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Abstract
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Thanks to recent
improvements in NMR spectrometer hardware and
pulse sequence design, modern 13C NMR has become a useful
tool for biomolecular applications. The complete assignment of a protein
can be accomplished by using 13C detected multinuclear
experiments and it can provide unique information relevant for the
study of a variety of different biomolecules including paramagnetic
proteins and intrinsically disordered proteins. A wide range of NMR
observables can be measured, concurring to the structural and dynamic
characterization of a protein in isolation, as part of a larger complex,
or even inside a living cell. We present the different properties
of 13C with respect to 1H, which provide the
rationale for the experiments developed and their application, the
technical aspects that need to be faced, and the many experimental
variants designed to address different cases. Application areas where
these experiments successfully complement proton NMR are also described.
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Affiliation(s)
- Isabella C Felli
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (Florence), Italy
| | - Roberta Pierattelli
- Department of Chemistry "Ugo Schiff" and Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (Florence), Italy
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2
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Yoshimura Y, So M, Miyanoiri Y. Carbonyl 13C-detect solution-state protein NMR experiments to circumvent amide-solvent exchange broadening: Application to β 2-microglobulin. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1869:140593. [PMID: 33359410 DOI: 10.1016/j.bbapap.2020.140593] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 12/03/2020] [Accepted: 12/18/2020] [Indexed: 10/22/2022]
Abstract
The 15N-1H heteronuclear single-quantum correlation (HSQC) technique in protein NMR spectroscopy suffers from line-broadening effects, such as chemical exchange of labile protons with solvent, and exchange broadening for residues undergoing conformational dynamics. The amide resonance of β2-microglobulin residue S88 is not observed in the HSQC spectrum but can be obtained through 13C-detect experiments that circumvent the problem of amide-solvent exchange broadening. Line broadening of S88 resonance beyond detection in the HSQC spectrum is not attributed to conformational exchange but rather to solvent exchange occurring on the order of ~103 s-1.
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Affiliation(s)
- Yuichi Yoshimura
- Institute for Protein Research, Osaka University, Yamada-oka 3-2, Suita, 565-0871 Osaka, Japan; Program of Mathematical and Life Sciences, Graduate School of Integrated Sciences for Life, Hiroshima University, Kagamiyama 1-3-1, Higashi-Hiroshima, 739-8526 Hiroshima, Japan; Lifematics West-Japan Branch, Hirano-machi 4-6-16, Chuo-ku, 541-0046 Osaka, Japan.
| | - Masatomo So
- Institute for Protein Research, Osaka University, Yamada-oka 3-2, Suita, 565-0871 Osaka, Japan
| | - Yohei Miyanoiri
- Institute for Protein Research, Osaka University, Yamada-oka 3-2, Suita, 565-0871 Osaka, Japan
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3
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Pontoriero L, Schiavina M, Murrali MG, Pierattelli R, Felli IC. Monitoring the Interaction of α‐Synuclein with Calcium Ions through Exclusively Heteronuclear Nuclear Magnetic Resonance Experiments. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008079] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Letizia Pontoriero
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
| | - Marco Schiavina
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
| | - Maria Grazia Murrali
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
- Present address: Department of Chemistry and Biochemistry University of California at Los Angeles USA
| | - Roberta Pierattelli
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
| | - Isabella C. Felli
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
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4
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Pontoriero L, Schiavina M, Murrali MG, Pierattelli R, Felli IC. Monitoring the Interaction of α‐Synuclein with Calcium Ions through Exclusively Heteronuclear Nuclear Magnetic Resonance Experiments. Angew Chem Int Ed Engl 2020; 59:18537-18545. [DOI: 10.1002/anie.202008079] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2020] [Revised: 07/14/2020] [Indexed: 12/14/2022]
Affiliation(s)
- Letizia Pontoriero
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
| | - Marco Schiavina
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
| | - Maria Grazia Murrali
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
- Present address: Department of Chemistry and Biochemistry University of California at Los Angeles USA
| | - Roberta Pierattelli
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
| | - Isabella C. Felli
- CERM and Department of Chemistry “Ugo Schiff” University of Florence Via Luigi Sacconi 6 50019 Sesto Fiorentino Florence Italy
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5
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Mateos B, Conrad-Billroth C, Schiavina M, Beier A, Kontaxis G, Konrat R, Felli IC, Pierattelli R. The Ambivalent Role of Proline Residues in an Intrinsically Disordered Protein: From Disorder Promoters to Compaction Facilitators. J Mol Biol 2019; 432:3093-3111. [PMID: 31794728 DOI: 10.1016/j.jmb.2019.11.015] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2019] [Revised: 10/23/2019] [Accepted: 11/14/2019] [Indexed: 12/31/2022]
Abstract
Intrinsically disordered proteins (IDPs) carry out many biological functions. They lack a stable three-dimensional structure, but rather adopt many different conformations in dynamic equilibrium. The interplay between local dynamics and global rearrangements is key for their function. In IDPs, proline residues are significantly enriched. Given their unique physicochemical and structural properties, a more detailed understanding of their potential role in stabilizing partially folded states in IDPs is highly desirable. Nuclear magnetic resonance (NMR) spectroscopy, and in particular 13C-detected NMR, is especially suitable to address these questions. We applied a 13C-detected strategy to study Osteopontin, a largely disordered IDP with a central compact region. By using the exquisite sensitivity and spectral resolution of these novel techniques, we gained unprecedented insight into cis-Pro populations, their local structural dynamics, and their role in mediating long-range contacts. Our findings clearly call for a reassessment of the structural and functional role of proline residues in IDPs. The emerging picture shows that proline residues have ambivalent structural roles. They are not simply disorder promoters but rather can, depending on the primary sequence context, act as nucleation sites for structural compaction in IDPs. These unexpected features provide a versatile mechanistic toolbox to enrich the conformational ensembles of IDPs with specific features for adapting to changing molecular and cellular environments.
