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Barthelmes D, Gränz M, Barthelmes K, Allen KN, Imperiali B, Prisner T, Schwalbe H. Encoded loop-lanthanide-binding tags for long-range distance measurements in proteins by NMR and EPR spectroscopy. JOURNAL OF BIOMOLECULAR NMR 2015; 63:275-282. [PMID: 26341230 DOI: 10.1007/s10858-015-9984-x] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2015] [Accepted: 09/01/2015] [Indexed: 06/05/2023]
Abstract
We recently engineered encodable lanthanide binding tags (LBTs) into proteins and demonstrated their applicability in Nuclear Magnetic Resonance (NMR) spectroscopy, X-ray crystallography and luminescence studies. Here, we engineered two-loop-LBTs into the model protein interleukin-1β (IL1β) and measured (1)H, (15)N-pseudocontact shifts (PCSs) by NMR spectroscopy. We determined the Δχ-tensors associated with each Tm(3+)-loaded loop-LBT and show that the experimental PCSs yield structural information at the interface between the two metal ion centers at atomic resolution. Such information is very valuable for the determination of the sites of interfaces in protein-protein-complexes. Combining the experimental PCSs of the two-loop-LBT construct IL1β-S2R2 and the respective single-loop-LBT constructs IL1β-S2, IL1β-R2 we additionally determined the distance between the metal ion centers. Further, we explore the use of two-loop LBTs loaded with Gd(3+) as a novel tool for distance determination by Electron Paramagnetic Resonance spectroscopy and show the NMR-derived distances to be remarkably consistent with distances derived from Pulsed Electron-Electron Dipolar Resonance.
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Affiliation(s)
- Dominic Barthelmes
- Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt Am Main, Germany
| | - Markus Gränz
- Institute of Physical and Theoretical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt Am Main, Germany
| | - Katja Barthelmes
- Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt Am Main, Germany
- Department of Chemistry, Munich Center for Integrated Protein Science and Chair Biomolecular NMR, Technical University Munich, Lichtenbergstrasse 4, 85747, Garching, Germany
| | - Karen N Allen
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, MA, 02215, USA
| | - Barbara Imperiali
- Departments of Chemistry and Biology, Massachusetts Institute of Technology, 77 Massachusetts Avenue, Cambridge, MA, 02139, USA
| | - Thomas Prisner
- Institute of Physical and Theoretical Chemistry, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt Am Main, Germany.
| | - Harald Schwalbe
- Institute of Organic Chemistry and Chemical Biology, Center for Biomolecular Magnetic Resonance, Goethe University Frankfurt, Max-von-Laue-Straße 7, 60438, Frankfurt Am Main, Germany.
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53
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Witten J, Ruschak A, Poterba T, Jaramillo A, Miranker AD, Jaswal SS. Mapping Protein Conformational Landscapes under Strongly Native Conditions with Hydrogen Exchange Mass Spectrometry. J Phys Chem B 2015; 119:10016-24. [DOI: 10.1021/acs.jpcb.5b04528] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Jacob Witten
- Department
of Chemistry, Amherst College, P.O. Box 5000, Amherst, Massachusetts 01002, United States
| | - Amy Ruschak
- Department
of Molecular Biophysics and Biochemistry, Yale University, P.O. Box 208114, New Haven, Connecticut 06520-81114, United States
| | - Timothy Poterba
- Department
of Chemistry, Amherst College, P.O. Box 5000, Amherst, Massachusetts 01002, United States
| | - Alexis Jaramillo
- Department
of Chemistry, Amherst College, P.O. Box 5000, Amherst, Massachusetts 01002, United States
| | - Andrew D. Miranker
- Department
of Molecular Biophysics and Biochemistry, Yale University, P.O. Box 208114, New Haven, Connecticut 06520-81114, United States
| | - Sheila S. Jaswal
- Department
of Chemistry, Amherst College, P.O. Box 5000, Amherst, Massachusetts 01002, United States
- Department
of Molecular Biophysics and Biochemistry, Yale University, P.O. Box 208114, New Haven, Connecticut 06520-81114, United States
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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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55
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Marasco D, Scognamiglio PL. Identification of inhibitors of biological interactions involving intrinsically disordered proteins. Int J Mol Sci 2015; 16:7394-412. [PMID: 25849651 PMCID: PMC4425024 DOI: 10.3390/ijms16047394] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2015] [Revised: 03/01/2015] [Accepted: 03/06/2015] [Indexed: 11/16/2022] Open
Abstract
Protein-protein interactions involving disordered partners have unique features and represent prominent targets in drug discovery processes. Intrinsically Disordered Proteins (IDPs) are involved in cellular regulation, signaling and control: they bind to multiple partners and these high-specificity/low-affinity interactions play crucial roles in many human diseases. Disordered regions, terminal tails and flexible linkers are particularly abundant in DNA-binding proteins and play crucial roles in the affinity and specificity of DNA recognizing processes. Protein complexes involving IDPs are short-lived and typically involve short amino acid stretches bearing few "hot spots", thus the identification of molecules able to modulate them can produce important lead compounds: in this scenario peptides and/or peptidomimetics, deriving from structure-based, combinatorial or protein dissection approaches, can play a key role as hit compounds. Here, we propose a panoramic review of the structural features of IDPs and how they regulate molecular recognition mechanisms focusing attention on recently reported drug-design strategies in the field of IDPs.
