Готові списки джерел за темами / NMR, Paramagnetism, Protein Characterization / Статті в журналах
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Статті в журналах з теми "NMR, Paramagnetism, Protein Characterization"

Автор: Grafiati
Опубліковано: 10 березня 2023
Оновлено: 11 березня 2023

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1

Arnesano, Fabio, Lucia Banci, and Mario Piccioli. "NMR structures of paramagnetic metalloproteins." Quarterly Reviews of Biophysics 38, no. 2 (May 2005): 167–219. http://dx.doi.org/10.1017/s0033583506004161.

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Анотація:
1. Introduction 1681.1 Genomic annotation of metalloproteins 1681.2 Why NMR structures? 1681.3 Why paramagnetic metalloproteins? 1692. General theory 1702.1 Nuclear and electron spins 1702.2 Hyperfine coupling 1712.3 The effect of the hyperfine coupling on the NMR shift: the hyperfine shift 1732.4 The effect of the hyperfine coupling on nuclear relaxation 1742.5 Interplay between electron spin properties and features of the NMR spectra 1783. Paramagnetism-based structural restraints 1803.1 Contact shifts and relaxation rates as restraints 1813.2 Locating the metal ion within the protein frame: pseudocontact shifts 1843.3 Cross-correlation rates 1863.4 Residual dipolar couplings 1883.5 Interplay between different restraints 1904. NMR without1H detection 1914.1 The protocol for 13C-detected protonless assignment of backbone and side-chains 1944.2 Protonless heteronuclear NMR experiments tailored to paramagnetic systems 1965. The use of lanthanides as paramagnetic probes 1986. The case of Cu(II) proteins 2027. Perspectives 2088. Acknowledgments 2099. References 209Metalloproteins represent a large share of the proteome and many of them contain paramagnetic metal ions. The knowledge, at atomic resolution, of their structure in solution is important to understand processes in which they are involved, such as electron transfer mechanisms, enzymatic reactions, metal homeostasis and metal trafficking, as well as interactions with their partners. Formerly considered as unfeasible, the first structure in solution by nuclear magnetic resonance (NMR) of a paramagnetic protein was obtained in 1994. Methodological and instrumental advancements pursued over the last decade are such that NMR structure of paramagnetic proteins may be now routinely obtained. We focus here on approaches and problems related to the structure determination of paramagnetic proteins in solution through NMR spectroscopy. After a survey of the background theory, we show how the effects produced by the presence of a paramagnetic metal ion on the NMR parameters, which are in many cases deleterious for the detection of NMR spectra, can be overcome and turned into an additional source of structural restraints. We also briefly address features and perspectives given by the use of 13C-detected protonless NMR spectroscopy for proteins in solution. The structural information obtained through the exploitation of a paramagnetic center are discussed for some Cu2+-binding proteins and for Ca2+-binding proteins, where the replacement of a diamagnetic metal ion with suitable paramagnetic metal ions suggests novel approaches to the structural characterization of proteins containing diamagnetic and NMR-silent metal ions.
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2

Piccioli, Mario. "Paramagnetic NMR Spectroscopy Is a Tool to Address Reactivity, Structure, and Protein–Protein Interactions of Metalloproteins: The Case of Iron–Sulfur Proteins." Magnetochemistry 6, no. 4 (September 26, 2020): 46. http://dx.doi.org/10.3390/magnetochemistry6040046.

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Анотація:
The study of cellular machineries responsible for the iron–sulfur (Fe–S) cluster biogenesis has led to the identification of a large number of proteins, whose importance for life is documented by an increasing number of diseases linked to them. The labile nature of Fe–S clusters and the transient protein–protein interactions, occurring during the various steps of the maturation process, make their structural characterization in solution particularly difficult. Paramagnetic nuclear magnetic resonance (NMR) has been used for decades to characterize chemical composition, magnetic coupling, and the electronic structure of Fe–S clusters in proteins; it represents, therefore, a powerful tool to study the protein–protein interaction networks of proteins involving into iron–sulfur cluster biogenesis. The optimization of the various NMR experiments with respect to the hyperfine interaction will be summarized here in the form of a protocol; recently developed experiments for measuring longitudinal and transverse nuclear relaxation rates in highly paramagnetic systems will be also reviewed. Finally, we will address the use of extrinsic paramagnetic centers covalently bound to diamagnetic proteins, which contributed over the last twenty years to promote the applications of paramagnetic NMR well beyond the structural biology of metalloproteins.
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3

Clore, G. Marius. "Seeing the invisible by paramagnetic and diamagnetic NMR." Biochemical Society Transactions 41, no. 6 (November 20, 2013): 1343–54. http://dx.doi.org/10.1042/bst20130232.

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Анотація:
Sparsely populated transient states of proteins and their complexes play an important role in many biological processes including protein–protein and protein–DNA recognition, allostery, conformational selection, induced fit and self-assembly. These states are difficult to study as their low population and transient nature makes them effectively invisible to conventional structural and biophysical techniques. In the present article, I summarize recent NMR developments in our laboratory, including the use of paramagnetic relaxation enhancement, lifetime line broadening and dark-state exchange saturation transfer spectroscopy, that have permitted such sparsely populated states to be detected, characterized and, in some instances, visualized. I illustrate the application of these methods to the elucidation of mechanisms whereby transcription factors locate their specific target sites within an overwhelming sea of non-specific DNA, to the characterization of encounter complexes in protein–protein recognition, to large-scale interdomain motions involved in ligand binding, and to the interaction of monomeric amyloid β-peptide with the surface of amyloid protofibrils and the internal cavity surface of the chaperonin GroEL.
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4

Hunashal, Yamanappa, Cristina Cantarutti, Sofia Giorgetti, Loredana Marchese, Federico Fogolari, and Gennaro Esposito. "Insights into a Protein-Nanoparticle System by Paramagnetic Perturbation NMR Spectroscopy." Molecules 25, no. 21 (November 7, 2020): 5187. http://dx.doi.org/10.3390/molecules25215187.

