EPR Spectrometers at DU
We have a variety of devices being utilized in foundational research and are active in developing and improving new equipment.
250 MHz Spectrometer
The University of Denver’s 250 MHz electron paramagnetic resonance (EPR) spectrometer was constructed for the in-vivo EPR imaging of physiological samples. Flexible design of the imager hardware and software allow for any pulse EPR imaging modality. When applied, this precision of T2e determination would be equivalent to 2 torr resolution of oxygen partial pressure in animal tissues.
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Publications
250 MHz Rapid Scan Cross Loop Resonator, L. A. Buchanan, L. B. Woodcock, G. A. Rinard, R. W. Quine, Y. Shi, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson., 50, 333 - 345 (2019).
Resonators for In Vivo Imaging: Practical Experience, G. A. Rinard, R. W. Quine, L. A. Buchanan, S. S. Eaton, G. R. Eaton, B. Epel, S. V. Sundramoorthy, and H. J. Halpern, Appl. Magn. Reson. 48, 1227 – 1247 (2017).
Triarylmethyl Radical: EPR Signal to Noise at Frequencies between 250 MHz and 1.5 GHz and Dependence of Relaxation on Radical and Salt Concentration and on Frequency, Y. Shi, R. W. Quine, G. A. Rinard, L. Buchanan, S. S. Eaton, G. R. Eaton, B. Epel, S. W. Seagle, and H. J. Halpern, Z. Physik. Chem. 231, 923 – 937 (2017).
Triarylmethyl Radical OX063d24 Oximetry: Electron Spin Relaxation at 250 MHz and RF Frequency Dependence of Relaxation and Signal-to-Noise, Y. Shi, R. W. Quine, G. A. Rinard, L. Buchanan, S. S. Eaton, G. R. Eaton, B. Epel, S. W. Seagle, and H. J. Halpern, Adv. Exp. Med. Biol. 977, 327 - 334 (2017).
Imaging Disulfide Dinitroxides at 250 MHz to Monitor Thiol Redox Status, H. Elajaili, J. R. Biller, G. M. Rosen, J. P. Y. Kao, M. Tseytlin, L. A. Buchanan, G. A. Rinard, R. W. Quine, J. McPeak, Y. Shi, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 260, 77 – 82 (2015).
Improved Sensitivity for Imaging Spin Trapped Hydroxy Radical at 250 MHz, J. R. Biller, M. Tseitlin, D. G. Mitchell, Z. Yu, L. A. Buchanan, H. Elajaili, G. M. Rosen, J. P. Y. Kao, S. S. Eaton, and G. R. Eaton, ChemPhysChem. 16, 528 – 531 (2015).
New spectral-spatial imaging algorithm for full EPR spectra of multiline nitroxides and pH sensitive trityl radicals, M. Tseitlin, J. R. Biller, H. Elajaili, V. Khramtsov, I. Dhimitruka, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 245, 150 – 155 (2014).
Imaging of Nitroxides at 250 MHz using Rapid-Scan Electron Paramagnetic Resonance, J. R. Biller, M. Tseitlin, R. W. Quine, G. A. Rinard, H. A. Weismiller, H. Elajaili, G. M. Rosen, J. P. Y. Kao, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 242, 162 – 168 (2014).
Frequency Dependence of Electron Spin Relaxation Times in Aqueous Solution for a Nitronyl Nitroxide Radical and Per-deuterated-Tempone between 250 MHz and 34 GHz, J. R. Biller, V. M. Meyer, H. Elajaili, G. M. Rosen, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 225, 52 – 57 (2012).
Digital EPR with an arbitrary waveform generator and direct detection at the carrier frequency, M. Tseitlin, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 213, 119-125 (2011).
Use of polyphase continuous excitation based on the Frank sequence for EPR and EPR Imaging, M. Tseitlin, R. W. Quine, S. S. Eaton, G. R. Eaton, J. Magn. Reson. 211, 221-227 (2011).
