1
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Cucuzza S, Sitnik M, Jurt S, Michel E, Dai W, Müntener T, Ernst P, Häussinger D, Plückthun A, Zerbe O. Unexpected dynamics in femtomolar complexes of binding proteins with peptides. Nat Commun 2023; 14:7823. [PMID: 38016954 PMCID: PMC10684580 DOI: 10.1038/s41467-023-43596-2] [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: 02/18/2023] [Accepted: 11/13/2023] [Indexed: 11/30/2023] Open
Abstract
Ultra-tight binding is usually observed for proteins associating with rigidified molecules. Previously, we demonstrated that femtomolar binders derived from the Armadillo repeat proteins (ArmRPs) can be designed to interact very tightly with fully flexible peptides. Here we show for ArmRPs with four and seven sequence-identical internal repeats that the peptide-ArmRP complexes display conformational dynamics. These dynamics stem from transient breakages of individual protein-residue contacts that are unrelated to overall unbinding. The labile contacts involve electrostatic interactions. We speculate that these dynamics allow attaining very high binding affinities, since they reduce entropic losses. Importantly, only NMR techniques can pick up these local events by directly detecting conformational exchange processes without complications from changes in solvent entropy. Furthermore, we demonstrate that the interaction surface of the repeat protein regularizes upon peptide binding to become more compatible with the peptide geometry. These results provide novel design principles for ultra-tight binders.
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Affiliation(s)
- Stefano Cucuzza
- Department of Chemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland
| | - Malgorzata Sitnik
- Department of Chemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland
| | - Simon Jurt
- Department of Chemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland
| | - Erich Michel
- Department of Chemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland
- Department of Biochemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland
| | - Wenzhao Dai
- Department of Chemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland
| | - Thomas Müntener
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Patrick Ernst
- Department of Biochemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland
| | - Daniel Häussinger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056, Basel, Switzerland
| | - Andreas Plückthun
- Department of Biochemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland.
| | - Oliver Zerbe
- Department of Chemistry, University of Zürich, Winterthurerstrasse, 190, 8057, Zürich, Switzerland.
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2
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Li J, Byrd RA. A simple protocol for the production of highly deuterated proteins for biophysical studies. J Biol Chem 2022; 298:102253. [PMID: 35835218 PMCID: PMC9386462 DOI: 10.1016/j.jbc.2022.102253] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Revised: 07/07/2022] [Accepted: 07/08/2022] [Indexed: 11/06/2022] Open
Abstract
Highly deuterated protein samples expand the biophysics and biological tool kit by providing, among other qualities, contrast matching in neutron diffraction experiments and reduction of dipolar spin interactions from normally protonated proteins in magnetic resonance studies, impacting both electron paramagnetic resonance and NMR spectroscopy. In NMR applications, deuteration is often combined with other isotopic labeling patterns to expand the range of conventional NMR spectroscopy research in both solution and solid-state conditions. However, preparation of deuterated proteins is challenging. We present here a simple, effective, and user-friendly protocol to produce highly deuterated proteins in Escherichia coli cells. The protocol utilizes the common shaker flask growth method and the well-known pET system (which provides expression control via the T7 promotor) for large-scale recombinant protein expression. One liter expression typically yields 5 to 50 mg of highly deuterated protein. Our data demonstrate that the optimized procedure produces a comparable quantity of protein in deuterium (2H2O) oxide M9 medium compared with that in 1H2O M9 medium. The protocol will enable a broader utilization of deuterated proteins in a number of biophysical techniques.
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Affiliation(s)
- Jess Li
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201.
| | - R Andrew Byrd
- Center for Structural Biology, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201.