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Анотація:
Background: The interaction between proteins and nanoparticles is a very relevant subject because of the potential applications in medicine and material science in general. Further interest derives from the amyloidogenic character of the considered protein, β2-microglobulin (β2m), which may be regarded as a paradigmatic system for possible therapeutic strategies. Previous evidence showed in fact that gold nanoparticles (AuNPs) are able to inhibit β2m fibril formation in vitro. Methods: NMR (Nuclear Magnetic Resonance) and ESR (Electron Spin Resonance) spectroscopy are employed to characterize the paramagnetic perturbation of the extrinsic nitroxide probe Tempol on β2m in the absence and presence of AuNPs to determine the surface accessibility properties and the occurrence of chemical or conformational exchange, based on measurements conducted under magnetization equilibrium and non-equilibrium conditions. Results: The nitroxide perturbation analysis successfully identifies the protein regions where protein-protein or protein-AuNPs interactions hinder accessibility or/and establish exchange contacts. These information give interesting clues to recognize the fibrillation interface of β2m and hypothesize a mechanism for AuNPs fibrillogenesis inhibition. Conclusions: The presented approach can be advantageously applied to the characterization of the interface in protein-protein and protein-nanoparticles interactions.
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5

Anthis, Nicholas J., and G. Marius Clore. "Visualizing transient dark states by NMR spectroscopy." Quarterly Reviews of Biophysics 48, no. 1 (January 20, 2015): 35–116. http://dx.doi.org/10.1017/s0033583514000122.

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AbstractMyriad 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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6

Gong, Zhou, Shuai Yang, Qing-Fen Yang, Yue-Ling Zhu, Jing Jiang, and Chun Tang. "Refining RNA solution structures with the integrative use of label-free paramagnetic relaxation enhancement NMR." Biophysics Reports 5, no. 5-6 (November 15, 2019): 244–53. http://dx.doi.org/10.1007/s41048-019-00099-2.

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AbstractNMR structure calculation is inherently integrative, and can incorporate new experimental data as restraints. As RNAs have lower proton densities and are more conformational heterogenous than proteins, the refinement of RNA structures can benefit from additional types of restraints. Paramagnetic relaxation enhancement (PRE) provides distance information between a paramagnetic probe and protein or RNA nuclei. However, covalent conjugation of a paramagnetic probe is difficult for RNAs, thus limiting the use of PRE NMR for RNA structure characterization. Here, we show that the solvent PRE can be accurately measured for RNA labile imino protons, simply with the addition of an inert paramagnetic cosolute. Demonstrated on three RNAs that have increasingly complex topologies, we show that the incorporation of the solvent PRE restraints can significantly improve the precision and accuracy of RNA structures. Importantly, the solvent PRE data can be collected for RNAs without isotope enrichment. Thus, the solvent PRE method can work integratively with other biophysical techniques for better characterization of RNA structures.
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7

Larsen, Erik, Cristina Olivieri, Caitlin Walker, Manu V.S., Jiali Gao, David Bernlohr, Marco Tonelli, John Markley, and Gianluigi Veglia. "Probing Protein-Protein Interactions Using Asymmetric Labeling and Carbonyl-Carbon Selective Heteronuclear NMR Spectroscopy." Molecules 23, no. 8 (August 3, 2018): 1937. http://dx.doi.org/10.3390/molecules23081937.

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Protein-protein interactions (PPIs) regulate a plethora of cellular processes and NMR spectroscopy has been a leading technique for characterizing them at the atomic resolution. Technically, however, PPIs characterization has been challenging due to multiple samples required to characterize the hot spots at the protein interface. In this paper, we review our recently developed methods that greatly simplify PPI studies, which minimize the number of samples required to fully characterize residues involved in the protein-protein binding interface. This original strategy combines asymmetric labeling of two binding partners and the carbonyl-carbon label selective (CCLS) pulse sequence element implemented into the heteronuclear single quantum correlation (1H-15N HSQC) spectra. The CCLS scheme removes signals of the J-coupled 15N–13C resonances and records simultaneously two individual amide fingerprints for each binding partner. We show the application to the measurements of chemical shift correlations, residual dipolar couplings (RDCs), and paramagnetic relaxation enhancements (PRE). These experiments open an avenue for further modifications of existing experiments facilitating the NMR analysis of PPIs.
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8

Öster, Carl, Simone Kosol, Christoph Hartlmüller, Jonathan M. Lamley, Dinu Iuga, Andres Oss, Mai-Liis Org, et al. "Characterization of Protein–Protein Interfaces in Large Complexes by Solid-State NMR Solvent Paramagnetic Relaxation Enhancements." Journal of the American Chemical Society 139, no. 35 (August 25, 2017): 12165–74. http://dx.doi.org/10.1021/jacs.7b03875.

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9

Prestegard, J. H., H. M. Al-Hashimi, and J. R. Tolman. "NMR structures of biomolecules using field oriented media and residual dipolar couplings." Quarterly Reviews of Biophysics 33, no. 4 (November 2000): 371–424. http://dx.doi.org/10.1017/s0033583500003656.

