1
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Vogel R, Müntener T, Häussinger D. Intrinsic anisotropy parameters of a series of lanthanoid complexes deliver new insights into the structure-magnetism relationship. Chem 2021. [DOI: 10.1016/j.chempr.2021.08.011] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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2
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Lehr M, Paschelke T, Trumpf E, Vogt A, Näther C, Sönnichsen FD, McConnell AJ. A Paramagnetic NMR Spectroscopy Toolbox for the Characterisation of Paramagnetic/Spin-Crossover Coordination Complexes and Metal-Organic Cages. Angew Chem Int Ed Engl 2020; 59:19344-19351. [PMID: 33448544 PMCID: PMC7590057 DOI: 10.1002/anie.202008439] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2020] [Indexed: 12/14/2022]
Abstract
The large paramagnetic shifts and short relaxation times resulting from the presence of a paramagnetic centre complicate NMR data acquisition and interpretation in solution. As a result, NMR analysis of paramagnetic complexes is limited in comparison to diamagnetic compounds and often relies on theoretical models. We report a toolbox of 1D (1H, proton-coupled 13C, selective 1H-decoupling 13C, steady-state NOE) and 2D (COSY, NOESY, HMQC) paramagnetic NMR methods that enables unprecedented structural characterisation and in some cases, provides more structural information than would be observable for a diamagnetic analogue. We demonstrate the toolbox's broad versatility for fields from coordination chemistry and spin-crossover complexes to supramolecular chemistry through the characterisation of CoII and high-spin FeII mononuclear complexes as well as a Co4L6 cage.
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Affiliation(s)
- Marc Lehr
- Otto Diels Institute of Organic ChemistryChristian-Albrechts-Universität zu KielOtto-Hahn-Platz 4Kiel24098Germany
| | - Tobias Paschelke
- Otto Diels Institute of Organic ChemistryChristian-Albrechts-Universität zu KielOtto-Hahn-Platz 4Kiel24098Germany
| | - Eicke Trumpf
- Otto Diels Institute of Organic ChemistryChristian-Albrechts-Universität zu KielOtto-Hahn-Platz 4Kiel24098Germany
| | - Anna‐Marlene Vogt
- Otto Diels Institute of Organic ChemistryChristian-Albrechts-Universität zu KielOtto-Hahn-Platz 4Kiel24098Germany
| | - Christian Näther
- Institute of Inorganic ChemistryChristian-Albrechts-Universität zu KielMax-Eyth-Straße 2Kiel24118Germany
| | - Frank D. Sönnichsen
- Otto Diels Institute of Organic ChemistryChristian-Albrechts-Universität zu KielOtto-Hahn-Platz 4Kiel24098Germany
| | - Anna J. McConnell
- Otto Diels Institute of Organic ChemistryChristian-Albrechts-Universität zu KielOtto-Hahn-Platz 4Kiel24098Germany
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3
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Invernici M, Trindade IB, Cantini F, Louro RO, Piccioli M. Measuring transverse relaxation in highly paramagnetic systems. JOURNAL OF BIOMOLECULAR NMR 2020; 74:431-442. [PMID: 32710399 PMCID: PMC7508935 DOI: 10.1007/s10858-020-00334-w] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/17/2020] [Accepted: 07/09/2020] [Indexed: 05/16/2023]
Abstract
The enhancement of nuclear relaxation rates due to the interaction with a paramagnetic center (known as Paramagnetic Relaxation Enhancement) is a powerful source of structural and dynamics information, widely used in structural biology. However, many signals affected by the hyperfine interaction relax faster than the evolution periods of common NMR experiments and therefore they are broadened beyond detection. This gives rise to a so-called blind sphere around the paramagnetic center, which is a major limitation in the use of PREs. Reducing the blind sphere is extremely important in paramagnetic metalloproteins. The identification, characterization, and proper structural restraining of the first coordination sphere of the metal ion(s) and its immediate neighboring regions is key to understand their biological function. The novel HSQC scheme we propose here, that we termed R2-weighted, HSQC-AP, achieves this aim by detecting signals that escaped detection in a conventional HSQC experiment and provides fully reliable R2 values in the range of 1H R2 rates ca. 50-400 s-1. Independently on the type of paramagnetic center and on the size of the molecule, this experiment decreases the radius of the blind sphere and increases the number of detectable PREs. Here, we report the validation of this approach for the case of PioC, a small protein containing a high potential 4Fe-4S cluster in the reduced [Fe4S4]2+ form. The blind sphere was contracted to a minimal extent, enabling the measurement of R2 rates for the cluster coordinating residues.
