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Fandrei F, Havrišák T, Opálka L, Engberg O, Smith A, Pullmannová P, Kučerka N, Ondrejčeková V, Demé B, Nováková L, Steinhart M, Vávrová K, Huster D. The Intriguing Molecular Dynamics of Cer[EOS] in Rigid Skin Barrier Lipid Layers Requires Improvement of the Model. J Lipid Res 2023; 64:100356. [PMID: 36948272 PMCID: PMC10154977 DOI: 10.1016/j.jlr.2023.100356] [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: 01/23/2023] [Revised: 03/07/2023] [Accepted: 03/08/2023] [Indexed: 03/24/2023] Open
Abstract
Omega-O-acyl ceramides such as 32-linoleoyloxydotriacontanoyl sphingosine (Cer[EOS]) are essential components of the lipid skin barrier, which protects our body from excessive water loss and the penetration of unwanted substances. These ceramides drive the lipid assembly to epidermal-specific long periodicity phase (LPP), structurally much different than conventional lipid bilayers. Here, we synthesized Cer[EOS] with selectively deuterated segments of the ultralong N-acyl chain or deuterated or 13C-labeled linoleic acid and studied their molecular behavior in a skin lipid model. Solid-state 2H NMR data revealed surprising molecular dynamics for the ultralong N-acyl chain of Cer[EOS] with increased isotropic motion towards the isotropic ester-bound linoleate. The sphingosine moiety of Cer[EOS] is also highly mobile at skin temperature, in stark contrast to the other LPP components, N-lignoceroyl sphingosine acyl, lignoceric acid and cholesterol, which are predominantly rigid. The dynamics of the linoleic chain is quantitatively described by distributions of correlation times and using dynamic detector analysis. These NMR results along with neutron diffraction data suggest an LPP structure with alternating fluid (sphingosine chain-rich), rigid (acyl chain-rich), isotropic (linoleate-rich), rigid (acyl-chain rich), and fluid layers (sphingosine chain-rich). Such an arrangement of the skin barrier lipids with rigid layers separated with two different dynamic "fillings" i) agrees well with ultrastructural data, ii) satisfies the need for simultaneous rigidity (to ensure low permeability) and fluidity (to ensure elasticity, accommodate enzymes or antimicrobial peptides), and iii) offers a straightforward way to remodel the lamellar body lipids into the final lipid barrier.
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Affiliation(s)
- Ferdinand Fandrei
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
| | - Tomáš Havrišák
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Lukáš Opálka
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Oskar Engberg
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
| | - AlbertA Smith
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
| | - Petra Pullmannová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Norbert Kučerka
- Faculty of Pharmacy, Comenius University in Bratislava, Odbojárov 10, 832 32 Bratislava, Slovakia
| | - Veronika Ondrejčeková
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Bruno Demé
- Institut Laue-Langevin, 71 avenue des Martyrs, CS 20156, 38042 Grenoble, CEDEX 9, France
| | - Lucie Nováková
- Department of Analytical Chemistry, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Miloš Steinhart
- Institute of Macromolecular Chemistry, Czech Academy of Science in Prague, Heyrovského nám. 2, 162 06 Prague, Czech Republic
| | - Kateřina Vávrová
- Skin Barrier Research Group, Faculty of Pharmacy, Charles University, Akademika Heyrovského 1203, 50005 Hradec Králové, Czech Republic
| | - Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, 04275 Leipzig, Germany
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2
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Auger M, Lefèvre T, Otis F, Voyer N, Auger M. Lipid membrane interactions of a fluorinated peptide with potential ion channel-forming ability. Pept Sci (Hoboken) 2019. [DOI: 10.1002/pep2.24051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Maud Auger
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - Thierry Lefèvre
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - François Otis
- PROTEO, Département de chimie; Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - Normand Voyer
- PROTEO, Département de chimie; Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
| | - Michèle Auger
- Regroupement québécois de Recherche sur la Fonction, l'Ingénierie et les Applications des Protéines (PROTEO), Centre de Recherche sur les Matériaux Avancés (CERMA), Centre Québécois sur les Matériaux Fonctionnels (CQMF), Département de Chimie, Université Laval, 1045 avenue de la Médecine; Québec QC Canada G1V 0A6
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Mchinda S, Varma G, Prevost VH, Le Troter A, Rapacchi S, Guye M, Pelletier J, Ranjeva J, Alsop DC, Duhamel G, Girard OM. Whole brain inhomogeneous magnetization transfer (ihMT) imaging: Sensitivity enhancement within a steady‐state gradient echo sequence. Magn Reson Med 2017; 79:2607-2619. [DOI: 10.1002/mrm.26907] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2017] [Revised: 07/18/2017] [Accepted: 08/17/2017] [Indexed: 02/05/2023]
Affiliation(s)
| | - Gopal Varma
- Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBostonMassachusettsUSA
| | | | | | | | - Maxime Guye
- Aix Marseille Univ, CNRS, CRMBM UMR 7339MarseilleFrance
- Aix Marseille Univ, APHM, Hôpital de La Timone, Pôle d'Imagerie Médicale, CEMEREMMarseilleFrance
| | - Jean Pelletier
- Aix Marseille Univ, CNRS, CRMBM UMR 7339MarseilleFrance
- Aix Marseille Univ, APHM, Hôpital de La Timone, Pôle de Neurosciences Cliniques, Service de NeurologieMarseilleFrance
| | | | - David C. Alsop
- Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical SchoolBostonMassachusettsUSA
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Auger M. Membrane solid-state NMR in Canada: A historical perspective. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2017; 1865:1483-1489. [PMID: 28652206 DOI: 10.1016/j.bbapap.2017.06.019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 06/17/2017] [Accepted: 06/21/2017] [Indexed: 11/18/2022]
Abstract
This manuscript presents an overview of more than 40years of membrane solid-state nuclear magnetic resonance (NMR) research in Canada. This technique is a method of choice for the study of the structure and dynamics of lipid bilayers; bilayer interactions with a variety of molecules such as membrane peptides, membrane proteins and drugs; and to investigate membrane peptide and protein structure, dynamics, and topology. Canada has a long tradition in this field of research, starting with pioneering work on natural and model membranes in the 1970s in a context of emergence of biophysics in the country. The 1980s and 1990s saw an emphasis on studying lipid structures and dynamics, and peptide-lipid and protein-lipid interactions. The study of bicelles began in the 1990s, and in the 2000s there was a rise in the study of membrane protein structures. Novel perspectives include using dynamic nuclear polarization (DNP) for membrane studies and using NMR in live cells. This article is part of a Special Issue entitled: Biophysics in Canada, edited by Lewis Kay, John Baenziger, Albert Berghuis and Peter Tieleman.
