1
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Wilson CB, Qi M, Han S, Sherwin MS. Gadolinium Spin Decoherence Mechanisms at High Magnetic Fields. J Phys Chem Lett 2023; 14:10578-10584. [PMID: 37976425 PMCID: PMC10694812 DOI: 10.1021/acs.jpclett.3c01847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2023] [Revised: 10/23/2023] [Accepted: 10/24/2023] [Indexed: 11/19/2023]
Abstract
Favorable relaxation processes, high-field spectral properties, and biological compatibility have made spin-7/2 Gd3+-based spin labels an increasingly popular choice for protein structure studies using high-field electron paramagnetic resonance. However, high-field relaxation and decoherence in ensembles of half-integer high-spin systems, such as Gd3+, remain poorly understood. We report spin-lattice (T1) and phase memory (TM) relaxation times at 8.6 T (240 GHz), and we present the first comprehensive model of high-field, high-spin decoherence accounting for both the electron spin concentration and temperature. The model includes four principal mechanisms driving decoherence: energy-conserving electron spin flip-flops, direct "T1" spin-lattice relaxation-driven electron spin flip processes, indirect T1-driven flips of nearby electron spins, and nuclear spin flip-flops. Mechanistic insight into decoherence can inform the design of experiments making use of Gd3+ as spin probes or relaxivity agents and can be used to measure local average interspin distances as long as 17 nm.
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Affiliation(s)
- C. Blake Wilson
- Laboratory
of Chemical Physics, National Institute of Diabetes and Digestive
and Kidney Diseases, National Institutes
of Health, Bethesda, Maryland 20892, United States
| | - Mian Qi
- Faculty
of Chemistry and Center for Molecular Materials, Bielefeld University, 33615 Bielefeld, Germany
| | - Songi Han
- Department
of Chemistry and Biochemistry, University
of California, Santa Barbara, Santa Barbara, California 93106, United States
- Department
of Chemical Engineering, University of California,
Santa Barbara, Santa
Barbara, California 93106, United States
- Institute
for Terahertz Science and Technology, University
of California, Santa Barbara, Santa
Barbara, California 93106, United States
| | - Mark S. Sherwin
- Institute
for Terahertz Science and Technology, University
of California, Santa Barbara, Santa
Barbara, California 93106, United States
- Department
of Physics, University of California, Santa
Barbara, Santa Barbara, California 93106, United States
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2
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Dubroca T, Wang X, Mentink-Vigier F, Trociewitz B, Starck M, Parker D, Sherwin MS, Hill S, Krzystek J. Terahertz EPR spectroscopy using a 36-tesla high-homogeneity series-connected hybrid magnet. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 353:107480. [PMID: 37331305 DOI: 10.1016/j.jmr.2023.107480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2023] [Revised: 04/24/2023] [Accepted: 05/13/2023] [Indexed: 06/20/2023]
Abstract
Electron Paramagnetic Resonance (EPR) is a powerful technique to study materials and biological samples on an atomic scale. High-field EPR in particular enables extracting very small g-anisotropies in organic radicals and half-filled 3d and 4f metal ions such as MnII (3d5) or GdIII (4f7), and resolving EPR signals from unpaired spins with very close g-values, both of which provide high-resolution details of the local atomic environment. Before the recent commissioning of the high-homogeneity Series Connected Hybrid magnet (SCH, superconducting + resistive) at the National High Magnetic Field Laboratory (NHMFL), the highest-field, high-resolution EPR spectrometer available was limited to 25 T using a purely resistive "Keck" magnet at the NHMFL. Herein, we report the first EPR experiments performed using the SCH magnet capable of reaching the field of 36 T, corresponding to an EPR frequency of 1 THz for g = 2. The magnet's intrinsic homogeneity (25 ppm, that is 0.9 mT at 36 T over 1 cm diameter, 1 cm length cylinder) was previously established by NMR. We characterized the magnet's temporal stability (5 ppm, which is 0.2 mT at 36 T over one-minute, the typical acquisition time) using 2,2-diphenyl-1-picrylhydrazyl (DPPH). This high resolution enables resolving the weak g-anisotropy of 1,3-bis(diphenylene)-2-phenylallyl (BDPA), Δg = 2.5 × 10-4 obtained from measurements at 932 GHz and 33 T. Subsequently, we recorded EPR spectra at multiple frequencies for two GdIII complexes with potential applications as spin labels. We demonstrated a significant reduction in line broadening in Gd[DTPA], attributed to second order zero field splitting, and a resolution enhancement of g-tensor anisotropy for Gd[sTPATCN]-SL.
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Affiliation(s)
- Thierry Dubroca
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA.
| | - Xiaoling Wang
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Center for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, FL 32611, USA
| | - Frédéric Mentink-Vigier
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Bianca Trociewitz
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Matthieu Starck
- Department of Chemistry, University of Durham, Durham DH13LE, UK
| | - David Parker
- Department of Chemistry, University of Durham, Durham DH13LE, UK
| | - Mark S Sherwin
- Department of Physics, University of California Santa Barbara, CA 93106, USA
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Center for Molecular Magnetic Quantum Materials, University of Florida, Gainesville, FL 32611, USA; Department of Physics, Florida State University, Tallahassee FL 32306, USA
| | - J Krzystek
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA.
