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Ovcherenko SS, Raizvich AE, Rogozhnikova OY, Tormyshev VM, Trukhin DV, Koval VV, Salnikov GE, Genaev AM, Shernyukov AV, Bagryanskaya EG. Redox Transformations of the OX063 Radical in Biological Media: Oxidative Decay of Initial Trityl with Further Formation of Structurally-Modified TAM. Chemistry 2024; 30:e202400718. [PMID: 39003595 DOI: 10.1002/chem.202400718] [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: 02/22/2024] [Revised: 07/10/2024] [Accepted: 07/12/2024] [Indexed: 07/15/2024]
Abstract
Being a low-toxic and hydrophilic representative of TAM, OX063 has shown its suitability for in-vivo and in-cell EPR experiments and design of spin labels. Using 13C labeling, we investigated the course of oxidative degradation of OX063 into quinone-methide (QM) under the influence of superoxide as well as further thiol-promoted reduction of QM into TAM radical, which formally corresponds to substitution of a carboxyl function by a hydroxyl group. We found these transformations being quantitative in model reactions mimicking specific features of biological media and confirmed the presence of these reactions in the blood and liver homogenate of mice in vitro. The emergence of the trityl with the hydroxyl group can be masked by an initial TAM in EPR spectra and may introduce distortions into EPR-derived oximetry data if they have been obtained for objects under hypoxia. 13C labeling allows one to detect its presence, considering its different hyperfine splitting constant on 13C1 (2.04 mT) as compared to OX063 (2.30 mT). The potential involvement of these reactions should be considered when using TAM in spin-labeling of biopolymers intended for subsequent EPR experiments, as well as in the successful application of TAM in experiments in vivo and in cell.
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Affiliation(s)
- Sergey S Ovcherenko
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
- Novosibirsk State University, 2 Pirogova Street, Novosibirsk, 630090, Russian Federation
| | - Arthur E Raizvich
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
- Novosibirsk State University, 2 Pirogova Street, Novosibirsk, 630090, Russian Federation
| | - Olga Yu Rogozhnikova
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
| | - Victor M Tormyshev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
| | - Dmitry V Trukhin
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
| | - Vladimir V Koval
- Institute of Chemical Biology and Fundamental Medicine SB RAS, 8 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
| | - Georgii E Salnikov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
| | - Alexander M Genaev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
| | - Andrey V Shernyukov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
| | - Elena G Bagryanskaya
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, 9 Akad. Lavrentiev Avenue, Novosibirsk, 630090, Russian Federation
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2
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Pierro A, Bonucci A, Magalon A, Belle V, Mileo E. Impact of Cellular Crowding on Protein Structural Dynamics Investigated by EPR Spectroscopy. Chem Rev 2024; 124:9873-9898. [PMID: 39213496 DOI: 10.1021/acs.chemrev.3c00951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The study of how the intracellular medium influences protein structural dynamics and protein-protein interactions is a captivating area of research for scientists aiming to comprehend biomolecules in their native environment. As the cellular environment can hardly be reproduced in vitro, direct investigation of biomolecules within cells has attracted growing interest in the past two decades. Among magnetic resonances, site-directed spin labeling coupled to electron paramagnetic resonance spectroscopy (SDSL-EPR) has emerged as a powerful tool for studying the structural properties of biomolecules directly in cells. Since the first in-cell EPR experiment was reported in 2010, substantial progress has been made, and this Review provides a detailed overview of the developments and applications of this spectroscopic technique. The strategies available for preparing a cellular sample and the EPR methods that can be applied to cells will be discussed. The array of spin labels available, along with their strengths and weaknesses in cellular contexts, will also be described. Several examples will illustrate how in-cell EPR can be applied to different biological systems and how the cellular environment affects the structural and dynamic properties of different proteins. Lastly, the Review will focus on the future developments expected to expand the capabilities of this promising technique.
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Affiliation(s)
- Annalisa Pierro
- Department of Chemistry, Konstanz Research School Chemical Biology, University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany
| | - Alessio Bonucci
- Aix Marseille University, CNRS, Bioénergétique et Ingénierie des Protéines (BIP), IMM, IM2B, Marseille, France
| | - Axel Magalon
- Aix Marseille University, CNRS, Laboratoire de Chimie Bactérienne (LCB), IMM, IM2B, Marseille, France
| | - Valérie Belle
- Aix Marseille University, CNRS, Bioénergétique et Ingénierie des Protéines (BIP), IMM, IM2B, Marseille, France
| | - Elisabetta Mileo
- Aix Marseille University, CNRS, Bioénergétique et Ingénierie des Protéines (BIP), IMM, IM2B, Marseille, France
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3
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Li S, Deng P, Chang Q, Feng M, Shang Y, Song Y, Liu Y. In Situ Generation and High Bioresistance of Trityl-based Semiquinone Methide Radicals Under Anaerobic Conditions in Cellular Systems. Chemistry 2024; 30:e202400985. [PMID: 38932665 DOI: 10.1002/chem.202400985] [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: 03/09/2024] [Revised: 06/02/2024] [Accepted: 06/25/2024] [Indexed: 06/28/2024]
Abstract
Bioreduction of spin labels and polarizing agents (generally stable radicals) has been an obstacle limiting the in-cell applications of pulsed electron paramagnetic resonance (EPR) spectroscopy and dynamic nuclear polarization (DNP). In this work, we have demonstrated that two semiquinone methide radicals (OXQM⋅ and CTQM⋅) can be easily produced from the trityl-based quinone methides (OXQM and CTQM) via reduction by various reducing agents including biothiols and ascorbate under anaerobic conditions. Both radicals have relatively low pKa's and exhibit EPR single line signals at physiological pH. Moreover, the bioreduction of OXQM in three cell lysates enables quantitative generation of OXQM⋅ which was most likely mediated by flavoenzymes. Importantly, the resulting OXQM⋅ exhibited extremely high stability in the E.coli lysate under anaerobic conditions with 76- and 14.3-fold slower decay kinetics as compared to the trityl OX063 and a gem-diethyl pyrrolidine nitroxide, respectively. Intracellular delivery of OXQM into HeLa cells was also achieved by covalent conjugation with a cell-permeable peptide as evidenced by the stable intracellular EPR signal from the OXQM⋅ moiety. Owing to extremely high resistance of OXQM⋅ towards bioreduction, OXQM and its derivatives show great application potential in in-cell EPR and in-cell DNP studies for various cells which can endure short-term anoxic treatments.
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Affiliation(s)
- Shuai Li
- The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Peng Deng
- The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Qi Chang
- The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Meirong Feng
- The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Yixuan Shang
- The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Yuguang Song
- The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
| | - Yangping Liu
- The Province and Ministry Co-Sponsored Collaborative Innovation Center for Medical Epigenetics, Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, School of Pharmacy, Tianjin Medical University, Tianjin, 300070, P. R. China
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4
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Torricella F, Vitali V, Banci L. A systematic study on the effect of protonation and deuteration on electron spin Tm/ T2 in a cellular context. Phys Chem Chem Phys 2024. [PMID: 39037427 DOI: 10.1039/d4cp00599f] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/23/2024]
Abstract
In recent years, DEER experiments in pulsed EPR have garnered interest for their precise distance distribution insights in cellular and buffer setups. These measurements linked to electron spin Tm/T2 values of the labelled sample are impacted by the cellular environment being fully protonated or deuterated, as demonstrated in the present study.
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Affiliation(s)
- Francesco Torricella
- Magnetic Resonance Center, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy.
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institute of Health, Bethesda, Maryland 20892-0520, USA
| | - Valentina Vitali
- Magnetic Resonance Center, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy.
- Dipartimento di Chimica, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy
| | - Lucia Banci
- Magnetic Resonance Center, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy.
- Consorzio Interuniversitario Risonanza Magnetiche di Metallo Proteine, 50019 Sesto Fiorentino, Italy
- Dipartimento di Chimica, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy
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Ben‐Ishay Y, Barak Y, Feintuch A, Ouari O, Pierro A, Mileo E, Su X, Goldfarb D. Exploring the dynamics and structure of PpiB in living Escherichia coli cells using electron paramagnetic resonance spectroscopy. Protein Sci 2024; 33:e4903. [PMID: 38358137 PMCID: PMC10868451 DOI: 10.1002/pro.4903] [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: 11/14/2023] [Revised: 12/29/2023] [Accepted: 01/04/2024] [Indexed: 02/16/2024]
Abstract
The combined effects of the cellular environment on proteins led to the definition of a fifth level of protein structural organization termed quinary structure. To explore the implication of potential quinary structure for globular proteins, we studied the dynamics and conformations of Escherichia coli (E. coli) peptidyl-prolyl cis/trans isomerase B (PpiB) in E. coli cells. PpiB plays a major role in maturation and regulation of folded proteins by catalyzing the cis/trans isomerization of the proline imidic peptide bond. We applied electron paramagnetic resonance (EPR) techniques, utilizing both Gadolinium (Gd(III)) and nitroxide spin labels. In addition to using standard spin labeling approaches with genetically engineered cysteines, we incorporated an unnatural amino acid to achieve Gd(III)-nitroxide orthogonal labeling. We probed PpiB's residue-specific dynamics by X-band continuous wave EPR at ambient temperatures and its structure by double electron-electron resonance (DEER) on frozen samples. PpiB was delivered to E. coli cells by electroporation. We report a significant decrease in the dynamics induced by the cellular environment for two chosen labeling positions. These changes could not be reproduced by adding crowding agents and cell extracts. Concomitantly, we report a broadening of the distance distribution in E. coli, determined by Gd(III)-Gd(III) DEER measurements, as compared with solution and human HeLa cells. This suggests an increase in the number of PpiB conformations present in E. coli cells, possibly due to interactions with other cell components, which also contributes to the reduction in mobility and suggests the presence of a quinary structure.
