1
|
Sahoo BR, Subramanian V, Bardwell JCA. Backbone 1H, 13C, and 15N chemical shift assignments for human SERF2. Biomol NMR Assign 2024:10.1007/s12104-024-10167-5. [PMID: 38466543 DOI: 10.1007/s12104-024-10167-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Accepted: 02/28/2024] [Indexed: 03/13/2024]
Abstract
Human small EDRK-rich factor protein SERF2 is a cellular driver of protein amyloid formation, a process that has been linked to neurodegenerative diseases including Alzheimer's and Parkinson's disease. SERF2 is a 59 amino acid protein, highly charged, and well conserved whose structure and physiological function is unclear. SERF family proteins including human SERF2 have shown a tendency to form fuzzy complexes with misfolded proteins such as α-Synuclein which has been linked to Parkinson's disease. SERF family proteins have been recently identified to bind nucleic acids, but the binding mechanism(s) remain enigmatic. Here, using multidimensional solution NMR, we report the 1H, 15N, and 13C chemical shift assignments (~ 86% of backbone resonance assignments) for human SERF2. TALOS-N predicted secondary structure of SERF2 showed three very short helices (3-4 residues long) in the N-terminal region of the protein and a long helix in the C-terminal region spanning residues 37-46 which is consistent with the helical content indicated by circular dichroism spectroscopy. Paramagnetic relaxation enhancement NMR analysis revealed that a short C-terminal region E53-K55 is in the proximity of the N-terminus. Having the backbone assignment of SERF2 allowed us to probe its interaction with α-Synuclein and to identify the residues in SERF2 binding interfaces that likely promote α-Synuclein aggregation.
Collapse
Affiliation(s)
- Bikash R Sahoo
- Howard Hughes Medical Institute, Chevy Chase, MD-20815, USA.
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI-48109, USA.
| | | | - James C A Bardwell
- Howard Hughes Medical Institute, Chevy Chase, MD-20815, USA
- Department of Molecular, Cellular and Developmental Biology, University of Michigan, Ann Arbor, MI-48109, USA
| |
Collapse
|
2
|
Guillien M, Mouhand A, Sagar A, Fournet A, Allemand F, Pereira GAN, Thureau A, Bernadó P, Banères JL, Sibille N. Phosphorylation motif dictates GPCR C-terminal domain conformation and arrestin interaction. Structure 2023; 31:1394-1406.e7. [PMID: 37669668 DOI: 10.1016/j.str.2023.08.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2023] [Revised: 07/07/2023] [Accepted: 08/09/2023] [Indexed: 09/07/2023]
Abstract
Arrestin-dependent G protein-coupled receptor (GPCR) signaling pathway is regulated by the phosphorylation state of GPCR's C-terminal domain, but the molecular bases of arrestin:receptor interaction are to be further illuminated. Here we investigated the impact of phosphorylation on the conformational features of the C-terminal region from three rhodopsin-like GPCRs, the vasopressin V2 receptor (V2R), the growth hormone secretagogue or ghrelin receptor type 1a (GHSR), and the β2-adernergic receptor (β2AR). Using phosphomimetic variants, we identified pre-formed secondary structure elements, or short linear motifs (SLiMs), that undergo specific conformational transitions upon phosphorylation. Of importance, such conformational transitions appear to favor arrestin-2 binding. Hence, our results suggest a model in which the phosphorylation-dependent structuration of the GPCR C-terminal regions would modulate arrestin binding and therefore signaling outcomes in arrestin-dependent pathways.
Collapse
Affiliation(s)
- Myriam Guillien
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Assia Mouhand
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Amin Sagar
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Aurélie Fournet
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Frédéric Allemand
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Glaécia A N Pereira
- Institut des Biomolécules Max Mousseron (IBMM), UMR-5247, University Montpellier, CNRS, ENSCM, Montpellier, France
| | - Aurélien Thureau
- HélioBio Section, Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin BP 48, 91190 Gif-sur-Yvette, France
| | - Pau Bernadó
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France
| | - Jean-Louis Banères
- Institut des Biomolécules Max Mousseron (IBMM), UMR-5247, University Montpellier, CNRS, ENSCM, Montpellier, France
| | - Nathalie Sibille
- Centre de Biologie Structurale (CBS), CNRS, University Montpellier, Inserm, Montpellier, France.
| |
Collapse
|
3
|
Grifagni D, Silva JM, Cantini F, Piccioli M, Banci L. Relaxation-based NMR assignment: Spotlights on ligand binding sites in human CISD3. J Inorg Biochem 2023; 239:112089. [PMID: 36502664 DOI: 10.1016/j.jinorgbio.2022.112089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 11/26/2022] [Accepted: 12/01/2022] [Indexed: 12/12/2022]
Abstract
CISD3 is a mitochondrial protein belonging to the NEET proteins family, bearing two [Fe2S2] clusters coordinated by CDGSH domains. At variance with the other proteins of the NEET family, very little is known about its structure-function relationships. NMR is the only technique to obtain information at the atomic level in solution on the residues involved in intermolecular interactions; however, in paramagnetic proteins this is limited by the broadening of signals of residues around the paramagnetic center. Tailored experiments can revive signals of the cluster surrounding; however, signals identification without specific residue assignment remains useless. Here, we show how paramagnetic relaxation can drive the signal assignment of residues in the proximity of the paramagnetic center(s). This allowed us to identify the potential key players of the biological function of the CISD3 protein.
Collapse
Affiliation(s)
- Deborah Grifagni
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| | - José M Silva
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| | - Francesca Cantini
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| | - Mario Piccioli
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| | - Lucia Banci
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| |
Collapse
|
4
|
Jardón-Álvarez D, Malka T, van Tol J, Feldman Y, Carmieli R, Leskes M. Monitoring electron spin fluctuations with paramagnetic relaxation enhancement. J Magn Reson 2022; 336:107143. [PMID: 35085928 DOI: 10.1016/j.jmr.2022.107143] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Revised: 12/30/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
The magnetic interactions between the spin of an unpaired electron and the surrounding nuclear spins can be exploited to gain structural information, to reduce nuclear relaxation times as well as to create nuclear hyperpolarization via dynamic nuclear polarization (DNP). A central aspect that determines how these interactions manifest from the point of view of NMR is the timescale of the fluctuations of the magnetic moment of the electron spins. These fluctuations, however, are elusive, particularly when electron relaxation times are short or interactions among electronic spins are strong. Here we map the fluctuations by analyzing the ratio between longitudinal and transverse nuclear relaxation times T1/T2, a quantity which depends uniquely on the rate of the electron fluctuations and the Larmor frequency of the involved nuclei. This analysis enables rationalizing the evolution of NMR lineshapes, signal quenching as well as DNP enhancements as a function of the concentration of the paramagnetic species and the temperature, demonstrated here for LiMg1-xMnxPO4 and Fe(III) doped Li4Ti5O12, respectively. For the latter, we observe a linear dependence of the DNP enhancement and the electron relaxation time within a temperature range between 100 and 300 K.
