Pulsed electron–electron double resonance (PELDOR) distance measurements in detergent micelles

Bode, Bela E.; Dastvan, Reza; Prisner, Thomas F.

doi:10.1016/j.jmr.2011.03.014

Cited by 19 publications

(17 citation statements)

References 38 publications

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“…Applications include synthetic model systems [5,10], soluble proteins [11] and nucleic acids [12]. Recent advances have included membrane proteins [9], even though the local concentration of spins can pose a problem in phospholipid vesicle membranes [13,14] and care has to be taken when interpreting the data from detergent-solubilised samples [15]. In addition to the inter-spin distance, the number of coupled spin-labels [2,16], their relative orientation [17] and a potential exchange interaction [10,18] can be determined, yielding additional information.…”

Section: Introductionmentioning

confidence: 99%

“…This approach has been demonstrated to be reliable and robust [23] for spin pairs. The underpinning assumptions ignore some factors such as size-restriction effects [15] and effects caused by the presence of more than two spins in a molecule [24]. Other factors, including incomplete spin-labelling in multiply labelled samples and distributions of molecules not homogeneous in three dimensions [14] can introduce additional uncertainties in data analysis.…”

Section: Introductionmentioning

confidence: 99%

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PELDOR in rotationally symmetric homo-oligomers

et al. 2013

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Nanometre distance measurements by pulsed electron–electron double resonance (PELDOR) spectroscopy have become an increasingly important tool in structural biology. The theoretical underpinning of the experiment is well defined for systems containing two nitroxide spin-labels (spin pairs); however, recently experiments have been reported on homo-oligomeric membrane proteins consisting of up to eight spin-labelled monomers. We have explored the theory behind these systems by examining model systems based on multiple spins arranged in rotationally symmetric polygons. The results demonstrate that with a rising number of spins within the test molecule, increasingly strong distortions appear in distance distributions obtained from an analysis based on the simple spin pair approach. These distortions are significant over a range of system sizes and remain so even when random errors are introduced into the symmetry of the model. We present an alternative approach to the extraction of distances on such systems based on a minimisation that properly treats multi-spin correlations. We demonstrate the utility of this approach on a spin-labelled mutant of the heptameric Mechanosensitive Channel of Small Conductance of E. coli.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

PELDOR in rotationally symmetric homo-oligomers

et al. 2013

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“…The results show a homogenous decay with a dimensionality of 2.8 ( Figure S3), which implies that the SUV size does not lead to a characteristic distance due to confinement in a small volume, as was observed for micelles. [39,40] Therefore, the distance obtained for the singly labeled peptide can be attributed to peptide-peptide interactions within the membrane.…”

Section: Deer Measurementsmentioning

confidence: 98%

The Topology, in Model Membranes, of the Core Peptide Derived from the T‐Cell Receptor Transmembrane Domain

et al. 2013

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The T-cell receptor-CD3 complex (TCR-CD3) serves a critical role in protecting organisms from infectious agents. The TCR is a heterodimer composed of α- and β-chains, which are responsible for antigen recognition. Within the transmembrane domain of the α-subunit, a region has been identified to be crucial for the assembly and function of the TCR. This region, termed core peptide (CP), consists of nine amino acids (GLRILLLKV), two of which are charged (lysine and arginine) and are crucial for the interaction with CD3. Earlier studies have shown that a synthetic peptide corresponding to the CP sequence can suppress the immune response in animal models of T-cell-mediated inflammation, by disrupting proper assembly of the TCR. As a step towards the understanding of the source of the CP activity, we focused on CP in egg phosphatidylcholine/cholesterol (9:1, mol/mol) model membranes and determined its secondary structure, oligomerization state, and orientation with respect to the membrane. To achieve this goal, 15-residue segments of TCRα, containing the CP, were synthesized and spin-labeled at different locations with a nitroxide derivative. Electron spin-echo envelope modulation spectroscopy was used to probe the position and orientation of the peptides within the membrane, and double electron-electron resonance measurements were used to probe its conformation and oligomerization state. We found that the peptide is predominantly helical in a membrane environment and tends to form oligomers (mostly dimers) that are parallel to the membrane plane.