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3
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Osipov VY, Boukhvalov DW, Takai K. Isolated Spin-7/2 Species of Gadolinium (III) Chelate Complexes on the Surface of 5-nm Diamond Particles. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:1995. [PMID: 37446511 DOI: 10.3390/nano13131995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2023] [Revised: 06/24/2023] [Accepted: 06/28/2023] [Indexed: 07/15/2023]
Abstract
The magnetic characteristics of a system of triply charged gadolinium ions Gd3+ chelated with carboxyls on the surface of detonation nanodiamond (DND) particles have been studied. Gd3+ ions demonstrate almost perfect spin (S = 7/2) paramagnetism with negligible antiferromagnetic interaction between spins (Weiss temperature about -0.35 K) for a wide range of concentrations up to ~18 ions per 5 nm particle. The study of the concentration dependence of the electron paramagnetic resonance signal for DND intrinsic defects with spin ½ (g = 2.0027) shows that Gd3+ ions are located on average at a distance of no more than 1.4 nm from shallow subsurface defects with spin 1/2. At the same time, they are located (according to density functional theory calculations) at a distance of about or at least 0.28 nm from the particle surface. Magnetic studies also confirm the isolated nature of the gadolinium chelate complexes on the surface of DND particles. DND particles turn out to be an optimal carrier for high-spin 4f- ions (gadolinium) in a highly concentrated isolated state. This property makes DND-Gd particles a candidate for the role of a contrast agent for magnetic resonance imaging.
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Affiliation(s)
| | - Danil W Boukhvalov
- Institute of Materials Physics and Chemistry, College of Science, Nanjing Forestry University, Nanjing 210037, China
- Institute of Physics and Technology, Ural Federal University, Mira 19 Str., Yekaterinburg 620002, Russia
| | - Kazuyuki Takai
- Department of Chemical Science and Technology, Hosei University, Tokyo 184-8584, Japan
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4
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Maity S, Price BD, Wilson CB, Mukherjee A, Starck M, Parker D, Wilson MZ, Lovett JE, Han S, Sherwin MS. Triggered Functional Dynamics of AsLOV2 by Time-Resolved Electron Paramagnetic Resonance at High Magnetic Fields. Angew Chem Int Ed Engl 2023; 62:e202212832. [PMID: 36638360 DOI: 10.1002/anie.202212832] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 01/06/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
We present time-resolved Gd-Gd electron paramagnetic resonance (TiGGER) at 240 GHz for tracking inter-residue distances during a protein's mechanical cycle in the solution state. TiGGER makes use of Gd-sTPATCN spin labels, whose favorable qualities include a spin-7/2 EPR-active center, short linker, narrow intrinsic linewidth, and virtually no anisotropy at high fields (8.6 T) when compared to nitroxide spin labels. Using TiGGER, we determined that upon light activation, the C-terminus and N-terminus of AsLOV2 separate in less than 1 s and relax back to equilibrium with a time constant of approximately 60 s. TiGGER revealed that the light-activated long-range mechanical motion is slowed in the Q513A variant of AsLOV2 and is correlated to the similarly slowed relaxation of the optically excited chromophore as described in recent literature. TiGGER has the potential to valuably complement existing methods for the study of triggered functional dynamics in proteins.
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Affiliation(s)
- Shiny Maity
- Dept. of Chemistry and Biochemistry, Univ. of California, Santa Barbara, CA 93106, USA
| | - Brad D Price
- Dept. of Physics, Univ. of California, Santa Barbara, CA 93106, USA
| | - C Blake Wilson
- Dept. of Physics, Univ. of California, Santa Barbara, CA 93106, USA.,Laboratory of Chemical Physics, Nat. Institute of Diabetes and Digestive and Kidney Diseases, NIH, Bethesda, MD 20892-0520, USA
| | - Arnab Mukherjee
- Dept. of Chemical Engineering, Univ. of California, Santa Barbara, CA 93106, USA
| | | | - David Parker
- Dept. of Chemistry, Univ. of Durham, Durham, DH1 3LE, UK
| | - Maxwell Z Wilson
- Dept. of Molecular, Cellular, and Developmental Biology, Univ. of California, Santa Barbara, CA 93106, USA
| | - Janet E Lovett
- School of Physics and Astronomy and the Biomedical Sciences Research Complex, Univ. of St. Andrews, St. Andrews, KY16 9SS, UK
| | - Songi Han
- Dept. of Chemistry and Biochemistry, Univ. of California, Santa Barbara, CA 93106, USA
| | - Mark S Sherwin
- Dept. of Physics, Univ. of California, Santa Barbara, CA 93106, USA
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5
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Ossadnik D, Kuzin S, Qi M, Yulikov M, Godt A. A Gd III-Based Spin Label at the Limits for Linewidth Reduction through Zero-Field Splitting Optimization. Inorg Chem 2023; 62:408-432. [PMID: 36525400 DOI: 10.1021/acs.inorgchem.2c03531] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The remarkably narrow central line in the electron paramagnetic resonance spectrum and the very weak zero-field splitting (ZFS) make [GdIII(NO3Pic)] ([GdIII(TPATCN)]) an attractive starting point for the development of spin labels. For retaining the narrow line of this parent complex when modifying it with a substituent enabling bioconjugation, alkyl with a somehow remote functional group as a substituent at the picolinate moiety was found to be highly suitable because ZFS stayed weak, even if the threefold axial symmetry was broken. The ZFS is so weak that hyperfine coupling and/or g-value variations noticeably determine the linewidth in Q band and higher fields when the biomolecule is protonated, which is the standard situation, and in W band and higher fields for the protonated complex in a fully deuterated surrounding. Clearly, [NDSE-{GdIII(NO3Pic)}], a spin label targeting the cysteines in a peptide, is at a limit of linewidth narrowing through ZFS minimization. The labeling reaction is highly chemoselective and, applied to a polyproline with two cysteine units, it took no more than a minute at 7 °C and pH 7.8. Subsequent disulfide scrambling is very slow and can therefore be prevented. Double electron-electron resonance and relaxation-induced dipolar modulation enhancement applied to the spin-labeled polyproline proved the spin label useful for distance determination in peptides.
