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Schmidt T, Wang D, Jeon J, Schwieters CD, Clore GM. Quantitative Agreement between Conformational Substates of Holo Calcium-Loaded Calmodulin Detected by Double Electron-Electron Resonance EPR and Predicted by Molecular Dynamics Simulations. J Am Chem Soc 2022; 144:12043-12051. [PMID: 35759799 DOI: 10.1021/jacs.2c02201] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Calcium-loaded calmodulin (CaM/4Ca2+) comprises two domains that undergo rigid body reorientation from a predominantly extended conformation to a compact one upon binding target peptides. A recent replica-exchange molecular dynamics (MD) simulation on holo CaM/4Ca2+ suggested the existence of distinct structural clusters (substates) along the path from extended to compact conformers in the absence of substrates. Here, we experimentally demonstrate the existence of CaM/4Ca2+ substates trapped in local minima by three freezing/annealing regimes (slow, 40 s; intermediate, 1.5 s; fast, 0.5 ms) using pulsed Q-band double electron-electron resonance (DEER) EPR spectroscopy to measure interdomain distances between nitroxide spin-labels positioned at A17C and A128C in the N- and C-terminal domains, respectively. The DEER echo curves were directly fit to population-optimized P(r) pairwise distance distributions calculated from the coordinates of the MD clusters and compact crystal structure. DEER data on fully deuterated CaM/4Ca2+ were acquired at multiple values of the second echo period (10-35 μs) and analyzed globally to eliminate instrumental and overfitting artifacts and ensure accurate populations, peak positions, and widths. The DEER data for all three freezing regimes are quantitatively accounted for within experimental error by 5-6 distinct conformers comprising a predominantly populated extended form (60-75%) and progressively more compact states whose populations decrease as the degree of compactness increases. The shortest interdomain separation is found in the compact crystal structure, which has an occupancy of 4-6%. Thus, CaM/4Ca2+ samples high energy local minima comprising a few discrete substates of increasing compactness in a rugged energy landscape.
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Affiliation(s)
- Thomas Schmidt
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - David Wang
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Jaekyun Jeon
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - Charles D Schwieters
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
| | - G Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, United States
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2
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Miao Q, Nitsche C, Orton H, Overhand M, Otting G, Ubbink M. Paramagnetic Chemical Probes for Studying Biological Macromolecules. Chem Rev 2022; 122:9571-9642. [PMID: 35084831 PMCID: PMC9136935 DOI: 10.1021/acs.chemrev.1c00708] [Citation(s) in RCA: 31] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Indexed: 12/11/2022]
Abstract
Paramagnetic chemical probes have been used in electron paramagnetic resonance (EPR) and nuclear magnetic resonance (NMR) spectroscopy for more than four decades. Recent years witnessed a great increase in the variety of probes for the study of biological macromolecules (proteins, nucleic acids, and oligosaccharides). This Review aims to provide a comprehensive overview of the existing paramagnetic chemical probes, including chemical synthetic approaches, functional properties, and selected applications. Recent developments have seen, in particular, a rapid expansion of the range of lanthanoid probes with anisotropic magnetic susceptibilities for the generation of structural restraints based on residual dipolar couplings and pseudocontact shifts in solution and solid state NMR spectroscopy, mostly for protein studies. Also many new isotropic paramagnetic probes, suitable for NMR measurements of paramagnetic relaxation enhancements, as well as EPR spectroscopic studies (in particular double resonance techniques) have been developed and employed to investigate biological macromolecules. Notwithstanding the large number of reported probes, only few have found broad application and further development of probes for dedicated applications is foreseen.
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Affiliation(s)
- Qing Miao
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
- School
of Chemistry &Chemical Engineering, Shaanxi University of Science & Technology, Xi’an710021, China
| | - Christoph Nitsche
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Henry Orton
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Mark Overhand
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
| | - Gottfried Otting
- Research
School of Chemistry, The Australian National
University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
- ARC
Centre of Excellence for Innovations in Peptide & Protein Science,
Research School of Chemistry, Australian
National University, Sullivans Creek Road, Canberra, Australian Capital Territory 2601, Australia
| | - Marcellus Ubbink
- Leiden
Institute of Chemistry, Leiden University, Einsteinweg 55, Leiden 2333 CC, The Netherlands
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3
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Müntener T, Joss D, Häussinger D, Hiller S. Pseudocontact Shifts in Biomolecular NMR Spectroscopy. Chem Rev 2022; 122:9422-9467. [PMID: 35005884 DOI: 10.1021/acs.chemrev.1c00796] [Citation(s) in RCA: 21] [Impact Index Per Article: 10.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Paramagnetic centers in biomolecules, such as specific metal ions that are bound to a protein, affect the nuclei in their surrounding in various ways. One of these effects is the pseudocontact shift (PCS), which leads to strong chemical shift perturbations of nuclear spins, with a remarkably long range of 50 Å and beyond. The PCS in solution NMR is an effect originating from the anisotropic part of the dipole-dipole interaction between the magnetic momentum of unpaired electrons and nuclear spins. The PCS contains spatial information that can be exploited in multiple ways to characterize structure, function, and dynamics of biomacromolecules. It can be used to refine structures, magnify effects of dynamics, help resonance assignments, allows for an intermolecular positioning system, and gives structural information in sensitivity-limited situations where all other methods fail. Here, we review applications of the PCS in biomolecular solution NMR spectroscopy, starting from early works on natural metalloproteins, following the development of non-natural tags to chelate and attach lanthanoid ions to any biomolecular target to advanced applications on large biomolecular complexes and inside living cells. We thus hope to not only highlight past applications but also shed light on the tremendous potential the PCS has in structural biology.
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Affiliation(s)
- Thomas Müntener
- Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
| | - Daniel Joss
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Daniel Häussinger
- Department of Chemistry, University of Basel, St. Johanns-Ring 19, 4056 Basel, Switzerland
| | - Sebastian Hiller
- Biozentrum, University of Basel, Spitalstrasse 41, 4056 Basel, Switzerland
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4
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Hou XN, Sekiyama N, Ohtani Y, Yang F, Miyanoiri Y, Akagi KI, Su XC, Tochio H. Conformational Space Sampled by Domain Reorientation of Linear Diubiquitin Reflected in Its Binding Mode for Target Proteins. Chemphyschem 2021; 22:1505-1517. [PMID: 33928740 DOI: 10.1002/cphc.202100187] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2021] [Revised: 04/28/2021] [Indexed: 11/06/2022]
Abstract
Linear polyubiquitin chains regulate diverse signaling proteins, in which the chains adopt various conformations to recognize different target proteins. Thus, the structural plasticity of the chains plays an important role in controlling the binding events. Herein, paramagnetic NMR spectroscopy is employed to explore the conformational space sampled by linear diubiquitin, a minimal unit of linear polyubiquitin, in its free state. Rigorous analysis of the data suggests that, regarding the relative positions of the ubiquitin units, particular regions of conformational space are preferentially sampled by the molecule. By combining these results with further data collected for charge-reversal derivatives of linear diubiquitin, structural insights into the factors underlying the binding events of linear diubiquitin are obtained.
