1
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Silva JM, Cerofolini L, Carvalho AL, Ravera E, Fragai M, Parigi G, Macedo AL, Geraldes CFGC, Luchinat C. Elucidating the concentration-dependent effects of thiocyanate binding to carbonic anhydrase. J Inorg Biochem 2023; 244:112222. [PMID: 37068394 DOI: 10.1016/j.jinorgbio.2023.112222] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2023] [Revised: 03/28/2023] [Accepted: 04/09/2023] [Indexed: 04/19/2023]
Abstract
Many proteins naturally carry metal centers, with a large share of them being in the active sites of several enzymes. Paramagnetic effects are a powerful source of structural information and, therefore, if the native metal is paramagnetic, or it can be functionally substituted with a paramagnetic one, paramagnetic effects can be used to study the metal sites, as well as the overall structure of the protein. One notable example is cobalt(II) substitution for zinc(II) in carbonic anhydrase. In this manuscript we investigate the effects of sodium thiocyanate on the chemical environment of the metal ion of the human carbonic anhydrase II. The electron paramagnetic resonance (EPR) titration of the cobalt(II) protein with thiocyanate shows that the EPR spectrum changes from A-type to C-type on passing from 1:1 to 1:1000-fold ligand excess. This indicates the occurrence of a change in the electronic structure, which may reflect a sizable change in the metal coordination environment in turn caused by a modification of the frozen solvent glass. However, paramagnetic nuclear magnetic resonance (NMR) data indicate that the metal coordination cage remains unperturbed even in 1:1000-fold ligand excess. This result proves that the C-type EPR spectrum observed at large ligand concentration should be ascribed to the low temperature at which EPR measurements are performed, which impacts on the structure of the protein when it is destabilized by a high concentration of a chaotropic agent.
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Affiliation(s)
- José Malanho Silva
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal
| | - Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
| | - Ana Luísa Carvalho
- UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal; Associate Laboratory i4HB - Institute for Health and Bioeconomy, NOVA School of Science and Technology, Universidade NOVA de Lisboa, Caparica, Portugal
| | - Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy
| | - Giacomo Parigi
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy
| | - Anjos L Macedo
- UCIBIO, Department of Chemistry, NOVA School of Science and Technology, Universidade NOVA de Lisboa, 2819-516 Caparica, Portugal; Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy
| | - Carlos F G C Geraldes
- Department of Life Sciences, Faculty of Science and Technology, 3000-393 Coimbra, Portugal; Coimbra Chemistry Center- Institute of Molecular Sciences (CCC-IMS), University of Coimbra, 3004-535 Coimbra, Portugal
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Sesto Fiorentino 50019, Italy; Department of Chemistry "Ugo Schiff", University of Florence, Sesto Fiorentino 50019, Italy; Consorzio Interuniversitario Risonanze Magnetiche Metallo Proteine (CIRMMP), Sesto Fiorentino, 50019, Italy; Giotto Biotech, S.R.L, Sesto Fiorentino, Florence 50019, Italy.
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2
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Cerofolini L, Parigi G, Ravera E, Fragai M, Luchinat C. Solid-state NMR methods for the characterization of bioconjugations and protein-material interactions. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 122:101828. [PMID: 36240720 DOI: 10.1016/j.ssnmr.2022.101828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 08/26/2022] [Accepted: 09/07/2022] [Indexed: 06/16/2023]
Abstract
Protein solid-state NMR has evolved dramatically over the last two decades, with the development of new hardware and sample preparation methodologies. This technique is now ripe for complex applications, among which one can count bioconjugation, protein chemistry and functional biomaterials. In this review, we provide our account on this aspect of protein solid-state NMR.
