1
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Stehle J, Hülsmann M, Godt A, Drescher M, Azarkh M. Evaluation of Copper(II) Transfer between Amyloid-beta Peptides by Relaxation-Induced Dipolar Modulation Enhancement (RIDME). Chemphyschem 2024; 25:e202300928. [PMID: 38285014 DOI: 10.1002/cphc.202300928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2023] [Revised: 01/25/2024] [Accepted: 01/26/2024] [Indexed: 01/30/2024]
Abstract
In the brains of Alzheimer's disease patients, fibrillar aggregates containing amyloid-beta (Aβ) peptides are found, along with elevated concentrations of Cu(II) ions. The aggregation pathways of Aβ peptides can be modulated by Cu(II) ions and is determined by the formation and nature of the Cu(II)-Aβ complex. If spin-labeled, the Cu(II)-Aβ complex contains two dipolar coupled paramagnetic centers, the spin label and the Cu(II) ion. Measurement of the dipolar coupling between these paramagnetic centers by relaxation-induced dipolar modulation enhancement (RIDME) allows to monitor the complex formation and thus opens a way to follow the Cu(II) transfer between peptides if a mixture of wild-type and spin-labeled ones is used. We evaluate this approach for a specific Cu(II)-Aβ complex, the aggregation-inert Component II. The kinetics of the Cu(II) transfer can be resolved by performing RIDME in a time-dependent manner. A temporal resolution of seconds has been achieved, with the potential to reach milliseconds, using a rapid-freeze quench device to stop the Cu(II) transfer in solution after defined incubation times.
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Affiliation(s)
- Juliane Stehle
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
| | - Miriam Hülsmann
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615, Bielefeld, Germany
| | - Malte Drescher
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
| | - Mykhailo Azarkh
- Department of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstr. 10, 78457, Konstanz, Germany
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2
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Wort JL, Ackermann K, Giannoulis A, Bode BE. Enhanced sensitivity for pulse dipolar EPR spectroscopy using variable-time RIDME. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 352:107460. [PMID: 37167826 DOI: 10.1016/j.jmr.2023.107460] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2023] [Revised: 04/03/2023] [Accepted: 04/19/2023] [Indexed: 05/13/2023]
Abstract
Pulse dipolar EPR spectroscopy (PDS) measurements are an important complementary tool in structural biology and are increasingly applied to macromolecular assemblies implicated in human health and disease at physiological concentrations. This requires ever higher sensitivity, and recent advances have driven PDS measurements into the mid-nanomolar concentration regime, though optimization and acquisition of such measurements remains experimentally demanding and time expensive. One important consideration is that constant-time acquisition represents a hard limit for measurement sensitivity, depending on the maximum measured distance. Determining this distance a priori has been facilitated by machine-learning structure prediction (AlphaFold2 and RoseTTAFold) but is often confounded by non-representative behaviour in frozen solution that may mandate multiple rounds of optimization and acquisition. Herein, we endeavour to simultaneously enhance sensitivity and streamline PDS measurement optimization to one-step by benchmarking a variable-time acquisition RIDME experiment applied to CuII-nitroxide and CuII-CuII model systems. Results demonstrate marked sensitivity improvements of both 5- and 6-pulse variable-time RIDME of between 2- and 5-fold over the constant-time analogues.
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Affiliation(s)
- Joshua L Wort
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Angeliki Giannoulis
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland
| | - Bela E Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex and Centre of Magnetic Resonance, University of St Andrews, North Haugh, St Andrews, Scotland.
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3
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Hasanbasri Z, Poncelet M, Hunter H, Driesschaert B, Saxena S. A new 13C trityl-based spin label enables the use of DEER for distance measurements. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2023; 347:107363. [PMID: 36620971 PMCID: PMC9928843 DOI: 10.1016/j.jmr.2022.107363] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 12/15/2022] [Accepted: 12/21/2022] [Indexed: 06/17/2023]
Abstract
Triarylmethyl (TAM)-based labels, while still underutilized, are a powerful class of labels for pulsed-Electron Spin Resonance (ESR) distance measurements. They feature slow relaxation rates for long-lasting signals, high stability for cellular experiments, and narrow spectral features for efficient excitation of the spins. However, the typical narrow line shape limits the available distance measurements to only single-frequency experiments, such as Double Quantum Coherence (DQC) and Relaxation Induced Dipolar Modulation Enhancement (RIDME), which can be complicated to perform or hard to process. Therefore, widespread usage of TAM labels can be enhanced by the use of Double Electron-Electron Resonance (DEER) distance measurements. In this work, we developed a new spin label, 13C1-mOX063-d24, with a 13C isotope as the radical center. Due to the resolved hyperfine splitting, the spectrum is sufficiently broadened to permit DEER-based experiments at Q-band spectrometers. Additionally, this new label can be incorporated orthogonally with Cu(II)-based protein label. The orthogonal labeling scheme enables DEER distance measurement at X-band frequencies. Overall, the new trityl label allows for DEER-based distance measurements that complement existing TAM-label DQC and RIDME experiments.