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Affiliation(s)
- Xue-Ni Hou
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Naotaka Sekiyama
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Yasuko Ohtani
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
| | - Feng Yang
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, No.94 Weijin Road, Nankai District, Tianjin, 300071, P. R. China
| | - Yohei Miyanoiri
- Institute for Protein Research, Osaka University, 3-2 Yamadaoka, Suita, Osaka, 565-0871, Japan
| | - Ken-Ichi Akagi
- NIBIOHN, Section of Laboratory Equipment, Osaka, 567-0085, Japan.,RIKEN Center for Sustainable Resource Science, 1-7-22 Suehiro-cho, Tsurumi-ku, Yokohama, Kanagawa, 230-0045, Japan
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-Organic Chemistry, College of Chemistry, Nankai University, No.94 Weijin Road, Nankai District, Tianjin, 300071, P. R. China
| | - Hidehito Tochio
- Department of Biophysics, Graduate School of Science, Kyoto University, Sakyo-ku, Kyoto, 606-8502, Japan
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5
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Denis M, Softley C, Giuntini S, Gentili M, Ravera E, Parigi G, Fragai M, Popowicz G, Sattler M, Luchinat C, Cerofolini L, Nativi C. The Photocatalyzed Thiol-ene reaction: A New Tag to Yield Fast, Selective and reversible Paramagnetic Tagging of Proteins. Chemphyschem 2020; 21:863-869. [PMID: 32092218 PMCID: PMC7384118 DOI: 10.1002/cphc.202000071] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 02/21/2020] [Indexed: 11/18/2022]
Abstract
Paramagnetic restraints have been used in biomolecular NMR for the last three decades to elucidate and refine biomolecular structures, but also to characterize protein-ligand interactions. A common technique to generate such restraints in proteins, which do not naturally contain a (paramagnetic) metal, consists in the attachment to the protein of a lanthanide-binding-tag (LBT). In order to design such LBTs, it is important to consider the efficiency and stability of the conjugation, the geometry of the complex (conformational exchanges and coordination) and the chemical inertness of the ligand. Here we describe a photo-catalyzed thiol-ene reaction for the cysteine-selective paramagnetic tagging of proteins. As a model, we designed an LBT with a vinyl-pyridine moiety which was used to attach our tag to the protein GB1 in fast and irreversible fashion. Our tag T1 yields magnetic susceptibility tensors of significant size with different lanthanides and has been characterized using NMR and relaxometry measurements.
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Affiliation(s)
- Maxime Denis
- Giotto Biotech, S.R.LVia Madonna del piano 650019Sesto Fiorentino (FI)Italy
- Department of Chemistry “Ugo Schiff”University of FlorenceVia della Lastruccia 350019Sesto Fiorentino (FI), Italy
| | - Charlotte Softley
- Biomolecular NMR, Department ChemieTechnical University of MunichLichtenbergstrasse 485747GarchingGermany
- Institute of Structural BiologyHelmholtz Center MunichNeuherbergGermany
| | - Stefano Giuntini
- Department of Chemistry “Ugo Schiff”University of FlorenceVia della Lastruccia 350019Sesto Fiorentino (FI), Italy
- Magnetic Resonance Center (CERM)University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (C.I.R.M.M.P)Via L. Sacconi 650019Sesto FIorentino (FI)Italy
| | - Matteo Gentili
- Giotto Biotech, S.R.LVia Madonna del piano 650019Sesto Fiorentino (FI)Italy
| | - Enrico Ravera
- Magnetic Resonance Center (CERM)University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (C.I.R.M.M.P)Via L. Sacconi 650019Sesto FIorentino (FI)Italy
| | - Giacomo Parigi
- Department of Chemistry “Ugo Schiff”University of FlorenceVia della Lastruccia 350019Sesto Fiorentino (FI), Italy
- Magnetic Resonance Center (CERM)University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (C.I.R.M.M.P)Via L. Sacconi 650019Sesto FIorentino (FI)Italy
| | - Marco Fragai
- Department of Chemistry “Ugo Schiff”University of FlorenceVia della Lastruccia 350019Sesto Fiorentino (FI), Italy
- Magnetic Resonance Center (CERM)University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (C.I.R.M.M.P)Via L. Sacconi 650019Sesto FIorentino (FI)Italy
| | - Grzegorz Popowicz
- Institute of Structural BiologyHelmholtz Center MunichNeuherbergGermany
| | - Michael Sattler
- Biomolecular NMR, Department ChemieTechnical University of MunichLichtenbergstrasse 485747GarchingGermany
- Institute of Structural BiologyHelmholtz Center MunichNeuherbergGermany
| | - Claudio Luchinat
- Department of Chemistry “Ugo Schiff”University of FlorenceVia della Lastruccia 350019Sesto Fiorentino (FI), Italy
- Magnetic Resonance Center (CERM)University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (C.I.R.M.M.P)Via L. Sacconi 650019Sesto FIorentino (FI)Italy
| | - Linda Cerofolini
- Magnetic Resonance Center (CERM)University of Florence, and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (C.I.R.M.M.P)Via L. Sacconi 650019Sesto FIorentino (FI)Italy
| | - Cristina Nativi
- Department of Chemistry “Ugo Schiff”University of FlorenceVia della Lastruccia 350019Sesto Fiorentino (FI), Italy
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6
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Briganti M, Garcia GF, Jung J, Sessoli R, Le Guennic B, Totti F. Covalency and magnetic anisotropy in lanthanide single molecule magnets: the DyDOTA archetype. Chem Sci 2019; 10:7233-7245. [PMID: 31588292 PMCID: PMC6685353 DOI: 10.1039/c9sc01743g] [Citation(s) in RCA: 48] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2019] [Accepted: 06/08/2019] [Indexed: 01/19/2023] Open
Abstract
The unexpected covalent contribution in the DOTADy-OH2 bond revealed by ab initio calculations of the easy axis of magnetization through simple H2O rotations.
Lanthanide ions when complexed by polyamino-polycarboxylate chelators form a class of compounds of paramount importance in several research and technological areas, particularly in the fields of magnetic resonance and molecular magnetism. Indeed, the gadolinium derivative is one of the most employed contrast agents for magnetic resonance imaging while the dysprosium one belongs to a new generation of contrast agents for T2-weighted MRI. In molecular magnetism, Single Molecule Magnets (SMMs) containing lanthanide ions have become readily popular in the chemistry and physics communities since record energy barriers to the reversal of magnetization were reported. The success of lanthanide complexes lies in their large anisotropy due to the contribution of the unquenched orbital angular momentum. However, only a few efforts have been made so far to understand how the f-orbitals can be influenced by the surrounding ligands. The outcomes have been rationalized using mere electrostatic perturbation models. In the archetype compound [Na{Dy(DOTA) (H2O)}]·4H2O (Na{DyDOTA}·4H2O) an unexpected easy axis of magnetization perpendicular to the pseudo-tetragonal axis of the molecule was found. Interestingly, a dependency of the orientation of the principal magnetization axis on the simple rotation of the coordinating apical water molecule (AWM) – highly relevant for MRI contrast – around the Dy-OAWM bond was predicted by ab initio calculations, too. However, such a behaviour has been contested in a subsequent paper justifying their conclusions on pure electrostatic assumptions. In this paper, we want to shed some light on the nature of the subtle effects induced by the water molecule on the magnetic properties of the DyDOTA archetype complex. Therefore, we have critically reviewed the structural models already published in the literature along with new ones, showing how the easy axis orientation can dangerously depend on the chosen model. The different computed behaviors of the orientation of the easy axis of magnetization have been rationalized as a function of the energy gap between the ground and the first excited doublet. Magneto-structural correlations together with a mapping of the electrostatic potential generated by the ligands around the Dy(iii) ion through a multipolar expansion have also been used to evidence and quantify the covalent contribution of the AWM orbitals.