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Анотація:
1. Introduction 3721.1 Residual dipolar couplings as a route to structure and dynamics 3721.2 A brief history of oriented phase high resolution NMR 3742. Theoretical treatment of dipolar interactions 3762.1 Anisotropic interactions as probes of macromolecular structure and dynamics 3762.1.1 The dipolar interaction 3762.1.2 Averaging in the solution state 3772.2 Ordering of a rigid body 3772.2.1 The Saupe order tensor 3782.2.2 Orientational probability distribution function 3802.2.3 The generalized degree of order 3802.3 Molecular structure and internal dynamics 3813. Inducing molecular order in high resolution NMR 3833.1 Tensorial interactions between the magnetic field and anisotropic magnetic susceptibilities 3833.2 Dilute liquid crystal media: a tunable source of order 3843.2.1 Bicelles : from membrane mimics to aligning media 3853.2.2 Filamentous phage 3873.2.3 Transfer of alignment from ordered media to macromolecules 3883.3 Magnetic field alignment 3893.3.1 Paramagnetic assisted alignment 3893.3.2 Advantages of using magnetic alignment 3894. The measurement of residual dipolar couplings 3914.1 Introduction 3914.2 Frequency based methods 3924.2.1 Coupling enhanced pulse schemes 3924.2.2 In phase anti-phase methods (IPAP): 1DNH couplings in proteins 3934.2.3 Exclusive correlated spectroscopy (E-COSY): 1DNH, 1DNC′ and 2DHNC′ 3954.2.4 Extraction of splitting values from the frequency domain 3964.3 Intensity based experiments 3974.3.1 J-Modulated experiments: the measurement of 1DCαHα in proteins 3974.3.2 Phase modulated methods 3994.3.3 Constant time COSY – the measurement of DHH couplings 3994.3.4 Systematic errors in intensity based experiments 4005. Interpretation of residual dipolar coupling data 4015.1 Structure determination protocols utilizing orientational constraints 4015.1.1 The simulated annealing approach 4015.1.2 Order matrix analysis of dipolar couplings 4025.1.3 A discussion of the two approaches 4025.2 Reducing orientational degeneracy 4035.2.1 Multiple alignment media in the simulated annealing approach 4045.2.2 Multiple alignment media in the order matrix approach 4055.3 Simplifying effects arising due to molecular symmetry 4065.4 Database approaches for determining protein structure 4076. Applications to the characterization of macromolecular systems 4086.1 Protein structure refinement 4086.2 Protein domain orientation 4096.3 Oligosaccharides 4136.4 Biomolecular complexes 4156.5 Exchanging systems 4167. Acknowledgements 4188. References 419Within its relatively short history, nuclear magnetic resonance (NMR) spectroscopy has managed to play an important role in the characterization of biomolecular structure. However, the methods on which most of this characterization has been based, Nuclear Overhauser Effect (NOE) measurements for short-range distance constraints and scalar couplings measurements for torsional constraints, have limitations (Wüthrich, 1986). For extended structures, such as DNA helices, for example, propagation of errors in the short distance constraints derived from NOEs leaves the relative orientation of remote parts of the structures poorly defined. Also, the low density of observable protons in contact regions of molecules held together by factors other than hydrophobic packing, leads to poorly defined structures. This is especially true in carbohydrate containing complexes where hydrogen bonds often mediate contacts, and in multi-domain proteins where the area involved in domain–domain contact can also be small. Moreover, most NMR based structural applications are concerned with the characterization of a single, rigid conformer for the final structure. This can leave out important mechanistic information that depends on dynamic aspects and, when motion is present, this can lead to incorrect structural representations. This review focuses on one approach to alleviating some of the existing limitations in NMR based structure determination: the use of constraints derived from the measurement of residual dipolar couplings (D).
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10

Möbius, Klaus, Wolfgang Lubitz, Nicholas Cox, and Anton Savitsky. "Biomolecular EPR Meets NMR at High Magnetic Fields." Magnetochemistry 4, no. 4 (November 6, 2018): 50. http://dx.doi.org/10.3390/magnetochemistry4040050.

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Анотація:
In this review on advanced biomolecular EPR spectroscopy, which addresses both the EPR and NMR communities, considerable emphasis is put on delineating the complementarity of NMR and EPR regarding the measurement of interactions and dynamics of large molecules embedded in fluid-solution or solid-state environments. Our focus is on the characterization of protein structure, dynamics and interactions, using sophisticated EPR spectroscopy methods. New developments in pulsed microwave and sweepable cryomagnet technology as well as ultrafast electronics for signal data handling and processing have pushed the limits of EPR spectroscopy to new horizons reaching millimeter and sub-millimeter wavelengths and 15 T Zeeman fields. Expanding traditional applications to paramagnetic systems, spin-labeling of biomolecules has become a mainstream multifrequency approach in EPR spectroscopy. In the high-frequency/high-field EPR region, sub-micromolar concentrations of nitroxide spin-labeled molecules are now sufficient to characterize reaction intermediates of complex biomolecular processes. This offers promising analytical applications in biochemistry and molecular biology where sample material is often difficult to prepare in sufficient concentration for NMR characterization. For multifrequency EPR experiments on frozen solutions typical sample volumes are of the order of 250 μL (S-band), 150 μL (X-band), 10 μL (Q-band) and 1 μL (W-band). These are orders of magnitude smaller than the sample volumes required for modern liquid- or solid-state NMR spectroscopy. An important additional advantage of EPR over NMR is the ability to detect and characterize even short-lived paramagnetic reaction intermediates (down to a lifetime of a few ns). Electron–nuclear and electron–electron double-resonance techniques such as electron–nuclear double resonance (ENDOR), ELDOR-detected NMR, PELDOR (DEER) further improve the spectroscopic selectivity for the various magnetic interactions and their evolution in the frequency and time domains. PELDOR techniques applied to frozen-solution samples of doubly spin-labeled proteins allow for molecular distance measurements ranging up to about 100 Å. For disordered frozen-solution samples high-field EPR spectroscopy allows greatly improved orientational selection of the molecules within the laboratory axes reference system by means of the anisotropic electron Zeeman interaction. Single-crystal resolution is approached at the canonical g-tensor orientations—even for molecules with very small g-anisotropies. Unique structural, functional, and dynamic information about molecular systems is thus revealed that can hardly be obtained by other analytical techniques. On the other hand, the limitation to systems with unpaired electrons means that EPR is less widely used than NMR. However, this limitation also means that EPR offers greater specificity, since ordinary chemical solvents and matrices do not give rise to EPR in contrast to NMR spectra. Thus, multifrequency EPR spectroscopy plays an important role in better understanding paramagnetic species such as organic and inorganic radicals, transition metal complexes as found in many catalysts or metalloenzymes, transient species such as light-generated spin-correlated radical pairs and triplets occurring in protein complexes of photosynthetic reaction centers, electron-transfer relays, etc. Special attention is drawn to high-field EPR experiments on photosynthetic reaction centers embedded in specific sugar matrices that enable organisms to survive extreme dryness and heat stress by adopting an anhydrobiotic state. After a more general overview on methods and applications of advanced multifrequency EPR spectroscopy, a few representative examples are reviewed to some detail in two Case Studies: (I) High-field ELDOR-detected NMR (EDNMR) as a general method for electron–nuclear hyperfine spectroscopy of nitroxide radical and transition metal containing systems; (II) High-field ENDOR and EDNMR studies of the Oxygen Evolving Complex (OEC) in Photosystem II, which performs water oxidation in photosynthesis, i.e., the light-driven splitting of water into its elemental constituents, which is one of the most important chemical reactions on Earth.
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11

Trindade, I. B., G. Hernandez, E. Lebègue, F. Barrière, T. Cordeiro, M. Piccioli, and R. O. Louro. "Conjuring up a ghost: structural and functional characterization of FhuF, a ferric siderophore reductase from E. coli." JBIC Journal of Biological Inorganic Chemistry 26, no. 2-3 (February 9, 2021): 313–26. http://dx.doi.org/10.1007/s00775-021-01854-y.