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3
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Boyko KV, Rosenkranz EA, Smith DM, Miears HL, Oueld es cheikh M, Lund MZ, Young JC, Reardon PN, Okon M, Smirnov SL, Antos JM. Sortase-mediated segmental labeling: A method for segmental assignment of intrinsically disordered regions in proteins. PLoS One 2021; 16:e0258531. [PMID: 34710113 PMCID: PMC8553144 DOI: 10.1371/journal.pone.0258531] [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: 12/31/2020] [Accepted: 09/29/2021] [Indexed: 11/18/2022] Open
Abstract
A significant number of proteins possess sizable intrinsically disordered regions (IDRs). Due to the dynamic nature of IDRs, NMR spectroscopy is often the tool of choice for characterizing these segments. However, the application of NMR to IDRs is often hindered by their instability, spectral overlap and resonance assignment difficulties. Notably, these challenges increase considerably with the size of the IDR. In response to these issues, here we report the use of sortase-mediated ligation (SML) for segmental isotopic labeling of IDR-containing samples. Specifically, we have developed a ligation strategy involving a key segment of the large IDR and adjacent folded headpiece domain comprising the C-terminus of A. thaliana villin 4 (AtVLN4). This procedure significantly reduces the complexity of NMR spectra and enables group identification of signals arising from the labeled IDR fragment, a process we refer to as segmental assignment. The validity of our segmental assignment approach is corroborated by backbone residue-specific assignment of the IDR using a minimal set of standard heteronuclear NMR methods. Using segmental assignment, we further demonstrate that the IDR region adjacent to the headpiece exhibits nonuniform spectral alterations in response to temperature. Subsequent residue-specific characterization revealed two segments within the IDR that responded to temperature in markedly different ways. Overall, this study represents an important step toward the selective labeling and probing of target segments within much larger IDR contexts. Additionally, the approach described offers significant savings in NMR recording time, a valuable advantage for the study of unstable IDRs, their binding interfaces, and functional mechanisms.
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Affiliation(s)
- Kristina V. Boyko
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
| | - Erin A. Rosenkranz
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
| | - Derrick M. Smith
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
| | - Heather L. Miears
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
| | - Melissa Oueld es cheikh
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
| | - Micah Z. Lund
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
| | - Jeffery C. Young
- Department of Biology, Western Washington University, Bellingham, Washington, United States of America
| | - Patrick N. Reardon
- Oregon State University NMR Facility, Oregon State University, Corvallis, Oregon, United States of America
| | - Mark Okon
- Department of Biochemistry and Molecular Biology, Department of Chemistry, Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia, Canada
| | - Serge L. Smirnov
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
- * E-mail: (JMA); (SLS)
| | - John M. Antos
- Department of Chemistry, Western Washington University, Bellingham, Washington, United States of America
- * E-mail: (JMA); (SLS)
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4
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Vogl DP, Conibear AC, Becker CFW. Segmental and site-specific isotope labelling strategies for structural analysis of posttranslationally modified proteins. RSC Chem Biol 2021; 2:1441-1461. [PMID: 34704048 PMCID: PMC8496066 DOI: 10.1039/d1cb00045d] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 08/11/2021] [Indexed: 01/02/2023] Open
Abstract
Posttranslational modifications can alter protein structures, functions and locations, and are important cellular regulatory and signalling mechanisms. Spectroscopic techniques such as nuclear magnetic resonance, infrared and Raman spectroscopy, as well as small-angle scattering, can provide insights into the structural and dynamic effects of protein posttranslational modifications and their impact on interactions with binding partners. However, heterogeneity of modified proteins from natural sources and spectral complexity often hinder analyses, especially for large proteins and macromolecular assemblies. Selective labelling of proteins with stable isotopes can greatly simplify spectra, as one can focus on labelled residues or segments of interest. Employing chemical biology tools for modifying and isotopically labelling proteins with atomic precision provides access to unique protein samples for structural biology and spectroscopy. Here, we review site-specific and segmental isotope labelling methods that are employed in combination with chemical and enzymatic tools to access posttranslationally modified proteins. We discuss illustrative examples in which these methods have been used to facilitate spectroscopic studies of posttranslationally modified proteins, providing new insights into biology.