Rapid Frequency Scan EPR, M. Tseitlin, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 211, 156-161 (2011).
Use of the Frank Sequence in Pulse EPR, M. Tseitlin, R. W. Quine, S. S. Eaton,G. R. Eaton, H. J. Halpern, and J. H. Ardenkjaer-Larsen, J. Magn. Reson. 209, 306-309 (2011).
Quantitative Rapid Scan EPR Spectroscopy at 258 MHz, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 205, 23-27 (2010).
A Very Fast Switched Attenuator Circuit for Microwave and R.F. Applications, R. W. Quine, M. Tseytlin, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson. B, Magn. Reson. Engineer, 37B, 39-44 (2010).
Electron Spin T2 of a Nitroxyl Radical at 250 MHz Measured by Rapid Scan EPR, M. Tseitlin, A. Dhami, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 30, 651-656 (2006).
Pulsed Saturation Recovery 250 MHz Electron Paramagnetic Resonance Spectrometer, R. W. Quine, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson. B, (Magn. Reson. Engin.) 26B, 23-27 (2005).
Rapid-Scan EPR with Triangular Scans and Fourier Deconvolution to Recover the Slow-Scan Spectrum, J. P. Joshi, J. R. Ballard, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 175, 44-51 (2005).
Frequency (250 MHz to 9.2 GHz) and Viscosity Dependence of Electron Spin Relaxation of Triarylmethyl Radicals at Room Temperature, R. Owenius, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 172, 168-175 (2005).
Direct-detected rapid-scan EPR at 250 MHz, J. W. Stoner, D. Szymanski, S. S. Eaton, R. W. Quine, G. A. Rinard, and G. R. Eaton, J. Magn. Reson. 170, 127-135 (2004).
Frequency Dependence of EPR Signal Intensity, 250 MHz to 9.1 GHz, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 156, 113-121 (2002).
Magnet and Gradient Coil System for Low-Field EPR Imaging, G. A. Rinard, R. W. Quine, S. S. Eaton, G. R. Eaton, E. D. Barth, C. A. Pelizzari, and H. J. Halpern, Magn. Reson. Engineer. 15, 51-58 (2002).
Adapting a Hall Probe Controller for Current Control of an Air-Core Magnet, G. A. Rinard, R. W. Quine, G. R. Eaton, and S. S. Eaton, Magn. Reson. Engineer. 15, 47-50 (2002).
250 MHz Crossed Loop Resonator for Pulsed Electron Paramagnetic Resonance, G. A. Rinard, R. W. Quine, G. R. Eaton, and S. S. Eaton, Magn. Reson. Engineer. 15, 37-46 (2002).
Frequency Dependence of EPR Signal Intensity, 248 MHz to 1.4 GHz, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 154, 80-84 (2002).
A Pulsed and Continuous Wave 250 MHz Electron Paramagnetic Resonance Spectrometer, R. W. Quine, G. A. Rinard, S. S. Eaton, G. R. Eaton, Magn. Reson. Engineer. 15, 59-91 (2002).
700 MHz to 1 GHz Spectrometer
The tradeoff between increasing sensitivity and decreasing depth of penetration as frequency is increased led us to propose that this frequency range would be advantageous for experiments in mice. We are developing a table-top imager with capabilities for both rapid scan and pulse experiments. The light-weight air-core magnet holds 3D gradient coils, rapid scan coils, and a resonator sized for imaging mice.
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Publications
Tabletop 700 MHz EPR Imaging Spectrometer, L. A. Buchanan, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson. B, Magn. Reson. Engin. 48B, e21384, (2018).
UHF EPR spectrometer operating at frequencies between 400 MHz and 1 GHz, R. W. Quine, G. A. Rinard, Y. Shi, L. Buchanan, J. R. Biller, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson, Magn. Reson. Engineer 46B, 123 – 133 (2016).