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Affiliation(s)
- Borja Mateos
- Department of Structural and Computational Biology, University of Vienna, Max Perutz Labs, Vienna Biocenter Campus 5, 1030 Vienna, Austria
| | - Clara Conrad-Billroth
- Department of Structural and Computational Biology, University of Vienna, Max Perutz Labs, Vienna Biocenter Campus 5, 1030 Vienna, Austria
| | - Marco Schiavina
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy
| | - Andreas Beier
- Department of Structural and Computational Biology, University of Vienna, Max Perutz Labs, Vienna Biocenter Campus 5, 1030 Vienna, Austria
| | - Georg Kontaxis
- Department of Structural and Computational Biology, University of Vienna, Max Perutz Labs, Vienna Biocenter Campus 5, 1030 Vienna, Austria
| | - Robert Konrat
- Department of Structural and Computational Biology, University of Vienna, Max Perutz Labs, Vienna Biocenter Campus 5, 1030 Vienna, Austria.
| | - Isabella C Felli
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.
| | - Roberta Pierattelli
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.
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6
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Cook EC, Sahu D, Bastidas M, Showalter SA. Solution Ensemble of the C-Terminal Domain from the Transcription Factor Pdx1 Resembles an Excluded Volume Polymer. J Phys Chem B 2018; 123:106-116. [PMID: 30525611 DOI: 10.1021/acs.jpcb.8b10051] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The pancreatic and duodenal homeobox 1 (Pdx1) is an essential pancreatic transcription factor. The C-terminal intrinsically disordered domain of Pdx1 (Pdx1-C) has a heavily biased amino acid composition; most notably, 18 of 83 residues are proline, including a hexaproline cluster near the middle of the chain. For these reasons, Pdx1-C is an attractive target for structure characterization, given the availability of suitable methods. To determine the solution ensembles of disordered proteins, we have developed a suite of 13C direct-detect NMR experiments that provide high spectral quality, even in the presence of strong proline enrichment. Here, we have extended our suite of NMR experiments to include four new pulse programs designed to record backbone residual dipolar couplings in a 13C,15N-CON detection format. Using our NMR strategy, in combination with small-angle X-ray scattering measurements and Monte Carlo simulations, we have determined that Pdx1-C is extended in solution, with a radius of gyration and internal scaling similar to that of an excluded volume polymer, and a subtle tendency toward a collapsed structure to the N-terminal side of the hexaproline sequence. This structure leaves Pdx1-C exposed for interactions with trans-regulatory co-factors that contribute with Pdx1 to transcription control in the cell.
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15N detection harnesses the slow relaxation property of nitrogen: Delivering enhanced resolution for intrinsically disordered proteins. Proc Natl Acad Sci U S A 2018; 115:E1710-E1719. [PMID: 29432148 DOI: 10.1073/pnas.1717560115] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Studies over the past decade have highlighted the functional significance of intrinsically disordered proteins (IDPs). Due to conformational heterogeneity and inherent dynamics, structural studies of IDPs have relied mostly on NMR spectroscopy, despite IDPs having characteristics that make them challenging to study using traditional 1H-detected biomolecular NMR techniques. Here, we develop a suite of 3D 15N-detected experiments that take advantage of the slower transverse relaxation property of 15N nuclei, the associated narrower linewidth, and the greater chemical shift dispersion compared with those of 1H and 13C resonances. The six 3D experiments described here start with aliphatic 1H magnetization to take advantage of its higher initial polarization, and are broadly applicable for backbone assignment of proteins that are disordered, dynamic, or have unfavorable amide proton exchange rates. Using these experiments, backbone resonance assignments were completed for the unstructured regulatory domain (residues 131-294) of the human transcription factor nuclear factor of activated T cells (NFATC2), which includes 28 proline residues located in functionally important serine-proline (SP) repeats. The complete assignment of the NFATC2 regulatory domain enabled us to study phosphorylation of NFAT by kinase PKA and phosphorylation-dependent binding of chaperone protein 14-3-3 to NFAT, providing mechanistic insight on how 14-3-3 regulates NFAT nuclear translocation.