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Affiliation(s)
- Dominik P Vogl
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry Währinger Straße 38 1090 Vienna Austria +43-1-4277-870510 +43-1-4277-70510
| | - Anne C Conibear
- The University of Queensland, School of Biomedical Sciences St Lucia Brisbane 4072 QLD Australia
| | - Christian F W Becker
- University of Vienna, Faculty of Chemistry, Institute of Biological Chemistry Währinger Straße 38 1090 Vienna Austria +43-1-4277-870510 +43-1-4277-70510
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5
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Wiegand T. A solid-state NMR tool box for the investigation of ATP-fueled protein engines. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2020; 117:1-32. [PMID: 32471533 DOI: 10.1016/j.pnmrs.2020.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/30/2019] [Revised: 02/18/2020] [Accepted: 02/20/2020] [Indexed: 06/11/2023]
Abstract
Motor proteins are involved in a variety of cellular processes. Their main purpose is to convert the chemical energy released during adenosine triphosphate (ATP) hydrolysis into mechanical work. In this review, solid-state Nuclear Magnetic Resonance (NMR) approaches are discussed allowing studies of structures, conformational events and dynamic features of motor proteins during a variety of enzymatic reactions. Solid-state NMR benefits from straightforward sample preparation based on sedimentation of the proteins directly into the Magic-Angle Spinning (MAS) rotor. Protein resonance assignment is the crucial and often time-limiting step in interpreting the wealth of information encoded in the NMR spectra. Herein, potentials, challenges and limitations in resonance assignment for large motor proteins are presented, focussing on both biochemical and spectroscopic approaches. This work highlights NMR tools available to study the action of the motor domain and its coupling to functional processes, as well as to identify protein-nucleotide interactions during events such as DNA replication. Arrested protein states of reaction coordinates such as ATP hydrolysis can be trapped for NMR studies by using stable, non-hydrolysable ATP analogues that mimic the physiological relevant states as accurately as possible. Recent advances in solid-state NMR techniques ranging from Dynamic Nuclear Polarization (DNP), 31P-based heteronuclear correlation experiments, 1H-detected spectra at fast MAS frequencies >100 kHz to paramagnetic NMR are summarized and their applications to the bacterial DnaB helicase from Helicobacter pylori are discussed.
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Affiliation(s)
- Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
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6
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Li J, Zhang Y, Soubias O, Khago D, Chao FA, Li Y, Shaw K, Byrd RA. Optimization of sortase A ligation for flexible engineering of complex protein systems. J Biol Chem 2020; 295:2664-2675. [PMID: 31974162 DOI: 10.1074/jbc.ra119.012039] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2019] [Revised: 01/22/2020] [Indexed: 01/06/2023] Open
Abstract
Engineering and bioconjugation of proteins is a critically valuable tool that can facilitate a wide range of biophysical and structural studies. The ability to orthogonally tag or label a domain within a multidomain protein may be complicated by undesirable side reactions to noninvolved domains. Furthermore, the advantages of segmental (or domain-specific) isotopic labeling for NMR, or deuteration for neutron scattering or diffraction, can be realized by an efficient ligation procedure. Common methods-expressed protein ligation, protein trans-splicing, and native chemical ligation-each have specific limitations. Here, we evaluated the use of different variants of Staphylococcus aureus sortase A for a range of ligation reactions and demonstrate that conditions can readily be optimized to yield high efficiency (i.e. completeness of ligation), ease of purification, and functionality in detergents. These properties may enable joining of single domains into multidomain proteins, lipidation to mimic posttranslational modifications, and formation of cyclic proteins to aid in the development of nanodisc membrane mimetics. We anticipate that the method for ligating separate domains into a single functional multidomain protein reported here may enable many applications in structural biology.
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Affiliation(s)
- Jess Li
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201
| | - Yue Zhang
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201
| | - Olivier Soubias
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201
| | - Domarin Khago
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201
| | - Fa-An Chao
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201
| | - Yifei Li
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201
| | - Katherine Shaw
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201
| | - R Andrew Byrd
- Structural Biophysics Laboratory, Center for Cancer Research, NCI, National Institutes of Health, Frederick, Maryland 21702-1201.
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7
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Lapinaite A, Carlomagno T, Gabel F. Small-Angle Neutron Scattering of RNA-Protein Complexes. Methods Mol Biol 2020; 2113:165-188. [PMID: 32006315 DOI: 10.1007/978-1-0716-0278-2_13] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Small-angle neutron scattering (SANS) provides structural information on biomacromolecules and their complexes in dilute solutions at the nanometer length scale. The overall dimensions, shapes, and interactions can be probed and compared to information obtained by complementary structural biology techniques such as crystallography, NMR, and EM. SANS, in combination with solvent H2O/D2O exchange and/or deuteration, is particularly well suited to probe the internal structure of RNA-protein (RNP) complexes since neutrons are more sensitive than X-rays to the difference in scattering length densities of proteins and RNA, with respect to an aqueous solvent. In this book chapter we provide a practical guide on how to carry out SANS experiments on RNP complexes, as well as possibilities of data analysis and interpretation.
