1
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Dunkelmann DL, Chin JW. Engineering Pyrrolysine Systems for Genetic Code Expansion and Reprogramming. Chem Rev 2024. [PMID: 39235427 DOI: 10.1021/acs.chemrev.4c00243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/06/2024]
Abstract
Over the past 16 years, genetic code expansion and reprogramming in living organisms has been transformed by advances that leverage the unique properties of pyrrolysyl-tRNA synthetase (PylRS)/tRNAPyl pairs. Here we summarize the discovery of the pyrrolysine system and describe the unique properties of PylRS/tRNAPyl pairs that provide a foundation for their transformational role in genetic code expansion and reprogramming. We describe the development of genetic code expansion, from E. coli to all domains of life, using PylRS/tRNAPyl pairs, and the development of systems that biosynthesize and incorporate ncAAs using pyl systems. We review applications that have been uniquely enabled by the development of PylRS/tRNAPyl pairs for incorporating new noncanonical amino acids (ncAAs), and strategies for engineering PylRS/tRNAPyl pairs to add noncanonical monomers, beyond α-L-amino acids, to the genetic code of living organisms. We review rapid progress in the discovery and scalable generation of mutually orthogonal PylRS/tRNAPyl pairs that can be directed to incorporate diverse ncAAs in response to diverse codons, and we review strategies for incorporating multiple distinct ncAAs into proteins using mutually orthogonal PylRS/tRNAPyl pairs. Finally, we review recent advances in the encoded cellular synthesis of noncanonical polymers and macrocycles and discuss future developments for PylRS/tRNAPyl pairs.
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Affiliation(s)
- Daniel L Dunkelmann
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, England, United Kingdom
- Max Planck Institute of Molecular Plant Physiology, Am Mühlenberg 1, 14476 Potsdam-Golm, Germany
| | - Jason W Chin
- Medical Research Council Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge CB2 0QH, England, United Kingdom
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2
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Bogetti X, Saxena S. Integrating Electron Paramagnetic Resonance Spectroscopy and Computational Modeling to Measure Protein Structure and Dynamics. Chempluschem 2024; 89:e202300506. [PMID: 37801003 DOI: 10.1002/cplu.202300506] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2023] [Revised: 10/05/2023] [Accepted: 10/06/2023] [Indexed: 10/07/2023]
Abstract
Electron paramagnetic resonance (EPR) has become a powerful probe of conformational heterogeneity and dynamics of biomolecules. In this Review, we discuss different computational modeling techniques that enrich the interpretation of EPR measurements of dynamics or distance restraints. A variety of spin labels are surveyed to provide a background for the discussion of modeling tools. Molecular dynamics (MD) simulations of models containing spin labels provide dynamical properties of biomolecules and their labels. These simulations can be used to predict EPR spectra, sample stable conformations and sample rotameric preferences of label sidechains. For molecular motions longer than milliseconds, enhanced sampling strategies and de novo prediction software incorporating or validated by EPR measurements are able to efficiently refine or predict protein conformations, respectively. To sample large-amplitude conformational transition, a coarse-grained or an atomistic weighted ensemble (WE) strategy can be guided with EPR insights. Looking forward, we anticipate an integrative strategy for efficient sampling of alternate conformations by de novo predictions, followed by validations by systematic EPR measurements and MD simulations. Continuous pathways between alternate states can be further sampled by WE-MD including all intermediate states.
