Molecular distances from dipolar coupled spin-labels: the global analysis of multifrequency continuous wave electron paramagnetic resonance data

Hustedt, Eric J.; Smirnov, Alex I.; Laub, C.F.; Cobb, Charles E.; Beth, Albert H.

doi:10.1016/s0006-3495(97)78832-5

Cited by 147 publications

(148 citation statements)

References 40 publications

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“…The orientation of the magnetic field, H 0 , with respect to {x,y,z} was determined by Euler angles and . Following previously published work (30), the A-tensors for nitroxides 1 and 2 were given by,…”

Section: Methodsmentioning

confidence: 99%

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Organization of the Mitochondrial Apoptotic BAK Pore

Aluvila

Mandal

Hustedt

et al. 2014

Journal of Biological Chemistry

109

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Background: BAK and BAX permeabilize the mitochondrial membrane during apoptosis. Results: Helices ␣2-␣5 of BAK form the "BH3-in-groove homodimer" in the membrane, which oligomerizes by juxtaposing the carboxyl termini of ␣3 and ␣5, respectively. Conclusion: A novel "␣3:␣3Ј, ␣5:␣5Ј oligomerization interface" exists in the BAK oligomeric pore. Significance: These results support a model for BAX/BAK pore formation, which constitutes a key regulatory step in mitochondrial apoptosis.

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Section: Methodsmentioning

confidence: 99%

“…where r, the inter-electron distance, and all the other terms and symbols were as previously defined (30). Fitting was performed using Marquardt-Levenberg and simulated annealing algorithms developed in house.…”

Section: Methodsmentioning

confidence: 99%

Organization of the Mitochondrial Apoptotic BAK Pore

Aluvila

Mandal

Hustedt

et al. 2014

Journal of Biological Chemistry

109

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“…It has been well established that dipolar broadening interactions can be described by a Pake pattern-type broadening function, which can also be used to obtain interspin distances (34,(52)(53)(54). We therefore tested whether such an analysis could also be used to describe the broadening that occurs at low percentages of R1 (Fig.…”

Section: ␣-Synuclein Fibril Structure Analysismentioning

confidence: 99%

Investigation of α-Synuclein Fibril Structure by Site-directed Spin Labeling

Chen

Margittai

Chen

et al. 2007

Journal of Biological Chemistry

223

254

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The misfolding and fibril formation of ␣-synuclein plays an important role in neurodegenerative diseases such as Parkinson disease. Here we used electron paramagnetic resonance spectroscopy, together with site-directed spin labeling, to investigate the structural features of ␣-synuclein fibrils. We generated fibrils from a total of 83 different spin-labeled derivatives and observed single-line, exchange-narrowed EPR spectra for the majority of all sites located within the core region of ␣-synuclein fibrils. Such exchange narrowing requires the orbital overlap between multiple spin labels in close contact. The core region of ␣-synuclein fibrils must therefore be arranged in a parallel, inregister structure wherein same residues from different molecules are stacked on top of each other. This parallel, in-register core region extends from residue 36 to residue 98 and is tightly packed. Only a few sites within the core region, such as residues 62-67 located at the beginning of the NAC region, as well as the N-and C-terminal regions outside the core region, are significantly less ordered. Together with the accessibility measurements that suggest the location of potential ␤-sheet regions within the fibril, the data provide significant structural constraints for generating three-dimensional models. Furthermore, the data support the emerging view that parallel, in-register structure is a common feature shared by a number of naturally occurring amyloid fibrils.

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“…Some technical details and applications which are beyond the scope of this report are provided in our recent publications [3][4][5][6][7][8].…”

Section: The Mark II W-band (95 Ghz) Emr Spectrometermentioning

confidence: 99%

Coal and Coal Constituent Studies by Advanced EMR Techniques

Smirnov¹,

Nilges²,

Belford³

et al. 1998

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Advanced electronic magnetic resonance (EMR) methods are used to examine properties of coals, chars, and molecular species related to constituents of coal. We have achieved substantial progress on upgrading the high field (HF) EMR (W-band, 95 GHz) spectrometers that are especially advantageous for such studies. Particularly, we have built a new second W-band instrument (Mark II) in addition to our Mark I. Briefly, Mark II features: (i) an Oxford custombuilt 7 T superconducting magnet which is scannable from 0 to 7 T at up to 0.5 T/min; (ii) watercooled coaxial solenoid with up to ±550 G scan under digital (15 bits resolution) computer control; (iii) custom-engineered precision feed-back circuit, which is used to drive this solenoid, is based on an Ultrastab 860R sensor that has linearity better than 5 ppm and resolution of 0.05 ppm; (iv) an Oxford CF 1200 cryostat for variable temperature studies from 1.8 to 340 K. During this grant period we have completed several key upgrades of both Mark I and II, particularly microwave bridge, W-band probehead, and computer interfaces. We utilize these improved instruments for HF EMR studies of spin-spin interaction and existence of different paramagnetic species in carbonaceous solids.Semiannual Technical Report to DOE -PETC -Grant # DE-FG22-96PC96205 9/01/97-2/28/98Page 3 of EXECUTIVE SUMMARYThe main advanced magnetic resonance method that we report for the third half-year of this project was W-band (95 GHz) electron magnetic resonance (EMR, EPR, or ESR) spectroscopy. High field (HF) EMR, which usually refers to EMR at >90 GHz, among other specific advantages, provides an analytical tool to discriminate among very similar paramagnetic species that are constituents of coals and closely related materials such as chars. These species are difficult to identify from conventional EMR (X-band, 9.5 GHz) because of insufficient spectral resolution for radicals with similar g-factors. In addition to that conditions for fast Heisenberg exchange are often fulfilled at this frequency resulting in a featureless single-line EMR spectrum at 9.5 GHz. At 95 GHz (W-band), the g-factor resolution is ten-fold of that at X-band and the frequency of experiment usually exceeds the exchange frequency. This yields an information-rich spectrum. This report describes some experimental results obtained at 95 GHz and also considerable progress made on enhancing our W-band spectrometers used in such studies.This report focuses on the HF EMR work. The previous two Technical Reports described the use of pulsed proton DNP to study liquid-solid interactions in aqueous slurries of several newly synthesized chars. This report focuses primarily on studies of co-existing paramagnetic species and spin-spin interactions between those in carbonaceous materials and the role of molecular oxygen as a possible "bridge" for those magnetic interactions. Semiannual

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Molecular distances from dipolar coupled spin-labels: the global analysis of multifrequency continuous wave electron paramagnetic resonance data

Cited by 147 publications

References 40 publications

Organization of the Mitochondrial Apoptotic BAK Pore

Organization of the Mitochondrial Apoptotic BAK Pore

Investigation of α-Synuclein Fibril Structure by Site-directed Spin Labeling

Coal and Coal Constituent Studies by Advanced EMR Techniques

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