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Affiliation(s)
- Daniel Ossadnik
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615Bielefeld, Germany
| | - Sergei Kuzin
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093Zurich, Switzerland
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615Bielefeld, Germany
| | - Maxim Yulikov
- Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093Zurich, Switzerland
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615Bielefeld, Germany
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6
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Yu L, Liu A, Zhang B, Kuang J, Guo X, Tian C, Lu Y. Dipolar coupling-based electron paramagnetic resonance method for protease enzymatic characterization and inhibitor screening. Chem Commun (Camb) 2021; 57:9602-9605. [PMID: 34546243 DOI: 10.1039/d1cc03301h] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Herein, we report an EPR-based method for protease enzymatic characterization and inhibitor screening. This method utilizes dual paramagnetically-labeled probes consisting of a nitroxide spin probe and a Gd3+ ion flanking a peptide that could be specifically cleaved by protease caspase-3. Distance-dependent dipolar coupling between the two paramagnetic centers can be modulated by the protease cleavage activity, thus providing a straightforward and convenient method for protease activity detection using EPR spectroscopy under ambient conditions. Moreover, time-course monitoring of the protease-catalyzed cleavage reaction demonstrated that this EPR-based method could not only allow a direct quantitative enzymatic kinetic assessment, but also could be used for protease inhibitor screening, thus holding great potential in drug discovery studies.
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Affiliation(s)
- Lu Yu
- The Anhui Provincial Key Laboratory of High Field Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031, P. R. China.
| | - Aokun Liu
- The Anhui Provincial Key Laboratory of High Field Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031, P. R. China. .,The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Bingbo Zhang
- Department of Medical Ultrasound, Shanghai Tenth People's Hospital, Tongji University Cancer Center, The Institute for Biomedical Engineering & Nano Science, Tongji University School of Medicine, Shanghai, 200072, P. R. China
| | - Jian Kuang
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Xiaoqi Guo
- The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Changlin Tian
- The Anhui Provincial Key Laboratory of High Field Magnetic Resonance Image, High Magnetic Field Laboratory, Chinese Academy of Science, Hefei, Anhui 230031, P. R. China. .,The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, Center for BioAnalytical Chemistry, and Hefei National Laboratory for Physical Sciences at Microscale, University of Science and Technology of China, Hefei, Anhui 230026, P. R. China
| | - Yi Lu
- Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL, 61801, USA.
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7
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Fedel M, Callone E, Ziarelli F, Deflorian F, Dirè S. Influence of Gd3+ on molecular organization and electrochemical properties of Si-based organic/inorganic sol-gel layers. Electrochim Acta 2020. [DOI: 10.1016/j.electacta.2020.136033] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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8
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Milikisiyants S, Nevzorov AA, Smirnov AI. Photonic band-gap resonators for high-field/high-frequency EPR of microliter-volume liquid aqueous samples. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2018; 296:152-164. [PMID: 30268940 PMCID: PMC6235713 DOI: 10.1016/j.jmr.2018.09.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2018] [Revised: 09/17/2018] [Accepted: 09/19/2018] [Indexed: 05/12/2023]
Abstract
High-field EPR provides significant advantages for studying structure and dynamics of molecular systems possessing an unpaired electronic spin. However, routine use of high-field EPR in biophysical research, especially for aqueous biological samples, is still facing substantial technical difficulties stemming from high dielectric millimeter wave (mmW) losses associated with non-resonant absorption by water and other polar molecules. The strong absorbance of mmW's by water also limits the penetration depth to just fractions of mm or even less, thus making fabrication of suitable sample containers rather challenging. Here we describe a radically new line of high Q-factor mmW resonators that are based on forming lattice defects in one-dimensional photonic band-gap (PBG) structures composed of low-loss ceramic discs of λ/4 in thickness and having alternating dielectric constants. A sample (either liquid or solid) is placed within the E = 0 node of the standing mm wave confined within the defect. A resonator prototype has been built and tested at 94.3 GHz. The resonator performance is enhanced by employing ceramic nanoporous membranes as flat sample holders of controllable thickness and tunable effective dielectric constant. The experimental Q-factor of an empty resonator was ≈ 420. The Q-factor decreased slightly to ≈ 370 when loaded with a water-containing nanoporous disc of 50 μm in thickness. The resonator has been tested with a number of liquid biological samples and demonstrated about tenfold gain in concentration sensitivity vs. a high-Q cylindrical TE012-type cavity. Detailed HFSS Ansys simulations have shown that the resonator structure could be further optimized by properly choosing the thickness of the aqueous sample and employing metallized surfaces. The PBG resonator design is readily scalable to higher mmW frequencies and is capable of accommodating significantly larger sample volumes than previously achieved with either Fabry-Perot or cylindrical resonators.