Collapse
Affiliation(s)
- Daniel Jardón-Álvarez
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Tahel Malka
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Johan van Tol
- National High Magnetic Field Laboratory, Florida State University, 1800 E. Paul Dirac Dr, Tallahassee, FL 32310, United States
| | - Yishay Feldman
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Raanan Carmieli
- Department of Chemical Research Support, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Michal Leskes
- Department of Molecular Chemistry and Materials Science, Weizmann Institute of Science, Rehovot 76100, Israel.
| |
Collapse
|
5
|
He C, Li S, Xiao Y, Xu J, Deng F. Application of solid-state NMR techniques for structural characterization of metal-organic frameworks. Solid State Nucl Magn Reson 2022; 117:101772. [PMID: 35016011 DOI: 10.1016/j.ssnmr.2022.101772] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 12/27/2021] [Accepted: 01/03/2022] [Indexed: 06/14/2023]
Abstract
Solid-state NMR can afford the structural information about the chemical composition, local environment, and spatial coordination at the atomic level, which has been extensively applied to characterize the detailed structure and host-guest interactions in metal-organic frameworks (MOFs). In this review, recent advances for the structural characterizations of MOFs using versatile solid-state NMR techniques were briefly introduced. High-field sensitivity-enhanced solid-state NMR method enabled the direct observation of metal centers in MOFs containing low-γ nuclei. Two-dimensional (2D) homo- and hetero-nuclear correlation MAS NMR experiments provided the spatial proximity among linkers, metal clusters and the introduced guest molecules. Moreover, quantitative measurement of inter-nuclear distances using solid-state NMR provided valuable structural information about the connectivity geometry as well as the host-guest interactions within MOFs. Furthermore, solid-state NMR has exhibited great potential for unraveling the structure property of MOFs containing paramagnetic metal centers.
Collapse
Affiliation(s)
- Caiyan He
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Shenhui Li
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
| | - Yuqing Xiao
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Jun Xu
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China
| | - Feng Deng
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, National Center for Magnetic Resonance in Wuhan, Wuhan Institute of Physics and Mathematics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, 430071, PR China; University of Chinese Academy of Sciences, Beijing, 100049, PR China.
| |
Collapse
|
6
|
Kakeshpour T, Ramanujam V, Barnes CA, Shen Y, Ying J, Bax A. A lowly populated, transient β-sheet structure in monomeric Aβ 1-42 identified by multinuclear NMR of chemical denaturation. Biophys Chem 2020; 270:106531. [PMID: 33453683 DOI: 10.1016/j.bpc.2020.106531] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2020] [Revised: 12/08/2020] [Accepted: 12/13/2020] [Indexed: 02/07/2023]
Abstract
Chemical denaturation is a well-established approach for probing the equilibrium between folded and unfolded states of proteins. We demonstrate applicability of this method to the detection of a small population of a transiently folded structural element in a system that is often considered to be intrinsically fully disordered. The 1HN, 15N, 13Cα, and 13C' chemical shifts of Aβ1-40 and Aβ1-42 peptides and their M35-oxidized variants were monitored as a function of urea concentration and compared to analogous urea titrations of synthetic pentapeptides of homologous sequence. Fitting of the chemical shift titrations yields a 10 ± 1% population for a structured element at the C-terminus of Aβ1-42 that folds with a cooperativity of m = 0.06 kcal/mol·M. The fit also yields the chemical shifts of the folded state and, using a database search, for Aβ1-42 these shifts identified an antiparallel intramolecular β-sheet for residues I32-A42, linked by a type I' β-turn at G37 and G38. The structure is destabilized by oxidation of M35. Paramagnetic relaxation rates and two previously reported weak, medium-range NOE interactions are consistent with this transient β-sheet. Introduction of the requisite A42C mutation and tagging with MTSL resulted in a small stabilization of this β-sheet. Chemical shift analysis suggests a C-terminal β-sheet may be present in Aβ1-40 too, but the turn type at G37 is not type I'. The approach to derive Transient Structure from chemical Denaturation by NMR (TSD-NMR), demonstrated here for Aβ peptides, provides a sensitive tool for identifying the presence of lowly populated, transiently ordered elements in proteins that are considered to be intrinsically disordered, and permits extraction of structural data for such elements.
Collapse
Affiliation(s)
- Tayeb Kakeshpour
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Venkat Ramanujam
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - C Ashley Barnes
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Yang Shen
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Jinfa Ying
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Ad Bax
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA.
| |
Collapse
|
7
|
Invernici M, Trindade IB, Cantini F, Louro RO, Piccioli M. Measuring transverse relaxation in highly paramagnetic systems. J Biomol NMR 2020; 74:431-442. [PMID: 32710399 PMCID: PMC7508935 DOI: 10.1007/s10858-020-00334-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/09/2020] [Indexed: 05/16/2023]
Abstract
The enhancement of nuclear relaxation rates due to the interaction with a paramagnetic center (known as Paramagnetic Relaxation Enhancement) is a powerful source of structural and dynamics information, widely used in structural biology. However, many signals affected by the hyperfine interaction relax faster than the evolution periods of common NMR experiments and therefore they are broadened beyond detection. This gives rise to a so-called blind sphere around the paramagnetic center, which is a major limitation in the use of PREs. Reducing the blind sphere is extremely important in paramagnetic metalloproteins. The identification, characterization, and proper structural restraining of the first coordination sphere of the metal ion(s) and its immediate neighboring regions is key to understand their biological function. The novel HSQC scheme we propose here, that we termed R2-weighted, HSQC-AP, achieves this aim by detecting signals that escaped detection in a conventional HSQC experiment and provides fully reliable R2 values in the range of 1H R2 rates ca. 50-400 s-1. Independently on the type of paramagnetic center and on the size of the molecule, this experiment decreases the radius of the blind sphere and increases the number of detectable PREs. Here, we report the validation of this approach for the case of PioC, a small protein containing a high potential 4Fe-4S cluster in the reduced [Fe4S4]2+ form. The blind sphere was contracted to a minimal extent, enabling the measurement of R2 rates for the cluster coordinating residues.
Collapse
Affiliation(s)
- Michele Invernici
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Inês B Trindade
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal
| | - Francesca Cantini
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Ricardo O Louro
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal.
| | - Mario Piccioli
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
| |
Collapse
|
8
|
Abstract
The presence of an unpaired electron in paramagnetic molecules generates significant effects in NMR spectra, which can be exploited to provide restraints complementary to those used in standard structure-calculation protocols. NMR already occupies a central position in drug discovery for its use in fragment screening, structural biology and validation of ligand-target interactions. Paramagnetic restraints provide unique opportunities, for example, for more sensitive screening to identify weaker-binding fragments. A key application of paramagnetic NMR in drug discovery, however, is to provide new structural restraints in cases where crystallography proves intractable. This is particularly important at early stages in drug-discovery programs where crystal structures of weakly-binding fragments are difficult to obtain and crystallization artefacts are probable, but structural information about ligand poses is crucial to guide medicinal chemistry. Numerous applications show the value of paramagnetic restraints to filter computational docking poses and to generate interaction models. Paramagnetic relaxation enhancements (PREs) generate a distance-dependent effect, while pseudo-contact shift (PCS) restraints provide both distance and angular information. Here, we review strategies for introducing paramagnetic centers and discuss examples that illustrate the utility of paramagnetic restraints in drug discovery. Combined with standard approaches, such as chemical shift perturbation and NOE-derived distance information, paramagnetic NMR promises a valuable source of information for many challenging drug-discovery programs.