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AbstractIron is a fundamental element for virtually all forms of life. Despite its abundance, its bioavailability is limited, and thus, microbes developed siderophores, small molecules, which are synthesized inside the cell and then released outside for iron scavenging. Once inside the cell, iron removal does not occur spontaneously, instead this process is mediated by siderophore-interacting proteins (SIP) and/or by ferric-siderophore reductases (FSR). In the past two decades, representatives of the SIP subfamily have been structurally and biochemically characterized; however, the same was not achieved for the FSR subfamily. Here, we initiate the structural and functional characterization of FhuF, the first and only FSR ever isolated. FhuF is a globular monomeric protein mainly composed by α-helices sheltering internal cavities in a fold resembling the “palm” domain found in siderophore biosynthetic enzymes. Paramagnetic NMR spectroscopy revealed that the core of the cluster has electronic properties in line with those of previously characterized 2Fe–2S ferredoxins and differences appear to be confined to the coordination of Fe(III) in the reduced protein. In particular, the two cysteines coordinating this iron appear to have substantially different bond strengths. In similarity with the proteins from the SIP subfamily, FhuF binds both the iron-loaded and the apo forms of ferrichrome in the micromolar range and cyclic voltammetry reveals the presence of redox-Bohr effect, which broadens the range of ferric-siderophore substrates that can be thermodynamically accessible for reduction. This study suggests that despite the structural differences between FSR and SIP proteins, mechanistic similarities exist between the two classes of proteins. Graphic abstract
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12

Kumari, Pratibha, Dhiman Ghosh, Agathe Vanas, Yanick Fleischmann, Thomas Wiegand, Gunnar Jeschke, Roland Riek та Cédric Eichmann. "Structural insights into α-synuclein monomer–fibril interactions". Proceedings of the National Academy of Sciences 118, № 10 (1 березня 2021): e2012171118. http://dx.doi.org/10.1073/pnas.2012171118.

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Protein aggregation into amyloid fibrils is associated with multiple neurodegenerative diseases, including Parkinson’s disease. Kinetic data and biophysical characterization have shown that the secondary nucleation pathway highly accelerates aggregation via the absorption of monomeric protein on the surface of amyloid fibrils. Here, we used NMR and electron paramagnetic resonance spectroscopy to investigate the interaction of monomeric α-synuclein (α-Syn) with its fibrillar form. We demonstrate that α-Syn monomers interact transiently via their positively charged N terminus with the negatively charged flexible C-terminal ends of the fibrils. These intermolecular interactions reduce intramolecular contacts in monomeric α-Syn, yielding further unfolding of the partially collapsed intrinsically disordered states of α-Syn along with a possible increase in the local concentration of soluble α-Syn and alignment of individual monomers on the fibril surface. Our data indicate that intramolecular unfolding critically contributes to the aggregation kinetics of α-Syn during secondary nucleation.
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13

Courtade, Gaston, Luisa Ciano, Alessandro Paradisi, Peter J. Lindley, Zarah Forsberg, Morten Sørlie, Reinhard Wimmer, et al. "Mechanistic basis of substrate–O2coupling within a chitin-active lytic polysaccharide monooxygenase: An integrated NMR/EPR study." Proceedings of the National Academy of Sciences 117, no. 32 (July 28, 2020): 19178–89. http://dx.doi.org/10.1073/pnas.2004277117.

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Lytic polysaccharide monooxygenases (LPMOs) have a unique ability to activate molecular oxygen for subsequent oxidative cleavage of glycosidic bonds. To provide insight into the mode of action of these industrially important enzymes, we have performed an integrated NMR/electron paramagnetic resonance (EPR) study into the detailed aspects of an AA10 LPMO–substrate interaction. Using NMR spectroscopy, we have elucidated the solution-phase structure ofapo-BlLPMO10A fromBacillus licheniformis, along with solution-phase structural characterization of the Cu(I)-LPMO, showing that the presence of the metal has minimal effects on the overall protein structure. We have, moreover, used paramagnetic relaxation enhancement (PRE) to characterize Cu(II)-LPMO by NMR spectroscopy. In addition, a multifrequency continuous-wave (CW)-EPR and15N-HYSCORE spectroscopy study on the uniformly isotope-labeled63Cu(II)-bound15N-BlLPMO10A along with its natural abundance isotopologue determined copper spin-Hamiltonian parameters for LPMOs to markedly improved accuracy. The data demonstrate that large changes in the Cu(II) spin-Hamiltonian parameters are induced upon binding of the substrate. These changes arise from a rearrangement of the copper coordination sphere from a five-coordinate distorted square pyramid to one which is four-coordinate near-square planar. There is also a small reduction in metal–ligand covalency and an attendant increase in the d(x2−y2) character/energy of the singly occupied molecular orbital (SOMO), which we propose from density functional theory (DFT) calculations predisposes the copper active site for the formation of a stable Cu–O2intermediate. This switch in orbital character upon addition of chitin provides a basis for understanding the coupling of substrate binding with O2activation in chitin-active AA10 LPMOs.
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14

Beniamino, Ylenia, Vittoria Cenni, Mario Piccioli, Stefano Ciurli, and Barbara Zambelli. "The Ni(II)-Binding Activity of the Intrinsically Disordered Region of Human NDRG1, a Protein Involved in Cancer Development." Biomolecules 12, no. 9 (September 9, 2022): 1272. http://dx.doi.org/10.3390/biom12091272.