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Affiliation(s)
- Sergey Milikisiyants
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
| | - Alex I Smirnov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
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9
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Wilson CB, Aronson S, Clayton JA, Glaser SJ, Han S, Sherwin MS. Multi-step phase-cycling in a free-electron laser-powered pulsed electron paramagnetic resonance spectrometer. Phys Chem Chem Phys 2018; 20:18097-18109. [PMID: 29938285 DOI: 10.1039/c8cp01876f] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron paramagnetic resonance (EPR) is a powerful tool for research in chemistry, biology, physics and materials science, which can benefit significantly from moving to frequencies above 100 GHz. In pulsed EPR spectrometers driven by powerful sub-THz oscillators, such as the free electron laser (FEL)-powered EPR spectrometer at UCSB, control of the duration, power and relative phases of the pulses in a sequence must be performed at the frequency and power level of the oscillator. Here we report on the implementation of an all-quasioptical four-step phase cycling procedure carried out directly at the kW power level of the 240 GHz pulses used in the FEL-powered EPR spectrometer. Phase shifts are introduced by modifying the optical path length of a 240 GHz pulse with precision-machined dielectric plates in a procedure we call phase cycling with optomechanical phase shifters (POPS), while numerical receiver phase cycling is implemented in post-processing. The POPS scheme was successfully used to reduce experimental dead times, enabling pulsed EPR of fast-relaxing spin systems such as gadolinium complexes at temperatures above 190 K. Coherence transfer pathway selection with POPS was used to perform spin echo relaxation experiments to measure the phase memory time of P1 centers in diamond in the presence of a strong unwanted FID signal in the background. The large excitation bandwidth of FEL-EPR, together with phase cycling, enabled the quantitative measurement of instantaneous electron spectral diffusion, from which the P1 center concentration was estimated to within 10%. Finally, phase cycling enabled saturation-recovery measurements of T1 in a trityl-water solution at room temperature - the first FEL-EPR measurement of electron T1.
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Affiliation(s)
- C Blake Wilson
- Department of Physics, University of California, Santa Barbara, Santa Barbara, California, USA.
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10
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Clayton JA, Keller K, Qi M, Wegner J, Koch V, Hintz H, Godt A, Han S, Jeschke G, Sherwin MS, Yulikov M. Quantitative analysis of zero-field splitting parameter distributions in Gd(iii) complexes. Phys Chem Chem Phys 2018; 20:10470-10492. [PMID: 29617015 DOI: 10.1039/c7cp08507a] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The magnetic properties of paramagnetic species with spin S > 1/2 are parameterized by the familiar g tensor as well as "zero-field splitting" (ZFS) terms that break the degeneracy between spin states even in the absence of a magnetic field. In this work, we determine the mean values and distributions of the ZFS parameters D and E for six Gd(iii) complexes (S = 7/2) and critically discuss the accuracy of such determination. EPR spectra of the Gd(iii) complexes were recorded in glassy frozen solutions at 10 K or below at Q-band (∼34 GHz), W-band (∼94 GHz) and G-band (240 GHz) frequencies, and simulated with two widely used models for the form of the distributions of the ZFS parameters D and E. We find that the form of the distribution of the ZFS parameter D is bimodal, consisting roughly of two Gaussians centered at D and -D with unequal amplitudes. The extracted values of D (σD) for the six complexes are, in MHz: Gd-NO3Pic, 485 ± 20 (155 ± 37); Gd-DOTA/Gd-maleimide-DOTA, -714 ± 43 (328 ± 99); iodo-(Gd-PyMTA)/MOMethynyl-(Gd-PyMTA), 1213 ± 60 (418 ± 141); Gd-TAHA, 1361 ± 69 (457 ± 178); iodo-Gd-PCTA-[12], 1861 ± 135 (467 ± 292); and Gd-PyDTTA, 1830 ± 105 (390 ± 242). The sign of D was adjusted based on the Gaussian component with larger amplitude. We relate the extracted P(D) distributions to the structure of the individual Gd(iii) complexes by fitting them to a model that superposes the contribution to the D tensor from each coordinating atom of the ligand. Using this model, we predict D, σD, and E values for several additional Gd(iii) complexes that were not measured in this work. The results of this paper may be useful as benchmarks for the verification of quantum chemical calculations of ZFS parameters, and point the way to designing Gd(iii) complexes for particular applications and estimating their magnetic properties a priori.
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Affiliation(s)
- Jessica A Clayton
- University of California, Santa Barbara, Department of Physics, Santa Barbara, CA, USA.