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Affiliation(s)
- Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Martin Poncelet
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance (IMMR) Center, Health Sciences Center, West Virginia University, Morgantown, WV 26506, United States
| | - Hannah Hunter
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States
| | - Benoit Driesschaert
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance (IMMR) Center, Health Sciences Center, West Virginia University, Morgantown, WV 26506, United States; C. Eugene Bennett Department of Chemistry West Virginia University, Morgantown, WV 26506, United States.
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, PA 15260, United States.
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4
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Rogers CJ, Asthana D, Brookfield A, Chiesa A, Timco GA, Collison D, Natrajan LS, Carretta S, Winpenny REP, Bowen AM. Modelling Conformational Flexibility in a Spectrally Addressable Molecular Multi‐Qubit Model System. Angew Chem Int Ed Engl 2022. [DOI: 10.1002/ange.202207947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Ciarán J. Rogers
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Deepak Asthana
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
- Department of Chemistry Ashoka University Sonipat Haryana India
| | - Adam Brookfield
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Alessandro Chiesa
- Dipartimento di Scienze Matematiche Fisiche e Informatiche Università di Parma 43124 Parma Italy
- INFN–Sezione di Milano-Bicocca Gruppo Collegato di Parma I-43124 Parma Italy
- UdR Parma INSTM I-43124 Parma Italy
| | - Grigore A. Timco
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
| | - David Collison
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Louise S. Natrajan
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Stefano Carretta
- Dipartimento di Scienze Matematiche Fisiche e Informatiche Università di Parma 43124 Parma Italy
- INFN–Sezione di Milano-Bicocca Gruppo Collegato di Parma I-43124 Parma Italy
- UdR Parma INSTM I-43124 Parma Italy
| | - Richard E. P. Winpenny
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
| | - Alice M. Bowen
- National Research Facility for Electron Paramagnetic Resonance Spectroscopy Department of Chemistry and Photon Science Institute The University of Manchester Oxford Road Manchester M13 9PL UK
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5
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Rogers CJ, Asthana D, Brookfield A, Chiesa A, Timco GA, Collison D, Natrajan LS, Carretta S, Winpenny REP, Bowen AM. Modelling Conformational Flexibility in a Spectrally Addressable Molecular Multi-Qubit Model System. Angew Chem Int Ed Engl 2022; 61:e202207947. [PMID: 36222278 PMCID: PMC9828767 DOI: 10.1002/anie.202207947] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2022] [Indexed: 11/11/2022]
Abstract
Dipolar coupled multi-spin systems have the potential to be used as molecular qubits. Herein we report the synthesis of a molecular multi-qubit model system with three individually addressable, weakly interacting, spin 1 / 2 ${{ 1/2 }}$ centres of differing g-values. We use pulsed Electron Paramagnetic Resonance (EPR) techniques to characterise and separately address the individual electron spin qubits; CuII , Cr7 Ni ring and a nitroxide, to determine the strength of the inter-qubit dipolar interaction. Orientation selective Relaxation-Induced Dipolar Modulation Enhancement (os-RIDME) detecting across the CuII spectrum revealed a strongly correlated CuII -Cr7 Ni ring relationship; detecting on the nitroxide resonance measured both the nitroxide and CuII or nitroxide and Cr7 Ni ring correlations, with switchability of the interaction based on differing relaxation dynamics, indicating a handle for implementing EPR-based quantum information processing (QIP) algorithms.
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Affiliation(s)
- Ciarán J. Rogers
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Deepak Asthana
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK,Department of ChemistryAshoka UniversitySonipatHaryanaIndia
| | - Adam Brookfield
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Alessandro Chiesa
- Dipartimento di Scienze Matematiche Fisiche e InformaticheUniversità di Parma43124ParmaItaly,INFN–Sezione di Milano-BicoccaGruppo Collegato di ParmaI-43124ParmaItaly,UdR ParmaINSTMI-43124ParmaItaly
| | - Grigore A. Timco
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - David Collison
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Louise S. Natrajan
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Stefano Carretta
- Dipartimento di Scienze Matematiche Fisiche e InformaticheUniversità di Parma43124ParmaItaly,INFN–Sezione di Milano-BicoccaGruppo Collegato di ParmaI-43124ParmaItaly,UdR ParmaINSTMI-43124ParmaItaly
| | - Richard E. P. Winpenny
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
| | - Alice M. Bowen
- National Research Facility for Electron Paramagnetic Resonance SpectroscopyDepartment of Chemistry and Photon Science InstituteThe University of ManchesterOxford RoadManchesterM13 9PLUK
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6
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Oranges M, Wort JL, Fukushima M, Fusco E, Ackermann K, Bode BE. Pulse Dipolar Electron Paramagnetic Resonance Spectroscopy Reveals Buffer-Modulated Cooperativity of Metal-Templated Protein Dimerization. J Phys Chem Lett 2022; 13:7847-7852. [PMID: 35976741 PMCID: PMC9421889 DOI: 10.1021/acs.jpclett.2c01719] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2022] [Accepted: 08/10/2022] [Indexed: 05/26/2023]
Abstract
Self-assembly of protein monomers directed by metal ion coordination constitutes a promising strategy for designing supramolecular architectures complicated by the noncovalent interaction between monomers. Herein, two pulse dipolar electron paramagnetic resonance spectroscopy (PDS) techniques, pulse electron-electron double resonance and relaxation-induced dipolar modulation enhancement, were simultaneously employed to study the CuII-templated dimerization behavior of a model protein (Streptococcus sp. group G, protein G B1 domain) in both phosphate and Tris-HCl buffers. A cooperative binding model could simultaneously fit all data and demonstrate that the cooperativity of protein dimerization across α-helical double-histidine motifs in the presence of CuII is strongly modulated by the buffer, representing a platform for highly tunable buffer-switchable templated dimerization. Hence, PDS enriches the family of techniques for monitoring binding processes, supporting the development of novel strategies for bioengineering structures and stable architectures assembled by an initial metal-templated dimerization.