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Affiliation(s)
- Xiaowei Bogetti
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
| | - Sunil Saxena
- Department of Chemistry, University of Pittsburgh, 219 Parkman Avenue, Pittsburgh, PA, 15260, USA
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3
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Jana S, Evans EGB, Jang HS, Zhang S, Zhang H, Rajca A, Gordon SE, Zagotta WN, Stoll S, Mehl RA. Ultrafast Bioorthogonal Spin-Labeling and Distance Measurements in Mammalian Cells Using Small, Genetically Encoded Tetrazine Amino Acids. J Am Chem Soc 2023; 145:14608-14620. [PMID: 37364003 PMCID: PMC10440187 DOI: 10.1021/jacs.3c00967] [Citation(s) in RCA: 12] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2023]
Abstract
Site-directed spin-labeling (SDSL)─in combination with double electron-electron resonance (DEER) spectroscopy─has emerged as a powerful technique for determining both the structural states and the conformational equilibria of biomacromolecules. DEER combined with in situ SDSL in live cells is challenging since current bioorthogonal labeling approaches are too slow to allow for complete labeling with low concentrations of spin label prior to loss of signal from cellular reduction. Here, we overcome this limitation by genetically encoding a novel family of small, tetrazine-bearing noncanonical amino acids (Tet-v4.0) at multiple sites in proteins expressed in Escherichia coli and in human HEK293T cells. We achieved specific and quantitative spin-labeling of Tet-v4.0-containing proteins by developing a series of strained trans-cyclooctene (sTCO)-functionalized nitroxides─including a gem-diethyl-substituted nitroxide with enhanced stability in cells─with rate constants that can exceed 106 M-1 s-1. The remarkable speed of the Tet-v4.0/sTCO reaction allowed efficient spin-labeling of proteins in live cells within minutes, requiring only sub-micromolar concentrations of sTCO-nitroxide. DEER recorded from intact cells revealed distance distributions in good agreement with those measured from proteins purified and labeled in vitro. Furthermore, DEER was able to resolve the maltose-dependent conformational change of Tet-v4.0-incorporated and spin-labeled MBP in vitro and support assignment of the conformational state of an MBP mutant within HEK293T cells. We anticipate the exceptional reaction rates of this system, combined with the relatively short and rigid side chains of the resulting spin labels, will enable structure/function studies of proteins directly in cells, without any requirements for protein purification.
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Affiliation(s)
- Subhashis Jana
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Eric G B Evans
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington 98195, United States
| | - Hyo Sang Jang
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Shuyang Zhang
- Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States
| | - Hui Zhang
- 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
| | - Sharona E Gordon
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington 98195, United States
| | - William N Zagotta
- Department of Physiology & Biophysics, University of Washington, Seattle, Washington 98195, United States
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, Washington 98195, United States
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
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4
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Tessmer MH, Stoll S. chiLife: An open-source Python package for in silico spin labeling and integrative protein modeling. PLoS Comput Biol 2023; 19:e1010834. [PMID: 37000838 PMCID: PMC10096462 DOI: 10.1371/journal.pcbi.1010834] [Citation(s) in RCA: 15] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Revised: 04/12/2023] [Accepted: 03/16/2023] [Indexed: 04/03/2023] Open
Abstract
Here we introduce chiLife, a Python package for site-directed spin label (SDSL) modeling for electron paramagnetic resonance (EPR) spectroscopy, in particular double electron-electron resonance (DEER). It is based on in silico attachment of rotamer ensemble representations of spin labels to protein structures. chiLife enables the development of custom protein analysis and modeling pipelines using SDSL EPR experimental data. It allows the user to add custom spin labels, scoring functions and spin label modeling methods. chiLife is designed with integration into third-party software in mind, to take advantage of the diverse and rapidly expanding set of molecular modeling tools available with a Python interface. This article describes the main design principles of chiLife and presents a series of examples.
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Affiliation(s)
- Maxx H. Tessmer
- Department of Chemistry, University of Washington, Seattle, Washington United States of America
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, Washington United States of America
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5
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Jana S, Evans EGB, Jang HS, Zhang S, Zhang H, Rajca A, Gordon SE, Zagotta WN, Stoll S, Mehl RA. Ultra-Fast Bioorthogonal Spin-Labeling and Distance Measurements in Mammalian Cells Using Small, Genetically Encoded Tetrazine Amino Acids. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525763. [PMID: 36747808 PMCID: PMC9901033 DOI: 10.1101/2023.01.26.525763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Studying protein structures and dynamics directly in the cellular environments in which they function is essential to fully understand the molecular mechanisms underlying cellular processes. Site-directed spin-labeling (SDSL)-in combination with double electron-electron resonance (DEER) spectroscopy-has emerged as a powerful technique for determining both the structural states and the conformational equilibria of biomacromolecules. In-cell DEER spectroscopy on proteins in mammalian cells has thus far not been possible due to the notable challenges of spin-labeling in live cells. In-cell SDSL requires exquisite biorthogonality, high labeling reaction rates and low background signal from unreacted residual spin label. While the bioorthogonal reaction must be highly specific and