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Nickel exposition is associated with tumors of the respiratory tract such as lung and nasal cancers, acting through still-uncharacterized mechanisms. Understanding the molecular basis of nickel-induced carcinogenesis requires unraveling the mode and the effects of Ni(II) binding to its intracellular targets. A possible Ni(II)-binding protein and a potential focus for cancer treatment is hNDRG1, a protein induced by Ni(II) through the hypoxia response pathway, whose expression correlates with higher cancer aggressiveness and resistance to chemotherapy in lung tissue. The protein sequence contains a unique C-terminal sequence of 83 residues (hNDRG1*C), featuring a three-times-repeated decapeptide, involved in metal binding, lipid interaction and post-translational phosphorylation. In the present work, the biochemical and biophysical characterization of unmodified hNDRG1*C was performed. Bioinformatic analysis assigned it to the family of the intrinsically disordered regions and the absence of secondary and tertiary structure was experimentally proven by circular dichroism and NMR. Isothermal titration calorimetry revealed the occurrence of a Ni(II)-binding event with micromolar affinity. Detailed information on the Ni(II)-binding site and on the residues involved was obtained in an extensive NMR study, revealing an octahedral paramagnetic metal coordination that does not cause any major change of the protein backbone, which is coherent with CD analysis. hNDRG1*C was found in a monomeric form by light-scattering experiments, while the full-length hNDRG1 monomer was found in equilibrium between the dimer and tetramer, both in solution and in human cell lines. The results are the first essential step for understanding the cellular function of hNDRG1*C at the molecular level, with potential future applications to clarify its role and the role of Ni(II) in cancer development.
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15

Invernici, Michele, Inês B. Trindade, Francesca Cantini, Ricardo O. Louro, and Mario Piccioli. "Measuring transverse relaxation in highly paramagnetic systems." Journal of Biomolecular NMR 74, no. 8-9 (July 24, 2020): 431–42. http://dx.doi.org/10.1007/s10858-020-00334-w.

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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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16

Kawasaki, Ryosuke, and Shin-ichi Tate. "Impact of the Hereditary P301L Mutation on the Correlated Conformational Dynamics of Human Tau Protein Revealed by the Paramagnetic Relaxation Enhancement NMR Experiments." International Journal of Molecular Sciences 21, no. 11 (May 30, 2020): 3920. http://dx.doi.org/10.3390/ijms21113920.

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Tau forms intracellular insoluble aggregates as a neuropathological hallmark of Alzheimer’s disease. Tau is largely unstructured, which complicates the characterization of the tau aggregation process. Recent studies have demonstrated that tau samples two distinct conformational ensembles, each of which contains the soluble and aggregation-prone states of tau. A shift to populate the aggregation-prone ensemble may promote tau fibrillization. However, the mechanism of this ensemble transition remains elusive. In this study, we explored the conformational dynamics of a tau fragment by using paramagnetic relaxation enhancement (PRE) and interference (PRI) NMR experiments. The PRE correlation map showed that tau is composed of segments consisting of residues in correlated motions. Intriguingly, residues forming the β-structures in the heparin-induced tau filament coincide with residues in these segments, suggesting that each segment behaves as a structural unit in fibrillization. PRI data demonstrated that the P301L mutation exclusively alters the transiently formed tau structures by changing the short- and long-range correlated motions among residues. The transient conformations of P301L tau expose the amyloid motif PHF6 to promote tau self-aggregation. We propose the correlated motions among residues within tau determine the population sizes of the conformational ensembles, and perturbing the correlated motions populates the aggregation-prone form.
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17

Orton, Henry W., Ilya Kuprov, Choy-Theng Loh, and Gottfried Otting. "Using Paramagnetism to Slow Down Nuclear Relaxation in Protein NMR." Journal of Physical Chemistry Letters 7, no. 23 (November 14, 2016): 4815–18. http://dx.doi.org/10.1021/acs.jpclett.6b02417.

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18

Querci, Leonardo, Inês B. Trindade, Michele Invernici, José Malanho Silva, Francesca Cantini, Ricardo O. Louro, and Mario Piccioli. "NMR of Paramagnetic Proteins: 13C Derived Paramagnetic Relaxation Enhancements Are an Additional Source of Structural Information in Solution." Magnetochemistry 9, no. 3 (February 26, 2023): 66. http://dx.doi.org/10.3390/magnetochemistry9030066.

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In paramagnetic metalloproteins, longitudinal relaxation rates of 13C′ and 13Cα nuclei can be measured using 13C detected experiments and converted into electron spin-nuclear spin distance restraints, also known as Paramagnetic Relaxation Enhancement (PRE) restraints. 13C are less sensitive to paramagnetism than 1H nuclei, therefore, 13C based PREs constitute an additional, non-redundant, structural information. We will discuss the complementarity of 13C PRE restraints with 1H PRE restraints in the case of the High Potential Iron Sulfur Protein (HiPIP) PioC, for which the NMR structure of PioC has been already solved by a combination of classical and paramagnetism-based restraints. We will show here that 13C R1 values can be measured also at very short distances from the paramagnetic center and that the obtained set of 13C based restraints can be added to 1H PREs and to other classical and paramagnetism based NMR restraints to improve quality and quantity of the NMR information.
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19

Heletta, Lukas, Stefan Seidel, Christopher Benndorf, Hellmut Eckert, and Rainer Pöttgen. "Gallium-containing Heusler phases ScRh2Ga, ScPd2Ga, TmRh2Ga and LuRh2Ga – magnetic and solid state NMR-spectroscopic characterization." Zeitschrift für Naturforschung B 72, no. 8 (August 28, 2017): 609–15. http://dx.doi.org/10.1515/znb-2017-0084.

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AbstractThe gallium-containing Heusler phases ScRh2Ga, ScPd2Ga, TmRh2Ga and LuRh2Ga have been synthesized by arc-melting of the elements followed by different annealing sequences to improve phase purity. The samples have been studied by powder X-ray diffraction. The structures of Lu0.97Rh2Ga1.03 (Fm3̅m, a=632.94(5) pm, wR2=0.0590, 46 F2 values, seven variables) and Sc0.88Rh2Ga1.12 (a=618.91(4) pm, wR2=0.0284, 44 F2 values, six variables) have been refined from single crystal X-ray diffractometer data. Both gallides show structural disorder through Lu/Ga and Sc/Ga mixing. Temperature dependent magnetic susceptibility measurements showed Pauli paramagnetism for ScRh2Ga, ScPd2Ga, and LuRh2Ga and Curie-Weiss paramagnetism for TmRh2Ga. 45Sc and 71Ga solid state MAS NMR spectroscopic investigations of the Sc containing compounds confirmed the site mixing effects typically observed for Heusler phases. The data indicate that the effect of mixed Sc/Ga occupancy is significantly stronger in ScRh2Ga than in ScPd2Ga.
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20

Jensen, Malene Ringkjøbing, Gitte Petersen, Conni Lauritzen, John Pedersen, and Jens J. Led. "Metal Binding Sites in Proteins: Identification and Characterization by Paramagnetic NMR Relaxation†." Biochemistry 44, no. 33 (August 2005): 11014–23. http://dx.doi.org/10.1021/bi0508136.