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7
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Abstract
Different types of spin labels are currently available for structural studies of biomolecules both in vitro and in cells using Electron Paramagnetic Resonance (EPR) and pulse dipolar spectroscopy (PDS). Each type of label has its own advantages and disadvantages, that will be addressed in this chapter. The spectroscopically distinct properties of the labels have fostered new applications of PDS aimed to simultaneously extract multiple inter-label distances on the same sample. In fact, combining different labels and choosing the optimal strategy to address their inter-label distances can increase the information content per sample, and this is pivotal to better characterize complex multi-component biomolecular systems. In this review, we provide a brief background of the spectroscopic properties of the four most common orthogonal spin labels for PDS measurements and focus on the various methods at disposal to extract homo- and hetero-label distances in proteins. We also devote a section to possible artifacts arising from channel crosstalk and provide few examples of applications in structural biology.
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8
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A Low-Spin CoII/Nitroxide Complex for Distance Measurements at Q-Band Frequencies. MAGNETOCHEMISTRY 2022. [DOI: 10.3390/magnetochemistry8040043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Pulse dipolar electron paramagnetic resonance spectroscopy (PDS) is continuously furthering the understanding of chemical and biological assemblies through distance measurements in the nanometer range. New paramagnets and pulse sequences can provide structural insights not accessible through other techniques. In the pursuit of alternative spin centers for PDS, we synthesized a low-spin CoII complex bearing a nitroxide (NO) moiety, where both the CoII and NO have an electron spin S of 1/2. We measured CoII-NO distances with the well-established double electron–electron resonance (DEER aka PELDOR) experiment, as well as with the five- and six-pulse relaxation-induced dipolar modulation enhancement (RIDME) spectroscopies at Q-band frequencies (34 GHz). We first identified challenges related to the stability of the complex in solution via DEER and X-ray crystallography and showed that even in cases where complex disproportionation is unavoidable, CoII-NO PDS measurements are feasible and give good signal-to-noise (SNR) ratios. Specifically, DEER and five-pulse RIDME exhibited an SNR of ~100, and while the six-pulse RIDME exhibited compromised SNR, it helped us minimize unwanted signals from the RIDME traces. Last, we demonstrated RIDME at a 10 μM sample concentration. Our results demonstrate paramagnetic CoII to be a feasible spin center in medium magnetic fields with opportunities for PDS studies involving CoII ions.
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9
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Ackermann K, Wort JL, Bode BE. Nanomolar Pulse Dipolar EPR Spectroscopy in Proteins: Cu II-Cu II and Nitroxide-Nitroxide Cases. J Phys Chem B 2021; 125:5358-5364. [PMID: 33998795 PMCID: PMC7611071 DOI: 10.1021/acs.jpcb.1c03666] [Citation(s) in RCA: 27] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The study of ever more complex biomolecular assemblies implicated in human health and disease is facilitated by a suite of complementary biophysical methods. Pulse dipolar electron paramagnetic resonance spectroscopy (PDS) is a powerful tool that provides highly precise geometric constraints in frozen solutions; however, the drive toward PDS at physiologically relevant sub-μM concentrations is limited by the currently achievable concentration sensitivity. Recently, PDS using a combination of nitroxide- and CuII-based spin labels allowed measuring a 500 nM concentration of a model protein. Using commercial instrumentation and spin labels, we demonstrate CuII-CuII and nitroxide-nitroxide PDS measurements at protein concentrations below previous examples reaching 500 and 100 nM, respectively. These results demonstrate the general feasibility of sub-μM PDS measurements at short to intermediate distances (∼1.5 to 3.5 nm), and are of particular relevance for applications where the achievable concentration is limiting.
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10
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Wort JL, Ackermann K, Norman DG, Bode BE. A general model to optimise Cu II labelling efficiency of double-histidine motifs for pulse dipolar EPR applications. Phys Chem Chem Phys 2021; 23:3810-3819. [PMID: 33533341 DOI: 10.1039/d0cp06196d] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Electron paramagnetic resonance (EPR) distance measurements are making increasingly important contributions to studies of biomolecules underpinning health and disease by providing highly accurate and precise geometric constraints. Combining double-histidine (dH) motifs with CuII spin labels shows promise for further increasing the precision of distance measurements, and for investigating subtle conformational changes. However, non-covalent coordination-based spin labelling is vulnerable to low binding affinity. Dissociation constants of dH motifs for CuII-nitrilotriacetic acid were previously investigated via relaxation induced dipolar modulation enhancement (RIDME), and demonstrated the feasibility of exploiting the dH motif for EPR applications at sub-μM protein concentrations. Herein, the feasibility of using modulation depth quantitation in CuII-CuII RIDME to simultaneously estimate a pair of non-identical independent KD values in such a tetra-histidine model protein is addressed. Furthermore, we develop a general speciation model to optimise CuII labelling efficiency, depending upon pairs of identical or disparate KD values and total CuII label concentration. We find the dissociation constant estimates are in excellent agreement with previously determined values, and empirical modulation depths support the proposed model.