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Affiliation(s)
- Michele Invernici
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Inês B Trindade
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal
| | - Francesca Cantini
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Ricardo O Louro
- Instituto de Tecnologia Química e Biológica António Xavier (ITQB-NOVA), Universidade Nova de Lisboa, Av. da República (EAN), 2780-157, Oeiras, Portugal.
| | - Mario Piccioli
- Magnetic Resonance Center (CERM) and Department of Chemistry, University of Florence, Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
- Consorzio Interuniversitario Risonanze Magnetiche Di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy.
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4
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Lehr M, Paschelke T, Trumpf E, Vogt A, Näther C, Sönnichsen FD, McConnell AJ. Ein Methodenrepertoire für die paramagnetische NMR‐Spektroskopie zur Charakterisierung von paramagnetischen/Spin‐Crossover‐ Komplexen und Metall‐organischen Käfigverbindungen. Angew Chem Int Ed Engl 2020. [DOI: 10.1002/ange.202008439] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Marc Lehr
- Otto-Diels-Institut für Organische Chemie Christian-Albrechts-Universität zu Kiel Otto-Hahn-Platz 4 Kiel 24098 Deutschland
| | - Tobias Paschelke
- Otto-Diels-Institut für Organische Chemie Christian-Albrechts-Universität zu Kiel Otto-Hahn-Platz 4 Kiel 24098 Deutschland
| | - Eicke Trumpf
- Otto-Diels-Institut für Organische Chemie Christian-Albrechts-Universität zu Kiel Otto-Hahn-Platz 4 Kiel 24098 Deutschland
| | - Anna‐Marlene Vogt
- Otto-Diels-Institut für Organische Chemie Christian-Albrechts-Universität zu Kiel Otto-Hahn-Platz 4 Kiel 24098 Deutschland
| | - Christian Näther
- Institut für Anorganische Chemie Christian-Albrechts-Universität zu Kiel Max-Eyth-Straße 2 Kiel 24118 Deutschland
| | - Frank D. Sönnichsen
- Otto-Diels-Institut für Organische Chemie Christian-Albrechts-Universität zu Kiel Otto-Hahn-Platz 4 Kiel 24098 Deutschland
| | - Anna J. McConnell
- Otto-Diels-Institut für Organische Chemie Christian-Albrechts-Universität zu Kiel Otto-Hahn-Platz 4 Kiel 24098 Deutschland
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5
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Parigi G, Ravera E, Luchinat C. Magnetic susceptibility and paramagnetism-based NMR. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2019; 114-115:211-236. [PMID: 31779881 DOI: 10.1016/j.pnmrs.2019.06.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/08/2019] [Revised: 06/17/2019] [Accepted: 06/17/2019] [Indexed: 05/18/2023]
Abstract
The magnetic interactions between the nuclear magnetic moment and the magnetic moment of unpaired electron(s) depend on the structure and dynamics of the molecules where the paramagnetic center is located and of their partners. The long-range nature of the magnetic interactions is thus a reporter of invaluable information for structural biology studies, when other techniques often do not provide enough data for the atomic-level characterization of the system. This precious information explains the flourishing of paramagnetism-assisted NMR studies in recent years. Many paramagnetic effects are related to the magnetic susceptibility of the paramagnetic metal. Although these effects have been known for more than half a century, different theoretical models and new approaches have been proposed in the last decade. In this review, we have summarized the consequences for NMR spectroscopy of magnetic interactions between nuclear and electron magnetic moments, and thus of the presence of a magnetic susceptibility due to metals, and we do so using a unified notation.
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Affiliation(s)
- Giacomo Parigi
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), 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
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.
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6
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Orton HW, Kuprov I, Loh CT, Otting G. Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR. J Phys Chem Lett 2016; 7:4815-4818. [PMID: 27934036 DOI: 10.1021/acs.jpclett.6b02417] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Paramagnetic metal ions accelerate nuclear spin relaxation; this effect is widely used for distance measurement and called paramagnetic relaxation enhancement (PRE). Theoretical predictions established that, under special circumstances, it is also possible to achieve a reduction in nuclear relaxation rates (negative PRE). This situation would occur if the mechanism of nuclear relaxation in the diamagnetic state is counterbalanced by a paramagnetic relaxation mechanism caused by the metal ion. Here we report the first experimental evidence for such a cross-correlation effect. Using a uniformly 15N-labeled mutant of calbindin D9k loaded with either Tm3+ or Tb3+, reduced R1 and R2 relaxation rates of backbone 15N spins were observed compared with the diamagnetic reference (the same protein loaded with Y3+). The effect arises from the compensation of the chemical shift anisotropy tensor by the anisotropic dipolar shielding generated by the unpaired electron spin.