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Affiliation(s)
- Linda Cerofolini
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Giacomo Parigi
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Enrico Ravera
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy; Florence Data Science, Università degli Studi di Firenze, Italy.
| | - Marco Fragai
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy.
| | - Claudio Luchinat
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Magnetic Resonance Center (CERM), Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019, Sesto Fiorentino, Italy; Department of Chemistry "Ugo Schiff", Università degli Studi di Firenze, Via della Lastruccia 3, 50019, Sesto Fiorentino, Italy.
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3
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Rizzo D, Cerofolini L, Giuntini S, Iozzino L, Pergola C, Sacco F, Palmese A, Ravera E, Luchinat C, Baroni F, Fragai M. Epitope Mapping and Binding Assessment by Solid-State NMR Provide a Way for the Development of Biologics under the Quality by Design Paradigm. J Am Chem Soc 2022; 144:10006-10016. [PMID: 35617699 PMCID: PMC9185746 DOI: 10.1021/jacs.2c03232] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
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Multispecific biologics
are an emerging class of drugs, in which
antibodies and/or proteins designed to bind pharmacological targets
are covalently linked or expressed as fusion proteins to increase
both therapeutic efficacy and safety. Epitope mapping on the target
proteins provides key information to improve the affinity and also
to monitor the manufacturing process and drug stability. Solid-state
NMR has been here used to identify the pattern of the residues of
the programmed cell death ligand 1 (PD-L1) ectodomain that are involved
in the interaction with a new multispecific biological drug. This
is possible because the large size and the intrinsic flexibility of
the complexes are not limiting factors for solid-state NMR.
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Affiliation(s)
- Domenico Rizzo
- Magnetic Resonance Center (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
| | - Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Stefano Giuntini
- Magnetic Resonance Center (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
| | - Luisa Iozzino
- Analytical Development Biotech Department, Merck Serono S.p.a, Via Luigi Einaudi, 11, 00012 Guidonia, RM, Italy
| | - Carlo Pergola
- Analytical Development Biotech Department, Merck Serono S.p.a, Via Luigi Einaudi, 11, 00012 Guidonia, RM, Italy
| | - Francesca Sacco
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,Analytical Development Biotech Department, Merck Serono S.p.a, Via Luigi Einaudi, 11, 00012 Guidonia, RM, Italy
| | - Angelo Palmese
- Analytical Development Biotech Department, Merck Serono S.p.a, Via Luigi Einaudi, 11, 00012 Guidonia, RM, Italy
| | - Enrico Ravera
- Magnetic Resonance Center (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.,Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,Department of Chemistry "Ugo Schiff", University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy.,Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Fabio Baroni
- Analytical Development Biotech Department, Merck Serono S.p.a, Via Luigi Einaudi, 11, 00012 Guidonia, RM, Italy
| | - Marco Fragai
- Magnetic Resonance Center (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.,Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
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4
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Li M, Reichert P, Narasimhan C, Sorman B, Xu W, Cote A, Su Y. Investigating Crystalline Protein Suspension Formulations of Pembrolizumab from MAS NMR Spectroscopy. Mol Pharm 2022; 19:936-952. [PMID: 35107019 DOI: 10.1021/acs.molpharmaceut.1c00915] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Developing biological formulations to maintain the chemical and structural integrity of therapeutic antibodies remains a significant challenge. Monoclonal antibody (mAb) crystalline suspension formulation is a promising alternative for high concentration subcutaneous drug delivery. It demonstrates many merits compared to the solution formulation to reach a high concentration at the reduced viscosity and enhanced stability. One main challenge in drug development is the lack of high-resolution characterization of the crystallinity and stability of mAb microcrystals in the native formulations. Conventional analytical techniques often cannot evaluate structural details of mAb microcrystals in the native suspension due to the presence of visible particles, relatively small crystal size, high protein concentration, and multicomponent nature of a liquid formulation. This study demonstrates the first high-resolution characterization of mAb microcrystalline suspension using magic angle spinning (MAS) NMR spectroscopy. Crystalline suspension formulation of pembrolizumab (Keytruda, Merck & Co., Inc., Kenilworth, NJ 07033, U.S.) is utilized as a model system. Remarkably narrow 13C spectral linewidth of approximately 29 Hz suggests a high order of crystallinity and conformational homogeneity of pembrolizumab crystals. The impact of thermal stress and dehydration on the structure, dynamics, and stability of these mAb crystals in the formulation environment is evaluated. Moreover, isotopic labeling and heteronuclear 13C and 15N spectroscopies have been utilized to identify the binding of caffeine in the pembrolizumab crystal lattice, providing molecular insights into the cocrystallization of the protein and ligand. Our study provides valuable structural details for facilitating the design of crystalline suspension formulation of Keytruda and demonstrates the high potential of MAS NMR as an advanced tool for biophysical characterization of biological therapeutics.