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Affiliation(s)
- Joshua L Wort
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews North Haugh, St Andrews KY16 9ST, UK.
| | - Katrin Ackermann
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews North Haugh, St Andrews KY16 9ST, UK.
| | - David G Norman
- School of Life Sciences, University of Dundee, Medical Sciences Institute, Dundee, DD1 5EH, UK
| | - Bela E Bode
- EaStCHEM School of Chemistry, Biomedical Sciences Research Complex, and Centre of Magnetic Resonance, University of St Andrews North Haugh, St Andrews KY16 9ST, UK.
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11
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Russell H, Stewart R, Prior C, Oganesyan VS, Gaule TG, Lovett JE. DEER and RIDME Measurements of the Nitroxide-Spin Labelled Copper-Bound Amine Oxidase Homodimer from Arthrobacter Globiformis. APPLIED MAGNETIC RESONANCE 2021; 52:995-1015. [PMID: 34720439 PMCID: PMC8550341 DOI: 10.1007/s00723-021-01321-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 02/23/2021] [Accepted: 03/10/2021] [Indexed: 06/13/2023]
Abstract
In the study of biological structures, pulse dipolar spectroscopy (PDS) is used to elucidate spin-spin distances at nanometre-scale by measuring dipole-dipole interactions between paramagnetic centres. The PDS methods of Double Electron Electron Resonance (DEER) and Relaxation Induced Dipolar Modulation Enhancement (RIDME) are employed, and their results compared, for the measurement of the dipolar coupling between nitroxide spin labels and copper-II (Cu(II)) paramagnetic centres within the copper amine oxidase from Arthrobacter globiformis (AGAO). The distance distribution results obtained indicate that two distinct distances can be measured, with the longer of these at c.a. 5 nm. Conditions for optimising the RIDME experiment such that it may outperform DEER for these long distances are discussed. Modelling methods are used to show that the distances obtained after data analysis are consistent with the structure of AGAO. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s00723-021-01321-6.
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Affiliation(s)
- Hannah Russell
- SUPA School of Physics and Astronomy and BSRC, University of St Andrews, St Andrews, KY16 9SS UK
| | - Rachel Stewart
- SUPA School of Physics and Astronomy and BSRC, University of St Andrews, St Andrews, KY16 9SS UK
| | | | | | - Thembaninkosi G. Gaule
- School of Molecular and Cellular Biology, Astbury Centre for Structural Molecular Biology, University of Leeds, Leeds, UK
| | - Janet E. Lovett
- SUPA School of Physics and Astronomy and BSRC, University of St Andrews, St Andrews, KY16 9SS UK
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12
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Wort JL, Arya S, Ackermann K, Stewart AJ, Bode BE. Pulse Dipolar EPR Reveals Double-Histidine Motif Cu II-NTA Spin-Labeling Robustness against Competitor Ions. J Phys Chem Lett 2021. [PMID: 33715381 DOI: 10.17630/d7138874-55dd-4874-a2e8-c026fbc0b67f] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Pulse-dipolar EPR is an appealing strategy for structural characterization of complex systems in solution that complements other biophysical techniques. Significantly, the emergence of genetically encoded self-assembling spin labels exploiting exogenously introduced double-histidine motifs in conjunction with CuII-chelates offers high precision distance determination in systems nonpermissive to thiol-directed spin labeling. However, the noncovalency of this interaction exposes potential vulnerabilities to competition from adventitious divalent metal ions, and pH sensitivity. Herein, a combination of room-temperature isothermal titration calorimetry (ITC) and cryogenic relaxation-induced dipolar modulation enhancement (RIDME) measurements are applied to the model protein Streptococcus sp. group G. protein G, B1 domain (GB1). Results demonstrate double-histidine motif spin labeling using CuII-nitrilotriacetic acid (CuII-NTA) is robust against the competitor ligand ZnII-NTA at >1000-fold molar excess, and high nM binding affinity is surprisingly retained under acidic and basic conditions even though room temperature affinity shows a stronger pH dependence. This indicates the strategy is well-suited for diverse biological applications, with the requirement of other metal ion cofactors or slightly acidic pH not necessarily being prohibitive.