Collapse
Affiliation(s)
- Charlotte A Softley
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Lichtenbergstraße 4, 85747, Garching, Germany
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Mark J Bostock
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Lichtenbergstraße 4, 85747, Garching, Germany
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Grzegorz M Popowicz
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Lichtenbergstraße 4, 85747, Garching, Germany
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany
| | - Michael Sattler
- Biomolecular NMR and Center for Integrated Protein Science Munich at Department Chemie, Technical University of Munich, Lichtenbergstraße 4, 85747, Garching, Germany.
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstraße 1, 85764, Neuherberg, Germany.
| |
Collapse
|
9
|
Kowalewski J, Fries PH, Kruk D, Odelius M, Egorov AV, Krämer S, Stork H, Horvatić M, Berthier C. Field-dependent paramagnetic relaxation enhancement in solutions of Ni(II): What happens above the NMR proton frequency of 1 GHz? J Magn Reson 2020; 314:106737. [PMID: 32380383 DOI: 10.1016/j.jmr.2020.106737] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 06/11/2023]
Abstract
An extended set of paramagnetic relaxation enhancement (PRE) data, up to the field of 32.9 Tesla, is reported for protons in an acidified aqueous solution of a Ni(II) salt in the presence and in the absence of added glycerol. For the 55% w/w glycerol sample, a distinct maximum in the PRE vs magnetic field curve is observed for the first time. The data are analysed using the Swedish slow-motion theory, including both the intramolecular (inner-sphere) and intermolecular (outer-sphere) contributions. The results indicate that estimating the outer-sphere part in the presence of the more efficient inner-sphere term is a difficult task.
Collapse
Affiliation(s)
- Jozef Kowalewski
- Department of Materials and Environmental Chemistry, Stockholm University, SE-116 91 Stockholm, Sweden.
| | - Pascal H Fries
- Univ. Grenoble Alpes, CEA, IRIG-MEM, 38000 Grenoble, France
| | - Danuta Kruk
- University of Warmia and Mazury in Olsztyn, Faculty of Mathematics and Computer Science, Sloneczna 54, PL-10710 Olsztyn, Poland
| | - Michael Odelius
- Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Andrei V Egorov
- St.Petersburg State University, 7/9 Universitetskaya nab., St. Petersburg 199034, Russia
| | - Steffen Krämer
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, Univ. Grenoble Alpes, INSA Toulouse, Univ. Toulouse Paul Sabatier, B.P. 166, 38042 Grenoble Cedex 09, France
| | - Holger Stork
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, Univ. Grenoble Alpes, INSA Toulouse, Univ. Toulouse Paul Sabatier, B.P. 166, 38042 Grenoble Cedex 09, France
| | - Mladen Horvatić
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, Univ. Grenoble Alpes, INSA Toulouse, Univ. Toulouse Paul Sabatier, B.P. 166, 38042 Grenoble Cedex 09, France
| | - Claude Berthier
- Laboratoire National des Champs Magnétiques Intenses, LNCMI-CNRS (UPR3228), EMFL, Univ. Grenoble Alpes, INSA Toulouse, Univ. Toulouse Paul Sabatier, B.P. 166, 38042 Grenoble Cedex 09, France
| |
Collapse
|
10
|
Wang S, Gopinath T, Veglia G. Improving the quality of oriented membrane protein spectra using heat-compensated separated local field experiments. J Biomol NMR 2019; 73:617-624. [PMID: 31463642 PMCID: PMC6861693 DOI: 10.1007/s10858-019-00273-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/07/2019] [Accepted: 08/21/2019] [Indexed: 05/03/2023]
Abstract
Oriented sample solid-state NMR (OS-ssNMR) spectroscopy is a powerful technique to determine the topology of membrane proteins in oriented lipid bilayers. Separated local field (SLF) experiments are central to this technique as they provide first-order orientational restraints, i.e., dipolar couplings and anisotropic chemical shifts. Despite the use of low-E (or E-free) probes, the heat generated during the execution of 2D and 3D SLF pulse sequences causes sizeable line-shape distortions. Here, we propose a new heat-compensated SE-SAMPI4 (hcSE-SAMPI4) pulse sequence that holds the temperature constant for the duration of the experiment. This modification of the SE-SAMPI4 results in sharper and more intense resonances without line-shape distortions. The spectral improvements are even more apparent when paramagnetic relaxation agents are used to speed up data collection. We tested the hcSE-SAMPI4 pulse sequence on a single-span membrane protein, sarcolipin (SLN), reconstituted in magnetically aligned lipid bicelles. In addition to eliminating peak distortions, the hcSE-SAMPI4 experiment increased the average signal-to-noise ratio by 20% with respect to the original SE-SAMPI4.
Collapse
Affiliation(s)
- Songlin Wang
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - T Gopinath
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, Minneapolis, MN, 55455, USA.
| |
Collapse
|
11
|
Gong Z, Schwieters CD, Tang C. Theory and practice of using solvent paramagnetic relaxation enhancement to characterize protein conformational dynamics. Methods 2018; 148:48-56. [PMID: 29656079 DOI: 10.1016/j.ymeth.2018.04.006] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 03/19/2018] [Accepted: 04/06/2018] [Indexed: 01/01/2023] Open
Abstract
Paramagnetic relaxation enhancement (PRE) has been established as a powerful tool in NMR for investigating protein structure and dynamics. The PRE is usually measured with a paramagnetic probe covalently attached at a specific site of an otherwise diamagnetic protein. The present work provides the numerical formulation for probing protein structure and conformational dynamics based on the solvent PRE (sPRE) measurement, using two alternative approaches. An inert paramagnetic cosolute randomly collides with the protein, and the resulting sPRE manifests the relative solvent exposure of protein nuclei. To make the back-calculated sPRE values most consistent with the observed values, the protein structure is either refined against the sPRE, or an ensemble of conformers is selected from a pre-generated library using a Monte Carlo algorithm. The ensemble structure comprises either N conformers of equal occupancy, or two conformers with different relative populations. We demonstrate the sPRE method using GB1, a structurally rigid protein, and calmodulin, a protein comprising two domains and existing in open and closed states. The sPRE can be computed with a stand-alone program for rapid evaluation, or with the invocation of a module in the latest release of the structure calculation software Xplor-NIH. As a label-free method, the sPRE measurement can be readily integrated with other biophysical techniques. The current limitations of the sPRE method are also discussed, regarding accurate measurement and theoretical calculation, model selection and suitable timescale.
Collapse
Affiliation(s)
- Zhou Gong
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, and National Center for Magnetic Resonance at Wuhan, Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, Wuhan, Hubei Province 430071, China
| | - Charles D Schwieters
- Office of Intramural Research, Center for Information Technology, National Institutes of Health, Building 12A, Bethesda, MD 20892, United States
| | - Chun Tang
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, and National Center for Magnetic Resonance at Wuhan, Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, Wuhan, Hubei Province 430071, China.
| |
Collapse
|
12
|
Flügge F, Peters T. Complete assignment of Ala, Ile, Leu, Met and Val methyl groups of human blood group A and B glycosyltransferases using lanthanide-induced pseudocontact shifts and methyl-methyl NOESY. J Biomol NMR 2018; 70:245-259. [PMID: 29700756 DOI: 10.1007/s10858-018-0183-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/28/2018] [Accepted: 04/21/2018] [Indexed: 05/05/2023]
Abstract
Human blood group A and B glycosyltransferases (GTA, GTB) are highly homologous glycosyltransferases. A number of high-resolution crystal structures is available showing that these enzymes convert from an open conformation into a catalytically active closed conformation upon substrate binding. However, the mechanism of glycosyltransfer is still under debate, and the precise nature as well as the time scales of conformational transitions are unknown. NMR offers a variety of experiments to shine more light on these unresolved questions. Therefore, in a first step we have assigned all methyl resonance signals in MILVA labeled samples of GTA and GTB, still a challenging task for 70 kDa homodimeric proteins. Assignments were obtained from methyl-methyl NOESY experiments, and from measurements of lanthanide-induced pseudocontact shifts (PCS) using high resolution crystal structures as templates. PCSs and chemical shift perturbations, induced by substrate analogue binding, suggest that the fully closed state is not adopted in the presence of lanthanide ions.