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Affiliation(s)
- Mingyue Li
- Analytical Research and Development, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Paul Reichert
- Discovery Chemistry, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | | | - Bradley Sorman
- Analytical Research and Development, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Wei Xu
- Analytical Research and Development, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Aaron Cote
- Biologics Process Research and Development, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
| | - Yongchao Su
- Analytical Research and Development, Merck & Co., Inc., Kenilworth, New Jersey 07033, United States
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5
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Laveglia V, Giachetti A, Cerofolini L, Haubrich K, Fragai M, Ciulli A, Rosato A. Automated Determination of Nuclear Magnetic Resonance Chemical Shift Perturbations in Ligand Screening Experiments: The PICASSO Web Server. J Chem Inf Model 2021; 61:5726-5733. [PMID: 34843238 PMCID: PMC8715503 DOI: 10.1021/acs.jcim.1c00871] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Indexed: 11/28/2022]
Abstract
Nuclear magnetic resonance (NMR) is an effective, commonly used experimental approach to screen small organic molecules against a protein target. A very popular method consists of monitoring the changes of the NMR chemical shifts of the protein nuclei upon addition of the small molecule to the free protein. Multidimensional NMR experiments allow the interacting residues to be mapped along the protein sequence. A significant amount of human effort goes into manually tracking the chemical shift variations, especially when many signals exhibit chemical shift changes and when many ligands are tested. Some computational approaches to automate the procedure are available, but none of them as a web server. Furthermore, some methods require the adoption of a fairly specific experimental setup, such as recording a series of spectra at increasing small molecule:protein ratios. In this work, we developed a tool requesting a minimal amount of experimental data from the user, implemented it as an open-source program, and made it available as a web application. Our tool compares two spectra, one of the free protein and one of the small molecule:protein mixture, based on the corresponding peak lists. The performance of the tool in terms of correct identification of the protein-binding regions has been evaluated on different protein targets, using experimental data from interaction studies already available in the literature. For a total of 16 systems, our tool achieved between 79% and 100% correct assignments, properly identifying the protein regions involved in the interaction.
