1
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Raynes JK, Mata J, Wilde KL, Carver JA, Kelly SM, Holt C. Structure of biomimetic casein micelles: Critical tests of the hydrophobic colloid and multivalent-binding models using recombinant deuterated and phosphorylated β-casein. J Struct Biol X 2024; 9:100096. [PMID: 38318529 PMCID: PMC10840362 DOI: 10.1016/j.yjsbx.2024.100096] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2023] [Revised: 01/08/2024] [Accepted: 01/17/2024] [Indexed: 02/07/2024] Open
Abstract
Milk contains high concentrations of amyloidogenic casein proteins and is supersaturated with respect to crystalline calcium phosphates such as apatite. Nevertheless, the mammary gland normally remains unmineralized and free of amyloid. Unlike κ-casein, β- and αS-caseins are highly effective mineral chaperones that prevent ectopic and pathological calcification of the mammary gland. Milk invariably contains a mixture of two to five different caseins that act on each other as molecular chaperones. Instead of forming amyloid fibrils, several thousand caseins and hundreds of nanoclusters of amorphous calcium phosphate combine to form fuzzy complexes called casein micelles. To understand the biological functions of the casein micelle its structure needs to be understood better than at present. The location in micelles of the highly amyloidogenic κ-casein is disputed. In traditional hydrophobic colloid models, it, alone, forms a stabilizing surface coat that also determines the average size of the micelles. In the recent multivalent-binding model, κ-casein is present throughout the micelle, in intimate contact with the other caseins. To discriminate between these models, a range of biomimetic micelles was prepared using a fixed concentration of the mineral chaperone β-casein and nanoclusters of calcium phosphate, with variable concentrations of κ-casein. A biomimetic micelle was also prepared using a highly deuterated and in vivo phosphorylated recombinant β-casein with calcium phosphate and unlabelled κ-casein. Neutron and X-ray scattering experiments revealed that κ-casein is distributed throughout the micelle, in quantitative agreement with the multivalent-binding model but contrary to the hydrophobic colloid models.
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Affiliation(s)
- Jared K. Raynes
- CSIRO Agriculture & Food, 671 Sneydes Road, Werribee, VIC 3031, Australia
- All G Foods, Waterloo, NSW 2006, Australia
| | - Jitendra Mata
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
- School of Chemistry, University of New South Wales, Sydney 2052, Australia
| | - Karyn L. Wilde
- National Deuteration Facility, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - John A. Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Sharon M. Kelly
- School of Molecular Biosciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - Carl Holt
- School of Molecular Biosciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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2
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Turhan E, Pötzl C, Keil W, Negroni M, Kouřil K, Meier B, Romero JA, Kazimierczuk K, Goldberga I, Azaïs T, Kurzbach D. Biphasic NMR of Hyperpolarized Suspensions-Real-Time Monitoring of Solute-to-Solid Conversion to Watch Materials Grow. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2023; 127:19591-19598. [PMID: 37817917 PMCID: PMC10561236 DOI: 10.1021/acs.jpcc.3c04198] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Revised: 09/07/2023] [Indexed: 10/12/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a key method for the determination of molecular structures. Due to its intrinsically high (i.e., atomistic) resolution and versatility, it has found numerous applications for investigating gases, liquids, and solids. However, liquid-state NMR has found little application for suspensions of solid particles as the resonances of such systems are excessively broadened, typically beyond the detection threshold. Herein, we propose a route to overcoming this critical limitation by enhancing the signals of particle suspensions by >3.000-fold using dissolution dynamic nuclear polarization (d-DNP) coupled with rapid solid precipitation. For the proof-of-concept series of experiments, we employed calcium phosphate (CaP) as a model system. By d-DNP, we boosted the signals of phosphate 31P spins before rapid CaP precipitation inside the NMR spectrometer, leading to the inclusion of the hyperpolarized phosphate into CaP-nucleated solid particles within milliseconds. With our approach, within only 1 s of acquisition time, we obtained spectra of biphasic systems, i.e., micrometer-sized dilute solid CaP particles coexisting with their solution-state precursors. Thus, this work is a step toward real-time characterization of the solid-solution equilibrium. Finally, integrating the hyperpolarized data with molecular dynamics simulations and electron microscopy enabled us to shed light on the CaP formation mechanism in atomistic detail.