Collapse
Affiliation(s)
- Friedemann Flügge
- Institute for Chemistry and Metabolomics, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany
| | - Thomas Peters
- Institute for Chemistry and Metabolomics, Center for Structural and Cell Biology in Medicine, University of Lübeck, Ratzeburger Allee 160, 23562, Lübeck, Germany.
| |
Collapse
|
13
|
Olivieri C, Subrahmanian MV, Xia Y, Kim J, Porcelli F, Veglia G. Simultaneous detection of intra- and inter-molecular paramagnetic relaxation enhancements in protein complexes. J Biomol NMR 2018; 70:133-140. [PMID: 29396770 PMCID: PMC6029865 DOI: 10.1007/s10858-018-0165-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2017] [Accepted: 01/19/2018] [Indexed: 05/16/2023]
Abstract
Paramagnetic relaxation enhancement (PRE) measurements constitute a powerful approach for detecting both permanent and transient protein-protein interactions. Typical PRE experiments require an intrinsic or engineered paramagnetic site on one of the two interacting partners; while a second, diamagnetic binding partner is labeled with stable isotopes (15N or 13C). Multiple paramagnetic labeled centers or reversed labeling schemes are often necessary to obtain sufficient distance restraints to model protein-protein complexes, making this approach time consuming and expensive. Here, we show a new strategy that combines a modified pulse sequence (1HN-Γ2-CCLS) with an asymmetric labeling scheme to enable the detection of both intra- and inter-molecular PREs simultaneously using only one sample preparation. We applied this strategy to the non-covalent dimer of ubiquitin. Our method confirmed the previously identified binding interface for the transient di-ubiquitin complex, and at the same time, unveiled the internal structural dynamics rearrangements of ubiquitin upon interaction. In addition to reducing the cost of sample preparation and speed up PRE measurements, by detecting the intra-molecular PRE this new strategy will make it possible to measure and calibrate inter-molecular distances more accurately for both symmetric and asymmetric protein-protein complexes.
Collapse
Affiliation(s)
- Cristina Olivieri
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
- DIBAF - University of Tuscia - Largo dell'Università, Blocco D, 01100, Viterbo, Italy
| | - Manu Veliparambil Subrahmanian
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
| | - Youlin Xia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
- Department of Structural Biology, St Jude Children's Research Hospital, Memphis, TN, 38105, USA
| | - Jonggul Kim
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
- Department of Chemistry, University of Minnesota, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA
| | - Fernando Porcelli
- DIBAF - University of Tuscia - Largo dell'Università, Blocco D, 01100, Viterbo, Italy
| | - Gianluigi Veglia
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA.
- Department of Chemistry, University of Minnesota, 6-155 Jackson Hall, 321 Church St SE, Minneapolis, MN, 55455, USA.
| |
Collapse
|
14
|
Koroloff SN, Tesch DM, Awosanya EO, Nevzorov AA. Sensitivity enhancement for membrane proteins reconstituted in parallel and perpendicular oriented bicelles obtained by using repetitive cross-polarization and membrane-incorporated free radicals. J Biomol NMR 2017; 67:135-144. [PMID: 28205016 DOI: 10.1007/s10858-017-0090-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
Multidimensional separated local-field and spin-exchange experiments employed by oriented-sample solid-state NMR are essential for structure determination and spectroscopic assignment of membrane proteins reconstituted in macroscopically aligned lipid bilayers. However, these experiments typically require a large number of scans in order to establish interspin correlations. Here we have shown that a combination of optimized repetitive cross polarization (REP-CP) and membrane-embedded free radicals allows one to enhance the signal-to-noise ratio by factors 2.4-3.0 in the case of Pf1 coat protein reconstituted in magnetically aligned bicelles with their normals being either parallel or perpendicular to the main magnetic field. Notably, spectral resolution is not affected at the 2:1 radical-to-protein ratio. Spectroscopic assignment of Pf1 coat protein in the parallel bicelles has been established as an illustration of the method. The proposed methodology will advance applications of oriented-sample NMR technique when applied to samples containing smaller quantities of proteins and three-dimensional experiments.
Collapse
Affiliation(s)
- Sophie N Koroloff
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA
| | - Deanna M Tesch
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA
- Shaw University, 118 E. South Street, Raleigh, NC, 27601, USA
| | - Emmanuel O Awosanya
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA
| | - Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA.
| |
Collapse
|
15
|
Sjodt M, Clubb RT. Nitroxide Labeling of Proteins and the Determination of Paramagnetic Relaxation Derived Distance Restraints for NMR Studies. Bio Protoc 2017; 7:e2207. [PMID: 28616445 DOI: 10.21769/bioprotoc.2207] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Site-specific attachment of paramagnetic spin labels to biomolecules causes distance-dependent line-broadening effects, which can be exploited to study the structure and dynamics of these molecules in solution. This protocol describes how to attach nitroxide spin labels to proteins and how to collect and analyze NMR data using these labeled samples. We also explain how to derive distance restraints for paramagnetic relaxation enhancement nuclear magnetic resonance (PRE-NMR) studies.
Collapse
Affiliation(s)
- Megan Sjodt
- Department of Chemistry and Biochemistry, UCLA-DOE Institute of Genomics and Proteomics and Molecular Biology Institute, University of California, Los Angeles, USA
| | - Robert T Clubb
- Department of Chemistry and Biochemistry, UCLA-DOE Institute of Genomics and Proteomics and Molecular Biology Institute, University of California, Los Angeles, USA
| |
Collapse
|
16
|
Abstract
NMR spectroscopy is a well-established technique to determine the structure of peptides and small proteins in solution, also when bound to detergent micelles or phospholipid bicelles. The structure of the peptide alone is, however, not conveying the full picture, if the peptide is bound to a micelle, since it does not tell anything about the orientation of the peptide in the micelle. This article describes how to obtain that information together with information on peptide structure.
Collapse
Affiliation(s)
- Reinhard Wimmer
- Department of Chemistry and Bioscience, University of Aalborg, Frederik Bajers vej 7H, 9220, Aalborg, Denmark.
| | - Lars Erik Uggerhøj
- Department of Chemistry and Bioscience, University of Aalborg, Frederik Bajers vej 7H, 9220, Aalborg, Denmark
| |
Collapse
|
17
|
Marcink TC, Koppisetti RK, Fulcher YG, Van Doren SR. Mapping Lipid Bilayer Recognition Sites of Metalloproteinases and Other Prospective Peripheral Membrane Proteins. Methods Mol Biol 2017; 1579:61-86. [PMID: 28299733 DOI: 10.1007/978-1-4939-6863-3_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Peripheral binding of proteins to lipid bilayers is critical not only in intracellular signaling but also in metalloproteinase shedding of signaling proteins from cell surfaces. Assessment of how proteins recognize fluid bilayers peripherally using crystallography or structure-based predictions has been important but incomplete. Assay of dynamic protein-bilayer interactions in solution has become feasible and reliable using paramagnetic NMR and site-directed fluor labeling. Details of preparations and assay protocols for these spectroscopic measurements of bilayer proximity or contact, respectively, are described.