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Affiliation(s)
- Yasmin Ben‐Ishay
- Department of Chemical and Biological PhysicsWeizmann Institute of ScienceRehovotIsrael
| | - Yoav Barak
- Department of Chemical Research SupportWeizmann Institute of ScienceRehovotIsrael
| | - Akiva Feintuch
- Department of Chemical and Biological PhysicsWeizmann Institute of ScienceRehovotIsrael
| | - Olivier Ouari
- CNRS, ICR, Institut de Chimie RadicalaireAix‐Marseille UniversitéMarseilleFrance
| | - Annalisa Pierro
- CNRS, BIP, Laboratoire de Bioénergétique et Ingénierie des ProtéinesAix Marseille UniversitéMarseilleFrance
- Present address:
Konstanz Research School Chemical Biology, Department of ChemistryUniversity of KonstanzKonstanzGermany
| | - Elisabetta Mileo
- CNRS, BIP, Laboratoire de Bioénergétique et Ingénierie des ProtéinesAix Marseille UniversitéMarseilleFrance
| | - Xun‐Cheng Su
- State Key Laboratory of Elemento‐organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular RecognitionCollege of Chemistry, Nankai UniversityTianjinChina
| | - Daniella Goldfarb
- Department of Chemical and Biological PhysicsWeizmann Institute of ScienceRehovotIsrael
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Guo SL, Xiao YH, Pan BB, Su XC. Site-Specific Anchoring a Luminescent Tag in a Protein with Non-Emissive Iridium(III) Complex. Chembiochem 2024; 25:e202300798. [PMID: 38169080 DOI: 10.1002/cbic.202300798] [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: 11/24/2023] [Revised: 12/24/2023] [Accepted: 01/02/2024] [Indexed: 01/05/2024]
Abstract
Site-specific modification of proteins with synthetic fluorescent tag effectively improves the resolution of imaging, and such a labeling method with negligible three-dimensional structural perturbations and minimal impact on the biological functions of proteins is of high interest to dissect the high-resolution activities of biomolecules in complex systems. To this end, several non-emissive iridium(III) complexes [Ir(C-N)2 (H2 O)2 ]+ OTF- (C-N denotes various cyclometalated ligands) were designed and synthesized. These complexes were tested for attaching a protein by coordinating to H/X (HisMet, HisHis, and HisCys) that are separated by i and i+4 in α-helix. Replacement of the two labile water ligands in the iridium(III) complex by a protein HisHis pair increases the luminescent intensity up to over 100 folds. This labeling approach has been demonstrated in a highly specific and efficient manner in a number of proteins, and it is also feasible for labeling target proteins in cell lysates.
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Affiliation(s)
- Shu-Li Guo
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Yu-Hao Xiao
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Bin-Bin Pan
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Tianjin, 300071, China
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7
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Shu C, Yang Z, Rajca A. From Stable Radicals to Thermally Robust High-Spin Diradicals and Triradicals. Chem Rev 2023; 123:11954-12003. [PMID: 37831948 DOI: 10.1021/acs.chemrev.3c00406] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/15/2023]
Abstract
Stable radicals and thermally robust high-spin di- and triradicals have emerged as important organic materials due to their promising applications in diverse fields. New fundamental properties, such as SOMO/HOMO inversion of orbital energies, are explored for the design of new stable radicals, including highly luminescent ones with good photostability. A relation with the singlet-triplet energy gap in the corresponding diradicals is proposed. Thermally robust high-spin di- and triradicals, with energy gaps that are comparable to or greater than a thermal energy at room temperature, are more challenging to synthesize but more rewarding. We summarize a number of high-spin di- and triradicals, based on nitronyl nitroxides that provide a relation between the experimental pairwise exchange coupling constant J/k in the high-spin species vs experimental hyperfine coupling constants in the corresponding monoradicals. This relation allows us to identify outliers, which may correspond to radicals where J/k is not measured with sufficient accuracy. Double helical high-spin diradicals, in which spin density is delocalized over the chiral π-system, have been barely explored, with the sole example of such high-spin diradical possessing alternant π-system with Kekulé resonance form. Finally, we discuss a high-spin diradical with electrical conductivity and derivatives of triangulene diradicals.
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Affiliation(s)
- Chan Shu
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Zhimin Yang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
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8
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Igbaria-Jaber Y, Hofmann L, Gevorkyan-Airapetov L, Shenberger Y, Ruthstein S. Revealing the DNA Binding Modes of CsoR by EPR Spectroscopy. ACS OMEGA 2023; 8:39886-39895. [PMID: 37901548 PMCID: PMC10601412 DOI: 10.1021/acsomega.3c06336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Accepted: 09/28/2023] [Indexed: 10/31/2023]
Abstract
In pathogens, a unique class of metalloregulator proteins, called gene regulatory proteins, sense specific metal ions that initiate gene transcription of proteins that export metal ions from the cell, thereby preventing toxicity and cell death. CsoR is a metalloregulator protein found in various bacterial systems that "sense" Cu(I) ions with high affinity. Upon copper binding, CsoR dissociates from the DNA promoter region, resulting in initiation of gene transcription. Crystal structures of CsoR in the presence and absence of Cu(I) from various bacterial systems have been reported, suggesting either a dimeric or tetrameric structure of these helical proteins. However, structural information about the CsoR-DNA complex is missing. Here, we applied electron paramagnetic resonance (EPR) spectroscopy to follow the conformational and dynamical changes that Mycobacterium tuberculosis CsoR undergoes upon DNA binding in solution. We showed that the quaternary structure is predominantly dimeric in solution, and only minor conformational and dynamical changes occur in the DNA bound state. Also, labeling of the unresolved C- terminus revealed no significant change in dynamics upon DNA binding. These observations are unique, since for other bacterial copper metalloregulators, such as the MerR and CopY families, major conformational changes were observed upon DNA binding, indicating a different mode of action for this protein family.
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Affiliation(s)
- Yasmin Igbaria-Jaber
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Lukas Hofmann
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Lada Gevorkyan-Airapetov
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Yulia Shenberger
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
| | - Sharon Ruthstein
- Department of Chemistry and the Institute
of Nanotechnology and Advanced Materials (BINA), Bar-Ilan University, Ramat-Gan 52900, Israel
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9
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Mayländer M, Kopp K, Nolden O, Franz M, Thielert P, Vargas Jentzsch A, Gilch P, Schiemann O, Richert S. PDI-trityl dyads as photogenerated molecular spin qubit candidates. Chem Sci 2023; 14:10727-10735. [PMID: 37829028 PMCID: PMC10566479 DOI: 10.1039/d3sc04375d] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2023] [Accepted: 09/21/2023] [Indexed: 10/14/2023] Open
Abstract
Owing to their potential applications in the field of quantum information science, photogenerated organic triplet-radical conjugates have attracted an increasing amount of attention recently. Typically, these compounds are composed of a chromophore appended to a stable radical. After initialisation of the system by photoexcitation, a highly spin-polarised quartet state may be generated, which serves as a molecular spin qubit candidate. Here, we investigate three perylene diimide (PDI)-based chromophore-radical systems with different phenylene linkers and radical counterparts by both optical spectroscopy and transient electron paramagnetic resonance (EPR) techniques. Femtosecond transient absorption measurements demonstrate chromophore triplet state formation on a picosecond time scale for PDI-trityl dyads, while excited state deactivation is found to be slowed down considerably in a PDI-nitroxide analogue. The subsequent investigation of the coherent spin properties by transient EPR confirms quartet state formation by triplet-doublet spin mixing for all investigated dyads and the suitability of the two studied PDI-trityl dyads as spin qubit candidates. In particular, we show that using tetrathiaryl trityl as the radical counterpart, an intense spin polarisation is observed even at room temperature and quartet state coherence times of 3.0 μs can be achieved at 80 K, which represents a considerable improvement compared to previously studied systems.
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Affiliation(s)
- Maximilian Mayländer
- Institute of Physical Chemistry, University of Freiburg Albertstraße 21 79104 Freiburg Germany
| | - Kevin Kopp
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn Wegelerstraße 12 53115 Bonn Germany
| | - Oliver Nolden
- Institute of Physical Chemistry, Heinrich Heine University Düsseldorf Universitätsstraße 1 40225 Düsseldorf Germany
| | - Michael Franz
- Institute of Physical Chemistry, University of Freiburg Albertstraße 21 79104 Freiburg Germany
| | - Philipp Thielert
- Institute of Physical Chemistry, University of Freiburg Albertstraße 21 79104 Freiburg Germany
| | - Andreas Vargas Jentzsch
- SAMS Research Group, Université de Strasbourg, CNRS, Institut Charles Sadron UPR 22 67000 Strasbourg France
| | - Peter Gilch
- Institute of Physical Chemistry, Heinrich Heine University Düsseldorf Universitätsstraße 1 40225 Düsseldorf Germany
| | - Olav Schiemann
- Clausius Institute of Physical and Theoretical Chemistry, University of Bonn Wegelerstraße 12 53115 Bonn Germany
| | - Sabine Richert
- Institute of Physical Chemistry, University of Freiburg Albertstraße 21 79104 Freiburg Germany
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10
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Marcinkowski D, Kubicki M, Patroniak V, Muzioł T, Chorazy S, Shi L, Zychowicz M, Majcher-Fitas AM, Podgajny R, Gorczyński A. Trityl-Based Lanthanide-Supramolecular Assemblies Exhibiting Slow Magnetic Relaxation. Chemistry 2023; 29:e202300695. [PMID: 37408381 DOI: 10.1002/chem.202300695] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2023] [Revised: 06/26/2023] [Accepted: 07/03/2023] [Indexed: 07/07/2023]
Abstract
The triphenylmethane (trityl) group has been recognized as a supramolecular synthon in crystal engineering, molecular machine rotors and stereochemical chirality inductors in materials science. Herein we demonstrate for the first time how it can be utilized in the domain of molecular magnetic materials through shaping of single molecule magnet (SMM) properties within the lanthanide complexes in tandem with other non-covalent interactions. Trityl-appended mono- (HL1 ) and bis-compartmental (HL2 ) hydrazone ligands were synthesized and complexated with Dy(III) and Er(III) triflate and nitrate salts to generate four monometallic (1-4) and two bimetallic (5, 6) complexes. The static and dynamic magnetic properties of 1-6 were investigated, revealing that only ligand HL1 induces assemblies (1-4) capable of showing SMM behaviour, with Dy(III) congeners (1, 2) able to exhibit the phenomenon also under zero field conditions. Theoretical ab initio studies helped in determination of Dy(III) energetic levels, magnetic anisotropic axes and corroborated magnetic relaxation mechanisms to be a combination of Raman and quantum tunnelling in zero dc field, the latter being cancelled in the optimum non-zero dc field. Our work represents the first study of magneto-structural correlations within the trityl Ln-SMMs, leading to generation of slowly relaxing zero-field dysprosium complexes within the hydrogen-bonded assemblies.