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Affiliation(s)
- Ertan Turhan
- Institute
of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
- University
of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, Vienna 1090, Austria
| | - Christopher Pötzl
- Institute
of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
- University
of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, Vienna 1090, Austria
| | - Waldemar Keil
- Institute
of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
| | - Mattia Negroni
- Institute
of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
| | - Karel Kouřil
- Institute
of Biological Interfaces 4, Karlsruhe Institute
of Technology, Egenstein-Leopoldshafen 76344, Germany
| | - Benno Meier
- Institute
of Biological Interfaces 4, Karlsruhe Institute
of Technology, Egenstein-Leopoldshafen 76344, Germany
- Institute
of Physical Chemistry, Karlsruhe Institute
of Technology, Karlsruhe 76131, Germany
| | - Javier Agustin Romero
- Centre
of New Technologies, University of Warsaw, ul. Banacha 2c, Warsaw 02-097, Poland
| | | | - Ieva Goldberga
- Sorbonne
Université, CNRS, Laboratoire de Chimie de la Matière
Condensée de Paris (LCMCP), 4, place Jussieu, Paris F-75005, France
| | - Thierry Azaïs
- Sorbonne
Université, CNRS, Laboratoire de Chimie de la Matière
Condensée de Paris (LCMCP), 4, place Jussieu, Paris F-75005, France
| | - Dennis Kurzbach
- Institute
of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna 1090, Austria
- University
of Vienna, Vienna Doctoral School in Chemistry (DoSChem), Währinger Str. 42, Vienna 1090, Austria
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3
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Negroni M, Kurzbach D. Missing Pieces in Structure Puzzles: How Hyperpolarized NMR Spectroscopy Can Complement Structural Biology and Biochemistry. Chembiochem 2023; 24:e202200703. [PMID: 36624049 DOI: 10.1002/cbic.202200703] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 01/08/2023] [Accepted: 01/09/2023] [Indexed: 01/11/2023]
Abstract
Structure determination lies at the heart of many biochemical research programs. However, the "giants": X-ray diffraction, electron microscopy, molecular dynamics simulations, and nuclear magnetic resonance, among others, leave quite a few dark spots on the structural pictures drawn of proteins, nucleic acids, membranes, and other biomacromolecules. For example, structural models under physiological conditions or of short-lived intermediates often remain out of reach of the established experimental methods. This account frames the possibility of including hyperpolarized, that is, dramatically signal-enhanced NMR in existing workflows to fill these spots with detailed depictions. We highlight how integrating methods based on dissolution dynamic nuclear polarization can provide valuable complementary information about formerly inaccessible conformational spaces for many systems. A particular focus will be on hyperpolarized buffers to facilitate the NMR structure determination of challenging systems.
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Affiliation(s)
- Mattia Negroni
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna, Währinger Str. 38, 1090, Vienna, Austria
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute of Biological Chemistry, University of Vienna, Währinger Str. 38, 1090, Vienna, Austria
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4
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Strobl J, Kozak F, Kamalov M, Reichinger D, Kurzbach D, Becker CF. Understanding Self-Assembly of Silica-Precipitating Peptides to Control Silica Particle Morphology. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2023; 35:e2207586. [PMID: 36509953 DOI: 10.1002/adma.202207586] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/19/2022] [Revised: 12/05/2022] [Indexed: 06/17/2023]
Abstract
The most advanced materials are those found in nature. These evolutionary optimized substances provide highest efficiencies, e.g., in harvesting solar energy or providing extreme stability, and are intrinsically biocompatible. However, the mimicry of biological materials is limited to a few successful applications since there is still a lack of the tools to recreate natural materials. Herein, such means are provided based on a peptide library derived from the silaffin protein R5 that enables rational biomimetic materials design. It is now evident that biomaterials do not form via mechanisms observed in vitro. Instead, the material's function and morphology are predetermined by precursors that self-assemble in solution, often from a combination of protein and salts. These assemblies act as templates for biomaterials. The RRIL peptides used here are a small part of the silica-precipitation machinery in diatoms. By connecting RRIL motifs via varying central bi- or trifunctional residues, a library of stereoisomers is generated, which allows characterization of different template structures in the presence of phosphate ions by combining residue-resolved real-time NMR spectroscopy and molecular dynamics (MD) simulations. Understanding these templates in atomistic detail, the morphology of silica particles is controlled via manipulation of the template precursors.