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Affiliation(s)
| | - Swati Arya
- School of Medicine, University of St. Andrews, North Haugh, St. Andrews, KY16 9TF, U.K
| | | | - Alan J Stewart
- School of Medicine, University of St. Andrews, North Haugh, St. Andrews, KY16 9TF, U.K
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13
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Wort J, Arya S, Ackermann K, Stewart AJ, Bode BE. Pulse Dipolar EPR Reveals Double-Histidine Motif Cu II-NTA Spin-Labeling Robustness against Competitor Ions. J Phys Chem Lett 2021; 12:2815-2819. [PMID: 33715381 PMCID: PMC8006131 DOI: 10.1021/acs.jpclett.1c00211] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/09/2023]
Abstract
Pulse-dipolar EPR is an appealing strategy for structural characterization of complex systems in solution that complements other biophysical techniques. Significantly, the emergence of genetically encoded self-assembling spin labels exploiting exogenously introduced double-histidine motifs in conjunction with CuII-chelates offers high precision distance determination in systems nonpermissive to thiol-directed spin labeling. However, the noncovalency of this interaction exposes potential vulnerabilities to competition from adventitious divalent metal ions, and pH sensitivity. Herein, a combination of room-temperature isothermal titration calorimetry (ITC) and cryogenic relaxation-induced dipolar modulation enhancement (RIDME) measurements are applied to the model protein Streptococcus sp. group G. protein G, B1 domain (GB1). Results demonstrate double-histidine motif spin labeling using CuII-nitrilotriacetic acid (CuII-NTA) is robust against the competitor ligand ZnII-NTA at >1000-fold molar excess, and high nM binding affinity is surprisingly retained under acidic and basic conditions even though room temperature affinity shows a stronger pH dependence. This indicates the strategy is well-suited for diverse biological applications, with the requirement of other metal ion cofactors or slightly acidic pH not necessarily being prohibitive.
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Affiliation(s)
- Joshua
L. Wort
- EaStCHEM
School of Chemistry, Biomedical Sciences Research Complex, Centre
of Magnetic Resonance, University of St.
Andrews, North Haugh, St. Andrews, KY16 9ST, U.K.
| | - Swati Arya
- EaStCHEM
School of Chemistry, Biomedical Sciences Research Complex, Centre
of Magnetic Resonance, University of St.
Andrews, North Haugh, St. Andrews, KY16 9ST, U.K.
- School
of Medicine, University of St. Andrews, North Haugh, St. Andrews, KY16 9TF, U.K.
| | - Katrin Ackermann
- EaStCHEM
School of Chemistry, Biomedical Sciences Research Complex, Centre
of Magnetic Resonance, University of St.
Andrews, North Haugh, St. Andrews, KY16 9ST, U.K.
| | - Alan J. Stewart
- EaStCHEM
School of Chemistry, Biomedical Sciences Research Complex, Centre
of Magnetic Resonance, University of St.
Andrews, North Haugh, St. Andrews, KY16 9ST, U.K.
- School
of Medicine, University of St. Andrews, North Haugh, St. Andrews, KY16 9TF, U.K.
| | - Bela E. Bode
- EaStCHEM
School of Chemistry, Biomedical Sciences Research Complex, Centre
of Magnetic Resonance, University of St.
Andrews, North Haugh, St. Andrews, KY16 9ST, U.K.
- E-mail:
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14
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Abdullin D, Schiemann O. Localization of metal ions in biomolecules by means of pulsed dipolar EPR spectroscopy. Dalton Trans 2021; 50:808-815. [PMID: 33416053 DOI: 10.1039/d0dt03596c] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Metal ions are important for the folding, structure, and function of biomolecules. Thus, knowing where their binding sites are located in proteins or oligonucleotides is a critical objective. X-ray crystallography and nuclear magnetic resonance are powerful methods in this respect, but both have their limitations. Here, a complementary method is highlighted in which paramagnetic metal ions are localized by means of trilateration using a combination of site-directed spin labeling and pulsed dipolar electron paramagnetic resonance spectroscopy. The working principle, the requirements, and the limitations of the method are critically discussed. Several applications of the method are outlined and compared with each other.
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Affiliation(s)
- Dinar Abdullin
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstr. 12, 53115 Bonn, Germany.
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15
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Abdullin D, Schiemann O. Pulsed Dipolar EPR Spectroscopy and Metal Ions: Methodology and Biological Applications. Chempluschem 2020; 85:353-372. [DOI: 10.1002/cplu.201900705] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 01/16/2020] [Indexed: 01/18/2023]
Affiliation(s)
- Dinar Abdullin
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
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16
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Breitgoff FD, Keller K, Qi M, Klose D, Yulikov M, Godt A, Jeschke G. UWB DEER and RIDME distance measurements in Cu(II)-Cu(II) spin pairs. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2019; 308:106560. [PMID: 31377151 DOI: 10.1016/j.jmr.2019.07.047] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Revised: 07/12/2019] [Accepted: 07/15/2019] [Indexed: 06/10/2023]
Abstract
Distance determination by Electron Paramagnetic Resonance (EPR) based on measurements of the dipolar coupling are technically challenging for electron spin systems with broad spectra due to comparatively narrow microwave pulse excitation bandwidths. With Na4[{CuII(PyMTA)}-(stiff spacer)-{CuII(PyMTA)}] as a model compound, we compared DEER and RIDME measurements and investigated the use of frequency-swept pulses. We found very large improvements in sensitivity when substituting the monochromatic pump pulse by a frequency-swept one in DEER experiments with monochromatic observer pulses. This effect was especially strong in X band, where nearly the whole spectrum can be included in the experiment. The RIDME experiment is characterised by a trade-off in signal intensity and modulation depth. Optimal parameters are further influenced by varying steepness of the background decay. A simple 2-point optimization experiment was found to serve as good estimate to identify the mixing time of highest sensitivity. Using frequency-swept pulses in the observer sequences resulted in lower SNR in both the RIDME and the DEER experiment. Orientation selectivity was found to vary in both experiments with the detection position as well as with the settings of the pump pulse in DEER. In RIDME, orientation selection by relaxation anisotropy of the inverted spin appeared to be negligible as form factors remain relatively constant with varying mixing time. This reduces the overall observed orientation selection to the one given by the detection position. Field-averaged data from RIDME and DEER with a shaped pump pulse resulted in the same dipolar spectrum. We found that both methods have their advantages and disadvantages for given instrumental limitations and sample properties. Thus the choice of method depends on the situation at hand and we discuss which parameters should be considered for optimization.