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Affiliation(s)
- Michèle Auger
- Département de chimie, PROTEO, CERMA, CQMF, Université Laval, Québec, Québec G1V 0A6, Canada.
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Prevost VH, Girard OM, Mchinda S, Varma G, Alsop DC, Duhamel G. Optimization of inhomogeneous magnetization transfer (ihMT) MRI contrast for preclinical studies using dipolar relaxation time (T 1D ) filtering. NMR IN BIOMEDICINE 2017; 30:e3706. [PMID: 28195663 DOI: 10.1002/nbm.3706] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 01/10/2017] [Accepted: 01/11/2017] [Indexed: 06/06/2023]
Abstract
A pulsed inhomogeneous magnetization transfer (ihMT)-prepared fast imaging sequence was implemented at 11.75 T for preclinical studies on mouse central nervous system. A strategy based on filtering the ihMT signal originating from short dipolar relaxation time (T1D ) components is proposed. It involves increasing the repetition time of consecutive radiofrequency (RF) pulses of the dual saturation and allows improved signal specificity for long T1D myelinated structures. Furthermore, frequency offset, power and timing saturation parameters were adjusted to optimize the ihMT sensitivity. The optimization of the ihMT sensitivity, whilst preserving the strong specificity for the long T1D component of myelinated tissues, allowed measurements of ihMT ratios on the order of 4-5% in white matter (WM), 2.5% in gray matter (GM) and 1-1.3% in muscle. This led to high relative ihMT contrasts between myelinated tissues and others (~3-4 between WM and muscle, and ≥2 between GM and muscle). Conversely, higher ihMT ratios (~6-7% in WM) could be obtained using minimal T1D filtering achieved with short saturation pulse repetition time or cosine-modulated pulses for the dual-frequency saturation. This study represents a first stage in the process of validating ihMT as a myelin biomarker by providing optimized ihMT preclinical sequences, directly transposable and applicable to other preclinical magnetic fields and scanners. Finally, ihMT ratios measured in various central nervous system areas are provided for future reference.
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Affiliation(s)
- V H Prevost
- Aix Marseille Université, CNRS, Marseille, France
| | - O M Girard
- Aix Marseille Université, CNRS, Marseille, France
| | - S Mchinda
- Aix Marseille Université, CNRS, Marseille, France
| | - G Varma
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - D C Alsop
- Department of Radiology, Division of MR Research, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - G Duhamel
- Aix Marseille Université, CNRS, Marseille, France
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Manning AP, Chang KL, MacKay AL, Michal CA. The physical mechanism of "inhomogeneous" magnetization transfer MRI. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2017; 274:125-136. [PMID: 27918896 DOI: 10.1016/j.jmr.2016.11.013] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/26/2016] [Revised: 11/21/2016] [Accepted: 11/23/2016] [Indexed: 05/24/2023]
Abstract
Inhomogeneous MT (ihMT) is a new magnetic resonance imaging technique that shows promise for myelin selectivity. Materials with a high proportion of lipids, such as white matter tissue, show a reduced intensity in magnetic resonance images acquired with selective prepulses at positive and negative offsets simultaneously compared to images with a single positive or negative offset prepulse of the same power. This effect was initially explained on the basis of hole-burning in inhomogeneously broadened lines of the lipid proton spin system. Our results contradict this explanation. ihMT in lipids can be understood with a simple spin-1 model of a coupled methylene proton pair. More generally, Provotorov theory can be used to consider the evolution of dipolar order in the non-aqueous spins during the prepulses. We show that the flip-angle dependence of the proton spectrum of a model lipid system (Prolipid-161) following dipolar order generation is in quantitative agreement with the model. In addition, we directly observe dipolar order and ihMT signals in the non-aqueous components of Prolipid-161 and homogeneously-broadened systems (hair, wood, and tendon) following ihMT prepulses. The observation of ihMT signals in tendon suggests that the technique may not be as specific to myelin as previously thought. Our work shows that ihMT occurs because of dipolar couplings alone, not from a specific type of spectral line broadening as its name suggests.