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Affiliation(s)
- Johannes Strobl
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna, 109, Austria
- Vienna Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Str. 42, Vienna, 1090, Austria
| | - Fanny Kozak
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna, 109, Austria
- Vienna Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Str. 42, Vienna, 1090, Austria
| | - Meder Kamalov
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna, 109, Austria
- Vienna Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Str. 42, Vienna, 1090, Austria
| | - Daniela Reichinger
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna, 109, Austria
- Vienna Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Str. 42, Vienna, 1090, Austria
| | - Dennis Kurzbach
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna, 109, Austria
- Vienna Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Str. 42, Vienna, 1090, Austria
| | - Christian Fw Becker
- Institute of Biological Chemistry, Faculty of Chemistry, University of Vienna, Währinger Str. 38, Vienna, 109, Austria
- Vienna Doctoral School in Chemistry (DoSChem), University of Vienna, Währinger Str. 42, Vienna, 1090, Austria
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5
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Phosphates form spectroscopically dark state assemblies in common aqueous solutions. Proc Natl Acad Sci U S A 2023; 120:e2206765120. [PMID: 36580589 PMCID: PMC9910612 DOI: 10.1073/pnas.2206765120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
Phosphates and polyphosphates play ubiquitous roles in biology as integral structural components of cell membranes and bone, or as vehicles of energy storage via adenosine triphosphate and phosphocreatine. The solution phase space of phosphate species appears more complex than previously known. We present nuclear magnetic resonance (NMR) and cryogenic transmission electron microscopy (cryo-TEM) experiments that suggest phosphate species including orthophosphates, pyrophosphates, and adenosine phosphates associate into dynamic assemblies in dilute solutions that are spectroscopically "dark." Cryo-TEM provides visual evidence of the formation of spherical assemblies tens of nanometers in size, while NMR indicates that a majority population of phosphates remain as unassociated ions in exchange with spectroscopically invisible assemblies. The formation of these assemblies is reversibly and entropically driven by the partial dehydration of phosphate groups, as verified by diffusion-ordered spectroscopy (DOSY), indicating a thermodynamic state of assembly held together by multivalent interactions between the phosphates. Molecular dynamics simulations further corroborate that orthophosphates readily cluster in aqueous solutions. This study presents the surprising discovery that phosphate-containing molecules, ubiquitously present in the biological milieu, can readily form dynamic assemblies under a wide range of commonly used solution conditions, highlighting a hitherto unreported property of phosphate's native state in biological solutions.
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6
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Juramy M, Vioglio PC, Ziarelli F, Viel S, Thureau P, Mollica G. Monitoring the influence of additives on the crystallization processes of glycine with dynamic nuclear polarization solid-state NMR. SOLID STATE NUCLEAR MAGNETIC RESONANCE 2022; 122:101836. [PMID: 36327551 DOI: 10.1016/j.ssnmr.2022.101836] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/22/2022] [Revised: 09/12/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
Crystallization is fundamental in many domains, and the investigation of the sequence of solid phases produced as a function of crystallization time is thus key to understand and control crystallization processes. Here, we used a solid-state nuclear magnetic resonance strategy to monitor the crystallization process of glycine, which is a model compound in polymorphism, under the influence of crystallizing additives, such as methanol or sodium chloride. More specifically, our strategy is based on a combination of low-temperatures and dynamic nuclear polarization (DNP) to trap and detect transient crystallizing forms, which may be present only in low quantities. Interestingly, our results show that these additives yield valuable DNP signal enhancements even in the absence of glycerol within the crystallizing solution.