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Affiliation(s)
- Audrone Lapinaite
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Teresa Carlomagno
- Centre for Biomolecular Drug Research, Leibniz University Hannover, Hannover, Germany.,Helmholtz Centre for Infection Research, Group of Structural Chemistry, Braunschweig, Germany
| | - Frank Gabel
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France.
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8
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Iorgu AI, Cliff MJ, Waltho JP, Scrutton NS, Hay S. Isotopically labeled flavoenzymes and their uses in probing reaction mechanisms. Methods Enzymol 2019; 620:145-166. [PMID: 31072485 DOI: 10.1016/bs.mie.2019.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The incorporation of stable isotopes into proteins is beneficial or essential for a range of experiments, including NMR, neutron scattering and reflectometry, proteomic mass spectrometry, vibrational spectroscopy and "heavy" enzyme kinetic isotope effect (KIE) measurements. Here, we present detailed protocols for the stable isotopic labeling of pentaerythritol tetranitrate reductase (PETNR) via recombinant expression in E. coli. PETNR is an ene-reductase belonging to the Old Yellow Enzyme (OYE) family of flavoenzymes, and is regarded as a model system for studying hydride transfer reactions. Included is a discussion of how efficient back-exchange of amide protons in the protein core can be achieved and how the intrinsic flavin mononucleotide (FMN) cofactor can be exchanged, allowing the production of isotopologues with differentially labeled protein and cofactor. In addition to a thorough description of labeling strategies, we briefly exemplify how data analysis and interpretation of "heavy" enzyme KIEs can be performed.
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Affiliation(s)
- Andreea I Iorgu
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Matthew J Cliff
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Jonathan P Waltho
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Nigel S Scrutton
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, United Kingdom
| | - Sam Hay
- Manchester Institute of Biotechnology and School of Chemistry, The University of Manchester, Manchester, United Kingdom.
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9
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Lacabanne D, Fogeron ML, Wiegand T, Cadalbert R, Meier BH, Böckmann A. Protein sample preparation for solid-state NMR investigations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 110:20-33. [PMID: 30803692 DOI: 10.1016/j.pnmrs.2019.01.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 01/11/2019] [Accepted: 01/12/2019] [Indexed: 06/09/2023]
Abstract
Preparation of a protein sample for solid-state NMR is in many aspects similar to solution-state NMR approaches, mainly with respect to the need for stable isotope labeling. But the possibility of using solid-state NMR to investigate membrane proteins in (native) lipids adds the important requirement of adapted membrane-reconstitution schemes. Also, dynamic nuclear polarization and paramagnetic NMR in solids need specific schemes using metal ions and radicals. Sample sedimentation has enabled structural investigations of objects inaccessible to other structural techniques, but rotor filling using sedimentation has become increasingly complex with smaller and smaller rotors, as needed for higher and higher magic-angle spinning (MAS) frequencies. Furthermore, solid-state NMR can investigate very large proteins and their complexes without the concomitant increase in line widths, motivating the use of selective labeling and unlabeling strategies, as well as segmental labeling, to decongest spectra. The possibility of investigating sub-milligram amounts of protein today using advanced fast MAS techniques enables alternative protein synthesis schemes such as cell-free expression. Here we review these specific aspects of solid-state NMR sample preparation.
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Affiliation(s)
- Denis Lacabanne
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France; Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | - Marie-Laure Fogeron
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France
| | - Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland
| | | | - Beat H Meier
- Physical Chemistry, ETH Zurich, 8093 Zurich, Switzerland.
| | - Anja Böckmann
- Molecular Microbiology and Structural Biochemistry, Labex Ecofect, UMR 5086 CNRS/Université de Lyon, 69367 Lyon, France.