proceed under physiological conditions, many spin labels display time-dependent instability in the reducing cellular environment. Additionally, high concentrations of spin label can be toxic. Thus, an exceptionally fast bioorthogonal reaction is required that can allow for complete labeling with low concentrations of spin-label prior to loss of signal. Here we utilized genetic code expansion to site-specifically encode a novel family of small, tetrazine-bearing non-canonical amino acids (Tet-v4.0) at multiple sites in green fluorescent protein (GFP) and maltose binding protein (MBP) expressed both in E. coli and in human HEK293T cells. We achieved specific and quantitative spin-labeling of Tet-v4.0-containing proteins by developing a series of strained trans -cyclooctene (sTCO)-functionalized nitroxides-including a gem -diethyl-substituted nitroxide with enhanced stability in cells-with rate constants that can exceed 10 6 M -1 s -1 . The remarkable speed of the Tet-v4.0/sTCO reaction allowed efficient spin-labeling of proteins in live HEK293T cells within minutes, requiring only sub-micromolar concentrations of sTCO-nitroxide added directly to the culture medium. DEER recorded from intact cells revealed distance distributions in good agreement with those measured from proteins purified and labeled in vitro . Furthermore, DEER was able to resolve the maltose-dependent conformational change of Tet-v4.0-incorporated and spin-labeled MBP in vitro and successfully discerned the conformational state of MBP within HEK293T cells. We anticipate the exceptional reaction rates of this system, combined with the relatively short and rigid side chains of the resulting spin labels, will enable structure/function studies of proteins directly in cells, without any requirements for protein purification. TOC
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Affiliation(s)
- Subhashis Jana
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
- Equal contributors
| | - Eric G B Evans
- Department of Chemistry, University of Washington, Seattle, WA 98195, United States
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, United States
- Equal contributors
| | - Hyo Sang Jang
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Shuyang Zhang
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States
| | - Hui Zhang
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States
| | - Andrzej Rajca
- Department of Chemistry, University of Nebraska, Lincoln, NE 68588-0304, United States
| | - Sharona E Gordon
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, United States
| | - William N Zagotta
- Department of Physiology & Biophysics, University of Washington, Seattle, WA 98195, United States
| | - Stefan Stoll
- Department of Chemistry, University of Washington, Seattle, WA 98195, United States
| | - Ryan A Mehl
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
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6
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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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7
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Scherer A, Yao X, Qi M, Wiedmaier M, Godt A, Drescher M. Increasing the Modulation Depth of Gd III-Based Pulsed Dipolar EPR Spectroscopy (PDS) with Porphyrin-Gd III Laser-Induced Magnetic Dipole Spectroscopy. J Phys Chem Lett 2022; 13:10958-10964. [PMID: 36399541 PMCID: PMC9720741 DOI: 10.1021/acs.jpclett.2c02138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 10/03/2022] [Indexed: 06/16/2023]
Abstract
Distance determination with pulsed EPR has become an important technique for the structural investigation of biomacromolecules, with double electron-electron resonance spectroscopy (DEER) as the most important method. GdIII-based spin labels are one of the most frequently used spin labels for DEER owing to their stability against reduction, high magnetic moment, and absence of orientation selection. A disadvantage of GdIII-GdIII DEER is the low modulation depth due to the broad EPR spectrum of GdIII. Here, we introduce laser-induced magnetic dipole spectroscopy (LaserIMD) with a spin pair consisting of GdIII(PymiMTA) and a photoexcited porphyrin as an alternative technique. We show that the excited state of the porphyrin is not disturbed by the presence of the GdIII complex and that herewith modulation depths of almost 40% are possible. This is significantly higher than the value of 7.2% that was achieved with GdIII-GdIII DEER.
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Affiliation(s)
- Andreas Scherer
- Department
of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Xuemei Yao
- Faculty
of Chemistry and Center of Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Mian Qi
- Faculty
of Chemistry and Center of Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Max Wiedmaier
- Department
of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany
| | - Adelheid Godt
- Faculty
of Chemistry and Center of Molecular Materials (CM2), Bielefeld University, Universitätsstraße 25, 33615 Bielefeld, Germany
| | - Malte Drescher
- Department
of Chemistry and Konstanz Research School Chemical Biology, University of Konstanz, 78457 Konstanz, Germany
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8
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Kaiser F, Endeward B, Collauto A, Scheffer U, Prisner TF, Göbel MW. Spin-Labeled Riboswitch Synthesized from a Protected TPA Phosphoramidite Building Block. Chemistry 2022; 28:e202201822. [PMID: 35903916 PMCID: PMC9804336 DOI: 10.1002/chem.202201822] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Indexed: 01/05/2023]
Abstract
The nitroxide TPA (2,2,5,5-tetramethyl-pyrrolin-1-oxyl-3-acetylene) is an excellent spin label for EPR studies of RNA. Previous synthetic methods, however, are complicated and require special equipment. Herein, we describe a uridine derived phosphoramidite with a photocaged TPA unit attached. The light sensitive 2-nitrobenzyloxymethyl group can be removed in high yield by short irradiation at 365 nm. Based on this approach, a doubly spin-labeled 27mer neomycin sensing riboswitch was synthesized and studied by PELDOR. The overall thermal stability of the fold is not much reduced by TPA. In-line probing nevertheless detected changes in local mobility.
