How accurately defined are the overtone coefficients in Gd(III)-Gd(III) RIDME?

G. Jeschke, DEER distance measurements on proteins, in: M.A. Johnson, T.J. Martinez (Eds.), Annual Review of Physical Chemistry, vol. 63; Annual Reviews, Palo Alto, 2012, pp. 419–446. Schiemann, 2007, Long-range distance determinations in biomacromolecules by EPR spectroscopy, Q Rev. Biophys., 40, 1, 10.1017/S003358350700460X Hubbell, 2013, Technological advances in site-directed spin labeling of proteins, Curr. Opin. Struct. Biol., 23, 725, 10.1016/j.sbi.2013.06.008 Roser, 2016, Site-directed spin labeling of proteins for distance measurements in vitro and in cells, Org. Biomol. Chem., 14, 5468, 10.1039/C6OB00473C Fielding, 2014, New Developments in Spin Labels for Pulsed Dipolar EPR, Molecules, 19, 16998, 10.3390/molecules191016998 Bleicken, 2014, Structural model of active Bax at the membrane, Mol. Cell, 56, 496, 10.1016/j.molcel.2014.09.022 Lavery, 2014, Structural asymmetry in the closed state of mitochondrial Hsp90 (TRAP1) supports a two-step ATP hydrolysis mechanism, Mol. Cell, 53, 330, 10.1016/j.molcel.2013.12.023 Duss, 2014, Structural basis of the non-coding RNA RsmZ acting as a protein sponge, Nature, 509, 588, 10.1038/nature13271 Durr, 2014, Structure and dynamics of AMPA receptor GluA2 in resting, Pre-open, and desensitized states, Cell, 158, 778, 10.1016/j.cell.2014.07.023 M. Yulikov, Spectroscopically orthogonal spin labels and distance measurements in biomolecules, in: B.C. Gilbert, V. Chechik, D.M. Murphy (Eds.), Electron Paramagnetic Resonance, vol. 24, Electron Paramagnetic Resonance-Specialist Periodical Report, Royal Soc Chemistry, Cambridge, 2015, pp. 1–31. Ritsch, 2019, Pulsed EPR methods to study biomolecular interactions, Chimia, 73, 268, 10.2533/chimia.2019.268 Teucher, 2020, Orthogonally spin-labeled rulers help to identify crosstalk signals and improve DEER signal fidelity, Magn. Reson. Discuss. Akhmetzyanov, 2016, RIDME spectroscopy on high-spin Mn2+ centers, Phys. Chem. Chem. Phys., 18, 30857, 10.1039/C6CP05239H Wiegand, 2017, Solid-state NMR and EPR Spectroscopy of Mn2+-Substituted ATP-Fueled Protein Engines, Angew. Chem. Int. Edit., 56, 3369, 10.1002/anie.201610551 A.V. Astashkin, Mapping the Structure of Metalloproteins with RIDME, in: P.Z. Qin, K. Warncke (Eds.), Methods in Enzymology, Elsevier Academic Press Inc, San Diego, vol. 563, 2015, pp. 251–284. Abdullin, 2019, Pulsed EPR dipolar spectroscopy on spin pairs with one highly anisotropic spin center: The low-spin Fe-III case, Chem.-Eur. J., 25, 14388, 10.1002/chem.201902908 Abdullin, 2019, Pulsed EPR dipolar spectroscopy under the breakdown of the high-field approximation: The high-spin iron(III) case, Chem.-Eur. J., 25, 8820, 10.1002/chem.201900977 Cunningham, 2015, The double-histidine Cu2+-binding motif: A highly rigid, site-specific spin probe for electron spin resonance distance measurements, Angew. Chem. Int. Edit., 54, 6330, 10.1002/anie.201501968 Garbuio, 2015, Gd(III) complexes for electron-electron dipolar spectroscopy: Effects of deuteration, pH and zero field splitting, J. Magn. Reson., 259, 163, 10.1016/j.jmr.2015.08.009 Feintuch, 2015, Gd3+ Spin Labeling for Measuring Distances in Biomacromolecules: Why and How?, Method Enzymol., 563, 415, 10.1016/bs.mie.2015.07.006 Cacheris, 1990, The relationship between thermodynamics and the toxicity of gadolinium complexes, Magn. Reson. Imaging, 8, 467, 10.1016/0730-725X(90)90055-7 Bousquet, 1988, GD-DOTA - Characterization of a new paramagnetic complex, Radiology, 166, 693, 10.1148/radiology.166.3.3340763 Weinmann, 1984, Charateristics of gadolinium-DTPA complex - A potential NMR contrast agent, Am. J. Roentgenol., 142, 619, 10.2214/ajr.142.3.619 Kulik, 2001, Electron dipole-dipole interaction in ESEEM of nitroxide biradicals, Chem. Phys. Lett., 343, 315, 10.1016/S0009-2614(01)00721-7 Milikisyants, 2009, A pulsed EPR method to determine distances between paramagnetic centers with strong spectral anisotropy and radicals: The dead-time free RIDME sequence, J. Magn. Reson., 201, 48, 10.1016/j.jmr.2009.08.008 Razzaghi, 2014, RIDME spectroscopy with Gd(III) centers, J. Phys. Chem. Lett., 5, 3970, 10.1021/jz502129t Keller, 2017, Computing distance distributions from dipolar evolution data with overtones: RIDME spectroscopy with Gd(III)-based spin labels, Phys. Chem. Chem. Phys., 19, 17856, 10.1039/C7CP01524K Keller, 2019, Intermolecular background decay in RIDME experiments, Phys. Chem. Chem. Phys., 21, 8228, 10.1039/C8CP07815G Collauto, 2016, RIDME distance measurements using Gd(III) tags with a narrow central transition, Phys. Chem. Chem. Phys., 18, 19037, 10.1039/C6CP03299K Azarkh, 2019, Gd(III)-Gd(III) Relaxation-Induced Dipolar Modulation Enhancement for In-Cell Electron Paramagnetic Resonance Distance Determination, J. Phys. Chem. Lett., 10, 1477, 10.1021/acs.jpclett.9b00340 Dalaloyan, 2015, Gd(III)-Gd(III) EPR distance measurements - the range of accessible distances and the impact of zero field splitting, Phys. Chem. Chem. Phys., 17, 18464, 10.1039/C5CP02602D Qi, 2016, Spacers for geometrically well-defined water-soluble molecular rulers and their application, J. Org. Chem., 81, 2549, 10.1021/acs.joc.6b00125 Qi, 2016, Synthesis and hydrolysis of 4-chloro-PyMTA and 4-iodo-PyMTA esters and their oxidative degradation with Cu(I/II) and oxygen, Synthesis, 48, 3773, 10.1055/s-0035-1561660 Ibanez, 2020, Optimal background treatment in dipolar spectroscopy, Phys. Chem. Chem. Phys., 22, 1855, 10.1039/C9CP06111H Jeschke, 2006, DeerAnalysis2006 - a comprehensive software package for analyzing pulsed ELDOR data, Appl. Magn. Reson., 30, 473, 10.1007/BF03166213