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Affiliation(s)
- Matteo Briganti
- Dipartimento di Chimica "U. Schiff" and UdR INSTM , Università degli Studi di Firenze , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy . .,Universidade Federal Fluminense , Instituto de Física , Niterói , Rio de Janeiro , Brazil
| | - Guglielmo Fernandez Garcia
- Dipartimento di Chimica "U. Schiff" and UdR INSTM , Università degli Studi di Firenze , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy . .,Univ Rennes , CNRS , ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226 , F-35000 Rennes , France .
| | - Julie Jung
- Univ Rennes , CNRS , ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226 , F-35000 Rennes , France .
| | - Roberta Sessoli
- Dipartimento di Chimica "U. Schiff" and UdR INSTM , Università degli Studi di Firenze , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy .
| | - Boris Le Guennic
- Univ Rennes , CNRS , ISCR (Institut des Sciences Chimiques de Rennes) - UMR 6226 , F-35000 Rennes , France .
| | - Federico Totti
- Dipartimento di Chimica "U. Schiff" and UdR INSTM , Università degli Studi di Firenze , Via della Lastruccia 3-13 , 50019 Sesto Fiorentino , Italy .
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7
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Abstract
Large scale functional motions of molecules are studied experimentally using numerous molecular and biophysics techniques, the data from which are subsequently interpreted using diverse models of Brownian molecular dynamics. To unify all rotational physics techniques and motional models, the frame order tensor - a universal statistical mechanics theory based on the rotational ordering of rigid body frames - is herein formulated. The frame ordering is the fundamental physics that governs how motions modulate rotational molecular physics and it defines the properties and maximum information content encoded in the observable physics. Using the tensor to link residual dipolar couplings and pseudo-contact shifts, two distinct information-rich and atomic-level biophysical measurements from the field of nuclear magnetic resonance spectroscopy, to a number of basic mechanical joint models, a highly dynamic state of calmodulin (CaM) bound to a target peptide in a tightly closed conformation was observed. Intra- and inter-domain motions reveal the CaM complex to be entropically primed for peptide release.
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8
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Gigli L, Andrałojć W, Dalaloyan A, Parigi G, Ravera E, Goldfarb D, Luchinat C. Assessing protein conformational landscapes: integration of DEER data in Maximum Occurrence analysis. Phys Chem Chem Phys 2018; 20:27429-27438. [PMID: 30357188 DOI: 10.1039/c8cp06195e] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
The properties of the conformational landscape of a biomolecule are of capital importance to understand its function. It is widely accepted that a statistical ensemble is far more representative than a single structure, especially for proteins with disordered regions. While experimental data provide the most important handle on the conformational variability that the system is experiencing, they usually report on either time or ensemble averages. Since the available conformations largely outnumber the (independent) available experimental data, the latter can be equally well reproduced by a variety of ensembles. We have proposed the Maximum Occurrence (MaxOcc) approach to provide an upper bound of the statistical weight of each conformation. This method is expected to converge towards the true statistical weights by increasing the number of independent experimental datasets. In this paper we explore the ability of DEER (Double Electron Electron Resonance) data, which report on the distance distribution between two spin labels attached to a biomolecule, to restrain the MaxOcc values and its complementarity to previously introduced experimental techniques such as NMR and Small-Angle X-ray Scattering. We here present the case of Ca2+ bound calmodulin (CaM) as a test case and show that DEER data impose a sizeable reduction of the conformational space described by high MaxOcc conformations.
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Affiliation(s)
- Lucia Gigli
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (FI), Italy.
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9
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Identification of productive and futile encounters in an electron transfer protein complex. Proc Natl Acad Sci U S A 2017; 114:E1840-E1847. [PMID: 28223532 DOI: 10.1073/pnas.1616813114] [Citation(s) in RCA: 45] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Well-defined, stereospecific states in protein complexes are often in exchange with an ensemble of more dynamic orientations: the encounter states. The structure of the stereospecific complex between cytochrome P450cam and putidaredoxin was solved recently by X-ray diffraction as well as paramagnetic NMR spectroscopy. Other than the stereospecific complex, the NMR data clearly show the presence of additional states in the complex in solution. In these encounter states, populated for a small percentage of the time, putidaredoxin assumes multiple orientations and samples a large part of the surface of cytochrome P450cam. To characterize the nature of the encounter states, an extensive paramagnetic NMR dataset has been analyzed using the Maximum Occurrence of Regions methodology. The analysis reveals the location and maximal spatial extent of the additional states needed to fully explain the NMR data. Under the assumption of sparsity of the size of the conformational ensemble, several minor states can be located quite precisely. The distribution of these minor states correlates with the electrostatic potential map around cytochrome P450cam. Whereas some minor states are on isolated positively charged patches, others are connected to the stereospecific site via positively charged paths. The existence of electrostatically favorable pathways between the stereospecific interaction site and the different minor states or lack thereof suggests a means to discriminate between productive and futile encounter states.
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10
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Nitsche C, Otting G. Pseudocontact shifts in biomolecular NMR using paramagnetic metal tags. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2017; 98-99:20-49. [PMID: 28283085 DOI: 10.1016/j.pnmrs.2016.11.001] [Citation(s) in RCA: 84] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2016] [Revised: 11/11/2016] [Accepted: 11/12/2016] [Indexed: 05/14/2023]
Affiliation(s)
- Christoph Nitsche
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia.
| | - Gottfried Otting
- Australian National University, Research School of Chemistry, Canberra, ACT 2601, Australia. http://www.rsc.anu.edu.au/~go/index.html
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11
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Ravera E, Sgheri L, Parigi G, Luchinat C. A critical assessment of methods to recover information from averaged data. Phys Chem Chem Phys 2017; 18:5686-701. [PMID: 26565805 DOI: 10.1039/c5cp04077a] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
Conformational heterogeneity is key to the function of many biomacromolecules, but only a few groups have tried to characterize it until recently. Now, thanks to the increased throughput of experimental data and the increased computational power, the problem of the characterization of protein structural variability has become more and more popular. Several groups have devoted their efforts in trying to create quantitative, reliable and accurate protocols for extracting such information from averaged data. We analyze here different approaches, discussing strengths and weaknesses of each. All approaches can roughly be clustered into two groups: those satisfying the maximum entropy principle and those recovering ensembles composed of a restricted number of molecular conformations. In the first case, the solution focuses on the features that are common to all the infinite solutions satisfying the experimental data; in the second case, the reconstructed ensemble shows the conformational regions where a large probability can be placed. The upper limits for conformational probabilities (MaxOcc) can also be calculated. We also give an overview of the mainstream experimental observables, with considerations on the assumptions underlying their usage.