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Affiliation(s)
- Alan P Manning
- Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
| | - Kimberley L Chang
- Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada
| | - Alex L MacKay
- Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada; Radiology, University of British Columbia, 2211 Wesbrook Mall, Vancouver, BC V6T 2B5, Canada
| | - Carl A Michal
- Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, BC V6T 1Z1, Canada.
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Bärenwald R, Achilles A, Lange F, Ferreira TM, Saalwächter K. Applications of Solid-State NMR Spectroscopy for the Study of Lipid Membranes with Polyphilic Guest (Macro)Molecules. Polymers (Basel) 2016; 8:E439. [PMID: 30974716 PMCID: PMC6432237 DOI: 10.3390/polym8120439] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2016] [Revised: 12/01/2016] [Accepted: 12/08/2016] [Indexed: 11/16/2022] Open
Abstract
The incorporation of polymers or smaller complex molecules into lipid membranes allows for property modifications or the introduction of new functional elements. The corresponding molecular-scale details, such as changes in dynamics or features of potential supramolecular structures, can be studied by a variety of solid-state NMR techniques. Here, we review various approaches to characterizing the structure and dynamics of the guest molecules as well as the lipid phase structure and dynamics by different high-resolution magic-angle spinning proton and 13C NMR experiments as well as static 31P NMR experiments. Special emphasis is placed upon the incorporation of novel synthetic polyphilic molecules such as shape-persistent T- and X-shaped molecules as well as di- and tri-block copolymers. Most of the systems studied feature dynamic heterogeneities, for instance those arising from the coexistence of different phases; possibilities for a quantitative assessment are of particular concern.
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Affiliation(s)
- Ruth Bärenwald
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, D-06120 Halle, Germany
| | - Anja Achilles
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, D-06120 Halle, Germany
| | - Frank Lange
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, D-06120 Halle, Germany
| | - Tiago Mendes Ferreira
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, D-06120 Halle, Germany
| | - Kay Saalwächter
- Institut für Physik-NMR, Martin-Luther-Universität Halle-Wittenberg, D-06120 Halle, Germany.
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De Poli M, Zawodny W, Quinonero O, Lorch M, Webb SJ, Clayden J. Conformational photoswitching of a synthetic peptide foldamer bound within a phospholipid bilayer. Science 2016; 352:575-80. [PMID: 27033546 DOI: 10.1126/science.aad8352] [Citation(s) in RCA: 135] [Impact Index Per Article: 16.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/24/2016] [Indexed: 12/17/2022]
Abstract
The dynamic properties of foldamers, synthetic molecules that mimic folded biomolecules, have mainly been explored in free solution. We report on the design, synthesis, and conformational behavior of photoresponsive foldamers bound in a phospholipid bilayer akin to a biological membrane phase. These molecules contain a chromophore, which can be switched between two configurations by different wavelengths of light, attached to a helical synthetic peptide that both promotes membrane insertion and communicates conformational change along its length. Light-induced structural changes in the chromophore are translated into global conformational changes, which are detected by monitoring the solid-state (19)F nuclear magnetic resonance signals of a remote fluorine-containing residue located 1 to 2 nanometers away. The behavior of the foldamers in the membrane phase is similar to that of analogous compounds in organic solvents.
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Affiliation(s)
- Matteo De Poli
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - Wojciech Zawodny
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - Ophélie Quinonero
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK
| | - Mark Lorch
- Department of Chemistry, University of Hull, Hull HU6 7RX, UK
| | - Simon J Webb
- School of Chemistry, University of Manchester, Manchester M13 9PL, UK. Manchester Institute of Biotechnology, University of Manchester, Manchester M1 7DN, UK
| | - Jonathan Clayden
- School of Chemistry, University of Bristol, Bristol BS8 1TS, UK.