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8
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The Use of 13C Direct-Detect NMR to Characterize Flexible and Disordered Proteins. Methods Enzymol 2018; 611:81-100. [DOI: 10.1016/bs.mie.2018.08.025] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/06/2022]
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Rozentur-Shkop E, Goobes G, Chill JH. A J-modulated protonless NMR experiment characterizes the conformational ensemble of the intrinsically disordered protein WIP. JOURNAL OF BIOMOLECULAR NMR 2016; 66:243-257. [PMID: 27844185 DOI: 10.1007/s10858-016-0073-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/07/2016] [Accepted: 11/01/2016] [Indexed: 06/06/2023]
Abstract
Intrinsically disordered proteins (IDPs) are multi-conformational polypeptides that lack a single stable three-dimensional structure. It has become increasingly clear that the versatile IDPs play key roles in a multitude of biological processes, and, given their flexible nature, NMR is a leading method to investigate IDP behavior on the molecular level. Here we present an IDP-tailored J-modulated experiment designed to monitor changes in the conformational ensemble characteristic of IDPs by accurately measuring backbone one- and two-bond J(15N,13Cα) couplings. This concept was realized using a unidirectional (H)NCO 13C-detected experiment suitable for poor spectral dispersion and optimized for maximum coverage of amino acid types. To demonstrate the utility of this approach we applied it to the disordered actin-binding N-terminal domain of WASp interacting protein (WIP), a ubiquitous key modulator of cytoskeletal changes in a range of biological systems. One- and two-bond J(15N,13Cα) couplings were acquired for WIP residues 2-65 at various temperatures, and in denaturing and crowding environments. Under native conditions fitted J-couplings identified in the WIP conformational ensemble a propensity for extended conformation at residues 16-23 and 45-60, and a helical tendency at residues 28-42. These findings are consistent with a previous study of the based upon chemical shift and RDC data and confirm that the WIP2-65 conformational ensemble is biased towards the structure assumed by this fragment in its actin-bound form. The effects of environmental changes upon this ensemble were readily apparent in the J-coupling data, which reflected a significant decrease in structural propensity at higher temperatures, in the presence of 8 M urea, and under the influence of a bacterial cell lysate. The latter suggests that crowding can cause protein unfolding through protein-protein interactions that stabilize the unfolded state. We conclude that J-couplings are a useful measureable in characterizing structural ensembles in IDPs, and that the proposed experiment provides a practical method for accurately performing such measurements, once again emphasizing the power of NMR in studying IDP behavior.
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Affiliation(s)
| | - Gil Goobes
- Department of Chemistry, Bar Ilan University, 52900, Ramat Gan, Israel
| | - Jordan H Chill
- Department of Chemistry, Bar Ilan University, 52900, Ramat Gan, Israel.
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10
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Fürtig B, Schnieders R, Richter C, Zetzsche H, Keyhani S, Helmling C, Kovacs H, Schwalbe H. Direct ¹³C-detected NMR experiments for mapping and characterization of hydrogen bonds in RNA. JOURNAL OF BIOMOLECULAR NMR 2016; 64:207-221. [PMID: 26852414 DOI: 10.1007/s10858-016-0021-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2015] [Accepted: 01/29/2016] [Indexed: 06/05/2023]
Abstract
In RNA secondary structure determination, it is essential to determine whether a nucleotide is base-paired and not. Base-pairing of nucleotides is mediated by hydrogen bonds. The NMR characterization of hydrogen bonds relies on experiments correlating the NMR resonances of exchangeable protons and can be best performed for structured parts of the RNA, where labile hydrogen atoms are protected from solvent exchange. Functionally important regions in RNA, however, frequently reveal increased dynamic disorder which often leads to NMR signals of exchangeable protons that are broadened beyond (1)H detection. Here, we develop (13)C direct detected experiments to observe all nucleotides in RNA irrespective of whether they are involved in hydrogen bonds or not. Exploiting the self-decoupling of scalar couplings due to the exchange process, the hydrogen bonding behavior of the hydrogen bond donor of each individual nucleotide can be determined. Furthermore, the adaption of HNN-COSY experiments for (13)C direct detection allows correlations of donor-acceptor pairs and the localization of hydrogen-bond acceptor nucleotides. The proposed (13)C direct detected experiments therefore provide information about molecular sites not amenable by conventional proton-detected methods. Such information makes the RNA secondary structure determination by NMR more accurate and helps to validate secondary structure predictions based on bioinformatics.