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Affiliation(s)
- Marie Juramy
- Aix Marseille Univ, CNRS, ICR, Marseille, France
| | | | - Fabio Ziarelli
- Aix Marseille Univ, CNRS, Centrale Marseille, FSCM, Marseille, France
| | - Stéphane Viel
- Aix Marseille Univ, CNRS, ICR, Marseille, France; Institut Universitaire de France, Paris, France
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7
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Negroni M, Turhan E, Kress T, Ceillier M, Jannin S, Kurzbach D. Frémy’s Salt as a Low-Persistence Hyperpolarization Agent: Efficient Dynamic Nuclear Polarization Plus Rapid Radical Scavenging. J Am Chem Soc 2022; 144:20680-20686. [PMID: 36322908 PMCID: PMC9673139 DOI: 10.1021/jacs.2c07960] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
![]()
Nuclear magnetic resonance (NMR) spectroscopy is a key
technique
for molecular structure determination in solution. However, due to
its low sensitivity, many efforts have been made to improve signal
strengths and reduce the required substrate amounts. In this regard,
dissolution dynamic nuclear polarization (DDNP) is a versatile approach
as signal enhancements of over 10 000-fold are achievable.
Samples are signal-enhanced ex situ by transferring
electronic polarization from radicals to nuclear spins before dissolving
and shuttling the boosted sample to an NMR spectrometer for detection.
However, the applicability of DDNP suffers from one major drawback,
namely, paramagnetic relaxation enhancements (PREs) that critically
reduce relaxation times due to the codissolved radicals. PREs are
the primary source of polarization losses canceling the signal improvements
obtained by DNP. We solve this problem by using potassium nitrosodisulfonate
(Frémy’s salt) as polarization agent (PA), which provides
high nuclear spin polarization and allows for rapid scavenging under
mild reducing conditions. We demonstrate the potential of Frémy’s
salt, (i) showing that both 1H and 13C polarization
of ∼30% can be achieved and (ii) describing a hybrid sample
shuttling system (HySSS) that can be used with any DDNP/NMR combination
to remove the PA before NMR detection. This gadget mixes the hyperpolarized
solution with a radical scavenger and injects it into an NMR tube,
providing, within a few seconds, quantitatively radical-free, highly
polarized solutions. The cost efficiency and broad availability of
Frémy’s salt might facilitate the use of DDNP in many
fields of research.
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Affiliation(s)
- Mattia Negroni
- Faculty of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Straße 38, 1090 Vienna, Austria
| | - Ertan Turhan
- Faculty of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Straße 38, 1090 Vienna, Austria
| | - Thomas Kress
- Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, U.K
| | - Morgan Ceillier
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs (UMR 5082) Université de Lyon/CNRS/Université Claude Bernard Lyon 1/ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Sami Jannin
- Centre de Résonance Magnétique Nucléaire à Très Hauts Champs (UMR 5082) Université de Lyon/CNRS/Université Claude Bernard Lyon 1/ENS de Lyon, 5 Rue de la Doua, 69100 Villeurbanne, France
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Straße 38, 1090 Vienna, Austria
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8
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Juramy M, Mollica G. Recent Progress in Nuclear Magnetic Resonance Strategies for Time-Resolved Atomic-Level Investigation of Crystallization from Solution. Curr Opin Colloid Interface Sci 2022. [DOI: 10.1016/j.cocis.2022.101663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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9
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Gebauer D, Gale JD, Cölfen H. Crystal Nucleation and Growth of Inorganic Ionic Materials from Aqueous Solution: Selected Recent Developments, and Implications. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2022; 18:e2107735. [PMID: 35678091 DOI: 10.1002/smll.202107735] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 05/07/2022] [Indexed: 05/27/2023]
Abstract
In this review article, selected, latest theoretical, and experimental developments in the field of nucleation and crystal growth of inorganic materials from aqueous solution are highlighted, with a focus on literature after 2015 and on non-classical pathways. A key point is to emphasize the so far underappreciated role of water and solvent entropy in crystallization at all stages from solution speciation through to the final crystal. While drawing on examples from current inorganic materials where non-classical behavior has been proposed, the potential of these approaches to be adapted to a wide-range of systems is also discussed, while considering the broader implications of the current re-assessment of pathways for crystallization. Various techniques that are suitable for the exploration of crystallization pathways in aqueous solution, from nucleation to crystal growth are summarized, and a flow chart for the assignment of specific theories based on experimental observations is proposed.