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Swanson SD, Malyarenko DI, Fabiilli ML, Welsh RC, Nielsen JF, Srinivasan A. Molecular, dynamic, and structural origin of inhomogeneous magnetization transfer in lipid membranes. Magn Reson Med 2016; 77:1318-1328. [PMID: 27029318 DOI: 10.1002/mrm.26210] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 02/06/2016] [Accepted: 02/18/2016] [Indexed: 02/04/2023]
Abstract
PURPOSE To elucidate the dynamic, structural, and molecular properties that create inhomogeneous magnetization transfer (ihMT) contrast. METHODS Amphiphilic lipids, lamellar phospholipids with cholesterol, and bovine spinal cord (BSC) specimens were examined along with nonlipid systems. Magnetization transfer (MT), enhanced MT (eMT, obtained with double-sided radiofrequency saturation), ihMT (MT - eMT), and dipolar relaxation, T1D , were measured at 2.0 and 11.7 T. RESULTS The amplitude of ihMT ratio (ihMTR) is positively correlated with T1D values. Both ihMTR and T1D increase with increasing temperature in BSC white matter and in phospholipids and decrease with temperature in other lipids. Changes in ihMTR with temperature arise primarily from alterations in MT rather than eMT. Spectral width of MT, eMT, and ihMT increases with increasing carbon chain length. CONCLUSIONS Concerted motions of phospholipids in white matter decrease proton spin diffusion leading to increased proton T1D times and increased ihMT amplitudes, consistent with decoupling of Zeeman and dipolar spin reservoirs. Molecular specificity and dynamic sensitivity of ihMT contrast make it a suitable candidate for probing myelin membrane disorders. Magn Reson Med 77:1318-1328, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Scott D Swanson
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Robert C Welsh
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - Jon-Fredrik Nielsen
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Ashok Srinivasan
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
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Girard OM, Callot V, Prevost VH, Robert B, Taso M, Ribeiro G, Varma G, Rangwala N, Alsop DC, Duhamel G. Magnetization transfer from inhomogeneously broadened lines (ihMT): Improved imaging strategy for spinal cord applications. Magn Reson Med 2016; 77:581-591. [PMID: 26959278 DOI: 10.1002/mrm.26134] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2015] [Revised: 12/08/2015] [Accepted: 01/03/2016] [Indexed: 02/05/2023]
Abstract
PURPOSE Inhomogeneous magnetization transfer (ihMT) shows great promise for specific imaging of myelinated tissues. Whereas the ihMT technique has been previously applied in brain applications, the current report presents a strategy for cervical spinal cord (SC) imaging free of cerebrospinal fluid (CSF) pulsatility artifacts. METHODS A pulsed ihMT preparation was combined with a single-shot HASTE readout. Electrocardiogram (ECG) synchronization was used to acquire all images during the quiescent phase of SC motion. However ihMT signal quantification errors may occur when a variable recovery delay is introduced in the sequence as a consequence of variable cardiac cycle. A semiautomatic retrospective correction algorithm, based on repetition time (TR) -matching, is proposed to correct for signal variations of long T1 -components (e.g., CSF). RESULTS The proposed strategy combining ECG synchronization and retrospective data pairing led to clean SC images free of CSF artifacts. Lower variability of the ihMT metrics were obtained with the correction algorithm, and allowed for shorter TR to be used, hence improving signal-to-noise ratio efficiency. CONCLUSION The proposed methodology enabled faster acquisitions, while offering robust ihMT quantification and exquisite SC image quality. This opens great perspectives for widening the in vivo characterization of SC physiopathology using MRI, such as studying white matter tracts microstructure or impairment in degenerative pathologies. Magn Reson Med 77:581-591, 2017. © 2016 International Society for Magnetic Resonance in Medicine.
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Affiliation(s)
- Olivier M Girard
- Aix-Marseille Université, CRMBM, UMR 7339 CNRS - AMU, Marseille, France.,Pôle d'Imagerie Médicale, CEMEREM, AP-HM, Marseille, France
| | - Virginie Callot
- Aix-Marseille Université, CRMBM, UMR 7339 CNRS - AMU, Marseille, France.,Pôle d'Imagerie Médicale, CEMEREM, AP-HM, Marseille, France
| | - Valentin H Prevost
- Aix-Marseille Université, CRMBM, UMR 7339 CNRS - AMU, Marseille, France.,Pôle d'Imagerie Médicale, CEMEREM, AP-HM, Marseille, France
| | | | - Manuel Taso
- Aix-Marseille Université, CRMBM, UMR 7339 CNRS - AMU, Marseille, France.,Pôle d'Imagerie Médicale, CEMEREM, AP-HM, Marseille, France.,Aix-Marseille Université, IFSTTAR, LBA UMR T24, Marseille, France
| | - Guilherme Ribeiro
- Aix-Marseille Université, CRMBM, UMR 7339 CNRS - AMU, Marseille, France.,Pôle d'Imagerie Médicale, CEMEREM, AP-HM, Marseille, France
| | - Gopal Varma
- Department of Radiology, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, Massachusetts, USA
| | - Novena Rangwala
- Department of Radiology, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, Massachusetts, USA
| | - David C Alsop
- Department of Radiology, Beth Israel Deaconess Medical Center, and Harvard Medical School, Boston, Massachusetts, USA
| | - Guillaume Duhamel
- Aix-Marseille Université, CRMBM, UMR 7339 CNRS - AMU, Marseille, France.,Pôle d'Imagerie Médicale, CEMEREM, AP-HM, Marseille, France
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Davis JH, Komljenović I. Nuclear Overhauser effect as a probe of molecular structure, dynamics and order of axially reorienting molecules in membranes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:295-303. [DOI: 10.1016/j.bbamem.2015.11.016] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Revised: 10/21/2015] [Accepted: 11/18/2015] [Indexed: 10/22/2022]
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12
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Prevost VH, Girard OM, Varma G, Alsop DC, Duhamel G. Minimizing the effects of magnetization transfer asymmetry on inhomogeneous magnetization transfer (ihMT) at ultra-high magnetic field (11.75 T). MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2016; 29:699-709. [PMID: 26762244 DOI: 10.1007/s10334-015-0523-2] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/29/2015] [Accepted: 12/30/2015] [Indexed: 11/30/2022]
Abstract
OBJECTIVES The recently reported inhomogeneous magnetization transfer technique (ihMT) has been proposed for specific imaging of inhomogeneously broadened lines, and has shown great promise for characterizing myelinated tissues. The ihMT contrast is obtained by subtracting magnetization transfer images obtained with simultaneous saturation at positive and negative frequency offsets (dual frequency saturation experiment, MT (+/-)) from those obtained with single frequency saturation (MT (+)) at the same total power. Hence, ihMT may be biased by MT-asymmetry, especially at ultra-high magnetic field. Use of the average of single positive and negative frequency offset saturation MT images, i.e., (MT (+)+MT (-)) has been proposed to correct the ihMT signal from MT-asymmetry signal. MATERIALS AND METHODS The efficiency of this correction method was experimentally assessed in this study, performed at 11.75 T on mice. Quantitative corrected ihMT and MT-asymmetry ratios (ihMTR and MTRasym) were measured in mouse brain structures for several MT-asymmetry magnitudes and different saturation parameter sets. RESULTS Our results indicated a "safe" range of magnitudes (/MTRasym/<4 %) for which MT-asymmetry signal did not bias the corrected ihMT signal. Moreover, experimental evidence of the different natures of both MT-asymmetry and inhomogeneous MT contrasts were provided. In particular, non-zero ihMT ratios were obtained at zero MTRasym values. CONCLUSION MTRasym is not a confounding factor for ihMT quantification, even at ultra-high field, as long as MTRasym is restricted to ±4 %.