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Affiliation(s)
- Enrico Ravera
- Center for Magnetic Resonance (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
| | - Luca Sgheri
- Istituto per le Applicazioni del Calcolo, Sezione di Firenze, CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
| | - Giacomo Parigi
- Center for Magnetic Resonance (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
| | - Claudio Luchinat
- Center for Magnetic Resonance (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
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12
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Carlon A, Ravera E, Andrałojć W, Parigi G, Murshudov GN, Luchinat C. How to tackle protein structural data from solution and solid state: An integrated approach. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2016; 92-93:54-70. [PMID: 26952192 DOI: 10.1016/j.pnmrs.2016.01.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/15/2015] [Revised: 01/13/2016] [Accepted: 01/13/2016] [Indexed: 05/17/2023]
Abstract
Long-range NMR restraints, such as diamagnetic residual dipolar couplings and paramagnetic data, can be used to determine 3D structures of macromolecules. They are also used to monitor, and potentially to improve, the accuracy of a macromolecular structure in solution by validating or "correcting" a crystal model. Since crystal structures suffer from crystal packing forces they may not be accurate models for the macromolecular structures in solution. However, the presence of real differences should be tested for by simultaneous refinement of the structure using both crystal and solution NMR data. To achieve this, the program REFMAC5 from CCP4 was modified to allow the simultaneous use of X-ray crystallographic and paramagnetic NMR data and/or diamagnetic residual dipolar couplings. Inconsistencies between crystal structures and solution NMR data, if any, may be due either to structural rearrangements occurring on passing from the solution to solid state, or to a greater degree of conformational heterogeneity in solution with respect to the crystal. In the case of multidomain proteins, paramagnetic restraints can provide the correct mutual orientations and positions of domains in solution, as well as information on the conformational variability experienced by the macromolecule.
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Affiliation(s)
- Azzurra Carlon
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy(1).
| | - Enrico Ravera
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy(1).
| | - Witold Andrałojć
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy(1).
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy(1).
| | - Garib N Murshudov
- MRC Laboratory for Molecular Biology, Francis Crick Ave, Cambridge CB2 0QH, UK.
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) and Department of Chemistry "Ugo Schiff", University of Florence, Italy(1).
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13
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Chen JL, Yang Y, Zhang LL, Liang H, Huber T, Su XC, Otting G. Analysis of the solution conformations of T4 lysozyme by paramagnetic NMR spectroscopy. Phys Chem Chem Phys 2016; 18:5850-9. [DOI: 10.1039/c5cp07196h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Paramagnetic data show that the average structure of T4-lysozyme in solution is more open than its crystal structure.
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Affiliation(s)
- Jia-Liang Chen
- State Key Laboratory of Elemento-organic Chemistry
- The Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Yin Yang
- State Key Laboratory of Elemento-organic Chemistry
- The Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Lin-Lin Zhang
- State Key Laboratory of Elemento-organic Chemistry
- The Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Haobo Liang
- Research School of Chemistry
- Australian National University
- Canberra
- Australia
| | - Thomas Huber
- Research School of Chemistry
- Australian National University
- Canberra
- Australia
| | - Xun-Cheng Su
- State Key Laboratory of Elemento-organic Chemistry
- The Collaborative Innovation Center of Chemical Science and Engineering (Tianjin)
- Nankai University
- Tianjin 300071
- China
| | - Gottfried Otting
- Research School of Chemistry
- Australian National University
- Canberra
- Australia
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14
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Abdelkader EH, Yao X, Feintuch A, Adams LA, Aurelio L, Graham B, Goldfarb D, Otting G. Pulse EPR-enabled interpretation of scarce pseudocontact shifts induced by lanthanide binding tags. JOURNAL OF BIOMOLECULAR NMR 2016; 64:39-51. [PMID: 26597990 DOI: 10.1007/s10858-015-0003-z] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Accepted: 11/17/2015] [Indexed: 06/05/2023]
Abstract
Pseudocontact shifts (PCS) induced by tags loaded with paramagnetic lanthanide ions provide powerful long-range structure information, provided the location of the metal ion relative to the target protein is known. Usually, the metal position is determined by fitting the magnetic susceptibility anisotropy (Δχ) tensor to the 3D structure of the protein in an 8-parameter fit, which requires a large set of PCSs to be reliable. In an alternative approach, we used multiple Gd(3+)-Gd(3+) distances measured by double electron-electron resonance (DEER) experiments to define the metal position, allowing Δχ-tensor determinations from more robust 5-parameter fits that can be performed with a relatively sparse set of PCSs. Using this approach with the 32 kDa E. coli aspartate/glutamate binding protein (DEBP), we demonstrate a structural transition between substrate-bound and substrate-free DEBP, supported by PCSs generated by C3-Tm(3+) and C3-Tb(3+) tags attached to a genetically encoded p-azidophenylalanine residue. The significance of small PCSs was magnified by considering the difference between the chemical shifts measured with Tb(3+) and Tm(3+) rather than involving a diamagnetic reference. The integrative sparse data approach developed in this work makes poorly soluble proteins of limited stability amenable to structural studies in solution, without having to rely on cysteine mutations for tag attachment.
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Affiliation(s)
- Elwy H Abdelkader
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Xuejun Yao
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia
| | - Akiva Feintuch
- Department of Chemical Physics, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Luke A Adams
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Luigi Aurelio
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Bim Graham
- Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, 3052, Australia
| | - Daniella Goldfarb
- Department of Chemical Physics, Weizmann Institute of Science, 76100, Rehovot, Israel
| | - Gottfried Otting
- Research School of Chemistry, Australian National University, Canberra, ACT, 2601, Australia.
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15
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Andrałojć W, Berlin K, Fushman D, Luchinat C, Parigi G, Ravera E, Sgheri L. Information content of long-range NMR data for the characterization of conformational heterogeneity. JOURNAL OF BIOMOLECULAR NMR 2015; 62:353-71. [PMID: 26044033 PMCID: PMC4782772 DOI: 10.1007/s10858-015-9951-6] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Accepted: 05/25/2015] [Indexed: 05/16/2023]
Abstract
Long-range NMR data, namely residual dipolar couplings (RDCs) from external alignment and paramagnetic data, are becoming increasingly popular for the characterization of conformational heterogeneity of multidomain biomacromolecules and protein complexes. The question addressed here is how much information is contained in these averaged data. We have analyzed and compared the information content of conformationally averaged RDCs caused by steric alignment and of both RDCs and pseudocontact shifts caused by paramagnetic alignment, and found that, despite the substantial differences, they contain a similar amount of information. Furthermore, using several synthetic tests we find that both sets of data are equally good towards recovering the major state(s) in conformational distributions.
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Affiliation(s)
- Witold Andrałojć
- Center for Magnetic Resonance (CERM), University of Florence, Via
L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Konstantin Berlin
- Department of Chemistry and Biochemistry, Center for Biomolecular
Structure and Organization, University of Maryland, College Park, MD 20742, USA
| | - David Fushman
- Department of Chemistry and Biochemistry, Center for Biomolecular
Structure and Organization, University of Maryland, College Park, MD 20742, USA
- Corresponding authors: David Fushman, ,
Claudio Luchinat,
| | - Claudio Luchinat
- Center for Magnetic Resonance (CERM), University of Florence, Via
L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Department of Chemistry "Ugo Schiff", University
of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
- Corresponding authors: David Fushman, ,
Claudio Luchinat,
| | - Giacomo Parigi
- Center for Magnetic Resonance (CERM), University of Florence, Via
L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Department of Chemistry "Ugo Schiff", University
of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Enrico Ravera
- Center for Magnetic Resonance (CERM), University of Florence, Via
L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Department of Chemistry "Ugo Schiff", University
of Florence, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Luca Sgheri
- Istituto per le Applicazioni del Calcolo, Sezione di Firenze,
CNR, Via Madonna del Piano 10, 50019 Sesto Fiorentino, Italy
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16
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Lee MD, Loh CT, Shin J, Chhabra S, Dennis ML, Otting G, Swarbrick JD, Graham B. Compact, hydrophilic, lanthanide-binding tags for paramagnetic NMR spectroscopy. Chem Sci 2015; 6:2614-2624. [PMID: 29560247 PMCID: PMC5812434 DOI: 10.1039/c4sc03892d] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Accepted: 02/25/2015] [Indexed: 01/18/2023] Open
Abstract
The design, synthesis and evaluation of four novel lanthanide-binding tags for paramagnetic NMR spectroscopy are reported.