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“…Next, we mention a few more examples of spin-label EPR studies by other groups such as those of Heinz-Jürgen Steinhoff [81,288,290,[321][322][323][324][325][326][327][328][329][330][331][332][333][334][335], of Klaus Möbius [17,69,264,328,[336][337][338][339], of Thomas Prisner [242,243,[340][341][342][343][344][345][346], Olav Schiemann [33,[347][348][349][350][351][352][353][354][355][356][357][358], Gunnar Jeschke [35,…”

Section: Overview Of Studies On Nitroxide Spin-labeled Proteins and Dmentioning

confidence: 99%

Biomolecular EPR Meets NMR at High Magnetic Fields

et al. 2018

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In this review on advanced biomolecular EPR spectroscopy, which addresses both the EPR and NMR communities, considerable emphasis is put on delineating the complementarity of NMR and EPR regarding the measurement of interactions and dynamics of large molecules embedded in fluid-solution or solid-state environments. Our focus is on the characterization of protein structure, dynamics and interactions, using sophisticated EPR spectroscopy methods. New developments in pulsed microwave and sweepable cryomagnet technology as well as ultrafast electronics for signal data handling and processing have pushed the limits of EPR spectroscopy to new horizons reaching millimeter and sub-millimeter wavelengths and 15 T Zeeman fields. Expanding traditional applications to paramagnetic systems, spin-labeling of biomolecules has become a mainstream multifrequency approach in EPR spectroscopy. In the high-frequency/high-field EPR region, sub-micromolar concentrations of nitroxide spin-labeled molecules are now sufficient to characterize reaction intermediates of complex biomolecular processes. This offers promising analytical applications in biochemistry and molecular biology where sample material is often difficult to prepare in sufficient concentration for NMR characterization. For multifrequency EPR experiments on frozen solutions typical sample volumes are of the order of 250 μL (S-band), 150 μL (X-band), 10 μL (Q-band) and 1 μL (W-band). These are orders of magnitude smaller than the sample volumes required for modern liquid- or solid-state NMR spectroscopy. An important additional advantage of EPR over NMR is the ability to detect and characterize even short-lived paramagnetic reaction intermediates (down to a lifetime of a few ns). Electron–nuclear and electron–electron double-resonance techniques such as electron–nuclear double resonance (ENDOR), ELDOR-detected NMR, PELDOR (DEER) further improve the spectroscopic selectivity for the various magnetic interactions and their evolution in the frequency and time domains. PELDOR techniques applied to frozen-solution samples of doubly spin-labeled proteins allow for molecular distance measurements ranging up to about 100 Å. For disordered frozen-solution samples high-field EPR spectroscopy allows greatly improved orientational selection of the molecules within the laboratory axes reference system by means of the anisotropic electron Zeeman interaction. Single-crystal resolution is approached at the canonical g-tensor orientations—even for molecules with very small g-anisotropies. Unique structural, functional, and dynamic information about molecular systems is thus revealed that can hardly be obtained by other analytical techniques. On the other hand, the limitation to systems with unpaired electrons means that EPR is less widely used than NMR. However, this limitation also means that EPR offers greater specificity, since ordinary chemical solvents and matrices do not give rise to EPR in contrast to NMR spectra. Thus, multifrequency EPR spectroscopy plays an important role in better understanding paramagnetic species such as organic and inorganic radicals, transition metal complexes as found in many catalysts or metalloenzymes, transient species such as light-generated spin-correlated radical pairs and triplets occurring in protein complexes of photosynthetic reaction centers, electron-transfer relays, etc. Special attention is drawn to high-field EPR experiments on photosynthetic reaction centers embedded in specific sugar matrices that enable organisms to survive extreme dryness and heat stress by adopting an anhydrobiotic state. After a more general overview on methods and applications of advanced multifrequency EPR spectroscopy, a few representative examples are reviewed to some detail in two Case Studies: (I) High-field ELDOR-detected NMR (EDNMR) as a general method for electron–nuclear hyperfine spectroscopy of nitroxide radical and transition metal containing systems; (II) High-field ENDOR and EDNMR studies of the Oxygen Evolving Complex (OEC) in Photosystem II, which performs water oxidation in photosynthesis, i.e., the light-driven splitting of water into its elemental constituents, which is one of the most important chemical reactions on Earth.

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Pulsed electron–electron double resonance (PELDOR) distance measurements in detergent micelles

Cited by 19 publications

References 38 publications

PELDOR in rotationally symmetric homo-oligomers

PELDOR in rotationally symmetric homo-oligomers

The Topology, in Model Membranes, of the Core Peptide Derived from the T‐Cell Receptor Transmembrane Domain

Biomolecular EPR Meets NMR at High Magnetic Fields

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