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Affiliation(s)
- Vincenzo Laveglia
- Consorzio
Interuniversitario di Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Andrea Giachetti
- Consorzio
Interuniversitario di Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Linda Cerofolini
- Consorzio
Interuniversitario di Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Kevin Haubrich
- School
of Life Sciences, Division of Biological Chemistry and Drug Discovery, The University of Dundee, James Black Centre, Dow Street, DD1 5EH, Dundee, United Kingdom
| | - Marco Fragai
- Consorzio
Interuniversitario di Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Magnetic
Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department
of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Alessio Ciulli
- School
of Life Sciences, Division of Biological Chemistry and Drug Discovery, The University of Dundee, James Black Centre, Dow Street, DD1 5EH, Dundee, United Kingdom
| | - Antonio Rosato
- Consorzio
Interuniversitario di Risonanze Magnetiche di Metallo Proteine, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Magnetic
Resonance Center (CERM), University of Florence, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
- Department
of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
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6
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Luchinat E, Barbieri L, Cremonini M, Pennestri M, Nocentini A, Supuran CT, Banci L. Determination of intracellular protein-ligand binding affinity by competition binding in-cell NMR. ACTA CRYSTALLOGRAPHICA SECTION D-STRUCTURAL BIOLOGY 2021; 77:1270-1281. [PMID: 34605430 PMCID: PMC8489230 DOI: 10.1107/s2059798321009037] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/03/2021] [Accepted: 08/31/2021] [Indexed: 01/01/2023]
Abstract
Structure-based drug development suffers from high attrition rates due to the poor activity of lead compounds in cellular and animal models caused by low cell penetrance, off-target binding or changes in the conformation of the target protein in the cellular environment. The latter two effects cause a change in the apparent binding affinity of the compound, which is indirectly assessed by cellular activity assays. To date, direct measurement of the intracellular binding affinity remains a challenging task. In this work, in-cell NMR spectroscopy was applied to measure intracellular dissociation constants in the nanomolar range by means of protein-observed competition binding experiments. Competition binding curves relative to a reference compound could be retrieved either from a series of independent cell samples or from a single real-time NMR bioreactor run. The method was validated using a set of sulfonamide-based inhibitors of human carbonic anhydrase II with known activity in the subnanomolar to submicromolar range. The intracellular affinities were similar to those obtained in vitro, indicating that these compounds selectively bind to the intracellular target. In principle, the approach can be applied to any soluble intracellular target that gives rise to measurable chemical shift changes upon ligand binding.
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Affiliation(s)
- Enrico Luchinat
- CERM - Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Letizia Barbieri
- CERM - Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Matteo Cremonini
- CERM - Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Matteo Pennestri
- Pharmaceutical Business Unit, Bruker UK Limited, Banner Lane, Coventry CV4 9GH, United Kingdom
| | - Alessio Nocentini
- Dipartimento Neurofarba, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Claudiu T Supuran
- Dipartimento Neurofarba, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Lucia Banci
- CERM - Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi Sacconi 6, 50019 Sesto Fiorentino, Italy
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7
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Rizzo D, Cerofolini L, Pérez-Ràfols A, Giuntini S, Baroni F, Ravera E, Luchinat C, Fragai M. Evaluation of the Higher Order Structure of Biotherapeutics Embedded in Hydrogels for Bioprinting and Drug Release. Anal Chem 2021; 93:11208-11214. [PMID: 34339178 PMCID: PMC8382223 DOI: 10.1021/acs.analchem.1c01850] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2021] [Accepted: 07/20/2021] [Indexed: 01/16/2023]
Abstract
Biocompatible hydrogels for tissue regeneration/replacement and drug release with specific architectures can be obtained by three-dimensional bioprinting techniques. The preservation of the higher order structure of the proteins embedded in the hydrogels as drugs or modulators is critical for their biological activity. Solution nuclear magnetic resonance (NMR) experiments are currently used to investigate the higher order structure of biotherapeutics in comparability, similarity, and stability studies. However, the size of pores in the gel, protein-matrix interactions, and the size of the embedded proteins often prevent the use of this methodology. The recent advancements of solid-state NMR allow for the comparison of the higher order structure of the matrix-embedded and free isotopically enriched proteins, allowing for the evaluation of the functionality of the material in several steps of hydrogel development. Moreover, the structural information at atomic detail on the matrix-protein interactions paves the way for a structure-based design of these biomaterials.