Collapse
Affiliation(s)
- Tara C Marcink
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO, 65211, USA
| | - Rama K Koppisetti
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO, 65211, USA
- Department of Medical Microbiology and Immunology, Life Sciences Center, University of Missouri, Columbia, MO, 65211, USA
| | - Yan G Fulcher
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO, 65211, USA
| | - Steven R Van Doren
- Department of Biochemistry, University of Missouri, 117 Schweitzer Hall, Columbia, MO, 65211, USA.
| |
Collapse
|
18
|
Ceccon A, Marius Clore G, Tugarinov V. Towards interpretation of intermolecular paramagnetic relaxation enhancement outside the fast exchange limit. J Biomol NMR 2016; 66:1-7. [PMID: 27558624 DOI: 10.1007/s10858-016-0053-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2016] [Accepted: 08/12/2016] [Indexed: 06/06/2023]
Abstract
In an exchanging system between major and minor species, the transverse paramagnetic relaxation enhancement rate observed on the resonances of the major species (Γ 2 (app) ) is dependent upon the exchange regime between the species. Quantitative analysis of PRE data in such systems typically assumes that the overall exchange rate k ex between the species is fast on the PRE time scale (k ex ≫ Γ2). Recently, we have characterized the kinetics of binding of the model protein ubiquitin to large (LUV) and small (SUV) unilamellar lipid-based nanoparticles or liposomes (Ceccon A, Tugarinov V, Bax A, Clore GM (2016). J Am Chem Soc 138:5789-5792). Building upon these results and taking advantage of a strong paramagnetic agent with an isotropic g-tensor, Gd(3+), we were able to measure intermolecular methyl carbon and proton PREs between paramagnetically-tagged liposomes and ubiquitin. In the limit of fast exchange (k ex ≫ Γ2) the ratio of the apparent proton to carbon methyl PREs, ((1)Hm-Γ 2 (app) )/((13)Cm-Γ 2 (app) ), is equal to the square of the ratio of the gyromagnetic ratios of the two nuclei, (γΗ/γC)(2). However, outside the fast exchange regime, under intermediate exchange conditions (e.g. when Γ2 is comparable in magnitude to k ex) the ((1)Hm-Γ 2 (app) )/((13)Cm-Γ 2 (app) ) ratio provides a reliable measure of the 'true' methyl PREs.
Collapse
Affiliation(s)
- Alberto Ceccon
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| | - Vitali Tugarinov
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD, 20892-0520, USA.
| |
Collapse
|
19
|
Abstract
NMR interchain paramagnetic relaxation enhancement (PRE) techniques are a very powerful approach for detecting transient interchain interactions between intrinsically disordered proteins. These experiments, requiring a mixed sample containing a 1:1 ratio of isotope-labeled (15)N protein and natural abundance (14)N protein with a paramagnetic spin label, provide data that is limited to interchain interactions only. Application of these experiments to weakly associated transient species such as those that are present in the very early stages of self-assembly processes will aid our understanding of protein aggregation or fibril formation processes.
Collapse
Affiliation(s)
- Maria K Janowska
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA
| | - Jean Baum
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ, 08854, USA.
- Center for Integrative Proteomics Research, Rutgers University, 174 Frelinghuysen Road, Piscataway, NJ, 08854-8076, USA.
| |
Collapse
|
20
|
Baltisberger JH, Florian P, Keeler EG, Phyo PA, Sanders KJ, Grandinetti PJ. Modifier cation effects on (29)Si nuclear shielding anisotropies in silicate glasses. J Magn Reson 2016; 268:95-106. [PMID: 27187210 DOI: 10.1016/j.jmr.2016.05.003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/20/2015] [Revised: 04/29/2016] [Accepted: 05/08/2016] [Indexed: 05/06/2023]
Abstract
We have examined variations in the (29)Si nuclear shielding tensor parameters of SiO4 tetrahedra in a series of seven alkali and alkaline earth silicate glass compositions, Cs2O·4.81 SiO2, Rb2O·3.96 SiO2, Rb2O·2.25 SiO2, K2O·4.48 SiO2, Na2O·4.74 SiO2, BaO·2.64 SiO2, and SrO·2.36 SiO2, using natural abundance (29)Si two-dimensional magic-angle flipping (MAF) experiments. Our analyses of these 2D spectra reveal a linear dependence of the (29)Si nuclear shielding anisotropy of Q((3)) sites on the Si-non-bridging oxygen bond length, which in turn depends on the cation potential and coordination of modifier cations to the non-bridging oxygen. We also demonstrate how a combination of Cu(2+) as a paramagnetic dopant combined with echo train acquisition can reduce the total experiment time of (29)Si 2D NMR measurements by two orders of magnitude, enabling higher throughput 2D NMR studies of glass structure.
Collapse
Affiliation(s)
- Jay H Baltisberger
- Division of Natural Science, Mathematics, and Nursing, Berea College, Berea, KY 40403, United States
| | - Pierre Florian
- CNRS, UPR3079 CEMHTI, 1D Avenue de la Recherche Scientifique, 45071 Orléans Cedex 2, France
| | - Eric G Keeler
- Department of Chemistry and Francis Bitter Magnet Laboratory, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA 02139, United States
| | - Pyae A Phyo
- Division of Natural Science, Mathematics, and Nursing, Berea College, Berea, KY 40403, United States
| | - Kevin J Sanders
- Institut des Sciences Analytiques (CNRS, ENS de Lyon, UCB Lyon 1), Université de Lyon, 5 rue de la Doua, 69100 Villeurbanne, France
| | - Philip J Grandinetti
- Department of Chemistry, The Ohio State University, 120 W. 18(th) Avenue, Columbus, OH 43210-1173, United States.
| |
Collapse
|
21
|
Palamara J, Seidel K, Moini A, Prasad S. Ion distribution in copper exchanged zeolites by using Si-29 spin lattice relaxation analysis. J Magn Reson 2016; 267:9-14. [PMID: 27055207 DOI: 10.1016/j.jmr.2016.03.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/03/2016] [Revised: 03/29/2016] [Accepted: 03/30/2016] [Indexed: 06/05/2023]
Abstract
Transition metal-containing zeolites, particularly those with smaller pore size, have found extensive application in the selective catalytic reduction (SCR) of environmental pollutants containing nitrogen oxides. We report these zeolites have dramatically faster silicon-29 (Si-29) spin lattice relaxation times (T1) compared to their sodium-containing counterparts. Paramagnetic doping allows one to acquire Si-29 MAS spectra in the order of tens of seconds without significantly affecting the spectral resolution. Moreover, relaxation times depend on the method of preparation and the next-nearest neighbor silicon Qn(mAl) sites, where n=4 and m=0-4, respectively. A clear trend is noted between the effectiveness of Cu exchange and the Si-29 NMR relaxation times. It is anticipated that the availability of this tool, and the enhanced understanding of the nature of the active sites, will provide the means for designing improved SCR catalysts.