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Affiliation(s)
- Dawid Marcinkowski
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Maciej Kubicki
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Violetta Patroniak
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
| | - Tadeusz Muzioł
- Nicolaus Copernicus University in Torun, Faculty of Chemistry, Jurija Gagarina 11, 87-100, Toruń, Poland
| | - Szymon Chorazy
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Le Shi
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Mikołaj Zychowicz
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Anna M Majcher-Fitas
- Faculty of Physics, Astronomy and Applied Computer Science, Jagiellonian University, Łojasiewicza 11, 30-348, Kraków, Poland
| | - Robert Podgajny
- Faculty of Chemistry, Jagiellonian University, Gronostajowa 2, 30-387, Kraków, Poland
| | - Adam Gorczyński
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614, Poznań, Poland
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11
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Wang XW, Zhang X, Cui CY, Li B, Goldfarb D, Yang Y, Su XC. Stabilizing Nitroxide Spin Labels for Structural and Conformational Studies of Biomolecules by Maleimide Treatment. Chemistry 2023; 29:e202301350. [PMID: 37354082 DOI: 10.1002/chem.202301350] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/21/2023] [Accepted: 06/22/2023] [Indexed: 06/26/2023]
Abstract
Nitroxide (NO) spin radicals are effective in characterizing structures, interactions and dynamics of biomolecules. The EPR applications in cell lysates or intracellular milieu require stable spin labels, but NO radicals are unstable in such conditions. We showed that the destabilization of NO radicals in cell lysates or even in cells is caused by NADPH/NADH related enzymes, but not by the commonly believed reducing reagents such as GSH. Maleimide stabilizes the NO radicals in the cell lysates by consumption of the NADPH/NADH that are essential for the enzymes involved in destabilizing NO radicals, instead of serving as the solo thiol scavenger. The maleimide treatment retains the crowding properties of the intracellular components and allows to perform long-time EPR measurements of NO labeled biomolecules close to the intracellular conditions. The strategy of maleimide treatment on cell lysates for the EPR applications has been demonstrated on double electron-electron resonance (DEER) measurements on a number of NO labeled protein samples. The method opens a broad application range for the NO labeled biomolecules by EPR in conditions that resemble the intracellular milieu.
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Affiliation(s)
- Xi-Wei Wang
- State Key Laboratory of Elemento-organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Xing Zhang
- State Key Laboratory of Elemento-organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Chao-Yu Cui
- State Key Laboratory of Elemento-organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Bin Li
- State Key Laboratory of Elemento-organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 76100, Israel
| | - Yin Yang
- State Key Laboratory of Elemento-organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-organic Chemistry, Tianjin Key Laboratory of Biosensing and Molecular Recognition, College of Chemistry, Nankai University, Tianjin, 300071, China
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12
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Galazzo L, Bordignon E. Electron paramagnetic resonance spectroscopy in structural-dynamic studies of large protein complexes. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2023; 134-135:1-19. [PMID: 37321755 DOI: 10.1016/j.pnmrs.2022.11.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Revised: 11/11/2022] [Accepted: 11/17/2022] [Indexed: 06/17/2023]
Abstract
Macromolecular protein assemblies are of fundamental importance for many processes inside the cell, as they perform complex functions and constitute central hubs where reactions occur. Generally, these assemblies undergo large conformational changes and cycle through different states that ultimately are connected to specific functions further regulated by additional small ligands or proteins. Unveiling the 3D structural details of these assemblies at atomic resolution, identifying the flexible parts of the complexes, and monitoring with high temporal resolution the dynamic interplay between different protein regions under physiological conditions is key to fully understanding their properties and to fostering biomedical applications. In the last decade, we have seen remarkable advances in cryo-electron microscopy (EM) techniques, which deeply transformed our vision of structural biology, especially in the field of macromolecular assemblies. With cryo-EM, detailed 3D models of large macromolecular complexes in different conformational states became readily available at atomic resolution. Concomitantly, nuclear magnetic resonance (NMR) and electron paramagnetic resonance spectroscopy (EPR) have benefited from methodological innovations which also improved the quality of the information that can be achieved. Such enhanced sensitivity widened their applicability to macromolecular complexes in environments close to physiological conditions and opened a path towards in-cell applications. In this review we will focus on the advantages and challenges of EPR techniques with an integrative approach towards a complete understanding of macromolecular structures and functions.
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Affiliation(s)
- Laura Galazzo
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, CH-1211 Genève 4, Switzerland.
| | - Enrica Bordignon
- Department of Physical Chemistry, University of Geneva, Quai Ernest Ansermet 30, CH-1211 Genève 4, Switzerland.
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13
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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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14
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Pierro A, Drescher M. Dance with spins: site-directed spin labeling coupled to electron paramagnetic resonance spectroscopy directly inside cells. Chem Commun (Camb) 2023; 59:1274-1284. [PMID: 36633152 PMCID: PMC9890500 DOI: 10.1039/d2cc05907j] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2022] [Accepted: 01/04/2023] [Indexed: 01/06/2023]
Abstract
Depicting how biomolecules move and interact within their physiological environment is one of the hottest topics of structural biology. This Feature Article gives an overview of the most recent advances in Site-directed Spin Labeling coupled to Electron Paramagnetic Resonance spectroscopy (SDSL-EPR) to study biomolecules in living cells. The high sensitivity, the virtual absence of background, and the versatility of spin-labeling strategies make this approach one of the most promising techniques for the study of biomolecules in physiologically relevant environments. After presenting the milestones achieved in this field, we present a summary of the future goals and ambitions of this community.
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Affiliation(s)
- Annalisa Pierro
- Department of Chemistry, University of Konstanz, and Konstanz Research School Chemical Biology, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Malte Drescher
- Department of Chemistry, University of Konstanz, and Konstanz Research School Chemical Biology, Universitätsstraße 10, 78457 Konstanz, Germany.
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15
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Properties and applications of photoexcited chromophore–radical systems. Nat Rev Chem 2023; 7:75-90. [PMID: 37117913 DOI: 10.1038/s41570-022-00453-y] [Citation(s) in RCA: 27] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2022] [Indexed: 02/11/2023]
Abstract
Photoexcited organic chromophore-radical systems hold great promise for a range of technological applications in molecular spintronics, including quantum information technology and artificial photosynthesis. However, further development of such systems will depend on the ability to control the magnetic properties of these materials, which requires a profound understanding of the underlying excited-state dynamics. In this Review, we discuss photogenerated triplet-doublet systems and their potential to be used for applications in molecular spintronics. We outline the theoretical description of the spin system in the different coupling regimes and the invoked excited-state mechanisms governing the generation and transfer of spin polarization. The main characterization techniques used to evaluate the optical and magnetic properties of chromophore-radical systems are discussed. We conclude by giving an overview of previously investigated covalently linked triplet-radical systems, and highlight the need for further systematic investigations to improve our understanding of the magnetic interactions in such systems.
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16
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Ackermann BE, Lim BJ, Elathram N, Narayanan S, Debelouchina GT. A Comparative Study of Nitroxide-Based Biradicals for Dynamic Nuclear Polarization in Cellular Environments. Chembiochem 2022; 23:e202200577. [PMID: 36250276 PMCID: PMC9856215 DOI: 10.1002/cbic.202200577] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2022] [Revised: 10/15/2022] [Indexed: 01/25/2023]
Abstract
Dynamic nuclear polarization (DNP) is a powerful tool to enhance the NMR signals of molecules by transferring polarization from unpaired electron spins to nuclei through microwave irradiation. The resulting signal enhancements can enable the analysis of samples that have previously been intractable by NMR spectroscopy, including proteins, nucleic acids, and metabolites in cells. To carry out DNP, the sample is doped with a polarization agent, a biradical containing two nitroxide moieties. DNP applications in cells, however, present significant challenges as nitroxides are often susceptible to the reducing cellular environment. Here, we introduce a novel polarization agent, POPAPOL, that exhibits increased lifetimes under reducing conditions. We also compare its bioresistance and DNP performance with three popular, commercially available polarization agents. Our work indicates that pyrrolidine-based nitroxides can outperform piperidine-based nitroxides in cellular environments, and that future polarization agent designs must carefully balance DNP performance and stability for cellular applications.