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Affiliation(s)
- Valentin H Prevost
- Centre de Résonance Magnétique Biologique et Médicale, CRMBM-CEMEREM, UMR 7339, CNRS, Faculté de Médecine, Aix-Marseille Université (AMU), 27 Boulevard Jean Moulin, 13005, Marseille, France
| | - Olivier M Girard
- Centre de Résonance Magnétique Biologique et Médicale, CRMBM-CEMEREM, UMR 7339, CNRS, Faculté de Médecine, Aix-Marseille Université (AMU), 27 Boulevard Jean Moulin, 13005, Marseille, France
| | - Gopal Varma
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - David C Alsop
- Department of Radiology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA
| | - Guillaume Duhamel
- Centre de Résonance Magnétique Biologique et Médicale, CRMBM-CEMEREM, UMR 7339, CNRS, Faculté de Médecine, Aix-Marseille Université (AMU), 27 Boulevard Jean Moulin, 13005, Marseille, France.
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Pampel A, Müller DK, Anwander A, Marschner H, Möller HE. Orientation dependence of magnetization transfer parameters in human white matter. Neuroimage 2015; 114:136-46. [DOI: 10.1016/j.neuroimage.2015.03.068] [Citation(s) in RCA: 46] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2014] [Revised: 03/16/2015] [Accepted: 03/27/2015] [Indexed: 11/28/2022] Open
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14
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Huster D. Solid-state NMR spectroscopy to study protein-lipid interactions. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:1146-60. [PMID: 24333800 DOI: 10.1016/j.bbalip.2013.12.002] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2013] [Accepted: 12/04/2013] [Indexed: 12/22/2022]
Abstract
The appropriate lipid environment is crucial for the proper function of membrane proteins. There is a tremendous variety of lipid molecules in the membrane and so far it is often unclear which component of the lipid matrix is essential for the function of a respective protein. Lipid molecules and proteins mutually influence each other; parameters such as acyl chain order, membrane thickness, membrane elasticity, permeability, lipid-domain and annulus formation are strongly modulated by proteins. More recent data also indicates that the influence of proteins goes beyond a single annulus of next-neighbor boundary lipids. Therefore, a mesoscopic approach to membrane lipid-protein interactions in terms of elastic membrane deformations has been developed. Solid-state NMR has greatly contributed to the understanding of lipid-protein interactions and the modern view of biological membranes. Methods that detect the influence of proteins on the membrane as well as direct lipid-protein interactions have been developed and are reviewed here. Examples for solid-state NMR studies on the interaction of Ras proteins, the antimicrobial peptide protegrin-1, the G protein-coupled receptor rhodopsin, and the K(+) channel KcsA are discussed. This article is part of a Special Issue entitled Tools to study lipid functions.
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Affiliation(s)
- Daniel Huster
- Institute of Medical Physics and Biophysics, University of Leipzig, Härtelstr. 16-18, D-04107 Leipzig, Germany.
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15
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Dürr UN, Gildenberg M, Ramamoorthy A. The magic of bicelles lights up membrane protein structure. Chem Rev 2012; 112:6054-74. [PMID: 22920148 PMCID: PMC3497859 DOI: 10.1021/cr300061w] [Citation(s) in RCA: 266] [Impact Index Per Article: 22.2] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2012] [Indexed: 12/12/2022]
Affiliation(s)
| | - Melissa Gildenberg
- Biophysics
and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055,
United States
| | - Ayyalusamy Ramamoorthy
- Biophysics
and Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109-1055,
United States
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16
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Magic angle spinning NMR study of interaction of N-terminal sequence of dermorphin (Tyr-d-Ala-Phe-Gly) with phospholipids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2012; 1818:2579-87. [DOI: 10.1016/j.bbamem.2012.06.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Revised: 06/05/2012] [Accepted: 06/18/2012] [Indexed: 01/02/2023]
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17
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McIntyre DJO, Madhu B, Lee SH, Griffiths JR. Magnetic resonance spectroscopy of cancer metabolism and response to therapy. Radiat Res 2012; 177:398-435. [PMID: 22401303 DOI: 10.1667/rr2903.1] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Magnetic resonance spectroscopy allows noninvasive in vivo measurements of biochemical information from living systems, ranging from cultured cells through experimental animals to humans. Studies of biopsies or extracts offer deeper insights by detecting more metabolites and resolving metabolites that cannot be distinguished in vivo. The pharmacokinetics of certain drugs, especially fluorinated drugs, can be directly measured in vivo. This review briefly describes these methods and their applications to cancer metabolism, including glycolysis, hypoxia, bioenergetics, tumor pH, and tumor responses to radiotherapy and chemotherapy.