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Affiliation(s)
- Denis Gebauer
- Leibniz University Hannover, Institute of Inorganic Chemistry, Callinstr. 9, 30167, Hannover, Germany
| | - Julian D Gale
- Curtin Institute for Computation/The Institute for Geoscience Research (TiGER), School of Molecular and Life Sciences, Curtin University, PO Box U1987, Perth, Western Australia, 6845, Australia
| | - Helmut Cölfen
- University of Konstanz, Physical Chemistry, Universitätsstr. 10, 78465, Konstanz, Germany
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10
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Hilty C, Kurzbach D, Frydman L. Hyperpolarized water as universal sensitivity booster in biomolecular NMR. Nat Protoc 2022; 17:1621-1657. [PMID: 35546640 DOI: 10.1038/s41596-022-00693-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 02/25/2022] [Indexed: 11/09/2022]
Abstract
NMR spectroscopy is the only method to access the structural dynamics of biomolecules at high (atomistic) resolution in their native solution state. However, this method's low sensitivity has two important consequences: (i) typically experiments have to be performed at high concentrations that increase sensitivity but are not physiological, and (ii) signals have to be accumulated over long periods, complicating the determination of interaction kinetics on the order of seconds and impeding studies of unstable systems. Both limitations are of equal, fundamental relevance: non-native conditions are of limited pharmacological relevance, and the function of proteins, enzymes and nucleic acids often relies on their interaction kinetics. To overcome these limitations, we have developed applications that involve 'hyperpolarized water' to boost signal intensities in NMR of proteins and nucleic acids. The technique includes four stages: (i) preparation of the biomolecule in partially deuterated buffers, (ii) preparation of 'hyperpolarized' water featuring enhanced 1H NMR signals via cryogenic dynamic nuclear polarization, (iii) sudden melting of the cryogenic pellet and dissolution of the protein or nucleic acid in the hyperpolarized water (enabling spontaneous exchanges of protons between water and target) and (iv) recording signal-amplified NMR spectra targeting either labile 1H or neighboring 15N/13C nuclei in the biomolecule. Water in the ensuing experiments is used as a universal 'hyperpolarization' agent, rendering the approach versatile and applicable to any biomolecule possessing labile hydrogens. Thus, questions can be addressed, ranging from protein and RNA folding problems to resolving structure-function relationships of intrinsically disordered proteins to investigating membrane interactions.
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Affiliation(s)
- Christian Hilty
- Chemistry Department, Texas A&M University, College Station, TX, USA.
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute for Biological Chemistry, University of Vienna, Vienna, Austria.
| | - Lucio Frydman
- Department of Chemical and Biological Physics, Weizmann Institute of Science, Rehovot, Israel.
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11
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Wei T, Hauke F, Hirsch A. Evolution of Graphene Patterning: From Dimension Regulation to Molecular Engineering. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2021; 33:e2104060. [PMID: 34569112 DOI: 10.1002/adma.202104060] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/28/2021] [Revised: 06/28/2021] [Indexed: 05/26/2023]
Abstract
The realization that nanostructured graphene featuring nanoscale width can confine electrons to open its bandgap has aroused scientists' attention to the regulation of graphene structures, where the concept of graphene patterns emerged. Exploring various effective methods for creating graphene patterns has led to the birth of a new field termed graphene patterning, which has evolved into the most vigorous and intriguing branch of graphene research during the past decade. The efforts in this field have resulted in the development of numerous strategies to structure graphene, affording a variety of graphene patterns with tailored shapes and sizes. The established patterning approaches combined with graphene chemistry yields a novel chemical patterning route via molecular engineering, which opens up a new era in graphene research. In this review, the currently developed graphene patterning strategies is systematically outlined, with emphasis on the chemical patterning. In addition to introducing the basic concepts and the important progress of traditional methods, which are generally categorized into top-down, bottom-up technologies, an exhaustive review of established protocols for emerging chemical patterning is presented. At the end, an outlook for future development and challenges is proposed.