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Affiliation(s)
- Boris Fürtig
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe Universität Frankfurt, Max von Laue-Str. 7, 60438, Frankfurt, Germany.
| | - Robbin Schnieders
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe Universität Frankfurt, Max von Laue-Str. 7, 60438, Frankfurt, Germany
| | - Christian Richter
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe Universität Frankfurt, Max von Laue-Str. 7, 60438, Frankfurt, Germany
| | - Heidi Zetzsche
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe Universität Frankfurt, Max von Laue-Str. 7, 60438, Frankfurt, Germany
| | - Sara Keyhani
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe Universität Frankfurt, Max von Laue-Str. 7, 60438, Frankfurt, Germany
| | - Christina Helmling
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe Universität Frankfurt, Max von Laue-Str. 7, 60438, Frankfurt, Germany
| | - Helena Kovacs
- Bruker BioSpin, Industriestrasse 26, 8117, Fällanden, Switzerland
| | - Harald Schwalbe
- Center for Biomolecular Magnetic Resonance (BMRZ), Institute of Organic Chemistry and Chemical Biology, Johann Wolfgang Goethe Universität Frankfurt, Max von Laue-Str. 7, 60438, Frankfurt, Germany.
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11
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Zangger K. Pure shift NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 86-87:1-20. [PMID: 25919196 DOI: 10.1016/j.pnmrs.2015.02.002] [Citation(s) in RCA: 242] [Impact Index Per Article: 26.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/29/2014] [Revised: 02/04/2015] [Accepted: 02/05/2015] [Indexed: 05/08/2023]
Abstract
Although scalar-coupling provides important structural information, the resulting signal splittings significantly reduce the resolution of NMR spectra. Limited resolution is a particular problem in proton NMR experiments, resulting in part from the limited proton chemical shift range (∼10 ppm) but even more from the splittings due to scalar coupling to nearby protons. "Pure shift" NMR spectroscopy (also known as broadband homonuclear decoupling) has been developed for disentangling overlapped proton NMR spectra. The resulting spectra are considerably simplified as they consist of single lines, reminiscent of proton-decoupled C-13 spectra at natural abundance, with no multiplet structure. The different approaches to obtaining pure shift spectra are reviewed here and several applications presented. Pure shift spectra are especially useful for highly overlapped proton spectra, as found for example in reaction mixtures, natural products and biomacromolecules.
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Affiliation(s)
- Klaus Zangger
- Institute of Chemistry/Organic and Bioorganic Chemistry, University of Graz, Heinrichstrasse 28, A-8010 Graz, Austria.
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12
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Felli IC, Pierattelli R. Spin-state-selective methods in solution- and solid-state biomolecular 13C NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2015; 84-85:1-13. [PMID: 25669738 DOI: 10.1016/j.pnmrs.2014.10.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/14/2014] [Accepted: 10/26/2014] [Indexed: 06/04/2023]
Abstract
Spin-state-selective methods to achieve homonuclear decoupling in the direct acquisition dimension of (13)C detected NMR experiments have been one of the key contributors to converting (13)C detected NMR experiments into really useful tools for studying biomolecules. We discuss here in detail the various methods that have been proposed, summarize the large array of new experiments that have been developed and present applications to different kinds of proteins in different aggregation states.
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Affiliation(s)
- Isabella C Felli
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| | - Roberta Pierattelli
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
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13
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Elazari-Shalom H, Shaked H, Esteban-Martin S, Salvatella X, Barda-Saad M, Chill JH. New insights into the role of the disordered WIP N-terminal domain revealed by NMR structural characterization. FEBS J 2015; 282:700-14. [DOI: 10.1111/febs.13174] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2014] [Revised: 12/04/2014] [Accepted: 12/09/2014] [Indexed: 02/06/2023]
Affiliation(s)
| | - Hadassa Shaked
- Department of Chemistry; Bar Ilan University; Ramat Gan Israel
| | - Santiago Esteban-Martin
- Joint BSC-CRG-IRB Research Programme in Computational Biology; Barcelona Supercomputing Center; Spain
| | - Xavier Salvatella
- Joint BSC-CRG-IRB Research Programme in Computational Biology; Institute for Research in Biomedicine IRB Barcelona; Spain
- ICREA; Barcelona Spain
| | - Mira Barda-Saad
- Mina and Everard Goodman Faculty of Life Sciences; Bar Ilan University; Ramat Gan Israel
| | - Jordan H. Chill
- Department of Chemistry; Bar Ilan University; Ramat Gan Israel
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14
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Felli IC, Gonnelli L, Pierattelli R. In-cell ¹³C NMR spectroscopy for the study of intrinsically disordered proteins. Nat Protoc 2014; 9:2005-16. [PMID: 25079425 DOI: 10.1038/nprot.2014.124] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
A large number of proteins carry out their function in highly flexible and disordered states, lacking a well-defined 3D structure. These proteins, referred to as intrinsically disordered proteins (IDPs), are now in the spotlight of modern structural biology. Nuclear magnetic resonance (NMR) spectroscopy represents a unique tool for accessing atomic resolution information on IDPs in complex environments as whole cells, provided that the methods are optimized to their peculiar properties and to the characteristics of in-cell experiments. We describe procedures for the preparation of in-cell NMR samples, as well as for the setup of NMR experiments and their application to in-cell studies, using human α-synuclein overexpressed in Escherichia coli as an example. The expressed protein is labeled with (13)C and (15)N stable isotopes to enable the direct recording of (13)C-detected NMR experiments optimized for the properties of IDPs. The entire procedure covers 24 h, including cell transformation, cell growth overnight, setup of the spectrometer and NMR experiment recording.