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10
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Michel E, Plückthun A, Zerbe O. Peptide binding affinity redistributes preassembled repeat protein fragments. Biol Chem 2018; 400:395-404. [DOI: 10.1515/hsz-2018-0355] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2018] [Accepted: 11/21/2018] [Indexed: 01/21/2023]
Abstract
Abstract
Designed armadillo repeat proteins (dArmRPs) are modular peptide binders composed of N- and C-terminal capping repeats Y and A and a variable number of internal modules M that each specifically recognize two amino acids of the target peptide. Complementary fragments of dArmRPs obtained by splitting the protein between helices H1 and H2 of an internal module show conditional and specific assembly only in the presence of a target peptide (Michel, E., Plückthun, A., and Zerbe, O. (2018). Peptide-guided assembly of repeat protein fragments. Angew. Chem. Int. Ed. 57, 4576–4579). Here, we investigate dArmRP fragments that already spontaneously assemble with high affinity, e.g. those obtained from splits between entire modules or between helices H2 and H3. We find that the interaction of the peptide with the assembled fragments induces distal conformational rearrangements that suggest an induced fit on a global protein level. A population analysis of an equimolar mixture of an N-terminal and three C-terminal fragments with various affinities for the target peptide revealed predominant assembly of the weakest peptide binder. However, adding a target peptide to this mixture altered the population of the protein complexes such that the combination with the highest affinity for the peptide increased and becomes predominant when adding excess of peptide, highlighting the feasibility of peptide-induced enrichment of best binders from inter-modular fragment mixtures.
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Affiliation(s)
- Erich Michel
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zürich , Switzerland
| | - Andreas Plückthun
- Department of Biochemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zürich , Switzerland
| | - Oliver Zerbe
- Department of Chemistry , University of Zurich , Winterthurerstrasse 190 , CH-8057 Zürich , Switzerland
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11
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Demers JP, Fricke P, Shi C, Chevelkov V, Lange A. Structure determination of supra-molecular assemblies by solid-state NMR: Practical considerations. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2018; 109:51-78. [PMID: 30527136 DOI: 10.1016/j.pnmrs.2018.06.002] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 06/15/2018] [Accepted: 06/15/2018] [Indexed: 05/26/2023]
Abstract
In the cellular environment, biomolecules assemble in large complexes which can act as molecular machines. Determining the structure of intact assemblies can reveal conformations and inter-molecular interactions that are only present in the context of the full assembly. Solid-state NMR (ssNMR) spectroscopy is a technique suitable for the study of samples with high molecular weight that allows the atomic structure determination of such large protein assemblies under nearly physiological conditions. This review provides a practical guide for the first steps of studying biological supra-molecular assemblies using ssNMR. The production of isotope-labeled samples is achievable via several means, which include recombinant expression, cell-free protein synthesis, extraction of assemblies directly from cells, or even the study of assemblies in whole cells in situ. Specialized isotope labeling schemes greatly facilitate the assignment of chemical shifts and the collection of structural data. Advanced strategies such as mixed, diluted, or segmental subunit labeling offer the possibility to study inter-molecular interfaces. Detailed and practical considerations are presented with respect to first setting up magic-angle spinning (MAS) ssNMR experiments, including the selection of the ssNMR rotor, different methods to best transfer the sample and prepare the rotor, as well as common and robust procedures for the calibration of the instrument. Diagnostic spectra to evaluate the resolution and sensitivity of the sample are presented. Possible improvements that can reduce sample heterogeneity and improve the quality of ssNMR spectra are reviewed.
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Affiliation(s)
- Jean-Philippe Demers
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Laboratory of Cell Biology, Center for Cancer Research (CCR), National Cancer Institute (NCI), National Institutes of Health (NIH), Bethesda, MD 20892, USA
| | - Pascal Fricke
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Chaowei Shi
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Veniamin Chevelkov
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany
| | - Adam Lange
- Department of Molecular Biophysics, Leibniz-Forschungsinstitut für Molekulare Pharmakologie (FMP), 13125 Berlin, Germany; Institut für Biologie, Humboldt-Universität zu Berlin, 10115 Berlin, Germany.