Collapse
|
22
|
Schilder J, Ubbink M. Weak self-association of cytochrome c peroxidase molecules observed by paramagnetic NMR. J Biomol NMR 2016; 65:29-40. [PMID: 27236778 PMCID: PMC4908164 DOI: 10.1007/s10858-016-0035-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/22/2016] [Accepted: 05/03/2016] [Indexed: 06/05/2023]
Abstract
There is growing experimental evidence that many proteins exhibit a tendency for (ultra)weak homo- or hetero- oligomerization interactions. With the development of paramagnetic relaxation enhancement NMR spectroscopy it has become possible to characterize weak complexes experimentally and even detect complexes with affinities in the 1-25 mM range. We present evidence for a weak complex between cytochrome c peroxidase (CcP) molecules. In a previous study, we attached nitroxide based spin labels at three positions on CcP with the intent of observing intramolecular PRE effects. However, several intermolecular PRE effects were also observed suggesting a weak self-association between CcP molecules. The CcP-CcP complex was characterized using paramagnetic NMR and protein docking. The interaction occurs between the surface that is also part of the stereo-specific binding site for its physiological partner, cytochrome c (Cc), and several small, positively charged patches on the "back" of CcP. The CcP-CcP complex is not a stereo-specific complex. It is a dynamic ensemble of orientations, characteristic of an encounter state. The contact areas resemble those observed for CcP molecules in crystals. The CcP-CcP complex formation competes with that of the CcP-Cc complex. However, the affinity for Cc is much larger and thus it is expected that, under physiological conditions, auto-inhibition will be limited. A weak self-association between cytochrome c peroxidase molecules was characterized using paramagnetic NMR.
Collapse
Affiliation(s)
- Jesika Schilder
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
| | - Marcellus Ubbink
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands.
| |
Collapse
|
23
|
Liao SY, Lee M, Wang T, Sergeyev IV, Hong M. Efficient DNP NMR of membrane proteins: sample preparation protocols, sensitivity, and radical location. J Biomol NMR 2016; 64:223-37. [PMID: 26873390 PMCID: PMC4826309 DOI: 10.1007/s10858-016-0023-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 02/07/2016] [Indexed: 05/04/2023]
Abstract
Although dynamic nuclear polarization (DNP) has dramatically enhanced solid-state NMR spectral sensitivities of many synthetic materials and some biological macromolecules, recent studies of membrane-protein DNP using exogenously doped paramagnetic radicals as polarizing agents have reported varied and sometimes surprisingly limited enhancement factors. This motivated us to carry out a systematic evaluation of sample preparation protocols for optimizing the sensitivity of DNP NMR spectra of membrane-bound peptides and proteins at cryogenic temperatures of ~110 K. We show that mixing the radical with the membrane by direct titration instead of centrifugation gives a significant boost to DNP enhancement. We quantify the relative sensitivity enhancement between AMUPol and TOTAPOL, two commonly used radicals, and between deuterated and protonated lipid membranes. AMUPol shows ~fourfold higher sensitivity enhancement than TOTAPOL, while deuterated lipid membrane does not give net higher sensitivity for the membrane peptides than protonated membrane. Overall, a ~100 fold enhancement between the microwave-on and microwave-off spectra can be achieved on lipid-rich membranes containing conformationally disordered peptides, and absolute sensitivity gains of 105-160 can be obtained between low-temperature DNP spectra and high-temperature non-DNP spectra. We also measured the paramagnetic relaxation enhancement of lipid signals by TOTAPOL and AMUPol, to determine the depths of these two radicals in the lipid bilayer. Our data indicate a bimodal distribution of both radicals, a surface-bound fraction and a membrane-bound fraction where the nitroxides lie at ~10 Å from the membrane surface. TOTAPOL appears to have a higher membrane-embedded fraction than AMUPol. These results should be useful for membrane-protein solid-state NMR studies under DNP conditions and provide insights into how biradicals interact with phospholipid membranes.
Collapse
Affiliation(s)
- Shu Y Liao
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Myungwoon Lee
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Tuo Wang
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | | | - Mei Hong
- Department of Chemistry, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA.
| |
Collapse
|
24
|
Yang Y, Huang F, Huber T, Su XC. Site-specific tagging proteins with a rigid, small and stable transition metal chelator, 8-hydroxyquinoline, for paramagnetic NMR analysis. J Biomol NMR 2016; 64:103-113. [PMID: 26732873 DOI: 10.1007/s10858-016-0011-7] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2015] [Accepted: 01/01/2016] [Indexed: 06/05/2023]
Abstract
Design of a paramagnetic metal binding motif in a protein is a valuable way for understanding the function, dynamics and interactions of a protein by paramagnetic NMR spectroscopy. Several strategies have been proposed to site-specifically tag proteins with paramagnetic lanthanide ions. Here we report a simple approach of engineering a transition metal binding motif via site-specific labelling of a protein with 2-vinyl-8-hydroxyquinoline (2V-8HQ). The protein-2V-8HQ adduct forms a stable complex with transition metal ions, Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). The paramagnetic effects generated by these transition metal ions were evaluated by NMR spectroscopy. We show that 2V-8HQ is a rigid and stable transition metal binding tag. The coordination of the metal ion can be assisted by protein sidechains. More importantly, tunable paramagnetic tensors are simply obtained in an α-helix that possesses solvent exposed residues in positions i and i + 3, where i is the residue to be mutated to cysteine, i + 3 is Gln or Glu or i - 4 is His. The coordination of a sidechain carboxylate/amide or imidazole to cobalt(II) results in different structural geometries, leading to different paramagnetic tensors as shown by experimental data.
Collapse
Affiliation(s)
- Yin Yang
- State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China
| | - Feng Huang
- State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China
| | - Thomas Huber
- Research School of Chemistry, Australian National University, Canberra, ACT, 0200, Australia
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-Organic Chemistry, Collaborative Innovation Center of Chemical Science and Engineering (Tianjin), Nankai University, Tianjin, 300071, China.
| |
Collapse
|
25
|
Tamaki H, Egawa A, Kido K, Kameda T, Kamiya M, Kikukawa T, Aizawa T, Fujiwara T, Demura M. Structure determination of uniformly (13)C, (15)N labeled protein using qualitative distance restraints from MAS solid-state (13)C-NMR observed paramagnetic relaxation enhancement. J Biomol NMR 2016; 64:87-101. [PMID: 26728076 DOI: 10.1007/s10858-015-0010-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2015] [Accepted: 12/29/2015] [Indexed: 06/05/2023]
Abstract
Magic angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) is a powerful method for structure determination of insoluble biomolecules. However, structure determination by MAS solid-state NMR remains challenging because it is difficult to obtain a sufficient amount of distance restraints owing to spectral complexity. Collection of distance restraints from paramagnetic relaxation enhancement (PRE) is a promising approach to alleviate this barrier. However, the precision of distance restraints provided by PRE is limited in solid-state NMR because of incomplete averaged interactions and intermolecular PREs. In this report, the backbone structure of the B1 domain of streptococcal protein G (GB1) has been successfully determined by combining the CS-Rosetta protocol and qualitative PRE restraints. The derived structure has a Cα RMSD of 1.49 Å relative to the X-ray structure. It is noteworthy that our protocol can determine the correct structure from only three cysteine-EDTA-Mn(2+) mutants because this number of PRE sites is insufficient when using a conventional structure calculation method based on restrained molecular dynamics and simulated annealing. This study shows that qualitative PRE restraints can be employed effectively for protein structure determination from a limited conformational sampling space using a protein fragment library.