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Affiliation(s)
- Isabella C Felli
- Magnetic Resonance Center (CERM), Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino, Italy
| | - Leonardo Gonnelli
- Magnetic Resonance Center (CERM), Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino, Italy
| | - Roberta Pierattelli
- Magnetic Resonance Center (CERM), Department of Chemistry 'Ugo Schiff', University of Florence, Sesto Fiorentino, Italy
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15
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Felli IC, Pierattelli R. Novel methods based on (13)C detection to study intrinsically disordered proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 241:115-25. [PMID: 24656084 DOI: 10.1016/j.jmr.2013.10.020] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/11/2013] [Revised: 10/30/2013] [Accepted: 10/31/2013] [Indexed: 05/23/2023]
Abstract
Intrinsically disordered proteins (IDPs) are characterized by highly flexible solvent exposed backbones and can sample many different conformations. These properties confer them functional advantages, complementary to those of folded proteins, which need to be characterized to expand our view of how protein structural and dynamic features affect function beyond the static picture of a single well defined 3D structure that has influenced so much our way of thinking. NMR spectroscopy provides a unique tool for the atomic resolution characterization of highly flexible macromolecules in general and of IDPs in particular. The peculiar properties of IDPs however have profound effects on spectroscopic parameters. It is thus worth thinking about these aspects to make the best use of the great potential of NMR spectroscopy to contribute to this fascinating field of research. In particular, after many years of dealing with exclusively heteronuclear NMR experiments based on (13)C direct detection, we would like here to address their relevance when studying IDPs.
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Affiliation(s)
- Isabella C Felli
- Magnetic Resonance Center and Department of Chemistry "Ugo Schiff", University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
| | - Roberta Pierattelli
- Magnetic Resonance Center and Department of Chemistry "Ugo Schiff", University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
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16
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Haba NY, Gross R, Novacek J, Shaked H, Zidek L, Barda-Saad M, Chill JH. NMR determines transient structure and dynamics in the disordered C-terminal domain of WASp interacting protein. Biophys J 2014; 105:481-93. [PMID: 23870269 DOI: 10.1016/j.bpj.2013.05.046] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2013] [Revised: 04/30/2013] [Accepted: 05/20/2013] [Indexed: 01/07/2023] Open
Abstract
WASp-interacting protein (WIP) is a 503-residue proline-rich polypeptide expressed in human T cells. The WIP C-terminal domain binds to Wiskott-Aldrich syndrome protein (WASp) and regulates its activation and degradation, and the WIP-WASp interaction has been shown to be critical for actin polymerization and implicated in the onset of WAS and X-linked thrombocytopenia. WIP is predicted to be an intrinsically disordered protein, a class of polypeptides that are of great interest because they violate the traditional structure-function paradigm. In this first (to our knowledge) study of WIP in its unbound state, we used NMR to investigate the biophysical behavior of WIP(C), a C-terminal domain fragment of WIP that includes residues 407-503 and contains the WASp-binding site. In light of the poor spectral dispersion exhibited by WIP(C) and the high occurrence (25%) of proline residues, we employed 5D-NMR(13)C-detected NMR experiments with nonuniform sampling to accomplish full resonance assignment. Secondary chemical-shift analysis, (15)N relaxation rates, and protection from solvent exchange all concurred in detecting transient structure located in motifs that span the WASp-binding site. Residues 446-456 exhibited a propensity for helical conformation, and an extended conformation followed by a short, capped helix was observed for residues 468-478. The (13)C-detected approach allows chemical-shift assignment in the WIP(C) polyproline stretches and thus sheds light on their conformation and dynamics. The effects of temperature on chemical shifts referenced to a denatured sample of the polypeptide demonstrate that heating reduces the structural character of WIP(C). Thus, we conclude that the disordered WIP(C) fragment is comprised of regions with latent structure connected by flexible loops, an architecture with implications for binding affinity and function.
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Affiliation(s)
- Noam Y Haba
- Department of Chemistry, Bar Ilan University, Ramat Gan, Israel
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17
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Ferella L, Luchinat C, Ravera E, Rosato A. SedNMR: a web tool for optimizing sedimentation of macromolecular solutes for SSNMR. JOURNAL OF BIOMOLECULAR NMR 2013; 57:319-26. [PMID: 24243317 DOI: 10.1007/s10858-013-9795-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 11/11/2013] [Indexed: 05/09/2023]
Abstract
We have proposed solid state NMR (SSNMR) of sedimented solutes as a novel approach to sample preparation for biomolecular SSNMR without crystallization or other sample manipulations. The biomolecules are confined by high gravity--obtained by centrifugal forces either directly in a SSNMR rotor or in a ultracentrifugal device--into a hydrated non-crystalline solid suitable for SSNMR investigations. When gravity is removed, the sample reverts to solution and can be treated as any solution NMR sample. We here describe a simple web tool to calculate the relevant parameters for the success of the experiment.