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Affiliation(s)
- Henry W Orton
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Ilya Kuprov
- School of Chemistry, University of Southampton , Southampton, SO17 1BJ, United Kingdom
| | - Choy-Theng Loh
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
| | - Gottfried Otting
- Research School of Chemistry, Australian National University , Canberra, ACT 2601, Australia
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7
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Piccioli M, Turano P. Transient iron coordination sites in proteins: Exploiting the dual nature of paramagnetic NMR. Coord Chem Rev 2015. [DOI: 10.1016/j.ccr.2014.05.007] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
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8
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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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9
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Bertini I, Jiménez B, Piccioli M, Poggi L. Asymmetry in 13C-13C COSY spectra provides information on ligand geometry in paramagnetic proteins. J Am Chem Soc 2005; 127:12216-7. [PMID: 16131187 DOI: 10.1021/ja051058m] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The relative intensity of Calpha-C' cross-peaks in homonuclear 13C COSY spectra depends on the relaxation properties of Calpha and C' spins, which, in the proximity of a paramagnetic center, are related to the metal-to-carbon distance. Their quantitative analysis has lead, for the cerium-substituted dicalcium protein, calbindin D9k, to the straightforward identification of peaks arising from metal-coordinating groups. The monodentate or bidentate metal binding mode of carboxylates was identified directly via NMR.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.
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10
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Abstract
This article deals with the solution structure determination of paramagnetic metalloproteins by NMR spectroscopy. These proteins were believed not to be suitable for NMR investigations for structure determination until a decade ago, but eventually novel experiments and software protocols were developed, with the aim of making the approach suitable for the goal and as user-friendly and safe as possible. In the article, we also give hints for the optimization of experiments with respect to each particular metal ion, with the aim of also providing a handy tool for nonspecialists. Finally, a section is dedicated to the significant progress made on 13C direct detection, which reduces the negative effects of paramagnetism and may constitute a new chapter in the whole field of NMR spectroscopy.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center, University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy.
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11
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Bertini I, Jiménez B, Piccioli M. 13C direct detected experiments: optimization for paramagnetic signals. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2005; 174:125-132. [PMID: 15809180 DOI: 10.1016/j.jmr.2005.01.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2004] [Revised: 01/12/2005] [Indexed: 05/24/2023]
Abstract
To optimize 13C direct detected experiments for the observation of signals close to a paramagnetic center, we have assessed the sensitivity of different sequences based on CO-Cali coherence transfer. Features of CACO experiments were tested for Calbindin D9k, in which one of the two native Ca2+ ions is replaced by the paramagnetic Ce3+ ion. We have studied the comparison of single vs multiple quantum coherence transfer evolution as well as the influence of in-phase vs anti-phase detection of 13CO signals and finally the comparison of a coherence transfer step based on a CyO in plane with respect to a Cy ali in plane. The acquisition of the anti-phase component of the signal, accomplished by the removal of the last refocusing steps, allowed the identification of some signals unobserved with other pathways. The structural dependency of paramagnetism-induced nuclear relaxation is such that the identification of the most suitable coherence transfer pathway is not known "a priori" but it is driven by the relative proximity of Cali and CO to the paramagnetic center.
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Affiliation(s)
- Ivano Bertini
- Magnetic Resonance Center, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.
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12
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KOWALEWSKI JOZEF, KRUK DANUTA, PARIGI GIACOMO. NMR RELAXATION IN SOLUTION OF PARAMAGNETIC COMPLEXES: RECENT THEORETICAL PROGRESS FOR S≥1. ADVANCES IN INORGANIC CHEMISTRY 2005. [DOI: 10.1016/s0898-8838(05)57002-8] [Citation(s) in RCA: 107] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Kateb F, Piccioli M. New Routes to the Detection of Relaxation Allowed Coherence Transfer in Paramagnetic Molecules. J Am Chem Soc 2003; 125:14978-9. [PMID: 14653719 DOI: 10.1021/ja038101v] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A new pulse sequence is proposed to measure cross correlation rates between 1H Curie spin relaxation and 1H-15N or 1H-13C dipole-dipole coupling (%@mt;sys@%Gamma%@sx@%H,HX%@be@%CS,DD%@sxx@%%@mx@% ) in paramagnetic systems. The new sequence has been conceived to obtain quantitative measurements of cross correlation rates in the close proximity to the paramagnetic center, preventing the loss of information due to fast transverse relaxation. The approach was tested on the dicalcium protein calbindin D9k in which Ca2+ has been substituted at site II with Ce3+. At variance with previously reported experiments, all peaks observed in HSQC experiments tailored to paramagnetic signals give quantitative estimates of %@mt;sys@%Gamma%@sx@%H%@ital@%,%@rsf@%HX%@be@%CS%@ital@%,%@rsf@%DD%@sxx@%%@mx@% . This is crucial to refine the immediate proximity of the metal ion.