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Affiliation(s)
- Dominick J O McIntyre
- Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Robinson Way, Cambridge CB2 0RE, UK.
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18
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Warschawski DE, Arnold AA, Beaugrand M, Gravel A, Chartrand É, Marcotte I. Choosing membrane mimetics for NMR structural studies of transmembrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:1957-74. [DOI: 10.1016/j.bbamem.2011.03.016] [Citation(s) in RCA: 239] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/26/2010] [Revised: 03/28/2011] [Accepted: 03/29/2011] [Indexed: 12/11/2022]
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19
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20
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Esteban-Martín S, Giménez D, Fuertes G, Salgado J. Orientational Landscapes of Peptides in Membranes: Prediction of 2H NMR Couplings in a Dynamic Context. Biochemistry 2009; 48:11441-8. [DOI: 10.1021/bi901017y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Santi Esteban-Martín
- Instituto de Ciencia Molecular, Universitat de València, Polígono La Coma s/n, 46980 Paterna, Valencia, Spain
| | - Diana Giménez
- Instituto de Ciencia Molecular, Universitat de València, Polígono La Coma s/n, 46980 Paterna, Valencia, Spain
| | - Gustavo Fuertes
- Instituto de Ciencia Molecular, Universitat de València, Polígono La Coma s/n, 46980 Paterna, Valencia, Spain
| | - Jesús Salgado
- Instituto de Ciencia Molecular, Universitat de València, Polígono La Coma s/n, 46980 Paterna, Valencia, Spain
- Departamento de Bioquímica y Biología Molecular, Universitat de València, C/Dr. Moliner, 50, 46100 Burjassot, Valencia, Spain
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21
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Dvinskikh SV, Castro V, Sandström D. Efficient solid-state NMR methods for measuring heteronuclear dipolar couplings in unoriented lipid membrane systems. Phys Chem Chem Phys 2009; 7:607-13. [PMID: 19787876 DOI: 10.1039/b418131j] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Recently (Dvinskikh et al., J. Magn. Reson., 2003, 164, 165 and Dvinskikh et al., J. Magn. Reson., 2004, 168, 194), some of us introduced two efficient solid-state NMR techniques for the determination of heteronuclear dipolar couplings under magic-angle spinning (MAS). These two-dimensional (2D) recoupling methods have been applied previously to simple amino acids, and to columnar systems with high positional and orientational order. In this work, we show that the 2D MAS sequences produce unparalleled 1H-13C dipolar resolution in unoriented lipid membranes. The recoupling experiments were applied to hydrated dimyristoylphosphatidylcholine (DMPC) in the liquid-crystalline Lalpha phase, and the results agreed well with previous NMR investigations using specifically deuterated phospholipids.
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Affiliation(s)
- Sergey V Dvinskikh
- Division of Physical Chemistry, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden
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22
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Esteban-Martín S, Strandberg E, Salgado J, Ulrich AS. Solid state NMR analysis of peptides in membranes: Influence of dynamics and labeling scheme. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1798:252-7. [PMID: 19715662 DOI: 10.1016/j.bbamem.2009.08.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2009] [Revised: 07/28/2009] [Accepted: 08/12/2009] [Indexed: 11/17/2022]
Abstract
The functional state of a membrane-active peptide is often defined by its conformation, molecular orientation, and its oligomeric state in the lipid bilayer. These "static" structural properties can be routinely studied by solid state NMR using isotope-labeled peptides. In the highly dynamic environment of a liquid crystalline biomembrane, however, the whole-body fluctuations of a peptide are also of paramount importance, although difficult to address and most often ignored. Yet it turns out that disregarding such motional averaging in calculating the molecular alignment from orientational NMR-constraints may give a misleading, if not false picture of the system. Here, we demonstrate that the reliability of a simplified static or an advanced dynamic data analysis depends critically on the choice of isotope labeling scheme used. Two distinctly different scenarios have to be considered. When the labels are placed on the side chains of a helical peptide (such as a CD(3)- or CF(3)-group attached to the C(alpha)C(beta) bond), their nuclear spin interaction tensors are very sensitive to motional averaging. If this effect is not properly accounted for, the helix tilt angle tends to be severely underestimated. At the same time, the analysis of labels in the side chains allows to extract valuable dynamical information about whole-body fluctuations of the peptide helix in the membrane. On the other hand, the alternative labeling scheme where (15)N-labels are accommodated within the peptide backbone, will yield nearly correct helix tilt angles, irrespective as to whether dynamics are taken into account or not.