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Affiliation(s)
- Domenico Rizzo
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), Via L. Sacconi 6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, Sesto Fiorentino 50019, Italy
| | - Linda Cerofolini
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), Via L. Sacconi 6, Sesto Fiorentino 50019, Italy
| | - Anna Pérez-Ràfols
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, Sesto Fiorentino 50019, Italy
- Giotto
Biotech, S.R.L, Via Madonna
del piano 6, Sesto Fiorentino, Florence 50019, Italy
| | - Stefano Giuntini
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), Via L. Sacconi 6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, Sesto Fiorentino 50019, Italy
| | - Fabio Baroni
- Analytical
Development Biotech Department, Merck Serono
S.p.a, Merck KGaA, Guidonia, Rome 00012, Italy
| | - Enrico Ravera
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), Via L. Sacconi 6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, Sesto Fiorentino 50019, Italy
| | - Claudio Luchinat
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), Via L. Sacconi 6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, Sesto Fiorentino 50019, Italy
| | - Marco Fragai
- Magnetic
Resonance Center (CERM), University of Florence,
and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine
(CIRMMP), Via L. Sacconi 6, Sesto Fiorentino 50019, Italy
- Department
of Chemistry “Ugo Schiff”, University of Florence, Via della Lastruccia 3, Sesto Fiorentino 50019, Italy
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8
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Luchinat E, Barbieri L, Cremonini M, Nocentini A, Supuran CT, Banci L. Intracellular Binding/Unbinding Kinetics of Approved Drugs to Carbonic Anhydrase II Observed by in-Cell NMR. ACS Chem Biol 2020; 15:2792-2800. [PMID: 32955851 PMCID: PMC7735671 DOI: 10.1021/acschembio.0c00590] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
![]()
Candidate
drugs rationally designed in vitro often
fail due to low efficacy in vivo caused by low tissue
availability or because of unwanted side effects. To overcome the
limitations of in vitro rational drug design, the
binding of candidate drugs to their target needs to be evaluated in
the cellular context. Here, we applied in-cell NMR to investigate
the binding of a set of approved drugs to the isoform II of carbonic
anhydrase (CA) in living human cells. Some compounds were originally
developed toward other targets and were later found to inhibit CAs.
We observed strikingly different dose- and time-dependent binding,
wherein some drugs exhibited a more complex behavior than others.
Specifically, some compounds were shown to gradually unbind from intracellular
CA II, even in the presence of free compound in the external medium,
therefore preventing the quantitative formation of a stable protein–ligand
complex. Such observations could be correlated to the known off-target
binding activity of these compounds, suggesting that this approach
could provide information on the pharmacokinetic profiles of lead
candidates at the early stages of multitarget drug design.
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Affiliation(s)
- Enrico Luchinat
- CERM − Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi sacconi 6, 50019 Sesto Fiorentino, Italy
- Consorzio per lo Sviluppo dei Sistemi a Grande Interfase − CSGI, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Letizia Barbieri
- CERM − Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi sacconi 6, 50019 Sesto Fiorentino, Italy
- Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via Luigi Sacconi 6, Sesto Fiorentino, Italy
| | - Matteo Cremonini
- CERM − Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Alessio Nocentini
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
| | - Claudiu T. Supuran
- Dipartimento Neurofarba, Sezione di Scienze Farmaceutiche, Università degli Studi di Firenze, Via Ugo Schiff 6, 50019 Sesto Fiorentino, Italy
- Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Lucia Banci
- CERM − Magnetic Resonance Center, Università degli Studi di Firenze, Via Luigi sacconi 6, 50019 Sesto Fiorentino, Italy
- Dipartimento di Chimica, Università degli Studi di Firenze, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
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9
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Cerofolini L, Ravera E, Fragai M, Luchinat C. NMR of Immobilized Enzymes. Methods Mol Biol 2020; 2100:363-383. [PMID: 31939136 DOI: 10.1007/978-1-0716-0215-7_24] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/10/2023]
Abstract
Solid-state NMR has become the method of choice for the assessment of protein structure for insoluble objects lacking long-range order. In this context, it is apparent that solid-state NMR is also perfectly poised toward the characterization of immobilized proteins. For these systems, it is possible to understand at the atomic level which perturbations, if any, are occurring as a result of the functionalization. Here we describe how it is possible to accomplish the NMR characterization of enzymes that have been immobilized through different approaches, and we introduce the reader to the choice of the experimental strategy that can be useful in different cases. An outlook on the level of information that can be attained is also given, in view of recent methodological advancements.