The design, synthesis and evaluation of four novel lanthanide-binding tags for paramagnetic NMR spectroscopy are reported. Each tag is based on the ((2S,2′S,2′′S,2′′′S)-1,1′,1′′,1′′′-(1,4,7,10-tetraazacyclododecane-1,4,7,10-tetrayl)tetrakis(propan-2-ol)) scaffold, featuring small chiral alcohol coordinating pendants to minimise the size and hydrophobic character of each tag. The tags feature different linkers of variable length for conjugation to protein via a single cysteine residue. Each tag's ability to induce pseudocontact shifts (PCS) was assessed on a ubiquitin A28C mutant. Two enantiomeric tags of particular note, C7 and C8, produced significantly larger Δχ-tensors compared to a previously developed tag, C1, attributed to the extremely short linker utilised, limiting the mobility of the bound lanthanide ion. The C7 and C8 tags' capacity to induce PCSs was further demonstrated on GB1 Q32C and 6-hydroxymethyl-7,8-dihydropterin pyrophosphokinase (HPPK) S112C/C80A mutants. Whilst factors such as the choice of lanthanide ion, pH and site of conjugation influence the size of the PCSs obtained, the tags represent a significant advance in the field.
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Affiliation(s)
- M D Lee
- Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - C-T Loh
- Research School of Chemistry , Australian National University , Canberra , ACT 0200 , Australia
| | - J Shin
- Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - S Chhabra
- Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - M L Dennis
- Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - G Otting
- Research School of Chemistry , Australian National University , Canberra , ACT 0200 , Australia
| | - J D Swarbrick
- Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
| | - B Graham
- Monash Institute of Pharmaceutical Sciences , Monash University , Parkville , VIC 3052 , Australia . ;
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17
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Abstract
Myriad biological processes proceed through states that defy characterization by conventional atomic-resolution structural biological methods. The invisibility of these 'dark' states can arise from their transient nature, low equilibrium population, large molecular weight, and/or heterogeneity. Although they are invisible, these dark states underlie a range of processes, acting as encounter complexes between proteins and as intermediates in protein folding and aggregation. New methods have made these states accessible to high-resolution analysis by nuclear magnetic resonance (NMR) spectroscopy, as long as the dark state is in dynamic equilibrium with an NMR-visible species. These methods - paramagnetic NMR, relaxation dispersion, saturation transfer, lifetime line broadening, and hydrogen exchange - allow the exploration of otherwise invisible states in exchange with a visible species over a range of timescales, each taking advantage of some unique property of the dark state to amplify its effect on a particular NMR observable. In this review, we introduce these methods and explore two specific techniques - paramagnetic relaxation enhancement and dark state exchange saturation transfer - in greater detail.
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Affiliation(s)
- Nicholas J. Anthis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
| | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, USA
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18
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Hass MAS, Liu WM, Agafonov RV, Otten R, Phung LA, Schilder JT, Kern D, Ubbink M. A minor conformation of a lanthanide tag on adenylate kinase characterized by paramagnetic relaxation dispersion NMR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2015; 61:123-136. [PMID: 25563704 DOI: 10.1007/s10858-014-9894-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/30/2014] [Accepted: 12/22/2014] [Indexed: 06/04/2023]
Abstract
NMR relaxation dispersion techniques provide a powerful method to study protein dynamics by characterizing lowly populated conformations that are in dynamic exchange with the major state. Paramagnetic NMR is a versatile tool for investigating the structures and dynamics of proteins. These two techniques were combined here to measure accurate and precise pseudocontact shifts of a lowly populated conformation. This method delivers valuable long-range structural restraints for higher energy conformations of macromolecules in solution. Another advantage of combining pseudocontact shifts with relaxation dispersion is the increase in the amplitude of dispersion profiles. Lowly populated states are often involved in functional processes, such as enzyme catalysis, signaling, and protein/protein interactions. The presented results also unveil a critical problem with the lanthanide tag used to generate paramagnetic relaxation dispersion effects in proteins, namely that the motions of the tag can interfere severely with the observation of protein dynamics. The two-point attached CLaNP-5 lanthanide tag was linked to adenylate kinase. From the paramagnetic relaxation dispersion only motion of the tag is observed. The data can be described accurately by a two-state model in which the protein-attached tag undergoes a 23° tilting motion on a timescale of milliseconds. The work demonstrates the large potential of paramagnetic relaxation dispersion and the challenge to improve current tags to minimize relaxation dispersion from tag movements.
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Affiliation(s)
- Mathias A S Hass
- Leiden Institute of Chemistry, Leiden University, Einsteinweg 55, 2333 CC, Leiden, The Netherlands
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19
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Rinaldelli M, Carlon A, Ravera E, Parigi G, Luchinat C. FANTEN: a new web-based interface for the analysis of magnetic anisotropy-induced NMR data. JOURNAL OF BIOMOLECULAR NMR 2015; 61:21-34. [PMID: 25416616 DOI: 10.1007/s10858-014-9877-4] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 11/15/2014] [Indexed: 05/17/2023]
Abstract
Pseudocontact shifts (PCSs) and residual dipolar couplings (RDCs) arising from the presence of paramagnetic metal ions in proteins as well as RDCs due to partial orientation induced by external orienting media are nowadays routinely measured as a part of the NMR characterization of biologically relevant systems. PCSs and RDCs are becoming more and more popular as restraints (1) to determine and/or refine protein structures in solution, (2) to monitor the extent of conformational heterogeneity in systems composed of rigid domains which can reorient with respect to one another, and (3) to obtain structural information in protein-protein complexes. The use of both PCSs and RDCs proceeds through the determination of the anisotropy tensors which are at the origin of these NMR observables. A new user-friendly web tool, called FANTEN (Finding ANisotropy TENsors), has been developed for the determination of the anisotropy tensors related to PCSs and RDCs and has been made freely available through the WeNMR ( http://fanten-enmr.cerm.unifi.it:8080 ) gateway. The program has many new features not available in other existing programs, among which the possibility of a joint analysis of several sets of PCS and RDC data and the possibility to perform rigid body minimizations.
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Affiliation(s)
- Mauro Rinaldelli
- CERM and Department of Chemistry "Ugo Schiff", University of Florence, via Sacconi 6, Sesto Fiorentino, Florence, Italy
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20
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Ravera E, Salmon L, Fragai M, Parigi G, Al-Hashimi H, Luchinat C. Insights into domain-domain motions in proteins and RNA from solution NMR. Acc Chem Res 2014; 47:3118-26. [PMID: 25148413 PMCID: PMC4204921 DOI: 10.1021/ar5002318] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Many multidomain proteins and ribonucleic acids consist of domains
that autonomously fold and that are linked together by flexible junctions.
This architectural design allows domains to sample a wide range of
positions with respect to one another, yet do so in a way that retains
structural specificity, since the number of sampled conformations
remains extremely small compared to the total conformations that would
be sampled if the domains were connected by an infinitely long linker.