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11
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Prokopiou G, Lee MD, Collauto A, Abdelkader EH, Bahrenberg T, Feintuch A, Ramirez-Cohen M, Clayton J, Swarbrick JD, Graham B, Otting G, Goldfarb D. Small Gd(III) Tags for Gd(III)–Gd(III) Distance Measurements in Proteins by EPR Spectroscopy. Inorg Chem 2018; 57:5048-5059. [DOI: 10.1021/acs.inorgchem.8b00133] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Georgia Prokopiou
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michael D. Lee
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Alberto Collauto
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Elwy H. Abdelkader
- Research School of Chemistry, Australian National University, Canberra, ACT 2601,Australia
| | - Thorsten Bahrenberg
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Akiva Feintuch
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Marie Ramirez-Cohen
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Jessica Clayton
- Department of Physics, University of California, Santa Barbara, California 93106-9530, United States
| | - James D. Swarbrick
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC 3052, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT 2601,Australia
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
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12
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Yin J, Chen D, Zhang Y, Li C, Liu L, Shao Y. MRI relaxivity enhancement of gadolinium oxide nanoshells with a controllable shell thickness. Phys Chem Chem Phys 2018; 20:10038-10047. [DOI: 10.1039/c8cp00611c] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The relaxation enhancement mechanism and MRI application of the designed core–shelled silica–Gd2O3 nanoparticle contrast agents were studied.
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Affiliation(s)
- Jinchang Yin
- School of Physics
- State Key Laboratory of Optoelectronic Materials and Technologies
- Sun Yat-sen University
- Guangzhou 510275
- P. R. China
| | - Deqi Chen
- Medical Physics Graduate Program
- Duke Kunshan University
- Kunshan 215316
- P. R. China
| | - Yu Zhang
- Department of Pathology
- Sun Yat-sen University Cancer Center
- State Key Laboratory of Oncology in South China
- Collaborative Innovation Center for Cancer Medicine
- Guangzhou 510060
| | - Chaorui Li
- School of Physics
- State Key Laboratory of Optoelectronic Materials and Technologies
- Sun Yat-sen University
- Guangzhou 510275
- P. R. China
| | - Lizhi Liu
- Center of Medical Imaging and Image-guided Therapy
- Sun Yat-sen University Cancer Center
- State Key Laboratory of Oncology in South China
- Collaborative Innovation Center for Cancer Medicine
- Guangzhou 510060
| | - Yuanzhi Shao
- School of Physics
- State Key Laboratory of Optoelectronic Materials and Technologies
- Sun Yat-sen University
- Guangzhou 510275
- P. R. China
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13
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Manukovsky N, Feintuch A, Kuprov I, Goldfarb D. Time domain simulation of Gd3+–Gd3+ distance measurements by EPR. J Chem Phys 2017; 147:044201. [DOI: 10.1063/1.4994084] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Affiliation(s)
- Nurit Manukovsky
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Akiva Feintuch
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Ilya Kuprov
- School of Chemistry, University of Southampton, Southampton SO17 1BJ, United Kingdom
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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14
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Clayton JA, Qi M, Godt A, Goldfarb D, Han S, Sherwin MS. Gd 3+-Gd 3+ distances exceeding 3 nm determined by very high frequency continuous wave electron paramagnetic resonance. Phys Chem Chem Phys 2017; 19:5127-5136. [PMID: 28139788 PMCID: PMC5394103 DOI: 10.1039/c6cp07119h] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Electron paramagnetic resonance spectroscopy in combination with site-directed spin labeling is a very powerful tool for elucidating the structure and organization of biomolecules. Gd3+ complexes have recently emerged as a new class of spin labels for distance determination by pulsed EPR spectroscopy at Q- and W-band. We present CW EPR measurements at 240 GHz (8.6 Tesla) on a series of Gd-rulers of the type Gd-PyMTA-spacer-Gd-PyMTA, with Gd-Gd distances ranging from 1.2 nm to 4.3 nm. CW EPR measurements of these Gd-rulers show that significant dipolar broadening of the central |-1/2〉 → |1/2〉 transition occurs at 30 K for Gd-Gd distances up to ∼3.4 nm with Gd-PyMTA as the spin label. This represents a significant extension for distances accessible by CW EPR, as nitroxide-based spin labels at X-band frequencies can typically only access distances up to ∼2 nm. We show that this broadening persists at biologically relevant temperatures above 200 K, and that this method is further extendable up to room temperature by immobilizing the sample in glassy trehalose. We show that the peak-to-peak broadening of the central transition follows the expected 1/r3 dependence for the electron-electron dipolar interaction, from cryogenic temperatures up to room temperature. A simple procedure for simulating the dependence of the lineshape on interspin distance is presented, in which the broadening of the central transition is modeled as an S = 1/2 spin whose CW EPR lineshape is broadened through electron-electron dipolar interactions with a neighboring S = 7/2 spin.