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Affiliation(s)
- Frank Kaiser
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Burkhard Endeward
- Institute for Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Alberto Collauto
- Institute for Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Ute Scheffer
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Thomas F. Prisner
- Institute for Physical and Theoretical ChemistryGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
| | - Michael W. Göbel
- Institute for Organic Chemistry and Chemical BiologyGoethe University FrankfurtMax-von-Laue-Strasse 760438Frankfurt am MainGermany
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9
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Liu Y, Biczysko M, Moriarty NW. A radical approach to radicals. Acta Crystallogr D Struct Biol 2022; 78:43-51. [PMID: 34981760 DOI: 10.1107/s2059798321010809] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 10/18/2021] [Indexed: 11/10/2022] Open
Abstract
Nitroxide radicals are characterized by a long-lived spin-unpaired electronic ground state and are strongly sensitive to their chemical surroundings. Combined with electron paramagnetic resonance spectroscopy, these electronic features have led to the widespread application of nitroxide derivatives as spin labels for use in studying protein structure and dynamics. Site-directed spin labelling requires the incorporation of nitroxides into the protein structure, leading to a new protein-ligand molecular model. However, in protein crystallographic refinement nitroxides are highly unusual molecules with an atypical chemical composition. Because macromolecular crystallography is almost entirely agnostic to chemical radicals, their structural information is generally less accurate or even erroneous. In this work, proteins that contain an example of a radical compound (Chemical Component Dictionary ID MTN) from the nitroxide family were re-refined by defining its ideal structural parameters based on quantum-chemical calculations. The refinement results show that this procedure improves the MTN ligand geometries, while at the same time retaining higher agreement with experimental data.
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Affiliation(s)
- Youjia Liu
- International Center for Quantum and Molecular Structures, Shanghai University, Shanghai 200444, People's Republic of China
| | - Malgorzata Biczysko
- International Center for Quantum and Molecular Structures, Shanghai University, Shanghai 200444, People's Republic of China
| | - Nigel W Moriarty
- Molecular Biosciences and Integrated Bioimaging, Lawrence Berkeley National Laboratory, Berkeley, CA 94720-8235, USA
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10
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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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11
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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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12
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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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13
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Simon C, Lion C, Ahouari H, Vezin H, Hawkins S, Biot C. EPR imaging of sinapyl alcohol and its application to the study of plant cell wall lignification. Chem Commun (Camb) 2021; 57:387-390. [PMID: 33326527 DOI: 10.1039/d0cc05218c] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In bioimaging, bioorthogonal chemistry is most often used to visualize chemical reporters by fluorescence in their native environment. Herein, we show that TEMPO-based probes can be ligated to monolignol reporters by Diels-Alder chemistry in plant cell walls, paving the way for the study of lignification by EPR spectroscopy and imaging.
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Affiliation(s)
- Clémence Simon
- Univ. Lille, CNRS, UMR 8576 - UGSF - Unité de Glycobiologie Structurale et Fonctionnelle, 59000 Lille, France.
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14
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Müller D, Trucks S, Schwalbe H, Hengesbach M. Genetic Code Expansion Facilitates Position-Selective Modification of Nucleic Acids and Proteins. Chempluschem 2020; 85:1233-1243. [PMID: 32515171 DOI: 10.1002/cplu.202000150] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/11/2020] [Indexed: 12/12/2022]
Abstract
Transcription and translation obey to the genetic code of four nucleobases and 21 amino acids evolved over billions of years. Both these processes have been engineered to facilitate the use of non-natural building blocks in both nucleic acids and proteins, enabling researchers with a decent toolbox for structural and functional analyses. Here, we review the most common approaches for how labeling of both nucleic acids as well as proteins in a site-selective fashion with either modifiable building blocks or spectroscopic probes can be facilitated by genetic code expansion. We emphasize methodological approaches and how these can be adapted for specific modifications, both during as well as after biomolecule synthesis. These modifications can facilitate, for example, a number of different spectroscopic analysis techniques and can under specific circumstances even be used in combination.