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12
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Y-box proteins combine versatile cold shock domains and arginine-rich motifs (ARMs) for pleiotropic functions in RNA biology. Biochem J 2018; 475:2769-2784. [PMID: 30206185 DOI: 10.1042/bcj20170956] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2017] [Revised: 07/31/2018] [Accepted: 08/07/2018] [Indexed: 12/23/2022]
Abstract
Y-box proteins are single-strand DNA- and RNA-binding proteins distinguished by a conserved cold shock domain (CSD) and a variable C-terminal domain organized into alternating short modules rich in basic or acidic amino acids. A huge literature depicts Y-box proteins as highly abundant, staggeringly versatile proteins that interact with all mRNAs and function in most forms of mRNA-specific regulation. The mechanisms by which Y-box proteins recognize mRNAs are unclear, because their CSDs bind a jumble of diverse elements, and the basic modules in the C-terminal domain are considered to bind nonspecifically to phosphates in the RNA backbone. A survey of vertebrate Y-box proteins clarifies the confusing names for Y-box proteins, their domains, and RNA-binding motifs, and identifies several novel conserved sequences: first, the CSD is flanked by linkers that extend its binding surface or regulate co-operative binding of the CSD and N-terminal and C-terminal domains to proteins and RNA. Second, the basic modules in the C-terminal domain are bona fide arginine-rich motifs (ARMs), because arginine is the predominant amino acid and comprises 99% of basic residues. Third, conserved differences in AA (amino acid) sequences between isoforms probably affect RNA-binding specificity. C-terminal ARMs connect with many studies, demonstrating that ARMs avidly bind sites containing specific RNA structures. ARMs crystallize insights into the under-appreciated contributions of the C-terminal domain to site-specific binding by Y-box proteins and difficulties in identifying site-specific binding by the C-terminal domain. Validated structural biology techniques are available to elucidate the mechanisms by which YBXprot (Y-box element-binding protein) CSDs and ARMs identify targets.
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13
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Schütz S, Michel E, Damberger FF, Oplová M, Peña C, Leitner A, Aebersold R, Allain FHT, Panse VG. Molecular basis for disassembly of an importin:ribosomal protein complex by the escortin Tsr2. Nat Commun 2018; 9:3669. [PMID: 30201955 PMCID: PMC6131548 DOI: 10.1038/s41467-018-06160-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2018] [Accepted: 08/22/2018] [Indexed: 01/16/2023] Open
Abstract
Disordered extensions at the termini and short internal insertions distinguish eukaryotic ribosomal proteins (r-proteins) from their anucleated archaeal counterparts. Here, we report an NMR structure of such a eukaryotic-specific segment (ESS) in the r-protein eS26 in complex with the escortin Tsr2. The structure reveals how ESS attracts Tsr2 specifically to importin:eS26 complexes entering the nucleus in order to trigger non-canonical RanGTP-independent disassembly. Tsr2 then sequesters the released eS26 and prevents rebinding to the importin, providing an alternative allosteric mechanism to terminate the process of nuclear import. Notably, a Diamond–Blackfan anemia-associated Tsr2 mutant protein is impaired in binding to ESS, unveiling a critical role for this interaction in human hematopoiesis. We propose that eS26-ESS and Tsr2 are components of a nuclear sorting system that co-evolved with the emergence of the nucleocytoplasmic barrier and transport carriers. Ribosomal proteins are transported to the nucleus with the help of importins, from which they are released prior to incorporation into the nascent ribosome. Here the authors report the NMR structure of the ribosomal protein eS26 in complex with the escortin Tsr2 and shed light on the mechanism of eS26 release from importin.
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Affiliation(s)
- Sabina Schütz
- Institute of Medical Microbiology, University of Zurich, 8006, Zurich, Switzerland
| | - Erich Michel
- Department of Biochemistry, University of Zurich, 8057, Zurich, Switzerland
| | - Fred F Damberger
- Institute of Molecular Biology & Biophysics, ETH Zurich, 8093, Zurich, Switzerland
| | - Michaela Oplová
- Institute of Medical Microbiology, University of Zurich, 8006, Zurich, Switzerland.,Institute of Biochemistry, ETH Zurich, 8093, Zurich, Switzerland
| | - Cohue Peña
- Institute of Medical Microbiology, University of Zurich, 8006, Zurich, Switzerland
| | - Alexander Leitner
- Institute of Molecular Systems Biology, ETH Zurich, 8093, Zurich, Switzerland
| | - Ruedi Aebersold
- Institute of Molecular Systems Biology, ETH Zurich, 8093, Zurich, Switzerland.,Faculty of Science, University of Zurich, Zurich, 8057, Switzerland
| | - Frederic H-T Allain
- Institute of Molecular Biology & Biophysics, ETH Zurich, 8093, Zurich, Switzerland.
| | - Vikram Govind Panse
- Institute of Medical Microbiology, University of Zurich, 8006, Zurich, Switzerland.