This “tuned” flexibility in interdomain conformation
is in turn used in many biochemical processes. There is great
interest in characterizing the dynamic properties
of multidomain systems, and moving beyond conventional descriptions
in terms of static structures, toward the characterization of population-weighted
ensembles describing a distribution of many conformations sampled
in solution. There is also great interest in understanding the design
principles and underlying physical and chemical interactions that
specify the nature of interdomain flexibility. NMR spectroscopy is
one of the most powerful techniques for characterizing motions in
complex biomolecules and has contributed greatly toward our basic
understanding of dynamics in proteins and nucleic acids and its role
in folding, recognition, and signaling. Here, we review methods
that have been developed in our laboratories
to address these challenges. Our approaches are based on the ability
of one domain of the molecule to self-align in a magnetic field, or
to dominate the overall orientation of the molecule, so that the conformational
freedom of other domains can be assessed by their degree of alignment
induced by the aligned part. In turn, this self-alignment ability
can be intrinsic or can be caused by tagging appropriate constructs
to the molecule of interest. In general, self-alignment is due to
magnetic susceptibility anisotropy. Nucleic acids with elongated helices
have this feature, as well as several paramagnetic metal centers that
can be found in, or attached to, a protein domain.
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Affiliation(s)
- Enrico Ravera
- CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
- Department of Chemistry “U. Schiff”, University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Loïc Salmon
- Department
of Biophysics, University of Michigan, 830 N. University, Ann Arbor, Michigan 48109, United States
| | - Marco Fragai
- CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
- Department of Chemistry “U. Schiff”, University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Giacomo Parigi
- CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
- Department of Chemistry “U. Schiff”, University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Hashim Al-Hashimi
- Department
of Biochemistry and Department of Chemistry, Duke University School of Medicine, 307 Research Drive, Durham, North Carolina 27710, United States
| | - Claudio Luchinat
- CERM, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
- Department of Chemistry “U. Schiff”, University of Florence, via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
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21
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Andrałojć W, Luchinat C, Parigi G, Ravera E. Exploring regions of conformational space occupied by two-domain proteins. J Phys Chem B 2014; 118:10576-87. [PMID: 25144917 DOI: 10.1021/jp504820w] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
The presence of heterogeneity in the interdomain arrangement of several biomolecules is required for their function. Here we present a method to obtain crucial clues to distinguish between different kinds of protein conformational distributions based on experimental NMR data. The method explores subregions of the conformational space and provides both upper and lower bounds of probability for the system to be in each subregion.
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Affiliation(s)
- Witold Andrałojć
- Center for Magnetic Resonance, University of Florence , Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
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22
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23
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Liu W, Skinner SP, Timmer M, Blok A, Hass MAS, Filippov DV, Overhand M, Ubbink M. A Two‐Armed Lanthanoid‐Chelating Paramagnetic NMR Probe Linked to Proteins via Thioether Linkages. Chemistry 2014; 20:6256-8. [DOI: 10.1002/chem.201400257] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2014] [Indexed: 01/01/2023]
Affiliation(s)
- Wei‐Min Liu
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
| | - Simon P. Skinner
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
| | - Monika Timmer
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
| | - Anneloes Blok
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
| | - Mathias A. S. Hass
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
| | - Dmitri V. Filippov
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
| | - Mark Overhand
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
| | - Marcellus Ubbink
- Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden (The Netherlands)
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24
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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] [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.
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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.
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25
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Rinaldelli M, Ravera E, Calderone V, Parigi G, Murshudov GN, Luchinat C. Simultaneous use of solution NMR and X-ray data in REFMAC5 for joint refinement/detection of structural differences. ACTA CRYSTALLOGRAPHICA. SECTION D, BIOLOGICAL CRYSTALLOGRAPHY 2014; 70:958-67. [PMID: 24699641 PMCID: PMC4306559 DOI: 10.1107/s1399004713034160] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/05/2013] [Accepted: 12/18/2013] [Indexed: 11/12/2022]
Abstract
The program REFMAC5 from CCP4 was modified to allow the simultaneous use of X-ray crystallographic data and paramagnetic NMR data (pseudocontact shifts and self-orientation residual dipolar couplings) and/or diamagnetic residual dipolar couplings. Incorporation of these long-range NMR restraints in REFMAC5 can reveal differences between solid-state and solution conformations of molecules or, in their absence, can be used together with X-ray crystallographic data for structural refinement. Since NMR and X-ray data are complementary, when a single structure is consistent with both sets of data and still maintains reasonably `ideal' geometries, the reliability of the derived atomic model is expected to increase. The program was tested on five different proteins: the catalytic domain of matrix metalloproteinase 1, GB3, ubiquitin, free calmodulin and calmodulin complexed with a peptide. In some cases the joint refinement produced a single model consistent with both sets of observations, while in other cases it indicated, outside the experimental uncertainty, the presence of different protein conformations in solution and in the solid state.
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Affiliation(s)
- Mauro Rinaldelli
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - Enrico Ravera
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - Vito Calderone
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - Giacomo Parigi
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
| | - Garib N. Murshudov
- MRC Laboratory of Molecular Biology, Francis Crick Avenue, Cambridge Biomedical Campus, Cambridge CB2 0QH, England
| | - Claudio Luchinat
- Center for Magnetic Resonance (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
- Department of Chemistry ‘Ugo Schiff’, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino (FI), Italy
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26
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Hass MAS, Ubbink M. Structure determination of protein–protein complexes with long-range anisotropic paramagnetic NMR restraints. Curr Opin Struct Biol 2014; 24:45-53. [DOI: 10.1016/j.sbi.2013.11.010] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2013] [Revised: 11/22/2013] [Accepted: 11/22/2013] [Indexed: 10/25/2022]
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27
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Russo L, Maestre-Martinez M, Wolff S, Becker S, Griesinger C. Interdomain dynamics explored by paramagnetic NMR. J Am Chem Soc 2013; 135:17111-20. [PMID: 24111622 DOI: 10.1021/ja408143f] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
An ensemble-based approach is presented to explore the conformational space sampled by a multidomain protein showing moderate interdomain dynamics in terms of translational and rotational motions. The strategy was applied on a complex of calmodulin (CaM) with the IQ-recognition motif from the voltage-gated calcium channel Ca(v)1.2 (IQ), which adopts three different interdomain orientations in the crystal. The N60D mutant of calmodulin was used to collect pseudocontact shifts and paramagnetically induced residual dipolar couplings for six different lanthanide ions. Then, starting from the crystal structure, pools of conformations were generated by free MD. We found the three crystal conformations in solution, but four additional MD-derived conformations had to be included into the ensemble to fulfill all the paramagnetic data and cross-validate optimally against unused paramagnetic data. Alternative approaches led to similar ensembles. Our "ensemble" approach is a simple and efficient tool to probe and describe the interdomain dynamics and represents a general method that can be used to provide a proper ensemble description of multidomain proteins.