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Affiliation(s)
- Lucio Ferella
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, FI, Italy
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Gil S, Hošek T, Solyom Z, Kümmerle R, Brutscher B, Pierattelli R, Felli IC. NMR Spectroscopic Studies of Intrinsically Disordered Proteins at Near-Physiological Conditions. Angew Chem Int Ed Engl 2013; 52:11808-12. [DOI: 10.1002/anie.201304272] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2013] [Revised: 07/30/2013] [Indexed: 11/11/2022]
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Gil S, Hošek T, Solyom Z, Kümmerle R, Brutscher B, Pierattelli R, Felli IC. NMR Spectroscopic Studies of Intrinsically Disordered Proteins at Near-Physiological Conditions. Angew Chem Int Ed Engl 2013. [DOI: 10.1002/ange.201304272] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Kosol S, Contreras-Martos S, Cedeño C, Tompa P. Structural characterization of intrinsically disordered proteins by NMR spectroscopy. Molecules 2013; 18:10802-28. [PMID: 24008243 PMCID: PMC6269831 DOI: 10.3390/molecules180910802] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2013] [Revised: 08/19/2013] [Accepted: 08/30/2013] [Indexed: 01/25/2023] Open
Abstract
Recent advances in NMR methodology and techniques allow the structural investigation of biomolecules of increasing size with atomic resolution. NMR spectroscopy is especially well-suited for the study of intrinsically disordered proteins (IDPs) and intrinsically disordered regions (IDRs) which are in general highly flexible and do not have a well-defined secondary or tertiary structure under functional conditions. In the last decade, the important role of IDPs in many essential cellular processes has become more evident as the lack of a stable tertiary structure of many protagonists in signal transduction, transcription regulation and cell-cycle regulation has been discovered. The growing demand for structural data of IDPs required the development and adaption of methods such as 13C-direct detected experiments, paramagnetic relaxation enhancements (PREs) or residual dipolar couplings (RDCs) for the study of ‘unstructured’ molecules in vitro and in-cell. The information obtained by NMR can be processed with novel computational tools to generate conformational ensembles that visualize the conformations IDPs sample under functional conditions. Here, we address NMR experiments and strategies that enable the generation of detailed structural models of IDPs.
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Affiliation(s)
- Simone Kosol
- VIB Department of Structural Biology, Vrije Universiteit Brussel, Brussels 1050, Belgium; E-Mails: (S.C.M.); (C.C.)
- Authors to whom correspondence should be addressed; E-Mails: (S.K.); (P.T.)
| | - Sara Contreras-Martos
- VIB Department of Structural Biology, Vrije Universiteit Brussel, Brussels 1050, Belgium; E-Mails: (S.C.M.); (C.C.)
| | - Cesyen Cedeño
- VIB Department of Structural Biology, Vrije Universiteit Brussel, Brussels 1050, Belgium; E-Mails: (S.C.M.); (C.C.)
| | - Peter Tompa
- VIB Department of Structural Biology, Vrije Universiteit Brussel, Brussels 1050, Belgium; E-Mails: (S.C.M.); (C.C.)
- Institute of Enzymology, Biological Research Center, Hungarian Academy of Sciences, Budapest 1518, Hungary
- Authors to whom correspondence should be addressed; E-Mails: (S.K.); (P.T.)
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Cell-free expressed bacteriorhodopsin in different soluble membrane mimetics: biophysical properties and NMR accessibility. Structure 2013; 21:394-401. [PMID: 23415558 DOI: 10.1016/j.str.2013.01.005] [Citation(s) in RCA: 96] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2012] [Revised: 12/14/2012] [Accepted: 01/03/2013] [Indexed: 01/21/2023]
Abstract
Selecting a suitable membrane-mimicking environment is of fundamental importance for the investigation of membrane proteins. Nonconventional surfactants, such as amphipathic polymers (amphipols) and lipid bilayer nanodiscs, have been introduced as promising environments that may overcome intrinsic disadvantages of detergent micelle systems. However, structural insights into the effects of different environments on the embedded protein are limited. Here, we present a comparative study of the heptahelical membrane protein bacteriorhodopsin in detergent micelles, amphipols, and nanodiscs. Our results confirm that nonconventional environments can increase stability of functional bacteriorhodopsin, and demonstrate that well-folded heptahelical membrane proteins are, in principle, accessible by solution-NMR methods in amphipols and phospholipid nanodiscs. Our data distinguish regions of bacteriorhodopsin that mediate membrane/solvent contacts in the tested environments, whereas the protein's functional inner core remains almost unperturbed. The presented data allow comparing the investigated membrane mimetics in terms of NMR spectral quality and thermal stability required for structural studies.