Rapid Scan EPR
In rapid scan EPR the magnetic field is scanned through resonance in a time that is short relative to relaxation times. The signal is recorded with a quadrature double-balanced mixer at the resonance frequency. Passage effects on the trailing edge of the signal are removed by deconvolution, giving the absorption spectrum. For a wide range of samples the signal-to-noise obtained by rapid scan is substantially higher than for conventional continuous wave spectroscopy because the full spectrum is detected on each pass through resonance, higher microwave power can be used without signal saturation, and coherent averaging decreases noise. The benefits of detecting the full signal in each pass through resonance provides a sensitivity advantage even if the scan rate is slow relative to relaxation times. We are currently working on implementation for wider scans and at cryogenic temperatures. Rapid scan is implemented on our 250 MHz, 1 GHz, and X-band spectrometers.
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Publications
Rapid-Scan Electron Paramagnetic Resonance of Highly Resolved Hyperfine in Organic Radicals, J. McPeak, P. Höfer, S. Kacprzak, P. Carl, R. Weber, S. S. Eaton, and G. R. Eaton, ChemPhysChem, 21, 2564 – 2570 (2020)
Rapid-Scan EPR Imaging of a Phantom Comprised of Species with Different Linewidths and Relaxation Times, Y. Shi, S. S. Eaton, and G. R. Eaton, J. Magn. Reson, 308, 106593 (2019).
Background correction in rapid scan EPR spectroscopy, L. A. Buchanan, L. B. Woodcock, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 293, 1-8 (2018).
Using Rapid-scan EPR to improve the detection limit of quantitative EPR by more than one order of magnitude, J. Möser, K. Lips, M. Tseytlin, G. R. Eaton, S. S. Eaton, and A. Schnegg, J. Magn. Reson. 281, 17 – 25 (2017).
Rapid Scan EPR Imaging, S. S. Eaton, Y. Shi, L. Woodcock, L. A. Buchanan,J. McPeak, R. W. Quine, G. A. Rinard, B. Epel, H. J. Halpern, and G. R. Eaton, J. Magn. Reson. 280, 140 – 148 (2017).
Rapid Scan Electron Paramagnetic Resonance Opens New Avenues for Imaging Physiologically Important Parameters In Vivo, J. R. Biller, D. G. Mitchell, M. Tseytlin, H. Elajaili, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Visualized Exp. E54068, doi 10.3791/54068 (2016).
Comparison of continuous wave and rapid scan X-band electron paramagnetic resonance of irradiated clipped fingernails, H. Elajaili, J. McPeak, A. Romanyukha, P. Aggarwal, S. S. Eaton, and G. R. Eaton, Rad. Prot. Dos. 172, 133 - 138 (2016).
Rapid scan electron paramagnetic resonance at 1.0 GHz of defect centers in g-irradiated organic solids, Y. Shi, G. A. Rinard, R. W. Quine, S. S. Eaton, G. R. Eaton, Radiation Measurements 85, 57 – 63 (2016).
X-band Rapid Scan Electron Paramagnetic Resonance of Radiation Induced Defects in Tooth Enamel, Z. Yu, A. Romanyukha, S. S. Eaton, and G. R. Eaton, Radiation Research, 184, 175 - 179 (2015).
Field-Stepped Direct Detection Electron Paramagnetic Resonance, Z. Yu, T. Liu, H. Elajaili, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 258, 58 – 64 (2015).
Rapid-scan coherence signals in X-band EPR spectra of semiquinones with small hyperfine splittings, H. Elajaili, G. A. Rinard, Z. Yu, D. Mitchell, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 259, 20 - 23 (2015).
Electron Spin Relaxation Times and Rapid Scan EPR Imaging of pH-sensitive Amino Substituted Trityl Radicals, H. B. Elajaili, J. R. Biller, M. Tseitlin, I. Dhimitruka, V. V. Khramtsov, S. S. Eaton, and G. R. Eaton, Magn. Reson. Chem. 53, 280 – 284 (2015).