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Affiliation(s)
- Jessica A Clayton
- Department of Physics, University of California, Santa Barbara, Santa Barbara, CA, USA. and Institute for Terahertz Science and Technology, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Bielefeld, Germany
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Bielefeld, Germany
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Songi Han
- Institute for Terahertz Science and Technology, University of California, Santa Barbara, Santa Barbara, CA, USA and Department of Chemistry and Biochemistry, University of California, Santa Barbara, Santa Barbara, CA, USA and Department of Chemical Engineering, University of California, Santa Barbara, Santa Barbara, CA, USA
| | - Mark S Sherwin
- Department of Physics, University of California, Santa Barbara, Santa Barbara, CA, USA. and Institute for Terahertz Science and Technology, University of California, Santa Barbara, Santa Barbara, CA, USA
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15
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Demay-Drouhard P, Chamoreau LM, Guillot R, Policar C, Bertrand HC. Synthesis of Homoditopic Ligands with an Incrementable Rodlike Backbone. European J Org Chem 2016. [DOI: 10.1002/ejoc.201601081] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Paul Demay-Drouhard
- Département de Chimie, Ecole Normale Supérieure; PSL Research University, UPMC Univ Paris 06; CNRS, Laboratoire des Biomolécules (LBM); 24 rue Lhomond 75005 Paris France
- Sorbonne Universités, UPMC Univ. Paris 06; Ecole Normale Supérieure; CNRS, Laboratoire des Biomolécules (LBM); 24 rue Lhomond 75005 Paris France
| | - Lise-Marie Chamoreau
- Institut Parisien de Chimie Moléculaire; Sorbonne Universités, UPMC Univ Paris 06; CNRS UMR 8232; 4 place Jussieu 75252 Paris France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d′Orsay; Université Paris-Sud; UMR CNRS 8182, Université Paris-Saclay; 91405 Orsay France
| | - Clotilde Policar
- Département de Chimie, Ecole Normale Supérieure; PSL Research University, UPMC Univ Paris 06; CNRS, Laboratoire des Biomolécules (LBM); 24 rue Lhomond 75005 Paris France
- Sorbonne Universités, UPMC Univ. Paris 06; Ecole Normale Supérieure; CNRS, Laboratoire des Biomolécules (LBM); 24 rue Lhomond 75005 Paris France
| | - Hélène C. Bertrand
- Département de Chimie, Ecole Normale Supérieure; PSL Research University, UPMC Univ Paris 06; CNRS, Laboratoire des Biomolécules (LBM); 24 rue Lhomond 75005 Paris France
- Sorbonne Universités, UPMC Univ. Paris 06; Ecole Normale Supérieure; CNRS, Laboratoire des Biomolécules (LBM); 24 rue Lhomond 75005 Paris France
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16
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Kaushik M, Bahrenberg T, Can TV, Caporini MA, Silvers R, Heiliger J, Smith AA, Schwalbe H, Griffin RG, Corzilius B. Gd(iii) and Mn(ii) complexes for dynamic nuclear polarization: small molecular chelate polarizing agents and applications with site-directed spin labeling of proteins. Phys Chem Chem Phys 2016; 18:27205-27218. [PMID: 27545112 PMCID: PMC5053914 DOI: 10.1039/c6cp04623a] [Citation(s) in RCA: 58] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
We investigate complexes of two paramagnetic metal ions Gd3+ and Mn2+ to serve as polarizing agents for solid-state dynamic nuclear polarization (DNP) of 1H, 13C, and 15N at magnetic fields of 5, 9.4, and 14.1 T. Both ions are half-integer high-spin systems with a zero-field splitting and therefore exhibit a broadening of the mS = -1/2 ↔ +1/2 central transition which scales inversely with the external field strength. We investigate experimentally the influence of the chelator molecule, strong hyperfine coupling to the metal nucleus, and deuteration of the bulk matrix on DNP properties. At small Gd-DOTA concentrations the narrow central transition allows us to polarize nuclei with small gyromagnetic ratio such as 13C and even 15N via the solid effect. We demonstrate that enhancements observed are limited by the available microwave power and that large enhancement factors of >100 (for 1H) and on the order of 1000 (for 13C) can be achieved in the saturation limit even at 80 K. At larger Gd(iii) concentrations (≥10 mM) where dipolar couplings between two neighboring Gd3+ complexes become substantial a transition towards cross effect as dominating DNP mechanism is observed. Furthermore, the slow spin-diffusion between 13C and 15N, respectively, allows for temporally resolved observation of enhanced polarization spreading from nuclei close to the paramagnetic ion towards nuclei further removed. Subsequently, we present preliminary DNP experiments on ubiquitin by site-directed spin-labeling with Gd3+ chelator tags. The results hold promise towards applications of such paramagnetically labeled proteins for DNP applications in biophysical chemistry and/or structural biology.
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Affiliation(s)
- Monu Kaushik
- Institute of Physical and Theoretical Chemistry and Institute of Biophysical Chemistry, Goethe University Frankfurt, Max-von-Laue-Str. 7-9, 60438 Frankfurt am Main, Germany.
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17
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Song L, Liu Z, Kaur P, Esquiaqui JM, Hunter RI, Hill S, Smith GM, Fanucci GE. Toward increased concentration sensitivity for continuous wave EPR investigations of spin-labeled biological macromolecules at high fields. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 265:188-196. [PMID: 26923151 DOI: 10.1016/j.jmr.2016.02.007] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2015] [Revised: 02/09/2016] [Accepted: 02/10/2016] [Indexed: 06/05/2023]
Abstract
High-field, high-frequency electron paramagnetic resonance (EPR) spectroscopy at W-(∼94 GHz) and D-band (∼140 GHz) is important for investigating the conformational dynamics of flexible biological macromolecules because this frequency range has increased spectral sensitivity to nitroxide motion over the 100 ps to 2 ns regime. However, low concentration sensitivity remains a roadblock for studying aqueous samples at high magnetic fields. Here, we examine the sensitivity of a non-resonant thin-layer cylindrical sample holder, coupled to a quasi-optical induction-mode W-band EPR spectrometer (HiPER), for continuous wave (CW) EPR analyses of: (i) the aqueous nitroxide standard, TEMPO; (ii) the unstructured to α-helical transition of a model IDP protein; and (iii) the base-stacking transition in a kink-turn motif of a large 232 nt RNA. For sample volumes of ∼50 μL, concentration sensitivities of 2-20 μM were achieved, representing a ∼10-fold enhancement compared to a cylindrical TE011 resonator on a commercial Bruker W-band spectrometer. These results therefore highlight the sensitivity of the thin-layer sample holders employed in HiPER for spin-labeling studies of biological macromolecules at high fields, where applications can extend to other systems that are facilitated by the modest sample volumes and ease of sample loading and geometry.