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14
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Wiegand T, Cadalbert R, von Schroetter C, Allain FHT, Meier BH. Segmental isotope labelling and solid-state NMR of a 12 × 59 kDa motor protein: identification of structural variability. JOURNAL OF BIOMOLECULAR NMR 2018; 71:237-245. [PMID: 29948439 DOI: 10.1007/s10858-018-0196-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/28/2018] [Accepted: 06/01/2018] [Indexed: 05/26/2023]
Abstract
Segmental isotope labelling enables the NMR study of an individual domain within a multidomain protein, but still in the context of the entire full-length protein. Compared to the fully labelled protein, spectral overlap can be greatly reduced. We here describe segmental labelling of the (double-) hexameric DnaB helicase from Helicobacter pylori using a ligation approach. Solid-state spectra demonstrate that the ligated protein has the same structure and structural order as the directly expressed full-length protein. We uniformly 13C/15N labeled the N-terminal domain (147 residues) of the protein, while the C-terminal domain (311 residues) remained in natural abundance. The reduced signal overlap in solid-state NMR spectra allowed to identify structural "hotspots" for which the structure of the N-terminal domain in the context of the oligomeric full-length protein differs from the one in the isolated form. They are located near the linker between the two domains, in an α-helical hairpin.
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Affiliation(s)
- Thomas Wiegand
- Physical Chemistry, ETH Zurich, 8093, Zurich, Switzerland
| | | | | | - Frédéric H-T Allain
- Institute of Molecular Biology and Biophysics, ETH Zurich, 8093, Zurich, Switzerland.
| | - Beat H Meier
- Physical Chemistry, ETH Zurich, 8093, Zurich, Switzerland.
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15
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Gallagher C, Burlina F, Offer J, Ramos A. A method for the unbiased and efficient segmental labelling of RNA-binding proteins for structure and biophysics. Sci Rep 2017; 7:14083. [PMID: 29074846 PMCID: PMC5658380 DOI: 10.1038/s41598-017-13950-8] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2017] [Accepted: 10/03/2017] [Indexed: 01/05/2023] Open
Abstract
Most eukaryotic RNA regulators recognise their RNA and protein partners by the combinatorial use of several RNA binding domains. Inter-domain dynamics and interactions play a key role in recognition and can be analysed by techniques such as NMR or FRET, provided that the information relative to the individual interactions can be de-convoluted. Segmentally labelling the proteins by ligating labelled and unlabelled peptide chains allows one to filter out unwanted information and observe the labelled moieties only. Several strategies have been implemented to ligate two protein fragments, but multiple ligations, which are necessary to segmentally label proteins of more than two domains, are more challenging and often dependent on the structure and solubility of the domains. Here we report a method to ligate multiple protein segments that allows the fast, high yield labelling of both internal and end domains, depending on the requirements. We use TCEP and mercaptophenylacetic acid (MPAA) in an optimised reaction environment to achieve an efficient ligation of protein domains independently from their structure or solubility. We expect the method will provide a useful tool for the molecular study of combinatorial protein–RNA recognition in RNA regulation.
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Affiliation(s)
- Christopher Gallagher
- Institute of Structural and Molecular Biology, University College London, London, WC1E 6XA, UK.,The Francis Crick Institute, London, NW1 1AT, UK
| | - Fabienne Burlina
- Sorbonne Universités, UPMC Univ. Paris 06, École Normale Supérieure, PSL Research University, CNRS, Laboratoire des Biomolécules (LBM), 4 place Jussieu, Paris, 75005, France
| | - John Offer
- The Francis Crick Institute, London, NW1 1AT, UK.
| | - Andres Ramos
- Institute of Structural and Molecular Biology, University College London, London, WC1E 6XA, UK. .,The Francis Crick Institute, London, NW1 1AT, UK.