New spectral-spatial imaging algorithm for full EPR spectra of multiline nitroxides and pH sensitive trityl radicals, M. Tseitlin, J. R. Biller, H. Elajaili, V. V. Khramtsov, I. Dhimitruka, G. R. Eaton, and S. S. Eaton, J. Magn. Reson. 245, 150 – 155 (2014).
Imaging of Nitroxides at 250 MHz using Rapid-Scan Electron Paramagnetic Resonance, J. R. Biller, M. Tseitlin, R. W. Quine, G. A. Rinard, H. A. Weismiller, H. Elajaili, G. M. Rosen, J. P. Y. Kao, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 242, 162 – 164 (2014).
Rapid Scan Electron Paramagnetic Resonance, S. S. Eaton, R. W. Quine, M. Tseitlin, D. G. Mitchell, G. A. Rinard, and G. R. Eaton, in Multifrequency Electron Paramagnetic Resonance: Data and Techniques, S. K. Misra, ed., Wiley-VCH, ch. 2, 3 - 67 (2014).
Digitally generated excitation and near-baseband quadrature detection of rapid scan EPR signals M. Tseitlin, Z. Yu, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 249, 126 – 134 (2014).
Rapid-Scan EPR of Immobilized Nitroxides, Z. Yu, R. W. Quine, G. A. Rinard, M. Tseitlin, H. Elajaili, V. Kathirvelu, L. J. Clouston, P. J. Boratyński, A. Rajca, R. Stein, H. S. Mchaourab, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 247, 67-71 (2014).
Computationally Efficient Steady-State Solution of the Bloch Equations for Rapid Sinusoidal Scans Based on Fourier Expansion in Harmonics of the Scan Frequency, M. Tseitlin, G. R. Eaton, and S. S. Eaton, Appl. Magn. Reson. 44, 1373 – 1397 (2013).
Use of Rapid-Scan EPR to Improve Detection Sensitivity for Spin-Trapped Radicals, D. G. Mitchell, G. M. Rosen, M. Tseitlin, B. Symmes, S. S. Eaton, and G. R. Eaton, Biophys. J., 105, 338 – 342 (2013).
X-Band Rapid-scan EPR of Samples with Long Electron Relaxation Times: A Comparison of Continuous Wave, Pulse, and Rapid-scan EPR, D. G. Mitchell, M. Tseitlin, R. W. Quine, V. Meyer, M. Newton, A. Schnegg, B. George, S. S. Eaton, and G. R. Eaton, Mol. Phys. 111, 2664-2673 (2013).
A Resonated Coil Driver for Rapid Scan EPR, R. W. Quine, D. G. Mitchell, M. Tseitlin, S. S. Eaton, and G. R. Eaton, Conc. Magn. Reson, Magn. Reson. Engineer 41B, 95 – 110 (2012).
Uncertainty analysis for absorption and first-derivative EPR spectra, M. Tseitlin, S. S. Eaton, and G. R. Eaton, Concepts Magn. Reson. 40A, 295 – 305 (2012).
Corrections for sinusoidal background and non-orthogonality of signal channels in sinusoidal rapid magnetic field scans, M. Tseytlin, D. G. Mitchell, S. S. Eaton, and G. R. Eaton, J. Magn. Reson 223, 80 – 84 (2012).
X-band Rapid-Scan EPR of Nitroxyl Radicals, D. G. Mitchell, R. W. Quine, M. Tseitlin, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 214, 221-226 (2012).
Digital EPR with an arbitrary waveform generator and direct detection at the carrier frequency, M. Tseitlin, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 213, 119-125 (2011).
Rapid Frequency Scan EPR, M. Tseitlin, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 211, 156-161 (2011).
Electron Spin Relaxation and Heterogeneity of the 1:1 α,γ-Bisdiphenylene-β-phenylallyl (BDPA) : Benzene Complex, D. G. Mitchell, R. W. Quine, M. Tseitlin, R. T. Weber, V. Meyer, A. Avery, S. S. Eaton, and G. R. Eaton, J. Phys. Chem. B 115, 7986-7990 (2011).