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Affiliation(s)
- Likai Song
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA
| | - Zhanglong Liu
- Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL 32611, USA
| | - Pavanjeet Kaur
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Department of Physics, Florida State University, Tallahassee, FL 32306, USA
| | - Jackie M Esquiaqui
- Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL 32611, USA
| | - Robert I Hunter
- School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, United Kingdom
| | - Stephen Hill
- National High Magnetic Field Laboratory, Florida State University, Tallahassee, FL 32310, USA; Department of Physics, Florida State University, Tallahassee, FL 32306, USA
| | - Graham M Smith
- School of Physics and Astronomy, University of St. Andrews, North Haugh, St. Andrews KY16 9SS, United Kingdom
| | - Gail E Fanucci
- Department of Chemistry, University of Florida, PO Box 117200, Gainesville, FL 32611, USA.
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18
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Chang JY, Chen GR, Li JD. Synthesis of magnetofluorescence Gd-doped CuInS2/ZnS quantum dots with enhanced longitudinal relaxivity. Phys Chem Chem Phys 2016; 18:7132-40. [DOI: 10.1039/c5cp07063e] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Gd-doped CuInS2/ZnS quantum dots were synthesized in a one-pot reaction under microwave irradiation; these quantum dots exhibited great potential as dual-modal nanoprobes for optical/MR imaging.
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Affiliation(s)
- Jia-Yaw Chang
- Department of Chemical Engineering
- National Taiwan University of Science and Technology
- Taipei
- Republic of China
| | - Guan-Rong Chen
- Department of Chemical Engineering
- National Taiwan University of Science and Technology
- Taipei
- Republic of China
| | - Jyun-Dong Li
- Department of Chemical Engineering
- National Taiwan University of Science and Technology
- Taipei
- Republic of China
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19
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Doll A, Qi M, Wili N, Pribitzer S, Godt A, Jeschke G. Gd(III)-Gd(III) distance measurements with chirp pump pulses. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2015; 259:153-62. [PMID: 26340436 DOI: 10.1016/j.jmr.2015.08.010] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 08/13/2015] [Accepted: 08/14/2015] [Indexed: 05/15/2023]
Abstract
The broad EPR spectrum of Gd(III) spin labels restricts the dipolar modulation depth in distance measurements between Gd(III) pairs to a few percent. To overcome this limitation, frequency-swept chirp pulses are utilized as pump pulses in the DEER experiment. Using a model system with 3.4 nm Gd-Gd distance, application of one single chirp pump pulse at Q-band frequencies leads to modulation depths beyond 10%. However, the larger modulation depth is counteracted by a reduction of the absolute echo intensity due to the pump pulse. As supported by spin dynamics simulations, this effect is primarily driven by signal loss to double-quantum coherence and specific to the Gd(III) high spin state of S=7/2. In order to balance modulation depth and echo intensity for optimum sensitivity, a simple experimental procedure is proposed. An additional improvement by 25% in DEER sensitivity is achieved with two consecutive chirp pump pulses. These pulses pump the Gd(III) spectrum symmetrically around the observation position, therefore mutually compensating for dynamical Bloch-Siegert phase shifts at the observer spins. The improved sensitivity of the DEER data with modulation depths on the order of 20% is due to mitigation of the echo reduction effects by the consecutive pump pulses. In particular, the second pump pulse does not lead to additional signal loss if perfect inversion is assumed. Moreover, the compensation of the dynamical Bloch-Siegert phase prevents signal loss due to spatial dependence of the dynamical phase, which is caused by inhomogeneities in the driving field. The new methodology is combined with pre-polarization techniques to measure long distances up to 8.6 nm, where signal intensity and modulation depth become attenuated by long dipolar evolution windows. In addition, the influence of the zero-field splitting parameters on the echo intensity is studied with simulations. Herein, larger sensitivity is anticipated for Gd(III) complexes with zero-field splitting that is smaller than for the employed Gd-PyMTA complex.
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Affiliation(s)
- Andrin Doll
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials, Bielefeld University, Unversitätsstraße 25, 33615 Bielefeld, Germany
| | - Nino Wili
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Stephan Pribitzer
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials, Bielefeld University, Unversitätsstraße 25, 33615 Bielefeld, Germany
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry, ETH Zurich, Vladimir-Prelog-Weg 2, CH-8093 Zurich, Switzerland.