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Affiliation(s)
- Frauke D Breitgoff
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland.
| | - Katharina Keller
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland.
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Daniel Klose
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland
| | - Maxim Yulikov
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany.
| | - Gunnar Jeschke
- ETH Zürich, Lab. Phys. Chem., Vladimir-Prelog-Weg 2, 8063 Zürich 3 Switzerland
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17
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Wort JL, Ackermann K, Giannoulis A, Stewart AJ, Norman DG, Bode BE. Sub-Micromolar Pulse Dipolar EPR Spectroscopy Reveals Increasing Cu II -labelling of Double-Histidine Motifs with Lower Temperature. Angew Chem Int Ed Engl 2019; 58:11681-11685. [PMID: 31218813 PMCID: PMC6771633 DOI: 10.1002/anie.201904848] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 06/03/2019] [Indexed: 12/20/2022]
Abstract
Electron paramagnetic resonance (EPR) distance measurements are making increasingly important contributions to the studies of biomolecules by providing highly accurate geometric constraints. Combining double-histidine motifs with CuII spin labels can further increase the precision of distance measurements. It is also useful for proteins containing essential cysteines that can interfere with thiol-specific labelling. However, the non-covalent CuII coordination approach is vulnerable to low binding-affinity. Herein, dissociation constants (KD ) are investigated directly from the modulation depths of relaxation-induced dipolar modulation enhancement (RIDME) EPR experiments. This reveals low- to sub-μm CuII KD s under EPR distance measurement conditions at cryogenic temperatures. We show the feasibility of exploiting the double-histidine motif for EPR applications even at sub-μm protein concentrations in orthogonally labelled CuII -nitroxide systems using a commercial Q-band EPR instrument.
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Affiliation(s)
- Joshua L. Wort
- EaStCHEM School of ChemistryBiomedical Sciences Research Complex, and Centre of Magnetic ResonanceUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Katrin Ackermann
- EaStCHEM School of ChemistryBiomedical Sciences Research Complex, and Centre of Magnetic ResonanceUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Angeliki Giannoulis
- EaStCHEM School of ChemistryBiomedical Sciences Research Complex, and Centre of Magnetic ResonanceUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
| | - Alan J. Stewart
- School of MedicineBiomedical Sciences Research Complex, and Centre of Magnetic ResonanceUniversity of St AndrewsNorth HaughSt AndrewsKY16 9TFUK
| | - David G. Norman
- School of Life SciencesUniversity of Dundee, Medical Sciences InstituteDundeeDD1 5EHUK
| | - Bela E. Bode
- EaStCHEM School of ChemistryBiomedical Sciences Research Complex, and Centre of Magnetic ResonanceUniversity of St AndrewsNorth HaughSt AndrewsKY16 9STUK
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18
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Wort JL, Ackermann K, Giannoulis A, Stewart AJ, Norman DG, Bode BE. Sub‐Micromolar Pulse Dipolar EPR Spectroscopy Reveals Increasing Cu
II
‐labelling of Double‐Histidine Motifs with Lower Temperature. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201904848] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Joshua L. Wort
- EaStCHEM School of Chemistry Biomedical Sciences Research Complex, and Centre of Magnetic Resonance University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - Katrin Ackermann
- EaStCHEM School of Chemistry Biomedical Sciences Research Complex, and Centre of Magnetic Resonance University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - Angeliki Giannoulis
- EaStCHEM School of Chemistry Biomedical Sciences Research Complex, and Centre of Magnetic Resonance University of St Andrews North Haugh St Andrews KY16 9ST UK
| | - Alan J. Stewart
- School of Medicine Biomedical Sciences Research Complex, and Centre of Magnetic Resonance University of St Andrews North Haugh St Andrews KY16 9TF UK
| | - David G. Norman
- School of Life Sciences University of Dundee, Medical Sciences Institute Dundee DD1 5EH UK
| | - Bela E. Bode
- EaStCHEM School of Chemistry Biomedical Sciences Research Complex, and Centre of Magnetic Resonance University of St Andrews North Haugh St Andrews KY16 9ST UK
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19
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Ritsch I, Hintz H, Jeschke G, Godt A, Yulikov M. Improving the accuracy of Cu(ii)–nitroxide RIDME in the presence of orientation correlation in water-soluble Cu(ii)–nitroxide rulers. Phys Chem Chem Phys 2019; 21:9810-9830. [DOI: 10.1039/c8cp06573j] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Detailed analysis of artefacts in the Cu(ii)–nitroxide RIDME experiments, related to orientation averaging, echo-crossing, ESEEM and background-correction is presented.
