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Giannoulis A, Ben-Ishay Y, Goldfarb D. Characteristics of Gd(III) spin labels for the study of protein conformations. Methods Enzymol 2021; 651:235-290. [PMID: 33888206 DOI: 10.1016/bs.mie.2021.01.040] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Gd(III) complexes are currently established as spin labels for structural studies of biomolecules using pulse dipolar electron paramagnetic resonance (PD-EPR) techniques. This has been achieved by the availability of medium- and high-field spectrometers, understanding the spin physics underlying the spectroscopic properties of high spin Gd(III) (S=7/2) pairs and their dipolar interaction, the design of well-defined model compounds and optimization of measurement techniques. In addition, a variety of Gd(III) chelates and labeling schemes have allowed a broad scope of applications. In this review, we provide a brief background of the spectroscopic properties of Gd(III) pertinent for effective PD-EPR measurements and focus on the various labels available to date. We report on their use in PD-EPR applications and highlight their pros and cons for particular applications. We also devote a section to recent in-cell structural studies of proteins using Gd(III), which is an exciting new direction for Gd(III) spin labeling.
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Affiliation(s)
- Angeliki Giannoulis
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Yasmin Ben-Ishay
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
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2
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Gigli L, Andrałojć W, Dalaloyan A, Parigi G, Ravera E, Goldfarb D, Luchinat C. Assessing protein conformational landscapes: integration of DEER data in Maximum Occurrence analysis. Phys Chem Chem Phys 2018; 20:27429-27438. [PMID: 30357188 DOI: 10.1039/c8cp06195e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The properties of the conformational landscape of a biomolecule are of capital importance to understand its function. It is widely accepted that a statistical ensemble is far more representative than a single structure, especially for proteins with disordered regions. While experimental data provide the most important handle on the conformational variability that the system is experiencing, they usually report on either time or ensemble averages. Since the available conformations largely outnumber the (independent) available experimental data, the latter can be equally well reproduced by a variety of ensembles. We have proposed the Maximum Occurrence (MaxOcc) approach to provide an upper bound of the statistical weight of each conformation. This method is expected to converge towards the true statistical weights by increasing the number of independent experimental datasets. In this paper we explore the ability of DEER (Double Electron Electron Resonance) data, which report on the distance distribution between two spin labels attached to a biomolecule, to restrain the MaxOcc values and its complementarity to previously introduced experimental techniques such as NMR and Small-Angle X-ray Scattering. We here present the case of Ca2+ bound calmodulin (CaM) as a test case and show that DEER data impose a sizeable reduction of the conformational space described by high MaxOcc conformations.
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Affiliation(s)
- Lucia Gigli
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (FI), Italy.
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3
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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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4
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Chandra B, Maity BK, Das A, Maiti S. Fluorescence quenching by lipid encased nanoparticles shows that amyloid-β has a preferred orientation in the membrane. Chem Commun (Camb) 2018; 54:7750-7753. [DOI: 10.1039/c8cc02108b] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Short range plasmonic fields around a nanoparticle can modulate fluorescence or Raman processes.