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Affiliation(s)
- Bryce E. Ackermann
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Byung Joon Lim
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Nesreen Elathram
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Sirish Narayanan
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA
| | - Galia T. Debelouchina
- Department of Chemistry and Biochemistry, University of California, San Diego, La Jolla, CA 92093, USA,Corresponding author: , http://debelouchinalab.ucsd.edu/
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17
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Pierro A, Bonucci A, Normanno D, Ansaldi M, Pilet E, Ouari O, Guigliarelli B, Etienne E, Gerbaud G, Magalon A, Belle V, Mileo E. Probing the Structural Dynamics of a Bacterial Chaperone in Its Native Environment by Nitroxide‐Based EPR Spectroscopy. Chemistry 2022; 28:e202202249. [DOI: 10.1002/chem.202202249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Indexed: 11/07/2022]
Affiliation(s)
- Annalisa Pierro
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
- Department of Chemistry University of Konstanz, and Konstanz Research School Chemical Biology 78457 Konstanz Germany
| | - Alessio Bonucci
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
| | - Davide Normanno
- Aix Marseille Univ CNRS, Inserm Institut Paoli-Calmettes, CRCM Centre de Recherche en Cancérologie de Marseille 13273 Marseille France
- Univ Montpellier CNRS, IGH Institut de Génétique Humaine 34396 Montpellier France
| | - Mireille Ansaldi
- Aix Marseille Univ CNRS, LCB Laboratoire de Chimie Bacterienne, IMM 13009 Marseille France
| | - Eric Pilet
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
| | - Olivier Ouari
- Aix Marseille Univ CNRS, ICR Institut de Chimie Radicalaire 13397 Marseille France
| | - Bruno Guigliarelli
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
| | - Emilien Etienne
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
| | - Guillaume Gerbaud
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
| | - Axel Magalon
- Aix Marseille Univ CNRS, LCB Laboratoire de Chimie Bacterienne, IMM 13009 Marseille France
| | - Valérie Belle
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
| | - Elisabetta Mileo
- Aix Marseille Univ CNRS, BIP Bioénérgetique et Ingénierie des Protéines, IMM 13009 Marseille France
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18
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Protein delivery to living cells by thermal stimulation for biophysical investigation. Sci Rep 2022; 12:17190. [PMID: 36229511 PMCID: PMC9561116 DOI: 10.1038/s41598-022-21103-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 09/22/2022] [Indexed: 01/05/2023] Open
Abstract
Studying biomolecules in their native environment represents the ideal sample condition for structural biology investigations. Here we present a novel protocol which allows to delivery proteins into eukaryotic cells through a mild thermal stimulation. The data presented herein show the efficacy of this approach for delivering proteins in the intracellular environment of mammalian cells reaching a concentration range suitable for successfully applying biophysical methods, such as double electron electron resonance (DEER) measurements for characterising protein conformations.
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19
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Theillet FX, Luchinat E. In-cell NMR: Why and how? PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 132-133:1-112. [PMID: 36496255 DOI: 10.1016/j.pnmrs.2022.04.002] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Revised: 04/19/2022] [Accepted: 04/27/2022] [Indexed: 06/17/2023]
Abstract
NMR spectroscopy has been applied to cells and tissues analysis since its beginnings, as early as 1950. We have attempted to gather here in a didactic fashion the broad diversity of data and ideas that emerged from NMR investigations on living cells. Covering a large proportion of the periodic table, NMR spectroscopy permits scrutiny of a great variety of atomic nuclei in all living organisms non-invasively. It has thus provided quantitative information on cellular atoms and their chemical environment, dynamics, or interactions. We will show that NMR studies have generated valuable knowledge on a vast array of cellular molecules and events, from water, salts, metabolites, cell walls, proteins, nucleic acids, drugs and drug targets, to pH, redox equilibria and chemical reactions. The characterization of such a multitude of objects at the atomic scale has thus shaped our mental representation of cellular life at multiple levels, together with major techniques like mass-spectrometry or microscopies. NMR studies on cells has accompanied the developments of MRI and metabolomics, and various subfields have flourished, coined with appealing names: fluxomics, foodomics, MRI and MRS (i.e. imaging and localized spectroscopy of living tissues, respectively), whole-cell NMR, on-cell ligand-based NMR, systems NMR, cellular structural biology, in-cell NMR… All these have not grown separately, but rather by reinforcing each other like a braided trunk. Hence, we try here to provide an analytical account of a large ensemble of intricately linked approaches, whose integration has been and will be key to their success. We present extensive overviews, firstly on the various types of information provided by NMR in a cellular environment (the "why", oriented towards a broad readership), and secondly on the employed NMR techniques and setups (the "how", where we discuss the past, current and future methods). Each subsection is constructed as a historical anthology, showing how the intrinsic properties of NMR spectroscopy and its developments structured the accessible knowledge on cellular phenomena. Using this systematic approach, we sought i) to make this review accessible to the broadest audience and ii) to highlight some early techniques that may find renewed interest. Finally, we present a brief discussion on what may be potential and desirable developments in the context of integrative studies in biology.
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Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France.
| | - Enrico Luchinat
- Dipartimento di Scienze e Tecnologie Agro-Alimentari, Alma Mater Studiorum - Università di Bologna, Piazza Goidanich 60, 47521 Cesena, Italy; CERM - Magnetic Resonance Center, and Neurofarba Department, Università degli Studi di Firenze, 50019 Sesto Fiorentino, Italy
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20
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Tessmer MH, Canarie ER, Stoll S. Comparative evaluation of spin-label modeling methods for protein structural studies. Biophys J 2022; 121:3508-3519. [PMID: 35957530 PMCID: PMC9515001 DOI: 10.1016/j.bpj.2022.08.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 07/01/2022] [Accepted: 08/04/2022] [Indexed: 11/18/2022] Open
Abstract
Site-directed spin-labeling electron paramagnetic resonance spectroscopy is a powerful technique for the investigation of protein structure and dynamics. Accurate spin-label modeling methods are essential to make full quantitative use of site-directed spin-labeling electron paramagnetic resonance data for protein modeling and model validation. Using a set of double electron-electron resonance data from seven different site pairs on maltodextrin/maltose-binding protein under two different conditions using five different spin labels, we compare the ability of two widely used spin-label modeling methods, based on accessible volume sampling and rotamer libraries, to predict experimental distance distributions. We present a spin-label modeling approach inspired by canonical side-chain modeling methods and compare modeling accuracy with the established methods.
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Affiliation(s)
- Maxx H Tessmer
- Department of Chemistry, University of Washington, Seattle, Washington
| | | | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, Washington.
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21
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Goldfarb D. Exploring protein conformations in vitro and in cell with EPR distance measurements. Curr Opin Struct Biol 2022; 75:102398. [PMID: 35667279 DOI: 10.1016/j.sbi.2022.102398] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2022] [Revised: 04/20/2022] [Accepted: 04/30/2022] [Indexed: 11/18/2022]
Abstract
The electron-electron double resonance (DEER) method, which provides distance distributions between two spin labels, attached site specifically to biomolecules (proteins and nucleic acids), is currently a well-recognized biophysical tool in structural biology. The most commonly used spin labels are based on nitroxide stable radicals, conjugated to the proteins primarily via native or engineered cysteine residues. However, in recent years, new spin labels, along with different labeling chemistries, have been introduced, driven in part by the desire to study structural and dynamical properties of biomolecules in their native environment, the cell. This mini-review focuses on these new spin labels, which allow for DEER on orthogonal spin labels, and on the state of the art methods for in-cell DEER distance measurements.
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Affiliation(s)
- Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, 761001, Israel
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22
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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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23
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Abstract
In-cell structural biology aims at extracting structural information about proteins or nucleic acids in their native, cellular environment. This emerging field holds great promise and is already providing new facts and outlooks of interest at both fundamental and applied levels. NMR spectroscopy has important contributions on this stage: It brings information on a broad variety of nuclei at the atomic scale, which ensures its great versatility and uniqueness. Here, we detail the methods, the fundamental knowledge, and the applications in biomedical engineering related to in-cell structural biology by NMR. We finally propose a brief overview of the main other techniques in the field (EPR, smFRET, cryo-ET, etc.) to draw some advisable developments for in-cell NMR. In the era of large-scale screenings and deep learning, both accurate and qualitative experimental evidence are as essential as ever to understand the interior life of cells. In-cell structural biology by NMR spectroscopy can generate such a knowledge, and it does so at the atomic scale. This review is meant to deliver comprehensive but accessible information, with advanced technical details and reflections on the methods, the nature of the results, and the future of the field.
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Affiliation(s)
- Francois-Xavier Theillet
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198 Gif-sur-Yvette, France
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24
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25
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Hett T, Schiemann O. PELDOR Measurements on Nitroxide-Labeled Oligonucleotides. Methods Mol Biol 2022; 2439:241-274. [PMID: 35226326 DOI: 10.1007/978-1-0716-2047-2_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
In the past decades, pulsed dipolar electron paramagnetic resonance spectroscopy (PDS) has emerged as a powerful tool in biophysical chemistry to study the structure, dynamics, and function of biomolecules like oligonucleotides and proteins. Structural information is obtained from PDS methods in form of a distribution of distances between spin centers. Such spin centers can either be intrinsically present paramagnetic metal ions and organic radicals or may be attached to the biomolecule by means of site-directed spin labeling. The most common PDS experiment for probing interspin distances in the nanometer range is pulsed electron-electron double resonance (PELDOR or DEER). In the protocol presented here, we provide a step-by-step workflow on how to set up a PELDOR experiment on a commercially available pulsed EPR spectrometer, outline the data analysis, and highlight potential pitfalls. We suggest PELDOR measurements on nitroxide-labeled oligonucleotides to study the structure of either RNA-cleaving DNAzymes in complex with their RNA targets or modified DNAzymes with different functions and targets, in which deoxynucleotides are substituted by nitroxide-labeled nucleotides.
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Affiliation(s)
- Tobias Hett
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University, Bonn, Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, Rheinische Friedrich-Wilhelms-University, Bonn, Germany.