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Affiliation(s)
- Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario, Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy
| | - Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario, Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy.
- Department of Chemistry, University of Florence, Sesto Fiorentino, Italy.
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario, Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario, Risonanze Magnetiche di Metallo Proteine (CIRMMP), Sesto Fiorentino, Italy
- Department of Chemistry, University of Florence, Sesto Fiorentino, Italy
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10
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Cerofolini L, Giuntini S, Ravera E, Luchinat C, Berti F, Fragai M. Structural characterization of a protein adsorbed on aluminum hydroxide adjuvant in vaccine formulation. NPJ Vaccines 2019; 4:20. [PMID: 31149351 PMCID: PMC6538755 DOI: 10.1038/s41541-019-0115-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2019] [Accepted: 05/03/2019] [Indexed: 12/11/2022] Open
Abstract
The heterogeneous composition of vaccine formulations and the relatively low concentration make the characterization of the protein antigens extremely challenging. Aluminum-containing adjuvants have been used to enhance the immune response of several antigens over the last 90 years and still remain the most commonly used. Here, we show that solid-state NMR and isotope labeling methods can be used to characterize the structural features of the protein antigen component of vaccines and to investigate the preservation of the folding state of proteins adsorbed on Alum hydroxide matrix, providing the way to identify the regions of the protein that are mainly affected by the presence of the inorganic matrix. l-Asparaginase from E. coli has been used as a pilot model of protein antigen. This methodology can find application in several steps of the vaccine development pipeline, from the antigen optimization, through the design of vaccine formulation, up to stability studies and manufacturing process.
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Affiliation(s)
- Linda Cerofolini
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy
| | - Stefano Giuntini
- 2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Enrico Ravera
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Claudio Luchinat
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
| | - Francesco Berti
- Technical R&D, GSK Vaccines, Via Fiorentina 1, 53100 Siena, Italy
| | - Marco Fragai
- 1Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metallo Proteine (CIRMMP), Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.,2Department of Chemistry, University of Florence, Via della Lastruccia 3, 50019 Sesto Fiorentino, Italy
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11
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Rai RK, Angelis AD, Greenwood A, Opella SJ, Cotten ML. Metal-ion Binding to Host Defense Peptide Piscidin 3 Observed in Phospholipid Bilayers by Magic Angle Spinning Solid-state NMR. Chemphyschem 2019; 20:295-301. [PMID: 30471190 PMCID: PMC6494093 DOI: 10.1002/cphc.201800855] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2018] [Revised: 11/21/2018] [Indexed: 12/21/2022]
Abstract
Cationic antimicrobial peptides (AMPs) are essential components of the innate immune system. They have attracted interest as novel compounds with the potential to treat infections associated with multi-drug resistant bacteria. In this study, we investigate piscidin 3 (P3), an AMP that was first discovered in the mast cells of hybrid striped bass. Prior studies showed that P3 is less active than its homolog piscidin 1 (P1) against planktonic bacteria. However, P3 has the advantage of being less toxic to mammalian cells and more active on biofilms and persister cells. Both P1 and P3 cross bacterial membranes and co-localize with intracellular DNA but P3 is more condensing to DNA while P1 is more membrane active. Recently, we showed that both peptides coordinate Cu2+ through an amino-terminal copper and nickel (ATCUN) motif. We also demonstrated that the bactericidal effects of P3 are linked to its ability to form radicals that nick DNA in the presence of Cu2+ . Since metal binding and membrane crossing by P3 is biologically important, we apply in this study solid-state NMR spectroscopy to uniformly 13 C-15 N-labeled peptide samples to structurally characterize the ATCUN motif of P3 bound to bilayers and coordinated to Ni2+ and Cu2+ . These experiments are supplemented with density functional theory calculations. Taken together, these studies refine the arrangement of not only the backbone but also side chain atoms of an AMP simultaneously bound to metal ions and phospholipid bilayers.