Comparison of Continuous Wave, Spin Echo, and Rapid Scan EPR of Irradiated Fused Quartz, D. G. Mitchell, R. W. Quine, M. Tseitlin, V. Meyer, S. S. Eaton, and G. R. Eaton, Radiation Measurements 46, 993-996 (2011).
Deconvolution of Sinusoidal Rapid EPR Scans, M. Tseitlin, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 208, 279-283 (2011).
Combining Absorption and Dispersion Signals to Improve Signal-to-noise for Rapid Scan EPR Imaging, M. Tseitlin, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton. J. Magn. Reson. 203, 305-310 (2010).
Quantitative Rapid Scan EPR Spectroscopy at 258 MHz, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 205, 23-27 (2010).
Background Removal Procedure for Rapid Scan EPR, M. Tseitlin, T. Czechowski, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 196, 48-53 (2009).
Comparison of Maximum Entropy and Filtered Back-Projection Methods to Reconstruct Rapid-Scan EPR Images, M. Tseitlin, A. Dhami, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 184, 157-168 (2007).
Electron Spin T2 of a Nitroxyl Radical at 250 MHz Measured by Rapid Scan EPR, M. Tseitlin, A. Dhami, R. W. Quine, G. A. Rinard, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 30, 651-656 (2006).
Rapid-Scan EPR with Triangular Scans and Fourier Deconvolution to Recover the Slow-Scan Spectrum, J. P. Joshi, J. R. Ballard, G. A. Rinard, R. W. Quine, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 175, 44-51 (2005).
Impact of Resonator on Direct-detected Rapid-scan EPR at 9.8 GHz, J. P. Joshi, G. R. Eaton, and S. S. Eaton, Appl. Magn. Reson. 28, 239-249 (2005).
Direct-detected rapid-scan EPR at 250 MHz, J. W. Stoner, D. Szymanski, S. S. Eaton, R. W. Quine, G. A. Rinard, and G. R. Eaton, J. Magn. Reson. 170, 127-135 (2004).
9.7 & 34 GHz Spectrometer
Continuous wave and pulsed EPR experiments are performed on a Bruker Elexsys E580 spectrometer at X-band and Q-band. A closed cycle helium system from ColdEdge/Bruker permits experiments at temperatures down to 4.2 K. Applications include study of electron spin relaxation process in organic radicals and transition metals and double electron-electron distance measurements in spin-labeled proteins.
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Publications
Electron Paramagnetic Resonance Characterization and Electron Spin Relaxation of Manganate Ion in Glassy Alkaline LiCl Solution and Doped into Cs2SO4, S. N. Mahapatro, T. A. Hovey, T. Ngendahimana, S. S. Eaton, and G. R. Eaton, J. Inorg. Biochem, 229, 111732 (2022).
Bis-Spiro-Oxetane and Bis-Spiro-Tetrahydrofuran Pyrroline Nitroxide Radicals: Synthesis and Electron Spin Relaxation Studies, S. Huang, M. Pink, T. Ngendahimana, S. Rajca, G. R. Eaton and S. S. Eaton, J. Org. Chem. 86, 13636 – 13643 (2021).
Nitroxide Diradical EPR Lineshapes and Spin Relaxation, J. P. Y. Kao, W. Moore, L. Woodcock, N. D. A. Dirda, E. A. Legenzov, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 52, (2021).
Electron spin relaxation of P1 centers in synthetic diamonds with potential as B1 standards for DNP enhanced NMR, A. M. Carroll, S. S. Eaton, G. R. Eaton, K. W. Zilm, J. Magn. Reson. 322, 106875 (2021).
13C Isotope Enrichment of the Central Trityl Carbon Decreases Fluid Solution Electron Spin Relaxation Times, W. Moore, J. McPeak, M. Poncelet, B. Driesschaert, S. S. Eaton, and G. R. Eaton, J. Magn. Reson. 318, 106797 (2020).