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Bertini I, Felli IC, Gonnelli L, Vasantha Kumar MV, Pierattelli R. High-resolution characterization of intrinsic disorder in proteins: expanding the suite of (13)C-detected NMR spectroscopy experiments to determine key observables. Chembiochem 2013; 12:2347-52. [PMID: 23106082 DOI: 10.1002/cbic.201100406] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Order in disorder: The characterization of intrinsically disordered proteins by NMR spectroscopy is a necessity on the one hand and a continuous challenge on the other. We propose two experiments that provide diagnostic parameters to monitor the degree of unfolding of a polypeptide. The test was performed on the yeast Cox17 protein, known to gain its function through maturation from an intrinsically disordered state (see figure).
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Affiliation(s)
- Ivano Bertini
- CERM University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy.
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Bertini I, Engelke F, Gonnelli L, Knott B, Luchinat C, Osen D, Ravera E. On the use of ultracentrifugal devices for sedimented solute NMR. JOURNAL OF BIOMOLECULAR NMR 2012; 54:123-7. [PMID: 22872367 DOI: 10.1007/s10858-012-9657-y] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2012] [Accepted: 07/26/2012] [Indexed: 05/09/2023]
Abstract
We have recently proposed sedimented solute NMR (SedNMR) as a solid-state method to access biomolecules without the need of crystallization or other sample manipulation. The drawback of SedNMR is that samples are intrinsically diluted and this is detrimental for the signal intensity. Ultracentrifugal devices can be used to increase the amount of sample inside the rotor, overcoming the intrinsic sensitivity limitation of the method. We designed two different devices and we here report the directions for using such devices and the relevant equations for determining the parameters for sedimentation.
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Affiliation(s)
- Ivano Bertini
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, FI, Italy.
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Bermel W, Bertini I, Felli IC, Gonnelli L, Koźmiński W, Piai A, Pierattelli R, Stanek J. Speeding up sequence specific assignment of IDPs. JOURNAL OF BIOMOLECULAR NMR 2012; 53:293-301. [PMID: 22684679 DOI: 10.1007/s10858-012-9639-0] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2012] [Accepted: 05/22/2012] [Indexed: 05/23/2023]
Abstract
The characterization of intrinsically disordered proteins (IDPs) by NMR spectroscopy is made difficult by the extensive spectral overlaps. To overcome the intrinsic low-resolution of the spectra the introduction of high-dimensionality experiments is essential. We present here a set of high-resolution experiments based on direct (13)C-detection which proved useful in the assignment of α-synuclein, a paradigmatic IDP. In particular, we describe the implementation of 4D HCBCACON, HCCCON, HCBCANCO, 4/5D HNCACON and HNCANCO and 3/4D HCANCACO experiments, specifically tailored for spin system identification and backbone resonances sequential assignment. The use of non-uniform-sampling in the indirect dimension and of the H-flip approach to achieve longitudinal relaxation enhancement rendered the experiments very practical.
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Affiliation(s)
- Wolfgang Bermel
- Bruker BioSpin GmbH, Silberstreifen, 76287 Rheinstetten, Germany
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25
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Lawrence CW, Showalter SA. Carbon-Detected (15)N NMR Spin Relaxation of an Intrinsically Disordered Protein: FCP1 Dynamics Unbound and in Complex with RAP74. J Phys Chem Lett 2012; 3:1409-1413. [PMID: 26286791 DOI: 10.1021/jz300432e] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Intrinsically disordered proteins (IDPs) lack unique 3D structures under native conditions and as such exist as highly dynamic ensembles in solution. We present two (13)C-direct detection experiments for the measurement of (15)N NMR spin relaxation called the CON(T1)-IPAP and CON(T2)-IPAP that quantify backbone dynamics on a per-residue basis for IDPs in solution. These experiments have been applied to the intrinsically disordered C-terminal of FCP1, both free in solution and while bound to the RAP74 winged-helix domain. The results provide evidence that most of FCP1 remains highly dynamic in both states, while the 20 residues forming direct contact with RAP74 become more ordered in the complex. Parallel analysis of RAP74 backbone (15)N NMR spin relaxation reveals only very limited ordering of RAP74 upon FCP1 binding. Taken together, these data show that folding-upon-binding is highly local in this system, with disorder prevailing even in the complex.