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26
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Kugele A, Ketter S, Silkenath B, Wittmann V, Joseph B, Drescher M. In situ EPR spectroscopy of a bacterial membrane transporter using an expanded genetic code. Chem Commun (Camb) 2021; 57:12980-12983. [PMID: 34792069 PMCID: PMC8640571 DOI: 10.1039/d1cc04612h] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Accepted: 11/03/2021] [Indexed: 12/12/2022]
Abstract
The membrane transporter BtuB is site-directedly spin labelled on the surface of living Escherichia coli via Diels-Alder click chemistry of the genetically encoded amino acid SCO-L-lysine. The previously introduced photoactivatable nitroxide PaNDA prevents off-target labelling, is used for distance measurements, and the temporally shifted activation of the nitroxide allows for advanced experimental setups. This study describes significant evolution of Diels-Alder-mediated spin labelling on cellular surfaces and opens up new vistas for the the study of membrane proteins.
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Affiliation(s)
- Anandi Kugele
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Sophie Ketter
- Institute of Biophysics, Department of Physics & The Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt/Main, Germany.
| | - Bjarne Silkenath
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Valentin Wittmann
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
| | - Benesh Joseph
- Institute of Biophysics, Department of Physics & The Center for Biomolecular Magnetic Resonance (BMRZ), Goethe University Frankfurt, Max-von-Laue-Str. 1, 60438 Frankfurt/Main, Germany.
| | - Malte Drescher
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
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27
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Ma B, Chen JL, Cui CY, Yang F, Gong YJ, Su XC. Rigid, Highly Reactive and Stable DOTA-like Tags Containing a Thiol-Specific Phenylsulfonyl Pyridine Moiety for Protein Modification and NMR Analysis*. Chemistry 2021; 27:16145-16152. [PMID: 34595784 DOI: 10.1002/chem.202102495] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2021] [Indexed: 11/06/2022]
Abstract
Site specific installation of a paramagnetic ion with magnetic anisotropy in a biomolecule generates valuable structural restraints, such as pseudocontact shifts (PCSs) and residual dipolar couplings (RDCs). These paramagnetic effects can be used to characterize the structures, interactions and dynamics of biological macromolecules and their complexes. Two single-armed DOTA-like tags, BrPSPy-DO3M(S)A-Ln and BrPSPy-6M-DO3M(S)A-Ln, each containing a thiol-specific reacting group, that is, a phenylsulfonyl pyridine moiety, are demonstrated as rigid, reactive and stable paramagnetic tags for protein modification by formation of a reducing resistant thioether bond between the protein and the tag. The two tags present high reactivity with the solvent exposed thiol group in aqueous solution at room temperature. The introduction of Br at the meta-position in pyridine enhances the reactivity of 4-phenylsulfonyl pyridine towards the solvent exposed thiol group in a protein, whereas the ortho-methyl group in pyridine increases the rigidity of the tag in the protein conjugates. The high performance of these two tags has been demonstrated in different cysteine mutants of ubiquitin and GB1. The high reactivity and rigidity of these two tags can be added in the toolbox of paramagnetic tags suitable for the high-resolution NMR measurements of biological macromolecules and their complexes.
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Affiliation(s)
- Bo Ma
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin, 300071, P.R. China
| | - Jia-Liang Chen
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin, 300071, P.R. China
| | - Chao-Yu Cui
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin, 300071, P.R. China
| | - Feng Yang
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin, 300071, P.R. China
| | - Yan-Jun Gong
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin, 300071, P.R. China
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-organic Chemistry, College of Chemistry, Nankai University, Weijin Road 94, Tianjin, 300071, P.R. China
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28
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Torricella F, Bonucci A, Polykretis P, Cencetti F, Banci L. Rapid protein delivery to living cells for biomolecular investigation. Biochem Biophys Res Commun 2021; 570:82-88. [PMID: 34274850 DOI: 10.1016/j.bbrc.2021.07.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2021] [Accepted: 07/04/2021] [Indexed: 12/24/2022]
Abstract
The lack of a simple, fast and efficient method for protein delivery is limiting the widespread application of in-cell experiments, which are crucial for understanding the cellular function. We present here an innovative strategy to deliver proteins into both prokaryotic and eukaryotic cells, exploiting thermal vesiculation. This method allows to internalize substantial amounts of proteins, with different molecular weight and conformation, without compromising the structural properties and cell viability. Characterizing proteins in a physiological environment is essential as the environment can dramatically affect the conformation and dynamics of biomolecules as shown by in-cell EPR spectra vs those acquired in buffer solution. Considering its versatility, this method opens the possibility to scientists to study proteins directly in living cells through a wide range of techniques.
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Affiliation(s)
- Francesco Torricella
- Magnetic Resonance Center - CERM, University of Florence, via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Alessio Bonucci
- Aix Marseille, Univ, CNRS, BIP, Laboratoire de Bioénergétique et Ingégnerie des protéines, Marseille, France
| | - Panagis Polykretis
- Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
| | - Francesca Cencetti
- Department of Experimental and Clinical Biomedical Sciences "Mario Serio", University of Florence, v.le GB Morgagni 50, 50134, Florence, Italy
| | - Lucia Banci
- Magnetic Resonance Center - CERM, University of Florence, via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy; Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy; Department of Chemistry, University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Florence, Italy.
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29
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Chen L, Wu L, Tan X, Rockenbauer A, Song Y, Liu Y. Synthesis and Redox Properties of Water-Soluble Asymmetric Trityl Radicals. J Org Chem 2021; 86:8351-8364. [PMID: 34043350 DOI: 10.1021/acs.joc.1c00766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Tetrathiatriarylmethyl (trityl) radicals have been recently shown to react with biological oxidoreductants including glutathione (GSH), ascorbic acid (Asc), and superoxide anion radical (O2•-). However, how the substituents affect the reactivity of trityl radicals is still unknown. In this work, five asymmetric trityl radicals were synthesized and their reactivities with GSH, Asc, and O2•- investigated. Under aerobic conditions, GSH induces fast decays for the thioether- (TSA) and N-methyleneglycine-substituted (TGA) derivatives and slow decay for the 4-carboxyphenyl-containing one (TPA). Under anaerobic conditions, the direct reduction of these radicals by GSH also occurs with rate constants (kGSH) from 1.8 × 10-4 M-1 s-1 for TPA to 1.0 × 10-2 M-1 s-1 for TGA. Moreover, these radicals can also react with O2•- with rate constants (kSO) from 1.2 × 103 M-1 s-1 for ET-01 to 1.6 × 104 M-1 s-1 for TGA. Surprisingly, these radicals are completely inert to Asc in both aerobic and anaerobic conditions. Additionally, the substituents exert an important effect on redox potentials of these trityl radicals. This work demonstrates that the redox properties of the trityl radicals strongly depend on their substituents, and TPA with high stability toward GSH shows great potential for intracellular applications.
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Affiliation(s)
- Li Chen
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Lanlan Wu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Xiaoli Tan
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Antal Rockenbauer
- Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, 1117 Budapest, Hungary.,Department of Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111 Budapest, Hungary
| | - Yuguang Song
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
| | - Yangping Liu
- Tianjin Key Laboratory on Technologies Enabling Development of Clinical Therapeutics and Diagnostics, Department of Medicinal Chemistry, School of Pharmacy, Tianjin Medical University, Tianjin 300070, P. R. China
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30
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Hasanbasri Z, Singewald K, Gluth TD, Driesschaert B, Saxena S. Cleavage-Resistant Protein Labeling With Hydrophilic Trityl Enables Distance Measurements In-Cell. J Phys Chem B 2021; 125:5265-5274. [PMID: 33983738 DOI: 10.1021/acs.jpcb.1c02371] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Sensitive in-cell distance measurements in proteins using pulsed-electron spin resonance (ESR) require reduction-resistant and cleavage-resistant spin labels. Among the reduction-resistant moieties, the hydrophilic trityl core known as OX063 is promising due to its long phase-memory relaxation time (Tm). This property leads to a sufficiently intense ESR signal for reliable distance measurements. Furthermore, the Tm of OX063 remains sufficiently long at higher temperatures, opening the possibility for measurements at temperatures above 50 K. In this work, we synthesized deuterated OX063 with a maleimide linker (mOX063-d24). We show that the combination of the hydrophilicity of the label and the maleimide linker enables high protein labeling that is cleavage-resistant in-cells. Distance measurements performed at 150 K using this label are more sensitive than the measurements at 80 K. The sensitivity gain is due to the significantly short longitudinal relaxation time (T1) at higher temperatures, which enables more data collection per unit of time. In addition to in vitro experiments, we perform distance measurements in Xenopus laevis oocytes. Interestingly, the Tm of mOX063-d24 is sufficiently long even in the crowded environment of the cell, leading to signals of appreciable intensity. Overall, mOX063-d24 provides highly sensitive distance measurements both in vitro and in-cells.
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Affiliation(s)
- Zikri Hasanbasri
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Kevin Singewald
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
| | - Teresa D Gluth
- Department of Pharmaceutical Sciences, School of Pharmacy & In Vivo Multifunctional Magnetic Resonance (IMMR) Center, Health Sciences Center, West Virginia University, Morgantown, West Virginia 26506, 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, West Virginia 26506, United States
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, Pittsburgh, Pennsylvania 15260, United States
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31
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Prusinowska N, Czapik A, Kwit M. Chiral Triphenylacetic Acid Esters: Residual Stereoisomerism and Solid-State Variability of Molecular Architectures. J Org Chem 2021; 86:6433-6448. [PMID: 33908243 PMCID: PMC8279475 DOI: 10.1021/acs.joc.1c00279] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2021] [Indexed: 12/29/2022]
Abstract
We have proven the usability and versatility of chiral triphenylacetic acid esters, compounds of high structural diversity, as chirality-sensing stereodynamic probes and as molecular tectons in crystal engineering. The low energy barrier to stereoisomer interconversion has been exploited to sense the chirality of an alkyl substituent in the esters. The structural information are cascaded from the permanently chiral alcohol (inducer) to the stereodynamic chromophoric probe through cooperative interactions. The ECD spectra of triphenylacetic acid esters are highly sensitive to very small structural differences in the inducer core. The tendencies to maximize the C-H···O hydrogen bonds, van der Waals interactions, and London dispersion forces determine the way of packing molecules in the crystal lattice. The phenyl embraces of trityl groups allowed, to some extent, the control of molecular organization in the crystal. However, the spectrum of possible molecular arrangements is very broad and depends on the type of substituent, the optical purity of the sample, and the presence of a second trityl group in the proximity. Racemates crystallize as the solid solution of enantiomers, where the trityl group acts as a protecting group for the stereogenic center. Therefore, the absolute configuration of the inducer is irrelevant to the packing mode of molecules in the crystal.