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Affiliation(s)
- Tao Wei
- Department of Chemistry and Pharmacy and Joint Institute of Advance Materials and Processes (ZMP), Friedrich-Alexander University of Erlangen-Nürnberg, Nikolaus-Fiebiger-Strasse 10, 91058, Erlangen, Germany
| | - Frank Hauke
- Department of Chemistry and Pharmacy and Joint Institute of Advance Materials and Processes (ZMP), Friedrich-Alexander University of Erlangen-Nürnberg, Nikolaus-Fiebiger-Strasse 10, 91058, Erlangen, Germany
| | - Andreas Hirsch
- Department of Chemistry and Pharmacy and Joint Institute of Advance Materials and Processes (ZMP), Friedrich-Alexander University of Erlangen-Nürnberg, Nikolaus-Fiebiger-Strasse 10, 91058, Erlangen, Germany
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12
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Epasto LM, Georges T, Selimović A, Guigner JM, Azaïs T, Kurzbach D. Formation and Evolution of Nanoscale Calcium Phosphate Precursors under Biomimetic Conditions. Anal Chem 2021; 93:10204-10211. [PMID: 34251166 PMCID: PMC8319911 DOI: 10.1021/acs.analchem.1c01561] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Simulated body fluids (SBFs) that mimic human blood plasma are widely used media for in vitro studies in an extensive array of research fields, from biomineralization to surface and corrosion sciences. We show that these solutions undergo dynamic nanoscopic conformational rearrangements on the timescale of minutes to hours, even though they are commonly considered stable or metastable. In particular, we find and characterize nanoscale inhomogeneities made of calcium phosphate (CaP) aggregates that emerge from homogeneous SBFs within a few hours and evolve into prenucleation species (PNS) that act as precursors in CaP crystallization processes. These ionic clusters consist of ∼2 nm large spherical building units that can aggregate into suprastructures with sizes of over 200 nm. We show that the residence times of phosphate ions in the PNS depend critically on the total PNS surface. These findings are particularly relevant for understanding nonclassical crystallization phenomena, in which PNS are assumed to act as building blocks for the final crystal structure.
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Affiliation(s)
- Ludovica M Epasto
- Faculty of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Str. 38, 1090 Vienna, Austria
| | - Tristan Georges
- Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4, Place Jussieu, F-75005 Paris, France
| | - Albina Selimović
- Faculty of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Str. 38, 1090 Vienna, Austria
| | - Jean-Michel Guigner
- Institut de Minéralogie et Physique des Milieux Condensés (IMPMC), Sorbonne Université, 4, Place Jussieu, F-75005 Paris, France
| | - Thierry Azaïs
- Sorbonne Université, CNRS, Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), 4, Place Jussieu, F-75005 Paris, France
| | - Dennis Kurzbach
- Faculty of Chemistry, Institute of Biological Chemistry, University Vienna, Währinger Str. 38, 1090 Vienna, Austria
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13
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Abhyankar N, Szalai V. Challenges and Advances in the Application of Dynamic Nuclear Polarization to Liquid-State NMR Spectroscopy. J Phys Chem B 2021; 125:5171-5190. [PMID: 33960784 PMCID: PMC9871957 DOI: 10.1021/acs.jpcb.0c10937] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Nuclear magnetic resonance (NMR) spectroscopy is a powerful method to study the molecular structure and dynamics of materials. The inherently low sensitivity of NMR spectroscopy is a consequence of low spin polarization. Hyperpolarization of a spin ensemble is defined as a population difference between spin states that far exceeds what is expected from the Boltzmann distribution for a given temperature. Dynamic nuclear polarization (DNP) can overcome the relatively low sensitivity of NMR spectroscopy by using a paramagnetic matrix to hyperpolarize a nuclear spin ensemble. Application of DNP to NMR can result in sensitivity gains of up to four orders of magnitude compared to NMR without DNP. Although DNP NMR is now more routinely utilized for solid-state (ss) NMR spectroscopy, it has not been exploited to the same degree for liquid-state samples. This Review will consider challenges and advances in the application of DNP NMR to liquid-state samples. The Review is organized into four sections: (i) mechanisms of DNP NMR relevant to hyperpolarization of liquid samples; (ii) applications of liquid-state DNP NMR; (iii) available detection schemes for liquid-state samples; and (iv) instrumental challenges and outlook for liquid-state DNP NMR.