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Affiliation(s)
- Chad W Lawrence
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Scott A Showalter
- Department of Chemistry, The Pennsylvania State University, 104 Chemistry Building, University Park, Pennsylvania 16802, United States
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Bertini I, Fragai M, Luchinat C, Melikian M, Toccafondi M, Lauer JL, Fields GB. Structural basis for matrix metalloproteinase 1-catalyzed collagenolysis. J Am Chem Soc 2012; 134:2100-10. [PMID: 22239621 PMCID: PMC3298817 DOI: 10.1021/ja208338j] [Citation(s) in RCA: 90] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The proteolysis of collagen triple-helical structure (collagenolysis) is a poorly understood yet critical physiological process. Presently, matrix metalloproteinase 1 (MMP-1) and collagen triple-helical peptide models have been utilized to characterize the events and calculate the energetics of collagenolysis via NMR spectroscopic analysis of 12 enzyme-substrate complexes. The triple-helix is bound initially by the MMP-1 hemopexin-like (HPX) domain via a four amino acid stretch (analogous to type I collagen residues 782-785). The triple-helix is then presented to the MMP-1 catalytic (CAT) domain in a distinct orientation. The HPX and CAT domains are rotated with respect to one another compared with the X-ray "closed" conformation of MMP-1. Back-rotation of the CAT and HPX domains to the X-ray closed conformation releases one chain out of the triple-helix, and this chain is properly positioned in the CAT domain active site for subsequent hydrolysis. The aforementioned steps provide a detailed, experimentally derived, and energetically favorable collagenolytic mechanism, as well as significant insight into the roles of distinct domains in extracellular protease function.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department of Chemistry “Ugo Shiff”, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department of Chemistry “Ugo Shiff”, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department of Chemistry “Ugo Shiff”, University of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Maxime Melikian
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Mirco Toccafondi
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Janelle L. Lauer
- Department of Biochemistry, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
- Department of Molecular Therapeutics, Scripps Florida, 130 Scripps Way, Jupiter, FL 33458, USA
| | - Gregg B. Fields
- Department of Biochemistry, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA
- Torrey Pines Institute for Molecular Studies, 11350 SW Village Parkway, Port St. Lucie, FL 34987 USA
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Ramalho TC, Pereira DH, Thiel W. Thermal and solvent effects on NMR indirect spin-spin coupling constants of a prototypical Chagas disease drug. J Phys Chem A 2011; 115:13504-12. [PMID: 21995614 DOI: 10.1021/jp201576u] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
NMR J-couplings across hydrogen bonds reflect the static and dynamic character of hydrogen bonding. They are affected by thermal and solvent effects and can therefore be used to probe such effects. We have applied density functional theory (DFT) to compute the NMR (n)J(N,H) scalar couplings of a prototypical Chagas disease drug (metronidazole). The calculations were done for the molecule in vacuo, in microsolvated cluster models with one or few water molecules, in snapshots obtained from molecular dynamics simulations with explicit water solvent, and in a polarizable dielectric continuum. Hyperconjugative and electrostatic effects on spin-spin coupling constants were assessed through DFT calculations using natural bond orbital (NBO) analysis and atoms in molecules (AIM) theory. In the calculations with explicit solvent molecules, special attention was given to the nature of the hydrogen bonds formed with the solvent molecules. The results highlight the importance of properly incorporating thermal and solvent effects into NMR calculations in the condensed phase.
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Affiliation(s)
- Teodorico C Ramalho
- Department of Chemistry, Federal University of Lavras, Lavras, Minas Gerais, Brazil.
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Koehler J, Meiler J. Expanding the utility of NMR restraints with paramagnetic compounds: background and practical aspects. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2011; 59:360-89. [PMID: 22027343 PMCID: PMC3202700 DOI: 10.1016/j.pnmrs.2011.05.001] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2011] [Accepted: 05/06/2011] [Indexed: 05/05/2023]
Affiliation(s)
- Julia Koehler
- Department of Chemistry, Center for Structural Biology, Vanderbilt University, Nashville, TN 37232-8725, USA.
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Abstract
Relatively large proteins in solution, spun in NMR rotors for solid samples at typical ultracentrifugation speeds, sediment at the rotor wall. The sedimented proteins provide high-quality solid-state-like NMR spectra suitable for structural investigation. The proteins fully revert to the native solution state when spinning is stopped, allowing one to study them in both conditions. Transiently sedimented proteins can be considered a novel phase as far as NMR is concerned. NMR of transiently sedimented molecules under fast magic angle spinning has the advantage of overcoming protein size limitations of solution NMR without the need of sample crystallization/precipitation required by solid-state NMR.
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31
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Madl T, Felli IC, Bertini I, Sattler M. Structural analysis of protein interfaces from 13C direct-detected paramagnetic relaxation enhancements. J Am Chem Soc 2010; 132:7285-7. [PMID: 20462243 DOI: 10.1021/ja1014508] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The measurement of (13)C directed-detected paramagnetic relaxation enhancements (PREs) on spin-labeled proteins combines the efficacy of PREs for the detection of long-range distance information with the favorable sensitivity and resolution of (13)C direct-detected experiments. The (13)C PREs provide long-range distance restraints to map binding interfaces in proteins and protein complexes and are especially useful for studies of high-molecular weight perdeuterated molecules.
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Affiliation(s)
- Tobias Madl
- Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg, Germany
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