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Affiliation(s)
| | | | - Anirban Das
- Tata Institute of Fundamental Research
- Homi Bhabha Road
- Mumbai
- India
| | - Sudipta Maiti
- Tata Institute of Fundamental Research
- Homi Bhabha Road
- Mumbai
- India
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5
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Bahrenberg T, Rosenski Y, Carmieli R, Zibzener K, Qi M, Frydman V, Godt A, Goldfarb D, Feintuch A. Improved sensitivity for W-band Gd(III)-Gd(III) and nitroxide-nitroxide DEER measurements with shaped pulses. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 283:1-13. [PMID: 28834777 DOI: 10.1016/j.jmr.2017.08.003] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 08/08/2017] [Accepted: 08/09/2017] [Indexed: 06/07/2023]
Abstract
Chirp and shaped pulses have been recently shown to be highly advantageous for improving sensitivity in DEER (double electron-electron resonance, also called PELDOR) measurements due to their large excitation bandwidth. The implementation of such pulses for pulse EPR has become feasible due to the availability of arbitrary waveform generators (AWG) with high sampling rates to support pulse shaping for pulses with tens of nanoseconds duration. Here we present a setup for obtaining chirp pulses on our home-built W-band (95GHz) spectrometer and demonstrate its performance on Gd(III)-Gd(III) and nitroxide-nitroxide DEER measurements. We carried out an extensive optimization procedure on two model systems, Gd(III)-PyMTA-spacer-Gd(III)-PyMTA (Gd-PyMTA ruler; zero-field splitting parameter (ZFS) D∼1150MHz) as well as nitroxide-spacer-nitroxide (nitroxide ruler) to evaluate the applicability of shaped pulses to Gd(III) complexes and nitroxides, which are two important classes of spin labels used in modern DEER/EPR experiments. We applied our findings to ubiquitin, doubly labeled with Gd-DOTA-monoamide (D∼550MHz) asa model for a system with a small ZFS. Our experiments were focused on the questions (i) what are the best conditions for positioning of the detection frequency, (ii) which pump pulse parameters (bandwidth, positioning in the spectrum, length) yield the best signal-to-noise ratio (SNR) improvements when compared to classical DEER, and (iii) how do the sample's spectral parameters influence the experiment. For the nitroxide ruler, we report an improvement of up to 1.9 in total SNR, while for the Gd-PyMTA ruler the improvement was 3.1-3.4 and for Gd-DOTA-monoamide labeled ubiquitin it was a factor of 1.8. Whereas for the Gd-PyMTA ruler the two setups pump on maximum and observe on maximum gave about the same improvement, for Gd-DOTA-monoamide a significant difference was found. In general the choice of the best set of parameters depends on the D parameter of the Gd(III) complex.
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Affiliation(s)
- Thorsten Bahrenberg
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Yael Rosenski
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Raanan Carmieli
- Department of Chemical Research Support, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Koby Zibzener
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Mian Qi
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, 33615 Bielefeld, Germany
| | - Veronica Frydman
- Department of Chemical Research Support, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Adelheid Godt
- Faculty of Chemistry and Center for Molecular Materials (CM(2)), Bielefeld University, 33615 Bielefeld, Germany
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel
| | - Akiva Feintuch
- Department of Chemical Physics, Weizmann Institute of Science, 76100 Rehovot, Israel.
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6
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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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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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8
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Collauto A, Feintuch A, Qi M, Godt A, Meade T, Goldfarb D. Gd(III) complexes as paramagnetic tags: Evaluation of the spin delocalization over the nuclei of the ligand. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2016; 263:156-163. [PMID: 26802219 DOI: 10.1016/j.jmr.2015.12.025] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Revised: 12/28/2015] [Accepted: 12/30/2015] [Indexed: 05/15/2023]
Abstract
Complexes of the Gd(III) ion are currently being established as spin labels for distance determination in biomolecules by pulse dipolar spectroscopy. Because Gd(III) is an f ion, one expects electron spin density to be localized on the Gd(III) ion - an important feature for the mentioned application. Most of the complex ligands have nitrogens as Gd(III) coordinating atoms. Therefore, measurement of the (14)N hyperfine coupling gives access to information on the localization of the electron spin on the Gd(III) ion. We carried out W-band, 1D and 2D (14)N and (1)H ENDOR measurements on the Gd(III) complexes Gd-DOTA, Gd-538, Gd-595, and Gd-PyMTA that serve as spin labels for Gd-Gd distance measurements. The obtained (14)N spectra are particularly well resolved, revealing both the hyperfine and nuclear quadrupole splittings, which were assigned using 2D Mims ENDOR experiments. Additionally, the spectral contributions of the two different types of nitrogen atoms of Gd-PyMTA, the aliphatic N atom and the pyridine N atom, were distinguishable. The (14)N hyperfine interaction was found to have a very small isotropic hyperfine component of -0.25 to -0.37MHz. Furthermore, the anisotropic hyperfine interactions with the (14)N nuclei and with the non-exchangeable protons of the ligands are well described by the point-dipole approximation using distances derived from the crystal structures. We therefore conclude that the spin density is fully localized on the Gd(III) ion and that the spin density distribution over the nuclei of the ligands is rightfully ignored when analyzing distance measurements.
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Affiliation(s)
- A Collauto
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - A Feintuch
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel
| | - M Qi
- University Bielefeld, Faculty of Chemistry and Center for Molecular Materials, D-33615 Bielefeld, Germany
| | - A Godt
- University Bielefeld, Faculty of Chemistry and Center for Molecular Materials, D-33615 Bielefeld, Germany
| | - T Meade
- Department of Chemistry, Northwestern University, Evanston, IL 60208, USA
| | - D Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, Rehovot 76100, Israel.