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20
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Liu L, Mayo DJ, Sahu ID, Zhou A, Zhang R, McCarrick RM, Lorigan GA. Determining the Secondary Structure of Membrane Proteins and Peptides Via Electron Spin Echo Envelope Modulation (ESEEM) Spectroscopy. Methods Enzymol 2015; 564:289-313. [PMID: 26477255 DOI: 10.1016/bs.mie.2015.06.037] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
Revealing detailed structural and dynamic information of membrane embedded or associated proteins is challenging due to their hydrophobic nature which makes NMR and X-ray crystallographic studies challenging or impossible. Electron paramagnetic resonance (EPR) has emerged as a powerful technique to provide essential structural and dynamic information for membrane proteins with no size limitations in membrane systems which mimic their natural lipid bilayer environment. Therefore, tremendous efforts have been devoted toward the development and application of EPR spectroscopic techniques to study the structure of biological systems such as membrane proteins and peptides. This chapter introduces a novel approach established and developed in the Lorigan lab to investigate membrane protein and peptide local secondary structures utilizing the pulsed EPR technique electron spin echo envelope modulation (ESEEM) spectroscopy. Detailed sample preparation strategies in model membrane protein systems and the experimental setup are described. Also, the ability of this approach to identify local secondary structure of membrane proteins and peptides with unprecedented efficiency is demonstrated in model systems. Finally, applications and further developments of this ESEEM approach for probing larger size membrane proteins produced by overexpression systems are discussed.
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Affiliation(s)
- Lishan Liu
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA.
| | - Daniel J Mayo
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
| | - Indra D Sahu
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
| | - Andy Zhou
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
| | - Rongfu Zhang
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
| | - Robert M McCarrick
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
| | - Gary A Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio, USA
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21
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Vincent Ching HY, Demay-Drouhard P, Bertrand HC, Policar C, Tabares LC, Un S. Nanometric distance measurements between Mn(ii)DOTA centers. Phys Chem Chem Phys 2015; 17:23368-77. [DOI: 10.1039/c5cp03487f] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The distance between two Mn(ii)DOTA complexes attached to the ends of polyproline helices of varying lengths was measured by 94 GHz PELDOR spectroscopy with good accuracy demonstrating their effectiveness as spin-labels.
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Affiliation(s)
- H. Y. Vincent Ching
- Institute for Integrative Biology of the Cell (I2BC)
- Department of Biochemistry
- Biophysics and Structural Biology
- Université Paris-Saclay
- CEA
| | - Paul Demay-Drouhard
- Ecole Normale Supérieure-PSL Research University
- Départment de Chimie
- Sorbonne Universités – UPMC Univ Paris 06
- CNRS UMR 7203 LBM
- F-75005 Paris
| | - Hélène C. Bertrand
- Ecole Normale Supérieure-PSL Research University
- Départment de Chimie
- Sorbonne Universités – UPMC Univ Paris 06
- CNRS UMR 7203 LBM
- F-75005 Paris
| | - Clotilde Policar
- Ecole Normale Supérieure-PSL Research University
- Départment de Chimie
- Sorbonne Universités – UPMC Univ Paris 06
- CNRS UMR 7203 LBM
- F-75005 Paris
| | - Leandro C. Tabares
- Institute for Integrative Biology of the Cell (I2BC)
- Department of Biochemistry
- Biophysics and Structural Biology
- Université Paris-Saclay
- CEA
| | - Sun Un
- Institute for Integrative Biology of the Cell (I2BC)
- Department of Biochemistry
- Biophysics and Structural Biology
- Université Paris-Saclay
- CEA
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22
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Feintuch A, Otting G, Goldfarb D. Gd3+ Spin Labeling for Measuring Distances in Biomacromolecules. Methods Enzymol 2015; 563:415-57. [DOI: 10.1016/bs.mie.2015.07.006] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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23
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Razzaghi S, Qi M, Nalepa AI, Godt A, Jeschke G, Savitsky A, Yulikov M. RIDME Spectroscopy with Gd(III) Centers. J Phys Chem Lett 2014; 5:3970-5. [PMID: 26276479 DOI: 10.1021/jz502129t] [Citation(s) in RCA: 65] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
The relaxation induced dipolar modulation enhancement (RIDME) technique is applied at W-band microwave frequencies around 94 GHz to a pair of Gd(III) complexes that are connected by a rodlike spacer, and the extraction of the interspin distance distribution is discussed. A dipolar pattern derived from RIDME experimental data is a superposition of Pake-like dipolar patterns corresponding to the fundamental dipolar interaction and higher harmonics thereof. Intriguingly, the relative weights of the stretched patterns do not depend significantly on mixing time. As much larger modulation depths can be achieved than in double electron-electron resonance distance measurements at the same frequency, Gd(III)-Gd(III) RIDME may become attractive for structural characterization of biomacromolecules and biomolecular complexes.
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Affiliation(s)
- Sahand Razzaghi
- †Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Mian Qi
- ‡Faculty of Chemistry and Center for Molecular Materials, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Anna I Nalepa
- §Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Adelheid Godt
- ‡Faculty of Chemistry and Center for Molecular Materials, Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Gunnar Jeschke
- †Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
| | - Anton Savitsky
- §Max-Planck-Institut für Chemische Energiekonversion, Stiftstrasse 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Maxim Yulikov
- †Laboratory of Physical Chemistry, Department of Chemistry and Applied Biosciences, ETH Zurich, Vladimir-Prelog-Weg 2, 8093 Zurich, Switzerland
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Upadhyay A, Das C, Shanmugam M, Langley SK, Murray KS, Shanmugam M. Electronic and Magnetic Properties of a Gadolinium(III) Schiff Base Complex. Eur J Inorg Chem 2014. [DOI: 10.1002/ejic.201402219] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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25
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Goldfarb D. Gd3+ spin labeling for distance measurements by pulse EPR spectroscopy. Phys Chem Chem Phys 2014; 16:9685-99. [DOI: 10.1039/c3cp53822b] [Citation(s) in RCA: 145] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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