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Affiliation(s)
- Natalia Prusinowska
- Faculty
of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego
8, 61 614 Poznań, Poland
- Centre
for Advanced Technologies, Adam Mickiewicz
University, Uniwersytetu
Poznańskiego 10, 61 614 Poznań, Poland
| | - Agnieszka Czapik
- Faculty
of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego
8, 61 614 Poznań, Poland
| | - Marcin Kwit
- Faculty
of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego
8, 61 614 Poznań, Poland
- Centre
for Advanced Technologies, Adam Mickiewicz
University, Uniwersytetu
Poznańskiego 10, 61 614 Poznań, Poland
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32
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Hett T, Zbik T, Mukherjee S, Matsuoka H, Bönigk W, Klose D, Rouillon C, Brenner N, Peuker S, Klement R, Steinhoff HJ, Grubmüller H, Seifert R, Schiemann O, Kaupp UB. Spatiotemporal Resolution of Conformational Changes in Biomolecules by Combining Pulsed Electron-Electron Double Resonance Spectroscopy with Microsecond Freeze-Hyperquenching. J Am Chem Soc 2021; 143:6981-6989. [PMID: 33905249 DOI: 10.1021/jacs.1c01081] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
The function of proteins is linked to their conformations that can be resolved with several high-resolution methods. However, only a few methods can provide the temporal order of intermediates and conformational changes, with each having its limitations. Here, we combine pulsed electron-electron double resonance spectroscopy with a microsecond freeze-hyperquenching setup to achieve spatiotemporal resolution in the angstrom range and lower microsecond time scale. We show that the conformational change of the Cα-helix in the cyclic nucleotide-binding domain of the Mesorhizobium loti potassium channel occurs within about 150 μs and can be resolved with angstrom precision. Thus, this approach holds great promise for obtaining 4D landscapes of conformational changes in biomolecules.
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Affiliation(s)
- Tobias Hett
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstraße 12, 53115 Bonn, Germany
| | - Tobias Zbik
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Shatanik Mukherjee
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Hideto Matsuoka
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstraße 12, 53115 Bonn, Germany
| | - Wolfgang Bönigk
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Daniel Klose
- Fachbereich Physik, Universität Osnabrück, Barbarastraße 7, 49076 Osnabrück, Germany
| | - Christophe Rouillon
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Norbert Brenner
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Sebastian Peuker
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Reinhard Klement
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | | | - Helmut Grubmüller
- Department of Theoretical and Computational Biophysics, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Reinhard Seifert
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstraße 12, 53115 Bonn, Germany
| | - U Benjamin Kaupp
- Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany.,Life & Medical Sciences Institute (LIMES), University of Bonn, Carl-Troll-Straße 31, 53115 Bonn, Germany
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33
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Bahrenberg T, Jahn SM, Feintuch A, Stoll S, Goldfarb D. The decay of the refocused Hahn echo in double electron-electron resonance (DEER) experiments. MAGNETIC RESONANCE (GOTTINGEN, GERMANY) 2021; 2:161-173. [PMID: 37904783 PMCID: PMC10539729 DOI: 10.5194/mr-2-161-2021] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/19/2021] [Accepted: 03/13/2021] [Indexed: 11/01/2023]
Abstract
Double electron-electron resonance (DEER) is a pulse electron paramagnetic resonance (EPR) technique that measures distances between paramagnetic centres. It utilizes a four-pulse sequence based on the refocused Hahn spin echo. The echo decays with increasing pulse sequence length 2 ( τ 1 + τ 2 ) , where τ 1 and τ 2 are the two time delays. In DEER, the value of τ 2 is determined by the longest inter-spin distance that needs to be resolved, and τ 1 is adjusted to maximize the echo amplitude and, thus, sensitivity. We show experimentally that, for typical spin centres (nitroxyl, trityl, and Gd(III)) diluted in frozen protonated solvents, the largest refocused echo amplitude for a given τ 2 is obtained neither at very short τ 1 (which minimizes the pulse sequence length) nor at τ 1 = τ 2 (which maximizes dynamic decoupling for a given total sequence length) but rather at τ 1 values smaller than τ 2 . Large-scale spin dynamics simulations based on the coupled cluster expansion (CCE), including the electron spin and several hundred neighbouring protons, reproduce the experimentally observed behaviour almost quantitatively. They show that electron spin dephasing is driven by solvent protons via the flip-flop coupling among themselves and their hyperfine couplings to the electron spin.
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Affiliation(s)
- Thorsten Bahrenberg
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Samuel M. Jahn
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Akiva Feintuch
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, Washington 98195, USA
| | - Daniella Goldfarb
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot 7610001, Israel
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34
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Kucher S, Elsner C, Safonova M, Maffini S, Bordignon E. In-Cell Double Electron-Electron Resonance at Nanomolar Protein Concentrations. J Phys Chem Lett 2021; 12:3679-3684. [PMID: 33829785 DOI: 10.1021/acs.jpclett.1c00048] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy is an established technique to site-specifically monitor conformational changes of spin-labeled biomolecules. Emerging in-cell EPR approaches aiming to address spin-labeled proteins in their native environment still struggle to reach a broad applicability and to target physiologically relevant protein concentrations. Here, we present a comparative in vitro and in-cell double electron-electron resonance (DEER) study demonstrating that nanomolar protein concentrations are at reach to measure distances up to 4.5 nm between protein sites carrying commercial gadolinium spin labels.
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Affiliation(s)
- Svetlana Kucher
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Universitaetsstr. 150, 44801 Bochum, Germany
| | - Christina Elsner
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Universitaetsstr. 150, 44801 Bochum, Germany
| | - Mariya Safonova
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Universitaetsstr. 150, 44801 Bochum, Germany
| | - Stefano Maffini
- Max Planck Institute of Molecular Physiology, Department of Mechanistic Cell Biology, Otto-Hahn-Str. 11, 44227 Dortmund, Germany
| | - Enrica Bordignon
- Ruhr University Bochum, Faculty of Chemistry and Biochemistry, Universitaetsstr. 150, 44801 Bochum, Germany
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35
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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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36
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Torricella F, Pierro A, Mileo E, Belle V, Bonucci A. Nitroxide spin labels and EPR spectroscopy: A powerful association for protein dynamics studies. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2021; 1869:140653. [PMID: 33757896 DOI: 10.1016/j.bbapap.2021.140653] [Citation(s) in RCA: 49] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/31/2020] [Revised: 03/17/2021] [Accepted: 03/18/2021] [Indexed: 01/01/2023]
Abstract
Site-Directed Spin Labelling (SDSL) technique is based on the attachment of a paramagnetic label onto a specific position of a protein (or other bio-molecules) and the subsequent study by Electron Paramagnetic Resonance (EPR) spectroscopy. In particular, continuous-wave EPR (cw-EPR) spectra can detect the local conformational dynamics for proteins under various conditions. Moreover, pulse-EPR experiments on doubly spin-labelled proteins allow measuring distances between spin centres in the 1.5-8 nm range, providing information about structures and functions. This review focuses on SDSL-EPR spectroscopy as a structural biology tool to investigate proteins using nitroxide labels. The versatility of this spectroscopic approach for protein structural characterization has been demonstrated through the choice of recent studies. The main aim is to provide a general overview of the technique, particularly for non-experts, to spread the applicability of this technique in various fields of structural biology.
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Affiliation(s)
- F Torricella
- CERM-Magnetic Resonance Center, Department of Chemistry, University of Florence, via L.Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - A Pierro
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - E Mileo
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - V Belle
- Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France
| | - A Bonucci
- CERM-Magnetic Resonance Center, Department of Chemistry, University of Florence, via L.Sacconi 6, 50019 Sesto Fiorentino, Italy; Aix Marseille Univ, CNRS, BIP, Bioénergétique et Ingénierie des Protéines, IMM, Marseille, France.
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37
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Ketter S, Gopinath A, Rogozhnikova O, Trukhin D, Tormyshev VM, Bagryanskaya EG, Joseph B. In Situ Labeling and Distance Measurements of Membrane Proteins in E. coli Using Finland and OX063 Trityl Labels. Chemistry 2021; 27:2299-2304. [PMID: 33197077 PMCID: PMC7898545 DOI: 10.1002/chem.202004606] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2020] [Revised: 11/13/2020] [Indexed: 01/03/2023]
Abstract
In situ investigation of membrane proteins is a challenging task. Previously we demonstrated that nitroxide labels combined with pulsed ESR spectroscopy is a promising tool for this purpose. However, the nitroxide labels suffer from poor stability, high background labeling, and low sensitivity. Here we show that Finland (FTAM) and OX063 based labels enable labeling of the cobalamin transporter BtuB and BamA, the central component of the β-barrel assembly machinery (BAM) complex, in E coli. Compared to the methanethiosulfonate spin label (MTSL), trityl labels eliminated the background signals and enabled specific in situ labeling of the proteins with high efficiency. The OX063 labels show a long phase memory time (TM ) of ≈5 μs. All the trityls enabled distance measurements between BtuB and an orthogonally labeled substrate with high selectivity and sensitivity down to a few μm concentration. Our data corroborate the BtuB and BamA conformations in the cellular environment of E. coli.