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9
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Cohen MR, Frydman V, Milko P, Iron MA, Abdelkader EH, Lee MD, Swarbrick JD, Raitsimring A, Otting G, Graham B, Feintuch A, Goldfarb D. Overcoming artificial broadening in Gd3+–Gd3+ distance distributions arising from dipolar pseudo-secular terms in DEER experiments. Phys Chem Chem Phys 2016; 18:12847-59. [DOI: 10.1039/c6cp00829a] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Double electron–electron resonance (DEER) is used to probe structure of Gd3+-tagged biomolecules by determining Gd3+–Gd3+ distances.
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Affiliation(s)
- Marie Ramirez Cohen
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 7610001
- Israel
| | - Veronica Frydman
- Department of Chemical Research Support
- Weizmann Institute of Science
- Rehovot 7610001
- Israel
| | - Petr Milko
- Department of Chemical Research Support
- Weizmann Institute of Science
- Rehovot 7610001
- Israel
| | - Mark A. Iron
- Department of Chemical Research Support
- Weizmann Institute of Science
- Rehovot 7610001
- Israel
| | - Elwy H. Abdelkader
- Research School of Chemistry
- Australian National University
- Canberra
- Australia
| | - Michael D. Lee
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville
- Australia
| | - James D. Swarbrick
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville
- Australia
| | | | - Gottfried Otting
- Research School of Chemistry
- Australian National University
- Canberra
- Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences
- Monash University
- Parkville
- Australia
| | - Akiva Feintuch
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 7610001
- Israel
| | - Daniella Goldfarb
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 7610001
- Israel
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10
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Abdelkader EH, Lee MD, Feintuch A, Cohen MR, Swarbrick JD, Otting G, Graham B, Goldfarb D. A New Gd(3+) Spin Label for Gd(3+)-Gd(3+) Distance Measurements in Proteins Produces Narrow Distance Distributions. J Phys Chem Lett 2015; 6:5016-5021. [PMID: 26623480 DOI: 10.1021/acs.jpclett.5b02451] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Gd(3+) tags have been shown to be useful for performing distance measurements in biomolecules via the double electron-electron resonance (DEER) technique at Q- and W-band frequencies. We introduce a new cyclen-based Gd(3+) tag that exhibits a relatively narrow electron paramagnetic resonance (EPR) spectrum, affording high sensitivity, and which yields exceptionally narrow Gd(3+)-Gd(3+) distance distributions in doubly tagged proteins owing to a very short tether. Both the maxima and widths of distance distributions measured for tagged mutants of the proteins ERp29 and T4 lysozyme, featuring Gd(3+)-Gd(3+) distances of ca. 6 and 4 nm, respectively, were well reproduced by simulated distance distributions based on available crystal structures and sterically allowed rotamers of the tag. The precision of the position of the Gd(3+) ion is comparable to that of the nitroxide radical in an MTSL-tagged protein and thus the new tag represents an attractive tool for performing accurate distance measurements and potentially probing protein conformational equilibria.
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Affiliation(s)
- Elwy H Abdelkader
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Michael D Lee
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville VIC 3052, Australia
| | - 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
| | - James D Swarbrick
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville VIC 3052, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University , Parkville VIC 3052, Australia
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science , Rehovot 76100, Israel
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11
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Martorana A, Yang Y, Zhao Y, Li QF, Su XC, Goldfarb D. Mn(ii) tags for DEER distance measurements in proteins via C–S attachment. Dalton Trans 2015; 44:20812-6. [DOI: 10.1039/c5dt04123f] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Tags for Mn2+–Mn2+ distance measurements in proteins with a short and stable linker that generate narrow distance distributions were developed.
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Affiliation(s)
- Andrea Martorana
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 76100
- Israel
| | - Yin Yang
- State Key Laboratory of Elemento-organic Chemistry
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Yu Zhao
- State Key Laboratory of Elemento-organic Chemistry
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Qing-Feng Li
- State Key Laboratory of Elemento-organic Chemistry
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-organic Chemistry
- Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Daniella Goldfarb
- Department of Chemical Physics
- Weizmann Institute of Science
- Rehovot 76100
- Israel
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12
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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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