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Affiliation(s)
- Daniela Marasco
- Department of Pharmacy, Centro Interuniversitario di Ricerca sui Peptidi Bioattivi (CIRPEB), University of Naples "Federico II", DFM-Scarl, 80134 Naples, Italy.
| | - Pasqualina Liana Scognamiglio
- Department of Pharmacy, Centro Interuniversitario di Ricerca sui Peptidi Bioattivi (CIRPEB), University of Naples "Federico II", DFM-Scarl, 80134 Naples, Italy.
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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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57
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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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Russo L, Palmieri M, Caso JV, D'Abrosca G, Diana D, Malgieri G, Baglivo I, Isernia C, Pedone PV, Fattorusso R. Towards understanding the molecular recognition process in prokaryotic zinc-finger domain. Eur J Med Chem 2014; 91:100-8. [PMID: 25240418 DOI: 10.1016/j.ejmech.2014.09.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Revised: 09/05/2014] [Accepted: 09/11/2014] [Indexed: 10/24/2022]
Abstract
Eukaryotic Cys2His2 zinc finger domain is one of the most common and important structural motifs involved in protein-DNA interaction. The recognition motif is characterized by the tetrahedral coordination of a zinc ion by conserved cysteine and histidine residues. We have characterized the prokaryotic Cys2His2 zinc finger motif, included in the DNA binding region (Ros87) of Ros protein from Agrobacterium tumefaciens, demonstrating that, although possessing a similar zinc coordination sphere, this domain presents significant differences from its eukaryotic counterpart. Furthermore, basic residues flanking the zinc binding region on either side have been demonstrated, by Electrophoretic Mobility Shift Assay (EMSA) experiments, to be essential for Ros DNA binding. In spite of this wealth of knowledge, the structural details of the mechanism through which the prokaryotic zinc fingers recognize their target genes are still unclear. Here, to gain insights into the molecular DNA recognition process of prokaryotic zinc finger domains we applied a strategy in which we performed molecular docking studies using a combination of Nuclear Magnetic Resonance (NMR) and Molecular Dynamics (MD) simulations data. The results demonstrate that the MD ensemble provides a reasonable picture of Ros87 backbone dynamics in solution. The Ros87-DNA model indicates that the interaction involves the first two residue of the first α-helix, and several residues located in the basic regions flanking the zinc finger domain. Interestingly, the prokaryotic zinc finger domain, mainly with the C-terminal tail that is wrapped around the DNA, binds a more extended recognition site than the eukaryotic counterpart. Our analysis demonstrates that the introduction of the protein flexibility in docking studies can improve, in terms of accuracy, the quality of the obtained models and could be particularly useful for protein showing high conformational heterogeneity as well as for computational drug design applications.
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Affiliation(s)
- Luigi Russo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy
| | - Maddalena Palmieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy
| | - Jolanda Valentina Caso
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy
| | - Gianluca D'Abrosca
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy
| | - Donatella Diana
- Institute of Biostructures and Bioimaging -CNR, Via Mezzocannone 16, 80134 Naples, Italy
| | - Gaetano Malgieri
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy
| | - Ilaria Baglivo
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy
| | - Carla Isernia
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy; Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy
| | - Paolo V Pedone
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy
| | - Roberto Fattorusso
- Department of Environmental, Biological and Pharmaceutical Sciences and Technology, Via Vivaldi 43, 81100 Caserta, Italy; Interuniversity Centre for Research on Bioactive Peptides (CIRPEB), University of Naples Federico II, Via Mezzocannone 16, 80134 Naples, Italy.
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Gill ML, Palmer AG. Local isotropic diffusion approximation for coupled internal and overall molecular motions in NMR spin relaxation. J Phys Chem B 2014; 118:11120-8. [PMID: 25167331 PMCID: PMC4174990 DOI: 10.1021/jp506580c] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The present work demonstrates that NMR spin relaxation rate constants for molecules interconverting between states with different diffusion tensors can be modeled theoretically by combining orientational correlation functions for exchanging spherical molecules with locally isotropic approximations for the diffusion anisotropic tensors. The resulting expressions are validated by comparison with correlation functions obtained by Monte Carlo simulations and are accurate for moderate degrees of diffusion anisotropy typically encountered in investigations of globular proteins. The results are complementary to an elegant, but more complex, formalism that is accurate for all degrees of diffusion anisotropy [Ryabov, Y.; Clore, G. M.; Schwieters, C. D. J. Chem. Phys. 2012, 136, 034108].