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Affiliation(s)
- Ratan Kumar Rai
- Department of Chemistry and Biochemistry University of California San Diego La Jolla, California 92093-0307 (USA)
| | - Anna De Angelis
- Department of Chemistry and Biochemistry University of California San Diego La Jolla, California 92093-0307 (USA)
| | - Alexander Greenwood
- Department of Applied Science, Department of Physics The College of William and Mary Williamsburg, VA 23185 (USA), Fax: (757)-221-2050,
| | - Stanley J. Opella
- Department of Chemistry and Biochemistry University of California San Diego La Jolla, California 92093-0307 (USA)
| | - Myriam L. Cotten
- Department of Applied Science, Department of Physics The College of William and Mary Williamsburg, VA 23185 (USA), Fax: (757)-221-2050,
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12
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Trachta M, Bludský O, Rubeš M. The interaction of proteins with silica surfaces. Part II: Free energies of capped amino acids. COMPUT THEOR CHEM 2019. [DOI: 10.1016/j.comptc.2018.12.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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13
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Silva JM, Giuntini S, Cerofolini L, Geraldes CFGC, Macedo AL, Ravera E, Fragai M, Luchinat C, Calderone V. Non-crystallographic symmetry in proteins: Jahn-Teller-like and Butterfly-like effects? J Biol Inorg Chem 2018; 24:91-101. [PMID: 30470900 DOI: 10.1007/s00775-018-1630-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Accepted: 11/14/2018] [Indexed: 11/29/2022]
Abstract
Partial symmetry, i.e., the presence of more than one molecule in the asymmetric unit of a crystal, is a relatively rare phenomenon in small-molecule crystallography, but is quite common in protein crystallography, where it is typically known as non-crystallographic symmetry (NCS). Several papers in literature propose molecular determinants such as crystal contacts, thermal factors, or TLS parameters as an explanation for the phenomenon of intrinsic asymmetry among molecules that are in principle equivalent. Nevertheless, are all of the above determinants the cause or are they rather the effect? In the general frame of the NCS often observed in crystals of biomolecules, this paper deals with nickel(II)-substituted human carbonic anhydrase(II) (hCAII) and its SAD structure determination at the nickel edge. The structure revealed two non-equivalent molecules in the asymmetric unit, the presence of a secondary nickel-binding site at the N-terminus of both molecules (which had never been found before in the nickel-substituted enzyme) and two different coordination geometries of the active site nickel (hexa-coordinated in one molecule and mainly penta-coordinated in the other). The above-mentioned standard molecular crystallographic determinants of this asymmetry are analyzed and presented in detail for this particular case. From these considerations, we speculate on the existence of a fundamental, although yet unknown, common cause for the partial symmetry that is so often encountered in X-ray structures of biomolecules.