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Affiliation(s)
- Sophie Ketter
- Institute of BiophysicsDepartment of PhysicsGoethe University FrankfurtMax-von-Laue-Str. 160438Frankfurt/MainGermany
| | - Aathira Gopinath
- Institute of BiophysicsDepartment of PhysicsGoethe University FrankfurtMax-von-Laue-Str. 160438Frankfurt/MainGermany
| | - Olga Rogozhnikova
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Dmitrii Trukhin
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Victor M. Tormyshev
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Elena G. Bagryanskaya
- N. N. Vorozhtsov Novosibirsk Institute of Organic ChemistrySB RASPr. Lavrentieva 9Novosibirsk630090Russia
| | - Benesh Joseph
- Institute of BiophysicsDepartment of PhysicsGoethe University FrankfurtMax-von-Laue-Str. 160438Frankfurt/MainGermany
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38
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Miao Q, Zurlo E, de Bruin D, Wondergem JAJ, Timmer M, Blok A, Heinrich D, Overhand M, Huber M, Ubbink M. A Two-Armed Probe for In-Cell DEER Measurements on Proteins*. Chemistry 2020; 26:17128-17133. [PMID: 33200852 PMCID: PMC7839491 DOI: 10.1002/chem.202002743] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 08/27/2020] [Indexed: 12/21/2022]
Abstract
The application of double electron‐electron resonance (DEER) with site‐directed spin labeling (SDSL) to measure distances in proteins and protein complexes in living cells puts rigorous restraints on the spin‐label. The linkage and paramagnetic centers need to resist the reducing conditions of the cell. Rigid attachment of the probe to the protein improves precision of the measured distances. Here, three two‐armed GdIII complexes, GdIII‐CLaNP13a/b/c were synthesized. Rather than the disulfide linkage of most other CLaNP molecules, a thioether linkage was used to avoid reductive dissociation of the linker. The doubly GdIII labeled N55C/V57C/K147C/T151C variants of T4Lysozyme were measured by 95 GHz DEER. The constructs were measured in vitro, in cell lysate and in Dictyostelium discoideum cells. Measured distances were 4.5 nm, consistent with results from paramagnetic NMR. A narrow distance distribution and typical modulation depth, also in cell, indicate complete and durable labeling and probe rigidity due to the dual attachment sites.
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Affiliation(s)
- Qing Miao
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333, CC, Leiden, The Netherlands
| | - Enrico Zurlo
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO box 9504, 2300, RA, Leiden, The Netherlands
| | - Donny de Bruin
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO box 9504, 2300, RA, Leiden, The Netherlands
| | - Joeri A J Wondergem
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO box 9504, 2300, RA, Leiden, The Netherlands
| | - Monika Timmer
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333, CC, Leiden, The Netherlands
| | - Anneloes Blok
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333, CC, Leiden, The Netherlands
| | - Doris Heinrich
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO box 9504, 2300, RA, Leiden, The Netherlands.,Fraunhofer Institute for Silicate Research ISC, 97082, Würzburg, Germany
| | - Mark Overhand
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333, CC, Leiden, The Netherlands
| | - Martina Huber
- Department of Physics, Huygens-Kamerlingh Onnes Laboratory, Leiden University, PO box 9504, 2300, RA, Leiden, The Netherlands
| | - Marcellus Ubbink
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333, CC, Leiden, The Netherlands
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39
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Collauto A, Bülow S, Gophane DB, Saha S, Stelzl LS, Hummer G, Sigurdsson ST, Prisner TF. Compaction of RNA Duplexes in the Cell**. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202009800] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Alberto Collauto
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
| | - Sören Bülow
- Department of Theoretical Biophysics Max Planck Institute of Biophysics Max-von-Laue-Str. 3 60438 Frankfurt am Main Germany
| | - Dnyaneshwar B. Gophane
- Department of Chemistry Science Institute University of Iceland Dunhagi 3 107 Reykjavík Iceland
| | - Subham Saha
- Department of Chemistry Science Institute University of Iceland Dunhagi 3 107 Reykjavík Iceland
| | - Lukas S. Stelzl
- Department of Theoretical Biophysics Max Planck Institute of Biophysics Max-von-Laue-Str. 3 60438 Frankfurt am Main Germany
| | - Gerhard Hummer
- Department of Theoretical Biophysics Max Planck Institute of Biophysics Max-von-Laue-Str. 3 60438 Frankfurt am Main Germany
- Institute for Biophysics Goethe University Frankfurt Max-von-Laue-Str. 9 60438 Frankfurt am Main Germany
| | - Snorri T. Sigurdsson
- Department of Chemistry Science Institute University of Iceland Dunhagi 3 107 Reykjavík Iceland
| | - Thomas F. Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance Goethe University Frankfurt Max-von-Laue-Str. 7 60438 Frankfurt am Main Germany
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40
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Collauto A, von Bülow S, Gophane DB, Saha S, Stelzl LS, Hummer G, Sigurdsson ST, Prisner TF. Compaction of RNA Duplexes in the Cell*. Angew Chem Int Ed Engl 2020; 59:23025-23029. [PMID: 32804430 PMCID: PMC7756485 DOI: 10.1002/anie.202009800] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Indexed: 11/15/2022]
Abstract
The structure and flexibility of RNA depends sensitively on the microenvironment. Using pulsed electron-electron double-resonance (PELDOR)/double electron-electron resonance (DEER) spectroscopy combined with advanced labeling techniques, we show that the structure of double-stranded RNA (dsRNA) changes upon internalization into Xenopus laevis oocytes. Compared to dilute solution, the dsRNA A-helix is more compact in cells. We recapitulate this compaction in a densely crowded protein solution. Atomic-resolution molecular dynamics simulations of dsRNA semi-quantitatively capture the compaction, and identify non-specific electrostatic interactions between proteins and dsRNA as a possible driver of this effect.
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Affiliation(s)
- Alberto Collauto
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Str. 760438Frankfurt am MainGermany
| | - Sören von Bülow
- Department of Theoretical BiophysicsMax Planck Institute of BiophysicsMax-von-Laue-Str. 360438Frankfurt am MainGermany
| | - Dnyaneshwar B. Gophane
- Department of ChemistryScience InstituteUniversity of IcelandDunhagi 3107ReykjavíkIceland
| | - Subham Saha
- Department of ChemistryScience InstituteUniversity of IcelandDunhagi 3107ReykjavíkIceland
| | - Lukas S. Stelzl
- Department of Theoretical BiophysicsMax Planck Institute of BiophysicsMax-von-Laue-Str. 360438Frankfurt am MainGermany
| | - Gerhard Hummer
- Department of Theoretical BiophysicsMax Planck Institute of BiophysicsMax-von-Laue-Str. 360438Frankfurt am MainGermany
- Institute for BiophysicsGoethe University FrankfurtMax-von-Laue-Str. 960438Frankfurt am MainGermany
| | - Snorri T. Sigurdsson
- Department of ChemistryScience InstituteUniversity of IcelandDunhagi 3107ReykjavíkIceland
| | - Thomas F. Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic ResonanceGoethe University FrankfurtMax-von-Laue-Str. 760438Frankfurt am MainGermany
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41
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Williams L, Tischlik S, Scherer A, Fischer JWA, Drescher M. Site-directed attachment of photoexcitable spin labels for light-induced pulsed dipolar spectroscopy. Chem Commun (Camb) 2020; 56:14669-14672. [PMID: 33159780 DOI: 10.1039/d0cc03101a] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Photoexcited triplet states are gaining popularity as spin labels in pulsed electron paramagnetic resonance (EPR) spectroscopy. Here, we demonstrate that the fluorophores Eosin Y, Rose Bengal and Atto Thio12 are suitable markers for distance determination by laser-induced magnetic dipole (LaserIMD) spectroscopy in proteins that lack an intrinsic photoexcitable center.
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Affiliation(s)
- Lara Williams
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB), University of Konstanz, Universitätsstraße 10, 78457 Konstanz, Germany.
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42
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Nolden O, Fleck N, Lorenzo ER, Wasielewski MR, Schiemann O, Gilch P, Richert S. Excitation Energy Transfer and Exchange-Mediated Quartet State Formation in Porphyrin-Trityl Systems. Chemistry 2020; 27:2683-2691. [PMID: 32681763 PMCID: PMC7898503 DOI: 10.1002/chem.202002805] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Indexed: 01/07/2023]
Abstract
Photogenerated multi‐spin systems hold great promise for a range of technological applications in various fields, including molecular spintronics and artificial photosynthesis. However, the further development of these applications, via targeted design of materials with specific magnetic properties, currently still suffers from a lack of understanding of the factors influencing the underlying excited state dynamics and mechanisms on a molecular level. In particular, systematic studies, making use of different techniques to obtain complementary information, are largely missing. This work investigates the photophysics and magnetic properties of a series of three covalently‐linked porphyrin‐trityl compounds, bridged by a phenyl spacer. By combining the results from femtosecond transient absorption and electron paramagnetic resonance spectroscopies, we determine the efficiencies of the competing excited state reaction pathways and characterise the magnetic properties of the individual spin states, formed by the interaction between the chromophore triplet and the stable radical. The differences observed for the three investigated compounds are rationalised in the context of available theoretical models and the implications of the results of this study for the design of a molecular system with an improved intersystem crossing efficiency are discussed.