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Affiliation(s)
- Michelle L Gill
- Department of Biochemistry and Molecular Biophysics, Columbia University , 630 West 168th Street, New York, New York 10032, United States
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60
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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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61
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Huang JR, Warner LR, Sanchez C, Gabel F, Madl T, Mackereth CD, Sattler M, Blackledge M. Transient electrostatic interactions dominate the conformational equilibrium sampled by multidomain splicing factor U2AF65: a combined NMR and SAXS study. J Am Chem Soc 2014; 136:7068-76. [PMID: 24734879 DOI: 10.1021/ja502030n] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Multidomain proteins containing intrinsically disordered linkers exhibit large-scale dynamic modes that play key roles in a multitude of molecular recognition and signaling processes. Here, we determine the conformational space sampled by the multidomain splicing factor U2AF65 using complementary nuclear magnetic resonance spectroscopy and small-angle scattering data. Available degrees of conformational freedom are initially stochastically sampled and experimental data then used to delineate the potential energy landscape in terms of statistical probability. The spatial distribution of U2AF65 conformations is found to be highly anisotropic, comprising significantly populated interdomain contacts that appear to be electrostatic in origin. This hypothesis is supported by the reduction of signature PREs reporting on expected interfaces with increasing salt concentration. The described spatial distribution reveals the complete spectrum of the unbound forms of U2AF65 that coexist with the small percentage of a preformed RNA-bound domain arrangement required for polypyrimidine-tract recognition by conformational selection. More generally, the proposed approach to describing conformational equilibria of multidomain proteins can be further combined with other experimental data that are sensitive to domain dynamics.
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Affiliation(s)
- Jie-rong Huang
- University Grenoble Alpes, ‡CNRS, and §CEA, Protein Dynamics and Flexibility, Institut de Biologie Structurale , 38000 Grenoble, France
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62
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Determination of the individual roles of the linker residues in the interdomain motions of calmodulin using NMR chemical shifts. J Mol Biol 2014; 426:1826-38. [PMID: 24530797 DOI: 10.1016/j.jmb.2014.02.002] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2013] [Revised: 01/18/2014] [Accepted: 02/04/2014] [Indexed: 12/22/2022]
Abstract
Many protein molecules are formed by two or more domains whose structures and dynamics are closely related to their biological functions. It is thus important to develop methods to determine the structural properties of these multidomain proteins. Here, we characterize the interdomain motions in the calcium-bound state of calmodulin (Ca(2+)-CaM) using NMR chemical shifts as replica-averaged structural restraints in molecular dynamics simulations. We find that the conformational fluctuations of the interdomain linker, which are largely responsible for the overall interdomain motions of CaM, can be well described by exploiting the information provided by chemical shifts. We thus identify 10 residues in the interdomain linker region that change their conformations upon substrate binding. Five of these residues (Met76, Lys77, Thr79, Asp80 and Ser81) are highly flexible and cover the range of conformations observed in the substrate-bound state, while the remaining five (Arg74, Lys75, Asp78, Glu82 and Glu83) are much more rigid and do not populate conformations typical of the substrate-bound form. The ensemble of conformations representing the Ca(2+)-CaM state obtained in this study is in good agreement with residual dipolar coupling, paramagnetic resonance enhancement, small-angle X-ray scattering and fluorescence resonance energy transfer measurements, which were not used as restraints in the calculations. These results provide initial evidence that chemical shifts can be used to characterize the conformational fluctuations of multidomain proteins.
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63
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Ciofi-Baffoni S, Gallo A, Muzzioli R, Piccioli M. The IR-¹⁵N-HSQC-AP experiment: a new tool for NMR spectroscopy of paramagnetic molecules. JOURNAL OF BIOMOLECULAR NMR 2014; 58:123-8. [PMID: 24414179 DOI: 10.1007/s10858-013-9810-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/29/2013] [Accepted: 12/27/2013] [Indexed: 05/22/2023]
Abstract
A crucial factor for the understanding of structure-function relationships in metalloproteins is the identification of NMR signals from residues surrounding the metal cofactor. When the latter is paramagnetic, the NMR information in the proximity of the metal center may be scarce, because fast nuclear relaxation quenches signal intensity and coherence transfer efficiency. To identify residues at a short distance from a paramagnetic center, we developed a modified version of the ¹⁵N-HSQC experiment where (1) an inversion recovery filter is added prior to HSQC, (2) the INEPT period has been optimized according to fast relaxation of interested spins, (3) the inverse INEPT has been eliminated and signals acquired as antiphase doublets. The experiment has been successfully tested on a human [Fe₂S₂] protein which is involved in the biogenesis of iron-sulfur proteins. Thirteen HN resonances, unobserved with conventional HSQC experiments, could be identified. The structural arrangement of the protein scaffold in the proximity of the Fe/S cluster is fundamental to comprehend the molecular processes responsible for the transfer of Fe/S groups in the iron-sulfur protein assembly machineries.
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Affiliation(s)
- Simone Ciofi-Baffoni
- Magnetic Resonance Center and Department of Chemistry, University of Florence, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Florence, Italy
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