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Affiliation(s)
- Irina Ritsch
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Bioscience
- ETH Zurich
- 8093 Zurich
- Switzerland
| | - Henrik Hintz
- Faculty of Chemistry and Center for Molecular Materials (CM2)
- Bielefeld University
- 33615 Bielefeld
- Germany
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Bioscience
- ETH Zurich
- 8093 Zurich
- Switzerland
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2)
- Bielefeld University
- 33615 Bielefeld
- Germany
| | - Maxim Yulikov
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Bioscience
- ETH Zurich
- 8093 Zurich
- Switzerland
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20
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Keller K, Qi M, Gmeiner C, Ritsch I, Godt A, Jeschke G, Savitsky A, Yulikov M. Intermolecular background decay in RIDME experiments. Phys Chem Chem Phys 2019; 21:8228-8245. [DOI: 10.1039/c8cp07815g] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Theoretical and experimental studies of the RIDME background reveal electron and nuclear spectral diffusion contributions.
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Affiliation(s)
- Katharina Keller
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Biosciences
- ETH Zurich
- 8093 Zurich
- Switzerland
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials (CM2)
- Bielefeld University
- 33615 Bielefeld
- Germany
| | - Christoph Gmeiner
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Biosciences
- ETH Zurich
- 8093 Zurich
- Switzerland
| | - Irina Ritsch
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Biosciences
- ETH Zurich
- 8093 Zurich
- Switzerland
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM2)
- Bielefeld University
- 33615 Bielefeld
- Germany
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Biosciences
- ETH Zurich
- 8093 Zurich
- Switzerland
| | - Anton Savitsky
- Physics Department
- Technical University Dortmund
- Dortmund
- Germany
| | - Maxim Yulikov
- Laboratory of Physical Chemistry
- Department of Chemistry and Applied Biosciences
- ETH Zurich
- 8093 Zurich
- Switzerland
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21
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Affiliation(s)
- Katrin Ackermann
- Biomedical Sciences Research Complex, Centre of Magnetic Resonance and EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, Scotland
| | - Bela E. Bode
- Biomedical Sciences Research Complex, Centre of Magnetic Resonance and EaStCHEM School of Chemistry, University of St Andrews, St Andrews, KY16 9ST, Scotland
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22
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Giannoulis A, Ackermann K, Spindler PE, Higgins C, Cordes DB, Slawin AMZ, Prisner TF, Bode BE. Nitroxide–nitroxide and nitroxide–metal distance measurements in transition metal complexes with two or three paramagnetic centres give access to thermodynamic and kinetic stabilities. Phys Chem Chem Phys 2018; 20:11196-11205. [DOI: 10.1039/c8cp01611a] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Broadband and highly resolved EPR distance measurements reveal multimers and their kinetic stabilities.
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Affiliation(s)
- A. Giannoulis
- Biomedical Sciences Research Complex and Centre of Magnetic Resonance University of St Andrews
- St Andrews KY16 9ST
- UK
- EaStCHEM School of Chemistry
- University of St Andrews
| | - K. Ackermann
- Biomedical Sciences Research Complex and Centre of Magnetic Resonance University of St Andrews
- St Andrews KY16 9ST
- UK
- EaStCHEM School of Chemistry
- University of St Andrews
| | - P. E. Spindler
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance
- Goethe-University Frankfurt am Main
- D-60438 Frankfurt am Main
- Germany
| | - C. Higgins
- EaStCHEM School of Chemistry
- University of St Andrews
- St Andrews KY16 9ST
- UK
| | - D. B. Cordes
- EaStCHEM School of Chemistry
- University of St Andrews
- St Andrews KY16 9ST
- UK
| | - A. M. Z. Slawin
- EaStCHEM School of Chemistry
- University of St Andrews
- St Andrews KY16 9ST
- UK
| | - T. F. Prisner
- Institute of Physical and Theoretical Chemistry and Center for Biomolecular Magnetic Resonance
- Goethe-University Frankfurt am Main
- D-60438 Frankfurt am Main
- Germany
| | - B. E. Bode
- Biomedical Sciences Research Complex and Centre of Magnetic Resonance University of St Andrews
- St Andrews KY16 9ST
- UK
- EaStCHEM School of Chemistry
- University of St Andrews
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23
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Giannoulis A, Motion CL, Oranges M, Bühl M, Smith GM, Bode BE. Orientation selection in high-field RIDME and PELDOR experiments involving low-spin CoII ions. Phys Chem Chem Phys 2018; 20:2151-2154. [DOI: 10.1039/c7cp07248a] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Orientation selective pulse dipolar electron paramagnetic resonance unravels relative geometries of spin centres from RIDME and PELDOR data.