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Affiliation(s)
- Oliver Nolden
- Institute of Physical Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Nico Fleck
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstraße 12, 53115, Bonn, Germany
| | - Emmaline R Lorenzo
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208-3113, USA
| | - Michael R Wasielewski
- Department of Chemistry, Northwestern University, 2145 Sheridan Road, Evanston, IL, 60208-3113, USA
| | - Olav Schiemann
- Institute of Physical and Theoretical Chemistry, University of Bonn, Wegelerstraße 12, 53115, Bonn, Germany
| | - Peter Gilch
- Institute of Physical Chemistry, Heinrich Heine University Düsseldorf, Universitätsstraße 1, 40225, Düsseldorf, Germany
| | - Sabine Richert
- Institute of Physical Chemistry, University of Freiburg, Albertstraße 21, 79104, Freiburg, Germany
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43
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Demay-Drouhard P, Ching HYV, Decroos C, Guillot R, Li Y, Tabares LC, Policar C, Bertrand HC, Un S. Understanding the g-tensors of perchlorotriphenylmethyl and Finland-type trityl radicals. Phys Chem Chem Phys 2020; 22:20792-20800. [PMID: 32909565 DOI: 10.1039/d0cp03626a] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
The 285 GHz EPR spectra of perchlorotriphenylmethyl and tetrathiatriarylmethyl radicals in frozen solution have been accurately measured. The relationship between their molecular structures and their g-tensors has been investigated with the aid of DFT calculations, revealing that the degree of spin density delocalization away from the central methylene carbon is an important determining factor of the g-anisotropy. In particular, the small amount of spin densities on the Cl or S heteroatoms at the 2 and 6 positions with respect to the central carbon have the strongest influence. Furthermore, the amount of spin densities on these heteroatoms and thus the anisotropy can be modulated by the protonation (esterification) state of the carboxylate groups at the 4 position. These results provide unique insights into the g-anisotropy of persistent trityl radicals and how it can be tuned.
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Affiliation(s)
- Paul Demay-Drouhard
- Laboratoire des Biomolécules, LBM, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - H Y Vincent Ching
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Christophe Decroos
- Aix Marseille Université, CNRS, Centrale Marseille, iSm2, Marseille, France
| | - Régis Guillot
- Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud, CNRS UMR 8182, Université Paris-Saclay, 91405 Orsay, France
| | - Yun Li
- Laboratoire de Chimie des Processus Biologiques, CNRS UMR 8229, Collège de France, PSL University, Sorbonne Université, 11 Place Marcelin Berthelot, 75231 Paris Cedex 05, France
| | - Leandro C Tabares
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
| | - Clotilde Policar
- Laboratoire des Biomolécules, LBM, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Helene C Bertrand
- Laboratoire des Biomolécules, LBM, Département de Chimie, Ecole Normale Supérieure, PSL University, Sorbonne Université, CNRS, 75005 Paris, France.
| | - Sun Un
- Université Paris-Saclay, CEA, CNRS, Institute for Integrative Biology of the Cell (I2BC), 91198, Gif-sur-Yvette, France.
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44
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Kopp K, Schiemann O, Fleck N. Improved, Odorless Access to Benzo[1,2-d;4,5-d']- bis[1,3]dithioles and Tert-butyl Arylsulfides via C-S Cross Coupling. Molecules 2020; 25:molecules25163666. [PMID: 32806560 PMCID: PMC7464442 DOI: 10.3390/molecules25163666] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2020] [Revised: 08/07/2020] [Accepted: 08/11/2020] [Indexed: 11/26/2022] Open
Abstract
Benzo[1,2-d;4,5-d′]bis[1,3]dithioles are important building blocks within a range of functional materials such as fluorescent dyes, conjugated polymers, and stable trityl radicals. Access to these is usually gained via tert-butyl aryl sulfides, the synthesis of which requires the use of highly malodorous tert-butyl thiol and relies on SNAr-chemistry requiring harsh reaction conditions, while giving low yields. In the present work, S-tert-butyl isothiouronium bromide is successfully applied as an odorless surrogate for tert-butyl thiol. The C-S bond formation is carried out under palladium catalysis with the thiolate formed in situ resulting in high yields of tert-butyl aryl sulfides. The subsequent formation of benzo[1,2-d;4,5-d′]bis[1,3]dithioles is here achieved with scandium(III)triflate, a less harmful reagent than the usually used Lewis acids, e.g., boron trifluoride or tetrafluoroboric acid. This enables a convenient and environmentally more compliant access to high yields of benzo[1,2-d;4,5-d′]bis[1,3]dithioles.
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45
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In-cell destabilization of a homodimeric protein complex detected by DEER spectroscopy. Proc Natl Acad Sci U S A 2020; 117:20566-20575. [PMID: 32788347 DOI: 10.1073/pnas.2005779117] [Citation(s) in RCA: 42] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The complexity of the cellular medium can affect proteins' properties, and, therefore, in-cell characterization of proteins is essential. We explored the stability and conformation of the first baculoviral IAP repeat (BIR) domain of X chromosome-linked inhibitor of apoptosis (XIAP), BIR1, as a model for a homodimer protein in human HeLa cells. We employed double electron-electron resonance (DEER) spectroscopy and labeling with redox stable and rigid Gd3+ spin labels at three representative protein residues, C12 (flexible region), E22C, and N28C (part of helical residues 26 to 31) in the N-terminal region. In contrast to predictions by excluded-volume crowding theory, the dimer-monomer dissociation constant K D was markedly higher in cells than in solution and dilute cell lysate. As expected, this increase was partially recapitulated under conditions of high salt concentrations, given that conserved salt bridges at the dimer interface are critically required for association. Unexpectedly, however, also the addition of the crowding agent Ficoll destabilized the dimer while the addition of bovine serum albumin (BSA) and lysozyme, often used to represent interaction with charged macromolecules, had no effect. Our results highlight the potential of DEER for in-cell study of proteins as well as the complexities of the effects of the cellular milieu on protein structures and stability.
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46
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Bretschneider M, Spindler PE, Rogozhnikova OY, Trukhin DV, Endeward B, Kuzhelev AA, Bagryanskaya E, Tormyshev VM, Prisner TF. Multiquantum Counting of Trityl Radicals. J Phys Chem Lett 2020; 11:6286-6290. [PMID: 32667797 DOI: 10.1021/acs.jpclett.0c01615] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
We demonstrate a series of multitrityl radical compounds where accurate spin-counting by pulsed electron paramagnetic resonance (EPR) can be achieved at X-band (9 GHz) frequencies, even for molecules with very short and flexible linkers. Multiquantum filter experiments, well-known from NMR, were used to count the number of coupled electron spins in these compounds. The six pulse double quantum filter sequence used in EPR for distance determinations in biradicals was used. Precise phase settings to separate higher quantum coherences were achieved by an arbitrary waveform generator. The trityl radicals have narrow spectral width so that homogeneous excitation of all spins by the pulses is possible. The transversal relaxation times of higher quantum coherences of trityl radicals are sufficiently long to allow their detection. Our results on model compounds show the potential of this approach to determine oligomeric states in protein complexes in their native environment using functionalized trityl spin labels.
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Affiliation(s)
- Matthias Bretschneider
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60323 Frankfurt, Germany
| | - Phillip E Spindler
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60323 Frankfurt, Germany
| | - Olga Yu Rogozhnikova
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
| | - Dmitry V Trukhin
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
| | - Burkhard Endeward
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60323 Frankfurt, Germany
| | - Andrey A Kuzhelev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
| | - Elena Bagryanskaya
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
| | - Victor M Tormyshev
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
| | - Thomas F Prisner
- Institute of Physical and Theoretical Chemistry and Center of Biomolecular Magnetic Resonance, Goethe University Frankfurt am Main, 60323 Frankfurt, Germany
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47
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Fleck N, Heubach CA, Hett T, Haege FR, Bawol PP, Baltruschat H, Schiemann O. SLIM: A Short-Linked, Highly Redox-Stable Trityl Label for High-Sensitivity In-Cell EPR Distance Measurements. Angew Chem Int Ed Engl 2020; 59:9767-9772. [PMID: 32329172 PMCID: PMC7318235 DOI: 10.1002/anie.202004452] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Indexed: 12/15/2022]
Abstract
The understanding of biomolecular function is coupled to knowledge about the structure and dynamics of these biomolecules, preferably acquired under native conditions. In this regard, pulsed dipolar EPR spectroscopy (PDS) in conjunction with site-directed spin labeling (SDSL) is an important method in the toolbox of biophysical chemistry. However, the currently available spin labels have diverse deficiencies for in-cell applications, for example, low radical stability or long bioconjugation linkers. In this work, a synthesis strategy is introduced for the derivatization of trityl radicals with a maleimide-functionalized methylene group. The resulting trityl spin label, called SLIM, yields narrow distance distributions, enables highly sensitive distance measurements down to concentrations of 90 nm, and shows high stability against reduction. Using this label, the guanine-nucleotide dissociation inhibitor (GDI) domain of Yersinia outer protein O (YopO) is shown to change its conformation within eukaryotic cells.
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Affiliation(s)
- Nico Fleck
- Institute of Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
| | - Caspar A. Heubach
- Institute of Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
| | - Tobias Hett
- Institute of Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
| | - Florian R. Haege
- Institute of Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
| | - Pawel P. Bawol
- Institute of Physical and Theoretical ChemistryUniversity of BonnRömerstr. 16453117BonnGermany
| | - Helmut Baltruschat
- Institute of Physical and Theoretical ChemistryUniversity of BonnRömerstr. 16453117BonnGermany
| | - Olav Schiemann
- Institute of Physical and Theoretical ChemistryUniversity of BonnWegelerstr. 1253115BonnGermany
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48
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Fleck N, Heubach CA, Hett T, Haege FR, Bawol PP, Baltruschat H, Schiemann O. SLIM: A Short‐Linked, Highly Redox‐Stable Trityl Label for High‐Sensitivity In‐Cell EPR Distance Measurements. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202004452] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Affiliation(s)
- Nico Fleck
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Caspar A. Heubach
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Tobias Hett
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Florian R. Haege
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
| | - Pawel P. Bawol
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Römerstr. 164 53117 Bonn Germany
| | - Helmut Baltruschat
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Römerstr. 164 53117 Bonn Germany
| | - Olav Schiemann
- Institute of Physical and Theoretical ChemistryUniversity of Bonn Wegelerstr. 12 53115 Bonn Germany
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