  
Double Electron ◽  
Double Electron Electron Resonance
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