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Affiliation(s)
- Angeliki Giannoulis
- EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St Andrews
- UK
- Biomedical Sciences Research Complex, University of St Andrews
- UK
| | | | - Maria Oranges
- EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St Andrews
- UK
- Biomedical Sciences Research Complex, University of St Andrews
- UK
| | - Michael Bühl
- EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St Andrews
- UK
| | - Graham M. Smith
- SUPA, School of Physics & Astronomy, University of St Andrews
- UK
| | - Bela E. Bode
- EaStCHEM School of Chemistry and Centre of Magnetic Resonance, University of St Andrews
- UK
- Biomedical Sciences Research Complex, University of St Andrews
- UK
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24
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Gmeiner C, Klose D, Mileo E, Belle V, Marque SRA, Dorn G, Allain FHT, Guigliarelli B, Jeschke G, Yulikov M. Orthogonal Tyrosine and Cysteine Site-Directed Spin Labeling for Dipolar Pulse EPR Spectroscopy on Proteins. J Phys Chem Lett 2017; 8:4852-4857. [PMID: 28933855 DOI: 10.1021/acs.jpclett.7b02220] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Site-directed spin labeling of native tyrosine residues in isolated domains of the protein PTBP1, using a Mannich-type reaction, was combined with conventional spin labeling of cysteine residues. Double electron-electron resonance (DEER) EPR measurements were performed for both the nitroxide-nitroxide and Gd(III)-nitroxide label combinations within the same protein molecule. For the prediction of distance distributions from a structure model, rotamer libraries were generated for the two linker forms of the tyrosine-reactive isoindoline-based nitroxide radical Nox. Only moderate differences exist between the spatial spin distributions for the two linker forms of Nox. This strongly simplifies DEER data analysis, in particular, if only mean distances need to be predicted.
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Affiliation(s)
- Christoph Gmeiner
- Laboratory of Physical Chemistry, ETH Zurich , Zurich 8093, Switzerland
| | - Daniel Klose
- Laboratory of Physical Chemistry, ETH Zurich , Zurich 8093, Switzerland
| | - Elisabetta Mileo
- Aix Marseille Univ , CNRS, BIP, Laboratoire de Bioénergétique et Ingénierie des Protéines, Marseille 13402, France
| | - Valérie Belle
- Aix Marseille Univ , CNRS, BIP, Laboratoire de Bioénergétique et Ingénierie des Protéines, Marseille 13402, France
| | - Sylvain R A Marque
- Aix Marseille Univ , CNRS, ICR, Institut de Chimie Radicalaire, Marseille 13397, France
- N. N. Vorozhtsov Novosibirsk Insititute of Organic Chemistry , 630090 Novosibirsk, Russia
| | - Georg Dorn
- Institute of Molecular Biology and Biophysics, ETH Zurich , Zurich 8093, Switzerland
| | - Frédéric H T Allain
- Institute of Molecular Biology and Biophysics, ETH Zurich , Zurich 8093, Switzerland
| | - Bruno Guigliarelli
- Aix Marseille Univ , CNRS, BIP, Laboratoire de Bioénergétique et Ingénierie des Protéines, Marseille 13402, France
| | - Gunnar Jeschke
- Laboratory of Physical Chemistry, ETH Zurich , Zurich 8093, Switzerland
| | - Maxim Yulikov
- Laboratory of Physical Chemistry, ETH Zurich , Zurich 8093, Switzerland
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25
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Giannoulis A, Oranges M, Bode BE. Monitoring Complex Formation by Relaxation-Induced Pulse Electron Paramagnetic Resonance Distance Measurements. Chemphyschem 2017; 18:2318-2321. [PMID: 28672084 PMCID: PMC5601224 DOI: 10.1002/cphc.201700666] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Indexed: 12/14/2022]
Abstract
Biomolecular complexes are often multimers fueling the demand for methods that allow unraveling their composition and geometric arrangement. Pulse electron paramagnetic resonance (EPR) spectroscopy is increasingly applied for retrieving geometric information on the nanometer scale. The emerging RIDME (relaxation‐induced dipolar modulation enhancement) technique offers improved sensitivity in distance experiments involving metal centers (e.g. on metalloproteins or proteins labelled with metal ions). Here, a mixture of a spin labelled ligand with increasing amounts of paramagnetic CuII ions allowed accurate quantification of ligand‐metal binding in the model complex formed. The distance measurement was highly accurate and critical aspects for identifying multimerization could be identified. The potential to quantify binding in addition to the high‐precision distance measurement will further increase the scope of EPR applications.
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Affiliation(s)
- Angeliki Giannoulis
- Biomedical Sciences Research Complex, Centre of Magnetic Resonance and, EaStCHEM School of Chemistry, University of St AndrewsNorth Haugh, St Andrews, KY16 9ST, UK
| | - Maria Oranges
- Biomedical Sciences Research Complex, Centre of Magnetic Resonance and, EaStCHEM School of Chemistry, University of St AndrewsNorth Haugh, St Andrews, KY16 9ST, UK
| | - Bela E Bode
- Biomedical Sciences Research Complex, Centre of Magnetic Resonance and, EaStCHEM School of Chemistry, University of St AndrewsNorth Haugh, St Andrews, KY16 9ST, UK
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