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Affiliation(s)
- José Malanho Silva
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via L. Sacconi 6, 50019, Sesto Fiorentino, FI, Italy.,UCIBIO-Requimte, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, 2829-516, Portugal
| | - Stefano Giuntini
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, 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
| | - Linda Cerofolini
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, Via L. Sacconi 6, 50019, Sesto Fiorentino, FI, Italy
| | - Carlos F G C Geraldes
- Department of Life Sciences and Coimbra Chemistry Center, University of Coimbra, Coimbra, Portugal
| | - Anjos L Macedo
- UCIBIO-Requimte, Faculty of Sciences and Technology, Universidade NOVA de Lisboa, Caparica, 2829-516, Portugal
| | - Enrico Ravera
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, 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
| | - Marco Fragai
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, 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
| | - Claudio Luchinat
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, 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
- Magnetic Resonance Center (CERM), University of Florence and Consorzio Interuniversitario Risonanze Magnetiche di Metalloproteine, 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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14
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Varghese S, Halling PJ, Häussinger D, Wimperis S. Two-dimensional 1H and 1H-detected NMR study of a heterogeneous biocatalyst using fast MAS at high magnetic fields. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2018; 92:7-11. [PMID: 29587153 DOI: 10.1016/j.ssnmr.2018.03.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 03/13/2018] [Accepted: 03/13/2018] [Indexed: 05/08/2023]
Abstract
Nuclear magnetic resonance (NMR) is a powerful tool for investigating atomic-scale structure in heterogeneous or composite materials where long-range order is absent. In this work solid-state 1H and 1H-detected NMR experiments were performed with fast magic angle spinning (νR = 75 kHz) and at high magnetic fields (B0 = 20 T) and used to gain structural insight into a heterogeneous biocatalyst consisting of an enzyme, human carbonic anhydrase II (hCA II), covalently immobilized on epoxy-functionalized silica. Two-dimensional 1H-1H NOESY-type correlation experiments were able to provide information on 1H environments in silica, epoxy-silica and the immobilized enzyme. Two distinct signals originating from water protons were observed: water associated with the surface of the silica and the water associated with the immobilized enzyme. Additional two-dimensional 1H-1H double-single quantum (DQ-SQ) correlation experiments suggested that the immobilized enzyme is not in close contact with the silica surface. Most significantly, comparison of two-dimensional 1H-15N spectra of the immobilized enzyme and the solution-state enzyme confirmed that the structural integrity of the protein is well preserved upon covalent immobilization.
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Affiliation(s)
- Sabu Varghese
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK
| | - Peter J Halling
- WestCHEM, Department of Pure & Applied Chemistry, University of Strathclyde, Glasgow, G1 1XL, UK
| | - Daniel Häussinger
- Department of Chemistry, University of Basel, CH-4056, Basel, Switzerland
| | - Stephen Wimperis
- Department of Chemistry, Lancaster University, Lancaster, LA1 4YB, UK.
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15
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Cerofolini L, Staderini T, Giuntini S, Ravera E, Fragai M, Parigi G, Pierattelli R, Luchinat C. Long-range paramagnetic NMR data can provide a closer look on metal coordination in metalloproteins. J Biol Inorg Chem 2017; 23:71-80. [PMID: 29218635 DOI: 10.1007/s00775-017-1511-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2017] [Accepted: 11/06/2017] [Indexed: 11/24/2022]
Abstract
Paramagnetic NMR data can be profitably incorporated in structural refinement protocols of metalloproteins or metal-substituted proteins, mostly as distance or angle restraints. However, they could in principle provide much more information, because the magnetic susceptibility of a paramagnetic metal ion is largely determined by its coordination sphere. This information can in turn be used to evaluate changes occurring in the coordination sphere of the metal when ligands (e.g.: inhibitors) are bound to the protein. This gives an experimental handle on the molecular structure in the vicinity of the metal which falls in the so-called blind sphere. The magnetic susceptibility anisotropy tensors of cobalt(II) and nickel(II) ions bound to human carbonic anhydrase II in free and inhibited forms have been determined. The change of the magnetic susceptibility anisotropy is directly linked to the binding mode of different ligands in the active site of the enzyme. Indication about the metal coordination sphere in the presence of an inhibitor in pharmaceutically relevant proteins could be important in the design of selective drugs with a structure-based approach.
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Affiliation(s)
- Linda Cerofolini
- Magnetic Resonance Center (CERM) and Interuniversity Consortium for Magnetic Resonance of Metallo Proteins (CIRMMP), Via L. Sacconi 6, 50019, Sesto Fiorentino, Italy
| | - Tommaso Staderini
- Department of Chemistry "Ugo Schiff", University of Florence, Via Della Lastruccia 3, 50019, Sesto Fiorentino, Italy
| | - Stefano Giuntini
- 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
| | - Marco Fragai
- 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
- Giotto Biotech S.R.L., Via Madonna del Piano 6, 50019, Sesto Fiorentino, Italy
| | - 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
| | - Roberta Pierattelli
- 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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