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Affiliation(s)
- Luigi Russo
- NMR Based Structural Biology, Max Planck Institute for Biophysical Chemistry , Am Fassberg 11 37077 Göttingen, Germany
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28
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Fragai M, Luchinat C, Parigi G, Ravera E. Conformational freedom of metalloproteins revealed by paramagnetism-assisted NMR. Coord Chem Rev 2013. [DOI: 10.1016/j.ccr.2013.02.009] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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29
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Cerofolini L, Fields GB, Fragai M, Geraldes CFGC, Luchinat C, Parigi G, Ravera E, Svergun DI, Teixeira JMC. Examination of matrix metalloproteinase-1 in solution: a preference for the pre-collagenolysis state. J Biol Chem 2013; 288:30659-30671. [PMID: 24025334 DOI: 10.1074/jbc.m113.477240] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Catalysis of collagen degradation by matrix metalloproteinase 1 (MMP-1) has been proposed to critically rely on flexibility between the catalytic (CAT) and hemopexin-like (HPX) domains. A rigorous assessment of the most readily accessed conformations in solution is required to explain the onset of substrate recognition and collagenolysis. The present study utilized paramagnetic NMR spectroscopy and small angle x-ray scattering (SAXS) to calculate the maximum occurrence (MO) of MMP-1 conformations. The MMP-1 conformations with large MO values (up to 47%) are restricted into a relatively small conformational region. All conformations with high MO values differ largely from the closed MMP-1 structures obtained by x-ray crystallography. The MO of the latter is ~20%, which represents the upper limit for the presence of this conformation in the ensemble sampled by the protein in solution. In all the high MO conformations, the CAT and HPX domains are not in tight contact, and the residues of the HPX domain reported to be responsible for the binding to the collagen triple-helix are solvent exposed. Thus, overall analysis of the highest MO conformations indicated that MMP-1 in solution was poised to interact with collagen and then could readily proceed along the steps of collagenolysis.
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Affiliation(s)
| | - Gregg B Fields
- the Torrey Pines Institute for Molecular Studies, Port St. Lucie, Florida 34987,.
| | - Marco Fragai
- From the CERM and; the Department of Chemistry "U. Schiff," University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
| | - Carlos F G C Geraldes
- the Center for Neuroscience and Cell Biology and; the Department of Life Sciences, Faculty of Science and Technology, University of Coimbra, P.O. Box 3046, 3001-401 Coimbra, Portugal, and
| | - Claudio Luchinat
- From the CERM and; the Department of Chemistry "U. Schiff," University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (FI), Italy,.
| | - Giacomo Parigi
- From the CERM and; the Department of Chemistry "U. Schiff," University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
| | - Enrico Ravera
- From the CERM and; the Department of Chemistry "U. Schiff," University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino (FI), Italy
| | - Dmitri I Svergun
- the EMBL, c/o DESY, Notkestrasse 85, Geb. 25 A, 22603 Hamburg, Germany
| | - João M C Teixeira
- From the CERM and; the Center for Neuroscience and Cell Biology and; the Department of Life Sciences, Faculty of Science and Technology, University of Coimbra, P.O. Box 3046, 3001-401 Coimbra, Portugal, and
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30
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Guan JY, Keizers PHJ, Liu WM, Löhr F, Skinner SP, Heeneman EA, Schwalbe H, Ubbink M, Siegal G. Small-molecule binding sites on proteins established by paramagnetic NMR spectroscopy. J Am Chem Soc 2013; 135:5859-68. [PMID: 23509882 DOI: 10.1021/ja401323m] [Citation(s) in RCA: 80] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Determining the three-dimensional structure of a small molecule-protein complex with weak affinity can be a significant challenge. We present a paramagnetic NMR method to determine intermolecular structure restraints based on pseudocontact shifts (PCSs). Since the ligand must be in fast exchange between free and bound states and the fraction bound can be as low as a few percent, the method is ideal for ligands with high micromolar to millimolar dissociation constants. Paramagnetic tags are attached, one at a time, in a well-defined way via two arms at several sites on the protein surface. The ligand PCSs were measured from simple 1D (1)H spectra and used as docking restraints. An independent confirmation of the complex structure was carried out using intermolecular NOEs. The results show that structures derived from these two approaches are similar. The best results are obtained if the magnetic susceptibility tensors of the tags are known, but it is demonstrated that with two-armed probes, the magnetic susceptibility tensor can be predicted with sufficient accuracy to provide a low-resolution model of the ligand orientation and the location of the binding site in the absence of isotope-labeled protein. This approach can facilitate fragment-based drug discovery in obtaining structural information on the initial fragment hits.
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Affiliation(s)
- Jia-Ying Guan
- Gorlaeus Laboratories, Leiden Institute of Chemistry, Leiden University, Post Office Box 9502, 2300 RA Leiden, The Netherlands
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31
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Structural characterization of intrinsically disordered proteins by the combined use of NMR and SAXS. Biochem Soc Trans 2013; 40:955-62. [PMID: 22988847 DOI: 10.1042/bst20120149] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
In recent years, IDPs (intrinsically disordered proteins) have emerged as pivotal actors in biology. Despite IDPs being present in all kingdoms of life, they are more abundant in eukaryotes where they are involved in the vast majority of regulation and signalling processes. The realization that, in some cases, functional states of proteins were partly or fully disordered was in contradiction to the traditional view where a well defined three-dimensional structure was required for activity. Several experimental evidences indicate, however, that structural features in IDPs such as transient secondary-structural elements and overall dimensions are crucial to their function. NMR has been the main tool to study IDP structure by probing conformational preferences at residue level. Additionally, SAXS (small-angle X-ray scattering) has the capacity to report on the three-dimensional space sampled by disordered states and therefore complements the local information provided by NMR. The present review describes how the synergy between NMR and SAXS can be exploited to obtain more detailed structural and dynamic models of IDPs in solution. These combined strategies, embedded into computational approaches, promise the elucidation of the structure-function properties of this important, but elusive, family of biomolecules.
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32
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Bertini I, Ferella L, Luchinat C, Parigi G, Petoukhov MV, Ravera E, Rosato A, Svergun DI. MaxOcc: a web portal for maximum occurrence analysis. JOURNAL OF BIOMOLECULAR NMR 2012; 53:271-280. [PMID: 22639196 DOI: 10.1007/s10858-012-9638-1] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Accepted: 05/16/2012] [Indexed: 06/01/2023]
Abstract
The MaxOcc web portal is presented for the characterization of the conformational heterogeneity of two-domain proteins, through the calculation of the Maximum Occurrence that each protein conformation can have in agreement with experimental data. Whatever the real ensemble of conformations sampled by a protein, the weight of any conformation cannot exceed the calculated corresponding Maximum Occurrence value. The present portal allows users to compute these values using any combination of restraints like pseudocontact shifts, paramagnetism-based residual dipolar couplings, paramagnetic relaxation enhancements and small angle X-ray scattering profiles, given the 3D structure of the two domains as input. MaxOcc is embedded within the NMR grid services of the WeNMR project and is available via the WeNMR gateway at http://py-enmr.cerm.unifi.it/access/index/maxocc . It can be used freely upon registration to the grid with a digital certificate.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, FI, Italy.
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33
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Nagulapalli M, Parigi G, Yuan J, Gsponer J, Deraos G, Bamm VV, Harauz G, Matsoukas J, de Planque MRR, Gerothanassis IP, Babu MM, Luchinat C, Tzakos AG. Recognition pliability is coupled to structural heterogeneity: a calmodulin intrinsically disordered binding region complex. Structure 2012; 20:522-33. [PMID: 22405011 DOI: 10.1016/j.str.2012.01.021] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2011] [Revised: 12/01/2011] [Accepted: 01/03/2012] [Indexed: 11/18/2022]
Abstract
Protein interactions within regulatory networks should adapt in a spatiotemporal-dependent dynamic environment, in order to process and respond to diverse and versatile cellular signals. However, the principles governing recognition pliability in protein complexes are not well understood. We have investigated a region of the intrinsically disordered protein myelin basic protein (MBP(145-165)) that interacts with calmodulin, but that also promiscuously binds other biomolecules (membranes, modifying enzymes). To characterize this interaction, we implemented an NMR spectroscopic approach that calculates, for each conformation of the complex, the maximum occurrence based on recorded pseudocontact shifts and residual dipolar couplings. We found that the MBP(145-165)-calmodulin interaction is characterized by structural heterogeneity. Quantitative comparative analysis indicated that distinct conformational landscapes of structural heterogeneity are sampled for different calmodulin-target complexes. Such structural heterogeneity in protein complexes could potentially explain the way that transient and promiscuous protein interactions are optimized and tuned in complex regulatory networks.