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Affiliation(s)
- Fathia Kateb
- Magnetic Resonance Center, University of Florence, Via L. Sacconi 4, 50019 Sesto Fiorentino, Italy
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14
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Bertini I, Luchinat C, Parigi G. Paramagnetic constraints: An aid for quick solution structure determination of paramagnetic metalloproteins. ACTA ACUST UNITED AC 2002. [DOI: 10.1002/cmr.10027] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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15
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Piccioli M, Poggi L. Tailored HCCH-TOCSY experiment for resonance assignment in the proximity of a paramagnetic center. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 155:236-243. [PMID: 12036334 DOI: 10.1006/jmre.2002.2522] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The presence of a paramagnetic center may disturb both coherent and incoherent communication between nuclear spins that are affected, to some extent, by the hyperfine interaction. This is a limiting factor to an extensive use of paramagnetic probes in NMR spectroscopy to enhance partial alignment and to exploit cross correlation effects and pseudocontact shifts. We propose here an HCCH-TOCSY experiment tailored to identify spin systems involving resonances that are partly or completely affected by hyperfine interaction. The efficiency of polarization transfer steps when fast relaxing nuclei are involved is discussed. The sequence is tested for the protein Calbindin D(9k), in which one of the two native Ca2+ ions is replaced by the paramagnetic Ce3+ ion as well as for the oxidized form of cytochrome b(562).
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Affiliation(s)
- Mario Piccioli
- Magnetic Resonance Center, University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
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16
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Madhu PK, Mandal PK, Müller N. Cross-correlation effects involving curie spin relaxation in methyl groups. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 155:29-38. [PMID: 11945030 DOI: 10.1006/jmre.2001.2496] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cross-correlation effects arising in methyl protons due to the simultaneous presence of dipole-dipole, chemical shift anisotropy, and Curie spin relaxation mechanisms in paramagnetic systems are analyzed. We assess the potential of obtaining structural constraints from the cross-correlation of Curie spin relaxation with dipolar relaxation mechanisms among methyl proton spins. By theoretical analysis and numerical simulations we characterize the transfer functions describing the interconversion processes of different ranks of multispin order. The time dependence of these processes contains a new type of structural information, the orientation of the methyl C(3)-axis with respect to the electron center. Experimental confirmation is found for selected methyl groups in low spin Fe(3+) sperm whale myoglobin.
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Affiliation(s)
- P K Madhu
- Institut für Chemie, Johannes Kepler Universität, Linz, Austria
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17
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Bertini I, Kowalewski J, Luchinat C, Parigi G. Cross correlation between the dipole-dipole interaction and the Curie spin relaxation: the effect of anisotropic magnetic susceptibility. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2001; 152:103-108. [PMID: 11531369 DOI: 10.1006/jmre.2001.2378] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Cross-correlated relaxation caused by the interference of nuclear dipole-dipole interaction and the Curie spin relaxation (DD-CSR cross relaxation) is generalized to treat the case of anisotropic magnetic susceptibility, including the important case where the latter originates from zero-field splitting. It is shown that the phenomenon of DD-CSR cross relaxation is absolutely general and to be expected under any electronic configuration. The results of the generalization are presented for a model system, and the consequences for paramagnetic metalloproteins are illustrated with an example of cerium(III)-substituted calbindin. The effects of the magnetic anisotropy are found to be substantial.
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Affiliation(s)
- I Bertini
- CERM and Department of Chemistry, University of Florence, Via L. Sacconi, 6, I-50019 Sesto Fiorentino, Italy
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18
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Affiliation(s)
- I Bertini
- Magnetic Resonance Center (CERM), University of Florence, Florence 50019, Italy
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19
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Abstract
The detection and assignment of NMR spectroscopic signals of carbon atoms from carbonyl and carboxylate groups in the loop hosting the Ce(III) ion was performed for the cerium-substituted calcium-binding protein calbindin D9k. This provided a tool to characterize in solution the first coordination sphere of the metal ion. Due to the well-documented possibility of replacing calcium with metal ions of the Ln(III) series, this approach turns out to be extremely efficient for characterizing in solution the coordination of calcium ions in proteins, independently of the availability of X-ray crystal structures. The present approach completes the structural characterization of lanthanide-substituted calcium-binding proteins, for which the role of long-range constraints arising from hyperfine interaction and self-orientation has already been assessed.