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21

Donaldson, Logan W., Nikolai R. Skrynnikov, Wing-Yiu Choy, D. Ranjith Muhandiram, Bibudhendra Sarkar, Julie D. Forman-Kay, and Lewis E. Kay. "Structural Characterization of Proteins with an Attached ATCUN Motif by Paramagnetic Relaxation Enhancement NMR Spectroscopy." Journal of the American Chemical Society 123, no. 40 (October 2001): 9843–47. http://dx.doi.org/10.1021/ja011241p.

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22

Bertini, Ivano, Yogesh K. Gupta, Claudio Luchinat, Giacomo Parigi, Massimiliano Peana, Luca Sgheri, and Jing Yuan. "Paramagnetism-Based NMR Restraints Provide Maximum Allowed Probabilities for the Different Conformations of Partially Independent Protein Domains." Journal of the American Chemical Society 129, no. 42 (October 2007): 12786–94. http://dx.doi.org/10.1021/ja0726613.

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23

Prudêncio, Miguel, Robert R. Eady, and Gary Sawers. "The Blue Copper-Containing Nitrite Reductase fromAlcaligenes xylosoxidans: Cloning of the nirAGene and Characterization of the Recombinant Enzyme." Journal of Bacteriology 181, no. 8 (April 15, 1999): 2323–29. http://dx.doi.org/10.1128/jb.181.8.2323-2329.1999.

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ABSTRACT The nirA gene encoding the blue dissimilatory nitrite reductase from Alcaligenes xylosoxidans has been cloned and sequenced. To our knowledge, this is the first report of the characterization of a gene encoding a blue copper-containing nitrite reductase. The deduced amino acid sequence exhibits a high degree of similarity to other copper-containing nitrite reductases from various bacterial sources. The full-length protein included a 24-amino-acid leader peptide. The nirA gene was overexpressed inEscherichia coli and was shown to be exported to the periplasm. Purification was achieved in a single step, and analysis of the recombinant Nir enzyme revealed that cleavage of the signal peptide occurred at a position identical to that for the native enzyme isolated from A. xylosoxidans. The recombinant Nir isolated directly was blue and trimeric and, on the basis of electron paramagnetic resonance spectroscopy and metal analysis, possessed only type 1 copper centers. This type 2-depleted enzyme preparation also had a low nitrite reductase enzyme activity. Incubation of the periplasmic fraction with copper sulfate prior to purification resulted in the isolation of an enzyme with a full complement of type 1 and type 2 copper centers and a high specific activity. The kinetic properties of the recombinant enzyme were indistinguishable from those of the native nitrite reductase isolated from A. xylosoxidans. This rapid isolation procedure will greatly facilitate genetic and biochemical characterization of both wild-type and mutant derivatives of this protein.
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24

Holak, T. A., A. F. Frederick, and J. H. Prestegard. "Purification and NMR characterization of acyl carrier protein." Journal of Biological Chemistry 262, no. 8 (March 1987): 3685–89. http://dx.doi.org/10.1016/s0021-9258(18)61409-7.

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25

Mekkattu Tharayil, Sreelakshmi, Mithun C. Mahawaththa, Akiva Feintuch, Ansis Maleckis, Sven Ullrich, Richard Morewood, Michael J. Maxwell, et al. "Site-selective generation of lanthanoid binding sites on proteins using 4-fluoro-2,6-dicyanopyridine." Magnetic Resonance 3, no. 2 (September 13, 2022): 169–82. http://dx.doi.org/10.5194/mr-3-169-2022.

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Abstract. The paramagnetism of a lanthanoid tag site-specifically installed on a protein provides a rich source of structural information accessible by nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) spectroscopy. Here we report a lanthanoid tag for selective reaction with cysteine or selenocysteine with formation of a (seleno)thioether bond and a short tether between the lanthanoid ion and the protein backbone. The tag is assembled on the protein in three steps, comprising (i) reaction with 4-fluoro-2,6-dicyanopyridine (FDCP); (ii) reaction of the cyano groups with α-cysteine, penicillamine or β-cysteine to complete the lanthanoid chelating moiety; and (iii) titration with a lanthanoid ion. FDCP reacts much faster with selenocysteine than cysteine, opening a route for selective tagging in the presence of solvent-exposed cysteine residues. Loaded with Tb3+ and Tm3+ ions, pseudocontact shifts were observed in protein NMR spectra, confirming that the tag delivers good immobilisation of the lanthanoid ion relative to the protein, which was also manifested in residual dipolar couplings. Completion of the tag with different 1,2-aminothiol compounds resulted in different magnetic susceptibility tensors. In addition, the tag proved suitable for measuring distance distributions in double electron–electron resonance experiments after titration with Gd3+ ions.
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26

Wright, P. E., and H. J. Dyson. "NMR Structural Characterization of Protein Folding Pathways and Intermediates." Biochemical Society Transactions 28, no. 5 (October 1, 2000): A136. http://dx.doi.org/10.1042/bst028a136b.

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27

Mielke, Steven P., and V. V. Krishnan. "Characterization of protein secondary structure from NMR chemical shifts." Progress in Nuclear Magnetic Resonance Spectroscopy 54, no. 3-4 (April 2009): 141–65. http://dx.doi.org/10.1016/j.pnmrs.2008.06.002.

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28

Taraban, Marc B., Roberto A. DePaz, Brian Lobo, and Y. Bruce Yu. "Water Proton NMR: A Tool for Protein Aggregation Characterization." Analytical Chemistry 89, no. 10 (May 3, 2017): 5494–502. http://dx.doi.org/10.1021/acs.analchem.7b00464.