Collapse
Affiliation(s)
- Hajime Tamaki
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Ayako Egawa
- Institute for Protein Research, Osaka University, Osaka, Japan
| | - Kouki Kido
- Graduate School of Life Science, Hokkaido University, Sapporo, Japan
| | - Tomoshi Kameda
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Tokyo, Japan
| | - Masakatsu Kamiya
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Takashi Kikukawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | - Tomoyasu Aizawa
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan
| | | | - Makoto Demura
- Faculty of Advanced Life Science, Hokkaido University, Sapporo, Japan.
| |
Collapse
|
26
|
Abstract
In this brief review, we summarize various aspects of NMR paramagnetic relaxation enhancement (PRE). We discuss the types of spin labels used in NMR studies, describe the relevant theory used to accurately calculate PREs from coordinates, including how to take into account the fact that paramagnetic labels tend to be highly mobile and sample a wide range of conformational space, and outline methods to refine structures or ensembles of structures directly against PRE data using simulated annealing. Finally, we show how the PRE can be used to detect, characterize, and visualize sparsely populated states of proteins and their complexes that are invisible to all other biophysical techniques.
Collapse
|
27
|
Duss O, Diarra Dit Konté N, Allain FHT. Cut and paste RNA for nuclear magnetic resonance, paramagnetic resonance enhancement, and electron paramagnetic resonance structural studies. Methods Enzymol 2015; 565:537-62. [PMID: 26577744 DOI: 10.1016/bs.mie.2015.05.029] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
RNA is a crucial regulator involved in most molecular processes of life. Understanding its function at the molecular level requires high-resolution structural information. However, the dynamic nature of RNA complicates structure determination because crystallization is often not possible or can result in crystal-packing artifacts resulting in nonnative structures. To study RNA and its complexes in solution, we described an approach in which large multi-domain RNA or protein-RNA complex structures can be determined at high resolution from isolated domains determined by nuclear magnetic resonance (NMR) spectroscopy, and then constructing the entire macromolecular structure using electron paramagnetic resonance (EPR) long-range distance constraints. Every step in this structure determination approach requires different types of isotope or spin-labeled RNAs. Here, we present a simple modular RNA cut and paste approach including protocols to generate (1) small isotopically labeled RNAs (<10 nucleotides) for NMR structural studies, which cannot be obtained by standard protocols, (2) large segmentally isotope and/or spin-labeled RNAs for diamagnetic NMR and paramagnetic relaxation enhancement NMR, and (3) large spin-labeled RNAs for pulse EPR spectroscopy.
Collapse
Affiliation(s)
- Olivier Duss
- Institute for Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland.
| | | | - Frédéric H-T Allain
- Institute for Molecular Biology and Biophysics, ETH Zürich, Zürich, Switzerland.
| |
Collapse
|
28
|
Liu Z, Gong Z, Dong X, Tang C. Transient protein-protein interactions visualized by solution NMR. Biochim Biophys Acta 2015; 1864:115-22. [PMID: 25896389 DOI: 10.1016/j.bbapap.2015.04.009] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2015] [Revised: 04/09/2015] [Accepted: 04/10/2015] [Indexed: 01/18/2023]
Abstract
Proteins interact with each other to establish their identities in cell. The affinities for the interactions span more than ten orders of magnitude, and KD values in μM-mM regimen are considered transient and are important in cell signaling. Solution NMR including diamagnetic and paramagnetic techniques has enabled atomic-resolution depictions of transient protein-protein interactions. Diamagnetic NMR allows characterization of protein complexes with KD values up to several mM, whereas ultraweak and fleeting complexes can be modeled with the use of paramagnetic NMR especially paramagnetic relaxation enhancement (PRE). When tackling ever-larger protein complexes, PRE can be particularly useful in providing long-range intermolecular distance restraints. As NMR measurements are averaged over the ensemble of complex structures, structural information for dynamic protein-protein interactions besides the stereospecific one can often be extracted. Herein the protein interaction dynamics are exemplified by encounter complexes, alternative binding modes, and coupled binding/folding of intrinsically disordered proteins. Further integration of NMR with other biophysical techniques should allow better visualization of transient protein-protein interactions. In particular, single-molecule data may facilitate the interpretation of ensemble-averaged NMR data. Though same structures of proteins and protein complexes were found in cell as in diluted solution, we anticipate that the dynamics of transient protein protein-protein interactions be different, which awaits awaits exploration by NMR. This article is part of a Special Issue entitled: Physiological Enzymology and Protein Functions. This article is part of a Special Issue entitled: Physiological Enzymology and Protein Functions.
Collapse
Affiliation(s)
- Zhu Liu
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, Wuhan, Hubei Province 430071, China; Department of Pharmacology, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province 310028, China; Institute of Neuroscience, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province 310028, China
| | - Zhou Gong
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, Wuhan, Hubei Province 430071, China
| | - Xu Dong
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, Wuhan, Hubei Province 430071, China
| | - Chun Tang
- CAS Key Laboratory of Magnetic Resonance in Biological Systems, State Key Laboratory of Magnetic Resonance and Atomic Molecular Physics, Wuhan Institute of Physics and Mathematics of the Chinese Academy of Sciences, Wuhan, Hubei Province 430071, China.
| |
Collapse
|
29
|
Abstract
Paramagnetism-based nuclear pseudocontact shifts and spin relaxation enhancements contain a wealth of information in solid-state NMR spectra about electron-nucleus distances on the ∼20 Å length scale, far beyond that normally probed through measurements of nuclear dipolar couplings. Such data are especially vital in the context of structural studies of proteins and other biological molecules that suffer from a sparse number of experimentally-accessible atomic distances constraining their three-dimensional fold or intermolecular interactions. This perspective provides a brief overview of the recent developments and applications of paramagnetic magic-angle spinning NMR to biological systems, with primary focus on the investigations of metalloproteins and natively diamagnetic proteins modified with covalent paramagnetic tags.
Collapse
Affiliation(s)
- Christopher P Jaroniec
- Department of Chemistry and Biochemistry, The Ohio State University, 100 West 18th Avenue, Columbus, OH 43210, USA.
| |
Collapse
|
30
|
Columbus L, Kroncke B. Solution NMR Structure Determination of Polytopic α-Helical Membrane Proteins: A Guide to Spin Label Paramagnetic Relaxation Enhancement Restraints. Methods Enzymol 2015; 557:329-48. [PMID: 25950972 DOI: 10.1016/bs.mie.2014.12.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
Solution nuclear magnetic resonance structures of polytopic α-helical membrane proteins require additional restraints beyond the traditional Nuclear Overhauser Effect (NOE) restraints. Several methods have been developed and this review focuses on paramagnetic relaxation enhancement (PRE). Important aspects of spin labeling, PRE measurements, structure calculations, and structural quality are discussed.