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Affiliation(s)
- I Bertini
- Magnetic Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Florence, Italy.
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20
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Mandal PK, Madhu P, Müller N. Nuclear magnetic relaxation of methyl protons in a paramagnetic protein: cross-correlation effects. Chem Phys Lett 2000. [DOI: 10.1016/s0009-2614(00)00243-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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21
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DESVAUX HERVÉ, GOCHIN MIRIAM. Coherence transfer between nuclear spins in paramagnetic systems: effects of nucleus—electron dipole—dipole cross-correlation. Mol Phys 1999. [DOI: 10.1080/00268979909483076] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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22
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Bertini I, Luchinat C, Rosato A. NMR Spectra of Iron-Sulfur Proteins. ADVANCES IN INORGANIC CHEMISTRY 1999. [DOI: 10.1016/s0898-8838(08)60080-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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23
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Qiu F, Rivera M, Stark RE. An 1H-13C-13C-edited 1H NMR experiment for making resonance assignments in the active site of heme proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 1998; 130:76-81. [PMID: 9469900 DOI: 10.1006/jmre.1997.1276] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
In paramagnetic heme proteins, it is often problematic to make proton resonance assignments for heme substituents that do not have large isotropic shifts and consequently lie under the large envelope of polypeptide resonances. Furthermore, assignments that would normally be performed with the aid of HMBC experiments in diamagnetic molecules can prove difficult in the active site of paramagnetic heme proteins if T2(-1) > 2JCH. To circumvent this problem, a new method is presented to selectively detect 1H in 1Hn-13C-13C fragments biosynthetically introduced into the active site of heme proteins. The pulse sequence combines well-known building blocks such as INEPT to transfer 1H spin magnetization to bonded 13C nuclei, followed by INADEQUATE to generate 13C-13C double-quantum coherence that is selected with pulsed field gradients, and finally reverse-INEPT to transfer magnetization back to 1H nuclei for subsequent observation. The new 1Hn-13C-13C edited experiment takes advantage of the relatively large values of 1JCH and 1JCC, avoiding the long interpulse delays in HMBC that compromise the detectability of rapidly relaxing nuclei. The potential applicability of the pulse sequence is demonstrated by its contribution to the unambiguous assignment of the carbonyl carbons in the heme propionates of ferricytochrome b5.
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Affiliation(s)
- F Qiu
- Department of Chemistry, College of Staten Island, New York, USA
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24
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Banci L, Bertini I, Savellini GG, Romagnoli A, Turano P, Cremonini MA, Luchinat C, Gray HB. Pseudocontact shifts as constraints for energy minimization and molecular dynamics calculations on solution structures of paramagnetic metalloproteins. Proteins 1997; 29:68-76. [PMID: 9294867 DOI: 10.1002/(sici)1097-0134(199709)29:1<68::aid-prot5>3.0.co;2-b] [Citation(s) in RCA: 93] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The pseudocontact shifts of NMR signals, which arise from the magnetic susceptibility anisotropy of paramagnetic molecules, have been used as structural constraints under the form of a pseudopotential in the SANDER module of the AMBER 4.1 molecular dynamics software package. With this procedure, restrained energy minimization (REM) and restrained molecular dynamics (RMD) calculations can be performed on structural models by using pseudocontact shifts. The structure of the cyanide adduct of the Met80Ala mutant of the yeast iso-1-cytochrome c has been used for successfully testing the calculations. For this protein, a family of structures is available, which was obtained by using NOE and pseudocontact shifts as constraints in a distance geometry program. The structures obtained by REM and RMD calculations with the inclusion of pseudocontact shifts are analyzed.
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Affiliation(s)
- L Banci
- Department of Chemistry, University of Florence, Italy
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Banci L, Bertini I, Savellini GG, Romagnoli A, Turano P, Cremonini MA, Luchinat C, Gray HB. Pseudocontact shifts as constraints for energy minimization and molecular dynamics calculations on solution structures of paramagnetic metalloproteins. Proteins 1997. [DOI: 10.1002/(sici)1097-0134(199709)29:1%3c68::aid-prot5%3e3.0.co;2-b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Bertini I, Luchinat C, Rosato A. The solution structure of paramagnetic metalloproteins. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 1996; 66:43-80. [PMID: 9107132 DOI: 10.1016/s0079-6107(96)00016-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- I Bertini
- Department of Chemistry, University of Florence, Italy
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