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29

Raingeval, Claire, and Isabelle Krimm. "NMR investigation of protein–ligand interactions for G-protein coupled receptors." Future Medicinal Chemistry 11, no. 14 (July 2019): 1811–25. http://dx.doi.org/10.4155/fmc-2018-0312.

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In this review, we report NMR studies of ligand–GPCR interactions, including both ligand-observed and protein-observed NMR experiments. Published studies exemplify how NMR can be used as a powerful tool to design novel GPCR ligands and investigate the ligand-induced conformational changes of GPCRs. The strength of NMR also lies in its capability to explore the diverse signaling pathways and probe the allosteric modulation of these highly dynamic receptors. By offering unique opportunities for the identification, structural and functional characterization of GPCR ligands, NMR will likely play a major role for the generation of novel molecules both as new tools for the understanding of the GPCR function and as therapeutic compounds for a large diversity of pathologies.
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30

Vignovich, William P., and Vitor H. Pomin. "Saturation Transfer Difference in Characterization of Glycosaminoglycan-Protein Interactions." SLAS TECHNOLOGY: Translating Life Sciences Innovation 25, no. 4 (May 26, 2020): 307–19. http://dx.doi.org/10.1177/2472630320921130.

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Novel methods in nuclear magnetic resonance (NMR) spectroscopy have recently been developed to investigate the binding properties of intermolecular complexes endowed with biomedical functions. Among these methods is the saturation transfer difference (STD), which enables the mapping of specific binding motifs of functional ligands. STD can efficiently uncover the specific and preferential binding sites of these ligands in their intermolecular complexes. This is particularly useful in the case of glycosaminoglycans (GAGs), a group of sulfated polysaccharides that play pivotal roles in various biological and pathological processes. The activity of GAGs is ultimately mediated through molecular interactions with key functional proteins, namely, GAG-binding proteins (GBPs). The quality of the GAG-GBP interactions depends on sulfation patterns, oligosaccharide length, and the composing monosaccharides of GAGs. Through STD NMR, information about the atoms of the GAG ligands involved in the complexes is provided. Here we highlight the latest achievements of the literature using STD NMR on GAG oligosaccharide-GBP complexes. Interestingly, most of the GBPs studied so far by STD NMR belong to one of the three major classes: coagulation factors, growth factors, or chemokine/cytokines. Unveiling the structural requirements of GAG ligands in bindings with their protein partners is a crucial step to understand the biochemical and medical actions of GAGs. This process is also a requirement in GAG-based drug discovery and development.
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31

Mateos, Borja, Robert Konrat, Roberta Pierattelli, and Isabella C. Felli. "NMR Characterization of Long‐Range Contacts in Intrinsically Disordered Proteins from Paramagnetic Relaxation Enhancement in 13 C Direct‐Detection Experiments." ChemBioChem 20, no. 3 (December 10, 2018): 335–39. http://dx.doi.org/10.1002/cbic.201800539.

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32

Baker, Lindsay A., and Marc Baldus. "Characterization of membrane protein function by solid-state NMR spectroscopy." Current Opinion in Structural Biology 27 (August 2014): 48–55. http://dx.doi.org/10.1016/j.sbi.2014.03.009.

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33

Sakakura, Masayoshi, Arina Hadziselimovic, and Charles R. Sanders. "Structural Characterization of Human Peripheral Myelin Protein 22 Using NMR." Biophysical Journal 98, no. 3 (January 2010): 648a—649a. http://dx.doi.org/10.1016/j.bpj.2009.12.3553.

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34

Reardon, Patrick N., and Leonard D. Spicer. "Multidimensional NMR Spectroscopy for Protein Characterization and Assignment inside Cells." Journal of the American Chemical Society 127, no. 31 (August 2005): 10848–49. http://dx.doi.org/10.1021/ja053145k.

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35

Zhao, J., H. Zheng, and X. Xie. "NMR Characterization of Recombinant Transmembrane Protein CB2 Fragment CB2 180-233." Protein & Peptide Letters 13, no. 4 (April 1, 2006): 335–42. http://dx.doi.org/10.2174/092986606775974483.

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36

Martin, Rachel W., and Kurt W. Zilm. "Preparation of protein nanocrystals and their characterization by solid state NMR." Journal of Magnetic Resonance 165, no. 1 (November 2003): 162–74. http://dx.doi.org/10.1016/s1090-7807(03)00253-2.

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37

Bracken, Clay. "Applications of NMR for the characterization of protein dynamics and folding." Journal of Molecular Graphics and Modelling 18, no. 4-5 (2000): 549. http://dx.doi.org/10.1016/s1093-3263(00)80109-6.

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38

Chan, David I., Byron C. H. Chu, Cheryl K. Y. Lau, Howard N. Hunter, David M. Byers, and Hans J. Vogel. "NMR Solution Structure and Biophysical Characterization ofVibrio harveyiAcyl Carrier Protein A75H." Journal of Biological Chemistry 285, no. 40 (July 21, 2010): 30558–66. http://dx.doi.org/10.1074/jbc.m110.128298.

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39

Böckmann, Anja, Carole Gardiennet, René Verel, Andreas Hunkeler, Antoine Loquet, Guido Pintacuda, Lyndon Emsley, Beat H. Meier, and Anne Lesage. "Characterization of different water pools in solid-state NMR protein samples." Journal of Biomolecular NMR 45, no. 3 (September 25, 2009): 319–27. http://dx.doi.org/10.1007/s10858-009-9374-3.

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40

Friedrich, Daniel, Jacqueline Perodeau, Andrew J. Nieuwkoop, and Hartmut Oschkinat. "MAS NMR detection of hydrogen bonds for protein secondary structure characterization." Journal of Biomolecular NMR 74, no. 4-5 (March 17, 2020): 247–56. http://dx.doi.org/10.1007/s10858-020-00307-z.

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41

Yu, Fei, Sucharita Roy, Enrique Arevalo, John Schaeck, Jason Wang, Kimberly Holte, Jay Duffner, Nur Sibel Gunay, Ishan Capila, and Ganesh V. Kaundinya. "Characterization of heparin–protein interaction by saturation transfer difference (STD) NMR." Analytical and Bioanalytical Chemistry 406, no. 13 (March 25, 2014): 3079–89. http://dx.doi.org/10.1007/s00216-014-7729-4.