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Affiliation(s)
- Diana Müller
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Sven Trucks
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Harald Schwalbe
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
| | - Martin Hengesbach
- Institute for Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Strasse 7, 60438, Frankfurt am Main, Germany
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15
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Braun TS, Widder P, Osswald U, Groß L, Williams L, Schmidt M, Helmle I, Summerer D, Drescher M. Isoindoline-Based Nitroxides as Bioresistant Spin Labels for Protein Labeling through Cysteines and Alkyne-Bearing Noncanonical Amino Acids. Chembiochem 2020; 21:958-962. [PMID: 31657498 PMCID: PMC7187341 DOI: 10.1002/cbic.201900537] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Revised: 10/18/2019] [Indexed: 12/15/2022]
Abstract
Electron paramagnetic resonance (EPR) spectroscopy in combination with site-directed spin labeling (SDSL) is a powerful tool in protein structural research. Nitroxides are highly suitable spin labeling reagents, but suffer from limited stability, particularly in the cellular environment. Herein we present the synthesis of a maleimide- and an azide-modified tetraethyl-shielded isoindoline-based nitroxide (M- and Az-TEIO) for labeling of cysteines or the noncanonical amino acid para-ethynyl-l-phenylalanine (pENF). We demonstrate the high stability of TEIO site-specifically attached to the protein thioredoxin (TRX) against reduction in prokaryotic and eukaryotic environments, and conduct double electron-electron resonance (DEER) measurements. We further generate a rotamer library for the new residue pENF-Az-TEIO that affords a distance distribution that is in agreement with the measured distribution.
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Affiliation(s)
- Theresa Sophie Braun
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
- Konstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Pia Widder
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
- Konstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Uwe Osswald
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Lina Groß
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Lara Williams
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Moritz Schmidt
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Irina Helmle
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
- Present address: Faculty of ScienceDepartment of Pharmaceutical BiologyUniversity of TübingenAuf der Morgenstelle 872076TübingenGermany
| | - Daniel Summerer
- Faculty of Chemistry and Chemical BiologyTU DortmundOtto-Hahn-Strasse 4a44227DortmundGermany
| | - Malte Drescher
- Department of ChemistryUniversity of KonstanzUniversitätsstrasse 1078457KonstanzGermany
- Konstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
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16
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Widder P, Schuck J, Summerer D, Drescher M. Combining site-directed spin labeling in vivo and in-cell EPR distance determination. Phys Chem Chem Phys 2020; 22:4875-4879. [DOI: 10.1039/c9cp05584c] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Non-canonical amino acid incorporation via amber stop codon suppression and in vivo site-directed spin labeling allow in-cell EPR distance determination in E. coli.
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Affiliation(s)
- Pia Widder
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB)
- University of Konstanz
- Konstanz
- Germany
| | - Julian Schuck
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB)
- University of Konstanz
- Konstanz
- Germany
| | - Daniel Summerer
- Faculty of Chemistry and Chemical Biology
- TU Dortmund University
- Dortmund
- Germany
| | - Malte Drescher
- Department of Chemistry and Konstanz Research School Chemical Biology (KoRS-CB)
- University of Konstanz
- Konstanz
- Germany
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17
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Kugele A, Silkenath B, Langer J, Wittmann V, Drescher M. Protein Spin Labeling with a Photocaged Nitroxide Using Diels-Alder Chemistry. Chembiochem 2019; 20:2479-2484. [PMID: 31090999 PMCID: PMC6790680 DOI: 10.1002/cbic.201900318] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2019] [Indexed: 12/31/2022]
Abstract
EPR spectroscopy of diamagnetic bio-macromolecules is based on site-directed spin labeling (SDSL). Herein, a novel labeling strategy for proteins is presented. A nitroxide-based spin label has been developed and synthesized that can be ligated to proteins by an inverse-electron-demand Diels-Alder (DAinv ) cycloaddition to genetically encoded noncanonical amino acids. The nitroxide moiety is shielded by a photoremovable protecting group with an attached tetra(ethylene glycol) unit to achieve water solubility. SDSL is demonstrated on two model proteins with the photoactivatable nitroxide for DAinv reaction (PaNDA) label. The strategy features high reaction rates, combined with high selectivity, and the possibility to deprotect the nitroxide in Escherichia coli lysate.
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Affiliation(s)
- Anandi Kugele
- Department of Chemistry andKonstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Bjarne Silkenath
- Department of Chemistry andKonstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Jakob Langer
- Department of Chemistry andKonstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Valentin Wittmann
- Department of Chemistry andKonstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
| | - Malte Drescher
- Department of Chemistry andKonstanz Research School Chemical Biology (KoRS-CB)University of KonstanzUniversitätsstrasse 1078457KonstanzGermany
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