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Affiliation(s)
- Nandita Abhyankar
- Institute for Research in Electronics and Applied Physics, University of Maryland, College Park, MD 20742, USA,National Institute of Standards and Technology, Gaithersburg, MD 20899, USA,Corresponding authors: ,
| | - Veronika Szalai
- National Institute of Standards and Technology, Gaithersburg, MD 20899, USA,Corresponding authors: ,
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Juramy M, Chèvre R, Cerreia Vioglio P, Ziarelli F, Besson E, Gastaldi S, Viel S, Thureau P, Harris KDM, Mollica G. Monitoring Crystallization Processes in Confined Porous Materials by Dynamic Nuclear Polarization Solid-State Nuclear Magnetic Resonance. J Am Chem Soc 2021; 143:6095-6103. [PMID: 33856790 PMCID: PMC8154530 DOI: 10.1021/jacs.0c12982] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Establishing mechanistic understanding of crystallization processes at the molecular level is challenging, as it requires both the detection of transient solid phases and monitoring the evolution of both liquid and solid phases as a function of time. Here, we demonstrate the application of dynamic nuclear polarization (DNP) enhanced NMR spectroscopy to study crystallization under nanoscopic confinement, revealing a viable approach to interrogate different stages of crystallization processes. We focus on crystallization of glycine within the nanometric pores (7-8 nm) of a tailored mesoporous SBA-15 silica material with wall-embedded TEMPO radicals. The results show that the early stages of crystallization, characterized by the transition from the solution phase to the first crystalline phase, are straightforwardly observed using this experimental strategy. Importantly, the NMR sensitivity enhancement provided by DNP allows the detection of intermediate phases that would not be observable using standard solid-state NMR experiments. Our results also show that the metastable β polymorph of glycine, which has only transient existence under bulk crystallization conditions, remains trapped within the pores of the mesoporous SBA-15 silica material for more than 200 days.
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Affiliation(s)
- Marie Juramy
- Aix Marseille Univ, CNRS, ICR, 13397 Marseille, France
| | - Romain Chèvre
- Aix Marseille Univ, CNRS, ICR, 13397 Marseille, France
| | | | - Fabio Ziarelli
- Aix Marseille Univ, CNRS, Centrale Marseille, FSCM, 13397 Marseille, France
| | - Eric Besson
- Aix Marseille Univ, CNRS, ICR, 13397 Marseille, France
| | | | - Stéphane Viel
- Aix Marseille Univ, CNRS, ICR, 13397 Marseille, France.,Institut Universitaire de France, 75231 Paris, France
| | | | - Kenneth D M Harris
- School of Chemistry, Cardiff University, Park Place, Cardiff, Wales CF10 3AT, U. K
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Structural Biology of Calcium Phosphate Nanoclusters Sequestered by Phosphoproteins. CRYSTALS 2020. [DOI: 10.3390/cryst10090755] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Biofluids that contain stable calcium phosphate nanoclusters sequestered by phosphopeptides make it possible for soft and hard tissues to co-exist in the same organism with relative ease. The stability diagram of a solution of nanocluster complexes shows how the minimum concentration of phosphopeptide needed for stability increases with pH. In the stable region, amorphous calcium phosphate cannot precipitate. Nevertheless, if the solution is brought into contact with hydroxyapatite, the crystalline phase will grow at the expense of the nanocluster complexes. The physico-chemical principles governing the formation, composition, size, structure, and stability of the complexes are described. Examples are given of complexes formed by casein, osteopontin, and recombinant phosphopeptides. Application of these principles and properties to blood serum, milk, urine, and resting saliva is described to show that under physiological conditions they are in the stable region of their stability diagram and so cannot cause soft tissue calcification. Stimulated saliva, however, is in the metastable region, consistent with its role in tooth remineralization. Destabilization of biofluids, with consequential ill-effects, can occur when there is a failure of homeostasis, such as an increase in pH without a balancing increase in the concentration of sequestering phosphopeptides.
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