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Affiliation(s)
- Malini Nagulapalli
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
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34
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Negi S, Aykut AO, Atilgan AR, Atilgan C. Calmodulin readily switches conformation upon protonating high pKa acidic residues. J Phys Chem B 2012; 116:7145-53. [PMID: 22624501 DOI: 10.1021/jp3032995] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
We investigate protonation as a possible route for triggering conformational change in proteins by focusing on the calmodulin (CaM) example. Two hundred nanosecond molecular dynamics (MD) simulations are performed on both the extended and compact forms of calcium loaded CaM. The stability of both structures is confirmed under prevailing conditions. Protonation of nine acidic residues with upshifted pK(a) values leads to a large conformational change in less than 100 ns. The structure attained is consistent with fluorescence resonance energy transfer experimental results as well as structures from an ensemble compatible with NMR data. Analysis of the MD trajectories summing up to one microsecond implies that the key events leading to the completion of the conformational change begins with an initial formation of a salt bridge between the N-lobe and the linker, followed by the bending of the C-lobe and the organization of a stabilizing hydrophobic patch between the lobes. We find that CaM utilizes its Ca(2+) ions to harden/soften different regions so as to achieve various conformations. Thus, barrier crossing between extended and compact forms of CaM which is normally a rare event due to the repulsive electrostatic interactions between the two lobes is facilitated by protonation of high pK(a) residues. The results delineate how pH changes might be utilized in the cell to achieve different conformation-related functions.
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Affiliation(s)
- Sunita Negi
- Sabanci University, Faculty of Engineering & Natural Sciences, Tuzla, 34956 Istanbul, Turkey
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35
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Bertini I, Luchinat C, Nagulapalli M, Parigi G, Ravera E. Paramagnetic relaxation enhancement for the characterization of the conformational heterogeneity in two-domain proteins. Phys Chem Chem Phys 2012; 14:9149-56. [PMID: 22622816 DOI: 10.1039/c2cp40139h] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Multidomain proteins are often composed of rigid domains that can reorient in solution more or less freely. Calmodulin (CaM) is a two domain protein which can experience a large degree of conformational freedom thanks to a mobile linker connecting the N-terminal and C-terminal domains of the protein. The maximum occurrences (MOs) of the possible protein conformations have been analyzed using the paramagnetic relaxation enhancements (PREs) induced by a gadolinium(III) ion together with the paramagnetic pseudocontact shift and residual dipolar coupling restraints measured in the presence of terbium(III), thulium(III) or dysprosium(III) ions. The results suggest that the PREs provide complementary information useful for improving the description of the conformational heterogeneity of the protein. The data, acquired at 298 K and at 278 K, suggest that compact conformations are disfavoured by decreasing the temperature.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino (FI), Italy.
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36
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Luchinat C, Parigi G, Ravera E, Rinaldelli M. Solid-state NMR crystallography through paramagnetic restraints. J Am Chem Soc 2012; 134:5006-9. [PMID: 22393876 DOI: 10.1021/ja210079n] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Pseudocontact shifts (PCSs) measured by solid-state NMR spectroscopy (SS-NMR) on microcrystalline powders of a paramagnetic metalloprotein permit NMR crystallography. Along with other restraints for SS-NMR experiments, the protein molecular structure as well as the correct crystal packing are obtained.
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Affiliation(s)
- Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, via Sacconi 6, Sesto Fiorentino, Italy.
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37
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Luchinat C, Nagulapalli M, Parigi G, Sgheri L. Maximum occurrence analysis of protein conformations for different distributions of paramagnetic metal ions within flexible two-domain proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2012; 215:85-93. [PMID: 22264683 DOI: 10.1016/j.jmr.2011.12.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/15/2011] [Revised: 12/14/2011] [Accepted: 12/18/2011] [Indexed: 05/31/2023]
Abstract
Multidomain proteins are composed of rigid domains connected by (flexible) linkers. Therefore, the domains may experience a large degree of reciprocal reorientation. Pseudocontact shifts and residual dipolar couplings arising from one or more paramagnetic metals successively placed in a single metal binding site in the protein can be used as restraints to assess the degree of mobility of the different domains. They can be used to determine the maximum occurrence (MO) of each possible protein conformation, i.e. the maximum weight that such conformations can have independently of the real structural ensemble, in agreement with the provided restraints. In the case of two-domain proteins, the metal ions can be placed all in the same domain, or distributed between the two domains. It has been demonstrated that the quantity of independent information for the characterization of the system is larger when all metals are bound in the same domain. At the same time, it has been shown that there are practical advantages in placing the metals in different domains. Here, it is shown that distributing the metals between the domains provides a tool for defining a coefficient of compatibility among the restraints obtained from different metals, without a significant decrease of the capability of the MO values to discriminate among conformations with different weights.
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Affiliation(s)
- Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy.
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38
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Anthis NJ, Doucleff M, Clore GM. Transient, sparsely populated compact states of apo and calcium-loaded calmodulin probed by paramagnetic relaxation enhancement: interplay of conformational selection and induced fit. J Am Chem Soc 2011; 133:18966-74. [PMID: 21999431 PMCID: PMC3218299 DOI: 10.1021/ja2082813] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Calmodulin (CaM) is the universal calcium sensor in eukaryotes, regulating the function of numerous proteins. Crystallography and NMR show that free CaM-4Ca(2+) exists in an extended conformation with significant interdomain separation, but clamps down upon target peptides to form a highly compact structure. NMR has revealed substantial interdomain motions in CaM-4Ca(2+), enabled by a flexible linker. In one instance, CaM-4Ca(2+) has been crystallized in a compact configuration; however, no direct evidence for transient interdomain contacts has been observed in solution, and little is known about how large-scale interdomain motions contribute to biological function. Here, we use paramagnetic relaxation enhancement (PRE) to characterize transient compact states of free CaM that are too sparsely populated to observe by traditional NMR methods. We show that unbound CaM samples a range of compact structures, populated at 5-10%, and that Ca(2+) dramatically alters the distribution of these configurations in favor of states resembling the peptide-bound structure. In the absence of Ca(2+), the target peptide binds only to the C-terminal domain, and the distribution of compact states is similar with and without peptide. These data suggest an alternative pathway of CaM action in which CaM remains associated with its kinase targets even in the resting state. Only CaM-4Ca(2+), however, shows an innate propensity to form the physiologically active compact structures, suggesting that Ca(2+) activates CaM not only through local structural changes within each domain but also through more global remodeling of interdomain interactions. Thus, these findings illustrate the subtle interplay between conformational selection and induced fit.
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Affiliation(s)
- Nicholas J. Anthis
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, U.S.A
| | | | - G. Marius Clore
- Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland 20892-0520, U.S.A
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