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23
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Doherty T, Hong M. High-resolution solid-state NMR of anisotropically mobile molecules under very low-power (1)H decoupling and moderate magic-angle spinning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 199:225-232. [PMID: 19501003 PMCID: PMC3222301 DOI: 10.1016/j.jmr.2009.05.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/27/2009] [Revised: 05/13/2009] [Accepted: 05/14/2009] [Indexed: 05/27/2023]
Abstract
We show that for observing high-resolution heteronuclear NMR spectra of anisotropically mobile systems with order parameters less than 0.25, moderate magic-angle spinning (MAS) rates of approximately 11kHz combined with (1)H decoupling at 1-2kHz are sufficient. Broadband decoupling at this low (1)H nutation frequency is achieved by composite pulse sequences such as WALTZ-16. We demonstrate this moderate MAS low-power decoupling technique on hydrated POPC lipid membranes, and show that 1kHz (1)H decoupling yields spectra with the same resolution and sensitivity as spectra measured under 50kHz (1)H decoupling when the same acquisition times (approximately 50ms) are used, but the low-power decoupled spectra give higher resolution and sensitivity when longer acquisition times (>150ms) are used, which are not possible with high-power decoupling. The limits of validity of this approach are explored for a range of spinning rates and molecular mobilities using more rigid membrane systems such as POPC/cholesterol mixed bilayers. Finally, we show (15)N and (13)C spectra of a uniaxially diffusing membrane peptide assembly, the influenza A M2 transmembrane domain, under 11kHz MAS and 2kHz (1)H decoupling. The peptide (15)N and (13)C intensities at low-power decoupling are 70-80% of the high-power decoupled intensities. Therefore, it is possible to study anisotropically mobile lipids and membrane peptides using liquid-state NMR equipment, relatively large rotors, and moderate MAS frequencies.
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Affiliation(s)
| | - Mei Hong
- Corresponding author: Mei Hong, Department of Chemistry, Iowa State University, Ames, IA 50010. Tel: 515-294-3521, Fax: 515-294-0105,
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24
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Durrieu MP, Bond PJ, Sansom MSP, Lavery R, Baaden M. Coarse-Grain Simulations of the R-SNARE Fusion Protein in its Membrane Environment Detect Long-Lived Conformational Sub-States. Chemphyschem 2009; 10:1548-52. [DOI: 10.1002/cphc.200900216] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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25
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Esteban-Martín S, Strandberg E, Fuertes G, Ulrich AS, Salgado J. Influence of whole-body dynamics on 15N PISEMA NMR spectra of membrane proteins: a theoretical analysis. Biophys J 2009; 96:3233-41. [PMID: 19383467 DOI: 10.1016/j.bpj.2008.12.3950] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2008] [Revised: 12/12/2008] [Accepted: 12/18/2008] [Indexed: 11/29/2022] Open
Abstract
Membrane proteins and peptides exhibit a preferred orientation in the lipid bilayer while fluctuating in an anisotropic manner. Both the orientation and the dynamics have direct functional implications, but motions are usually not accessible, and structural descriptions are generally static. Using simulated data, we analyze systematically the impact of whole-body motions on the peptide orientations calculated from two-dimensional polarization inversion spin exchange at the magic angle (PISEMA) NMR. Fluctuations are found to have a significant effect on the observed spectra. Nevertheless, wheel-like patterns are still preserved, and it is possible to determine the average peptide tilt and azimuthal rotation angles using simple static models for the spectral fitting. For helical peptides undergoing large-amplitude fluctuations, as in the case of transmembrane monomers, improved fits can be achieved using an explicit dynamics model that includes Gaussian distributions of the orientational parameters. This method allows extracting the amplitudes of fluctuations of the tilt and azimuthal rotation angles. The analysis is further demonstrated by generating first a virtual PISEMA spectrum from a molecular dynamics trajectory of the model peptide, WLP23, in a lipid membrane. That way, the dynamics of the system from which the input spectrum originates is completely known at atomic detail and can thus be directly compared with the dynamic output obtained from the fit. We find that fitting our dynamics model to the polar index slant angles wheel gives an accurate description of the amplitude of underlying motions, together with the average peptide orientation.
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Affiliation(s)
- Santi Esteban-Martín
- Instituto de Ciencia Molecular, Universidad de Valencia, 46980 Paterna (Valencia), Spain
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26
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Strandberg E, Esteban-Martín S, Salgado J, Ulrich AS. Orientation and dynamics of peptides in membranes calculated from 2H-NMR data. Biophys J 2009; 96:3223-32. [PMID: 19383466 DOI: 10.1016/j.bpj.2009.02.040] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2008] [Revised: 02/12/2009] [Accepted: 02/17/2009] [Indexed: 11/28/2022] Open
Abstract
Solid-state (2)H-NMR is routinely used to determine the alignment of membrane-bound peptides. Here we demonstrate that it can also provide a quantitative measure of the fluctuations around the distinct molecular axes. Using several dynamic models with increasing complexity, we reanalyzed published (2)H-NMR data on two representative alpha-helical peptides: 1), the amphiphilic antimicrobial peptide PGLa, which permeabilizes membranes by going from a monomeric surface-bound to a dimeric tilted state and finally inserting as an oligomeric pore; and 2), the hydrophobic WALP23, which is a typical transmembrane segment, although previous analysis had yielded helix tilt angles much smaller than expected from hydrophobic mismatch and molecular dynamics simulations. Their (2)H-NMR data were deconvoluted in terms of the two main helix orientation angles (representing the time-averaged peptide tilt and azimuthal rotation), as well as the amplitudes of fluctuation about the corresponding molecular axes (providing the dynamic picture). The mobility of PGLa is found to be moderate and to correlate well with the respective oligomeric states. WALP23 fluctuates more vigorously, now in better agreement with the molecular dynamics simulations and mismatch predictions. The analysis demonstrates that when (2)H-NMR data are fitted to extract peptide orientation angles, an explicit representation of the peptide rigid-body angular fluctuations should be included.