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42

le Paige, Ulric B., ShengQi Xiang, Marco M. R. M. Hendrix, Yi Zhang, Gert E. Folkers, Markus Weingarth, Alexandre M. J. J. Bonvin, et al. "Characterization of nucleosome sediments for protein interaction studies by solid-state NMR spectroscopy." Magnetic Resonance 2, no. 1 (April 21, 2021): 187–202. http://dx.doi.org/10.5194/mr-2-187-2021.

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Abstract. Regulation of DNA-templated processes such as gene transcription and DNA repair depend on the interaction of a wide range of proteins with the nucleosome, the fundamental building block of chromatin. Both solution and solid-state NMR spectroscopy have become an attractive approach to study the dynamics and interactions of nucleosomes, despite their high molecular weight of ∼200 kDa. For solid-state NMR (ssNMR) studies, dilute solutions of nucleosomes are converted to a dense phase by sedimentation or precipitation. Since nucleosomes are known to self-associate, these dense phases may induce extensive interactions between nucleosomes, which could interfere with protein-binding studies. Here, we characterized the packing of nucleosomes in the dense phase created by sedimentation using NMR and small-angle X-ray scattering (SAXS) experiments. We found that nucleosome sediments are gels with variable degrees of solidity, have nucleosome concentration close to that found in crystals, and are stable for weeks under high-speed magic angle spinning (MAS). Furthermore, SAXS data recorded on recovered sediments indicate that there is no pronounced long-range ordering of nucleosomes in the sediment. Finally, we show that the sedimentation approach can also be used to study low-affinity protein interactions with the nucleosome. Together, our results give new insights into the sample characteristics of nucleosome sediments for ssNMR studies and illustrate the broad applicability of sedimentation-based NMR studies.
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43

Fagagnini, Andrea, Miguel Garavís, Irene Gómez-Pinto, Sabrina Fasoli, Giovanni Gotte, and Douglas V. Laurents. "NMR Characterization of Angiogenin Variants and tRNAAla Products Impacting Aberrant Protein Oligomerization." International Journal of Molecular Sciences 22, no. 3 (February 1, 2021): 1439. http://dx.doi.org/10.3390/ijms22031439.

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Protein oligomerization is key to countless physiological processes, but also to abnormal amyloid conformations implicated in over 25 mortal human diseases. Human Angiogenin (h-ANG), a ribonuclease A family member, produces RNA fragments that regulate ribosome formation, the creation of new blood vessels and stress granule function. Too little h-ANG activity leads to abnormal protein oligomerization, resulting in Amyotrophic Lateral Sclerosis (ALS) or Parkinson’s disease. While a score of disease linked h-ANG mutants has been studied by X-ray diffraction, some elude crystallization. There is also a debate regarding the structure that RNA fragments adopt after cleavage by h-ANG. Here, to better understand the beginning of the process that leads to aberrant protein oligomerization, the solution secondary structure and residue-level dynamics of WT h-ANG and two mutants i.e., H13A and R121C, are characterized by multidimensional heteronuclear NMR spectroscopy under near-physiological conditions. All three variants are found to adopt well folded and highly rigid structures in the solution, although the elements of secondary structure are somewhat shorter than those observed in crystallography studies. R121C alters the environment of nearby residues only. By contrast, the mutation H13A affects local residues as well as nearby active site residues K40 and H114. The conformation characterization by CD and 1D 1H NMR spectroscopies of tRNAAla before and after h-ANG cleavage reveals a retention of the duplex structure and little or no G-quadruplex formation.
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44

Zech, Stephan G., Edward Olejniczak, Philip Hajduk, Jamey Mack, and Ann E. McDermott. "Characterization of Protein−Ligand Interactions by High-Resolution Solid-State NMR Spectroscopy." Journal of the American Chemical Society 126, no. 43 (November 2004): 13948–53. http://dx.doi.org/10.1021/ja040086m.

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45

Huma, Zil E., Justin P. Ludeman, Brendan L. Wilkinson, Richard J. Payne, and Martin J. Stone. "NMR characterization of cooperativity: fast ligand binding coupled to slow protein dimerization." Chem. Sci. 5, no. 7 (2014): 2783–88. http://dx.doi.org/10.1039/c4sc00131a.

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46

Cross, Timothy A., Vindana Ekanayake, Joana Paulino, and Anna Wright. "Solid state NMR: The essential technology for helical membrane protein structural characterization." Journal of Magnetic Resonance 239 (February 2014): 100–109. http://dx.doi.org/10.1016/j.jmr.2013.12.006.

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47

Garbow, Joel R., Hideji Fujiwara, C. Ray Sharp, and Eugene W. Logusch. "Characterization of covalent protein conjugates using solid-state carbon-13 NMR spectroscopy." Biochemistry 30, no. 29 (July 23, 1991): 7057–62. http://dx.doi.org/10.1021/bi00243a004.

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48

Wang, Yingjie, Carlo Camilloni, Jonggul Kim, Michele Vendruscolo, Jiali Gao, and Gianluigi Veglia. "Characterization of Protein Kinase a Free Energy Landscape by NMR-Restrained Metadynamics." Biophysical Journal 112, no. 3 (February 2017): 50a. http://dx.doi.org/10.1016/j.bpj.2016.11.310.

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49

Zeeb, Markus, and Jochen Balbach. "NMR Spectroscopic Characterization of Millisecond Protein Folding by Transverse Relaxation Dispersion Measurements." Journal of the American Chemical Society 127, no. 38 (September 2005): 13207–12. http://dx.doi.org/10.1021/ja051141+.

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50

Maslennikov, Innokentiy, Martin Krupa, Christopher Dickson, Luis Esquivies, Katherine Blain, Georgia Kefala, Senyon Choe, and Witek Kwiatkowski. "Characterization of protein detergent complexes by NMR, light scattering, and analytical ultracentrifugation." Journal of Structural and Functional Genomics 10, no. 1 (February 12, 2009): 25–35. http://dx.doi.org/10.1007/s10969-009-9061-3.

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