Spectroscopic and Electrochemical Characterization of the Mycofactocin Biosynthetic Protein, MftC, Provides Insight into its Redox Flipping Mechanism, R. Ayikpoe, T. Ngendahimana, M. Langton, S. Bonitatibus, L. M. Walker, S. S. Eaton, G. R. Eaton, M. Eirini-Pandelia, S. J. Elliott, and J. A. Latham, Biochemistry 58, 940 – 950 (2019).
Electron Spin Relaxation and Biochemical Characterization of the Hydrogenase Maturase HydF: Insights into [2Fe-2S] and [4Fe-4S] Cluster Communication and Hydrogenase Activation, E. M. Shepard, A. S. Byer, P. Aggarwal, J. N. Betz, A. K. Scott, K. A. Shisler, R. J. Usselman, G. R. Eaton, S. S. Eaton, and J. B. Broderick, Biochemistry 56, 3234 – 3247 (2017).
Mycofactocin biosynthesis: Modification of the peptide MftA by the radical S-adenosylmethionine protein MftC, B. Khaliullin, P. Aggarwal, M. Bubas, G.R. Eaton, S. S. Eaton, and J. A. Latham, FEBS Lett. 590, 2538 – 2548 (2016).
Fracture and growth are competing forces determining the fate of conformers in tau fibril populations, V. Meyer, M. R. Holden, H. A. Weismiller, G. R. Eaton, S. S. Eaton, and M. Margittai, J. Biol. Chem. 291, 12271 – 12281 (2016).
Paramagnetic Viral Capsids as T2-Enhanced Magnetic Resonance Imaging Contrast Agents at High Magnetic Fields, R. J. Usselman, S. Qazib, P. Aggarwal, S. S. Eaton, G. R. Eaton, S. Russek, and T. Douglas, Appl. Magn. Reson. 46, 349 – 355 (2015).
An X-Band Crossed-Loop EPR Resonator, G. A. Rinard, R. W. Quine, J. McPeak, L. Buchanan, S. S. Eaton, and G. R. Eaton, Appl. Magn. Reson. 48, 1219 – 1226 (2017).
Multiharmonic Electron Paramagnetic Resonance for Extended Samples with both Narrow and Broad Lines, Z. Yu, M. Tseitlin, S. S. Eaton, G. R. Eaton, J. Magn. Reson, 254, 86 – 92 (2015).
Single Mutations in Tau Modulate the Populations of Fibril Conformers through Seed Selection, V. Meyer, P. D. Dinkel, Y. Luo, X. Yu, G. Wei, J. Zheng, G. R. Eaton, G. B. Ma, R. Nussinov, S. S. Eaton, and M. Margittai, Angew. Chem. Int. Ed., 53, 1590-1593 (2014).
Conformational Basis for Asymmetric Seeding Barrier in Filaments of Three- and Four-repeat Tau, A. Siddiqua, Y. Luo, V. Meyer, M. A. Swanson, X. Yu, G. Wei, J. Zheng, G. R. Eaton, B. Ma, R. Nussinov, S. S. Eaton, and M. Margittai, J. Amer. Chem. Soc. 134, 10271 – 10278 (2012).
The Iron-Sulfur Cluster of Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO) is the Electron Acceptor for Electron Transfer Flavoprotein, M. A. Swanson, R. J. Usselman, F. E. Frerman, G. R. Eaton, and S. S. Eaton, Biochemistry 47, 8894-8901 (2008).
Impact of Mutations on the Midpoint Potential of the [4Fe-4S]+ Cluster and on the Catalytic Activity in Electron Transfer Flavoprotein-ubiquinone Oxidoreductase (ETF-QO), R. J. Usselman, A. J. Fielding, F. E. Frerman, G. R. Eaton, and S. S. Eaton, Biochemistry 47, 92-100 (2008).