Collapse
|
31
|
Mroue KH, Zhang R, Zhu P, McNerny E, Kohn DH, Morris MD, Ramamoorthy A. Acceleration of natural-abundance solid-state MAS NMR measurements on bone by paramagnetic relaxation from gadolinium-DTPA. J Magn Reson 2014; 244:90-7. [PMID: 24881032 PMCID: PMC4094129 DOI: 10.1016/j.jmr.2014.04.020] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2014] [Revised: 03/27/2014] [Accepted: 04/27/2014] [Indexed: 05/05/2023]
Abstract
Reducing the data collection time without affecting the signal intensity and spectral resolution is one of the major challenges for the widespread application of multidimensional nuclear magnetic resonance (NMR) spectroscopy, especially in experiments conducted on complex heterogeneous biological systems such as bone. In most of these experiments, the NMR data collection time is ultimately governed by the proton spin-lattice relaxation times (T1). For over two decades, gadolinium(III)-DTPA (Gd-DTPA, DTPA=Diethylene triamine pentaacetic acid) has been one of the most widely used contrast-enhancement agents in magnetic resonance imaging (MRI). In this study, we demonstrate that Gd-DTPA can also be effectively used to enhance the longitudinal relaxation rates of protons in solid-state NMR experiments conducted on bone without significant line-broadening and chemical-shift-perturbation side effects. Using bovine cortical bone samples incubated in different concentrations of Gd-DTPA complex, the (1)H T1 values were calculated from data collected by (1)H spin-inversion recovery method detected in natural-abundance (13)C cross-polarization magic angle spinning (CPMAS) NMR experiments. Our results reveal that the (1)H T1 values can be successfully reduced by a factor of 3.5 using as low as 10mM Gd-DTPA without reducing the spectral resolution and thus enabling faster data acquisition of the (13)C CPMAS spectra. These results obtained from (13)C-detected CPMAS experiments were further confirmed using (1)H-detected ultrafast MAS experiments on Gd-DTPA doped bone samples. This approach considerably improves the signal-to-noise ratio per unit time of NMR experiments applied to bone samples by reducing the experimental time required to acquire the same number of scans.
Collapse
Affiliation(s)
- Kamal H Mroue
- Biophysics, The University of Michigan, Ann Arbor, MI 48109-1055, United States; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Rongchun Zhang
- Biophysics, The University of Michigan, Ann Arbor, MI 48109-1055, United States; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States; School of Physics, Nankai University, Tianjin 300071, PR China
| | - Peizhi Zhu
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Erin McNerny
- School of Dentistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - David H Kohn
- School of Dentistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Michael D Morris
- Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States
| | - Ayyalusamy Ramamoorthy
- Biophysics, The University of Michigan, Ann Arbor, MI 48109-1055, United States; Department of Chemistry, The University of Michigan, Ann Arbor, MI 48109-1055, United States.
| |
Collapse
|
32
|
Schilder J, Löhr F, Schwalbe H, Ubbink M. The cytochrome c peroxidase and cytochrome c encounter complex: the other side of the story. FEBS Lett 2014; 588:1873-8. [PMID: 24726731 DOI: 10.1016/j.febslet.2014.03.055] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 03/18/2014] [Accepted: 03/26/2014] [Indexed: 11/18/2022]
Abstract
Formation of an encounter complex is important for efficient protein complex formation. The encounter state consists of an ensemble of orientations of two proteins in the complex. Experimental description of such ensembles inherently suffers from insufficient data availability. We have measured paramagnetic relaxation enhancements (PRE) on cytochrome c peroxidase (CcP) caused by its partner cytochrome c (Cc) carrying a spin label. The data complement earlier PRE data of spin labelled CcP, identifying several new interactions. This work demonstrates the need of obtaining as many independent data sets as possible to achieve the most accurate description of an encounter complex.
Collapse
Affiliation(s)
- Jesika Schilder
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Frank Löhr
- Institute of Biophysical Chemistry, Goethe University Frankfurt and Centre for Biomolecular Magnetic Resonance, Max-von-Laue Strasse 9, 60438 Frankfurt am Main, Germany
| | - Harald Schwalbe
- Institute of Organic Chemistry and Chemical Biology, Goethe University Frankfurt and Centre for Biomolecular Magnetic Resonance, Max-von-Laue Strasse 7, 60438 Frankfurt am Main, Germany
| | - Marcellus Ubbink
- Leiden Institute of Chemistry, Gorlaeus Laboratories, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands.
| |
Collapse
|
33
|
Tesch DM, Nevzorov AA. Sensitivity enhancement and contrasting information provided by free radicals in oriented-sample NMR of bicelle-reconstituted membrane proteins. J Magn Reson 2014; 239:9-15. [PMID: 24355622 DOI: 10.1016/j.jmr.2013.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/13/2013] [Accepted: 11/18/2013] [Indexed: 06/03/2023]
Abstract
Elucidating structure and topology of membrane proteins (MPs) is essential for unveiling functionality of these important biological constituents. Oriented-sample solid-state NMR (OS-NMR) is capable of providing such information on MPs under nearly physiological conditions. However, two dimensional OS-NMR experiments can take several days to complete due to long longitudinal relaxation times combined with the large number of scans to achieve sufficient signal sensitivity in biological samples. Here, free radicals 5-DOXYL stearic acid, TEMPOL, and CAT-1 were added to uniformly (15)N-labeled Pf1 coat protein reconstituted in DMPC/DHPC bicelles, and their effect on the longitudinal relaxation times (T1Z) was investigated. The dramatically shortened T1Z's allowed for the signal gain per unit time to be used for either: (i) up to a threefold reduction of the total experimental time at 99% magnetization recovery or (ii) obtaining up to 74% signal enhancement between the control and radical samples during constant experimental time at "optimal" relaxation delays. In addition, through OS-NMR and high-field EPR studies, free radicals were able to provide positional constraints in the bicelle system, which provide a description of the location of each residue in Pf1 coat protein within the bicellar membranes. This information can be useful in the determination of oligomerization states and immersion depths of larger membrane proteins.
Collapse
Affiliation(s)
- Deanna M Tesch
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
| |
Collapse
|
34
|
Clore GM. Interplay between conformational selection and induced fit in multidomain protein-ligand binding probed by paramagnetic relaxation enhancement. Biophys Chem 2013; 186:3-12. [PMID: 24070540 DOI: 10.1016/j.bpc.2013.08.006] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2013] [Revised: 08/24/2013] [Accepted: 08/24/2013] [Indexed: 11/29/2022]
Abstract
The binding of ligands and substrates to proteins has been extensively studied for many years and can be described, in its simplest form, by two limiting mechanisms: conformational selection and induced fit. Conformational selection involves the binding of ligand to a pre-existing sparsely-populated conformation of the free protein that is the same as that in the final protein-ligand complex. In the case of induced fit, the ligand binds to the major conformation of the free protein and only subsequent to binding undergoes a conformational change to the final protein-ligand complex. While these two mechanisms can be dissected and distinguished by transient kinetic measurements, direct direction, characterization and visualization of transient, sparsely-populated states of proteins are experimentally challenging. Unless trapped, sparsely-populated states are generally invisible to conventional structural and biophysical techniques, including crystallography and most NMR measurements. In this review we summarize some recent developments in the use of paramagnetic relaxation enhancement to directly study sparsely-populated states of proteins and illustrate the application of this approach to two proteins, maltose binding protein and calmodulin, both of which undergo large rigid body conformational rearrangements upon ligand binding from an open apo state to a closed ligand-bound holo state. We show that the apo state ensemble comprises a small population of partially-closed configurations that are similar but not identical to that of the holo state. These results highlight the complementarity and interplay of induced fit and conformational selection and suggest that the existence of partially-closed states in the absence of ligand facilitates the transition to the closed ligand-bound state.
Collapse
Affiliation(s)
- G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520, USA.
| |
Collapse
|