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16
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Zhuravleva A, Korzhnev DM. Protein folding by NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 100:52-77. [PMID: 28552172 DOI: 10.1016/j.pnmrs.2016.10.002] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2016] [Revised: 10/17/2016] [Accepted: 10/17/2016] [Indexed: 06/07/2023]
Abstract
Protein folding is a highly complex process proceeding through a number of disordered and partially folded nonnative states with various degrees of structural organization. These transiently and sparsely populated species on the protein folding energy landscape play crucial roles in driving folding toward the native conformation, yet some of these nonnative states may also serve as precursors for protein misfolding and aggregation associated with a range of devastating diseases, including neuro-degeneration, diabetes and cancer. Therefore, in vivo protein folding is often reshaped co- and post-translationally through interactions with the ribosome, molecular chaperones and/or other cellular components. Owing to developments in instrumentation and methodology, solution NMR spectroscopy has emerged as the central experimental approach for the detailed characterization of the complex protein folding processes in vitro and in vivo. NMR relaxation dispersion and saturation transfer methods provide the means for a detailed characterization of protein folding kinetics and thermodynamics under native-like conditions, as well as modeling high-resolution structures of weakly populated short-lived conformational states on the protein folding energy landscape. Continuing development of isotope labeling strategies and NMR methods to probe high molecular weight protein assemblies, along with advances of in-cell NMR, have recently allowed protein folding to be studied in the context of ribosome-nascent chain complexes and molecular chaperones, and even inside living cells. Here we review solution NMR approaches to investigate the protein folding energy landscape, and discuss selected applications of NMR methodology to studying protein folding in vitro and in vivo. Together, these examples highlight a vast potential of solution NMR in providing atomistic insights into molecular mechanisms of protein folding and homeostasis in health and disease.
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Affiliation(s)
- Anastasia Zhuravleva
- Astbury Centre for Structural Molecular Biology and Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, United Kingdom.
| | - Dmitry M Korzhnev
- Department of Molecular Biology and Biophysics, University of Connecticut Health Center, Farmington, CT 06030, USA.
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17
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Williams FP, Milbradt AG, Embrey KJ, Bobby R. Segmental Isotope Labelling of an Individual Bromodomain of a Tandem Domain BRD4 Using Sortase A. PLoS One 2016; 11:e0154607. [PMID: 27128490 PMCID: PMC4851411 DOI: 10.1371/journal.pone.0154607] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2016] [Accepted: 04/17/2016] [Indexed: 11/19/2022] Open
Abstract
Bromodomain and extra-terminal (BET) family of proteins are one of the major readers of epigenetic marks and an important target class in oncology and other disease areas. The importance of the BET family of proteins is manifested by the explosion in the number of inhibitors against these targets that have successfully entered clinical trials. One important BET family member is bromodomain containing protein 4 (BRD4). Structural and biophysical studies of BRD4 are complicated by its tertiary-structure consisting of two bromodomains connected by a flexible inter-domain linker of approximately 180 amino acids. A detailed understanding of the interplay of these bromodomains will be key to rational drug design in BRD4, yet there are no reported three-dimensional structures of the multi-domain BRD4 and NMR studies of the tandem domain are hampered by the size of the protein. Here, we present a method for rapid Sortase A-mediated segmental labelling of the individual bromodomains of BRD4 that provides a powerful strategy that will enable NMR studies of ligand-bromodomain interactions with atomic detail. In our labelling strategy, we have used U-[2H,15N]-isotope labelling on the C-terminal bromodomain with selective introduction of 13CH3 methyl groups on Ile (δ1), Val and Leu, whereas the N-terminal bromodomain remained unlabelled. This labelling scheme resulted in significantly simplified NMR spectra and will allow for high-resolution interaction, structure and dynamics studies in the presence of ligands.
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Affiliation(s)
- Felix P. Williams
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Alderley Park, Macclesfield SK10 4TF, United Kingdom
| | - Alexander G. Milbradt
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Alderley Park, Macclesfield SK10 4TF, United Kingdom
| | - Kevin J. Embrey
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Alderley Park, Macclesfield SK10 4TF, United Kingdom
- * E-mail: (KJE); (RB)
| | - Romel Bobby
- Discovery Sciences, Innovative Medicines and Early Development Biotech Unit, AstraZeneca, Alderley Park, Macclesfield SK10 4TF, United Kingdom
- * E-mail: (KJE); (RB)
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