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Affiliation(s)
- Erik Strandberg
- Karlsruhe Institute of Technology, Institute for Biological Interfaces, Forschungszentrum Karlsruhe, 76021 Karlsruhe, Germany
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27
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Aucoin D, Camenares D, Zhao X, Jung J, Sato T, Smith SO. High-resolution 1H MAS RFDR NMR of biological membranes. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2009; 197:77-86. [PMID: 19121592 PMCID: PMC2802820 DOI: 10.1016/j.jmr.2008.12.009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2008] [Revised: 12/02/2008] [Accepted: 12/05/2008] [Indexed: 05/08/2023]
Abstract
The combination of magic angle spinning (MAS) with the high-resolution (1)H NOESY NMR experiment is an established method for measuring through-space (1)H...(1)H dipolar couplings in biological membranes. The segmental motion of the lipid acyl chains along with the overall rotational diffusion of the lipids provides sufficient motion to average the (1)H dipolar interaction to within the range where MAS can be effective. One drawback of the approach is the relatively long NOESY mixing times needed for relaxation processes to generate significant crosspeak intensity. In order to drive magnetization transfer more rapidly, we use solid-state radiofrequency driven dipolar recoupling (RFDR) pulses during the mixing time. We compare the (1)H MAS NOESY experiment with a (1)H MAS RFDR experiment on dimyristoylphosphocholine, a bilayer-forming lipid and show that the (1)H MAS RFDR experiment provides considerably faster magnetization exchange than the standard (1)H MAS NOESY experiment. We apply the method to model compounds containing basic and aromatic amino acids bound to membrane bilayers to illustrate the ability to locate the position of aromatic groups that have penetrated to below the level of the lipid headgroups.
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Affiliation(s)
- Darryl Aucoin
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5115
| | - Devin Camenares
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5115
| | - Xin Zhao
- Institute for Protein Research, Osaka University, Osaka, Japan
| | - Jay Jung
- Department of Physics and Astronomy Center for Structural Biology, Stony Brook University, Stony Brook, NY 11794-5115
| | - Takeshi Sato
- Institute for Protein Research, Osaka University, Osaka, Japan
| | - Steven O. Smith
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY 11794-5115
- Corresponding author. Tel.: 631-632-1210; Fax: 631-632-8575;
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28
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Local and translational dynamics in DNA–lipid assemblies monitored by solid-state and diffusion NMR. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:214-28. [DOI: 10.1016/j.bbamem.2007.09.035] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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29
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Scheidt HA, Huster D. The interaction of small molecules with phospholipid membranes studied by 1H NOESY NMR under magic-angle spinning. Acta Pharmacol Sin 2008; 29:35-49. [PMID: 18158864 DOI: 10.1111/j.1745-7254.2008.00726.x] [Citation(s) in RCA: 82] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
The interaction of small molecules with lipid membranes and the exact knowledge of their binding site and bilayer distribution is of great pharmacological importance and represents an active field of current biophysical research. Over the last decade, a highly resolved 1H solid-state NMR method has been developed that allows measuring localization and distribution of small molecules in membranes. The classical solution 1H NMR NOESY technique is applied to lipid membrane samples under magic-angle spinning (MAS) and NOESY cross-relaxation rates are determined quantitatively. These rates are proportional to the contact probability between molecular segments and therefore an ideal tool to study intermolecular interactions in membranes. Here, we review recent 1H MAS NOESY applications that were carried out to study lateral lipid organization in mixed membranes and the interaction of membranes with water, ethanol, small aromatic compounds, peptides, fluorescence labels, and lipophilic nucleosides.
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30
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Esteban-Martín S, Salgado J. The dynamic orientation of membrane-bound peptides: bridging simulations and experiments. Biophys J 2007; 93:4278-88. [PMID: 17720729 PMCID: PMC2098706 DOI: 10.1529/biophysj.107.113043] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2007] [Accepted: 08/07/2007] [Indexed: 02/02/2023] Open
Abstract
The structural organization in a peptide/membrane supramolecular complex is best described by knowledge of the peptide orientation plus its time-dependent and spatial fluctuations. The static orientation, defined by the peptide tilt and a rotation about its molecular axis, is accessible through a number of spectroscopic methods. However, peptide dynamics, although relevant to understand the functionality of these systems, remains largely unexplored. Here, we describe the orientation and dynamics of Trp-flanked and Lys-flanked hydrophobic peptides in a lipid bilayer from molecular dynamics simulations. A novel view is revealed, where collective nontrivial distributions of time-evolving and ensemble peptide orientations closely represent the systems as studied experimentally. Such global distributions are broad and unveil the existence of orientational states, which depend on the anchoring mode of interfacial residues. We show that this dynamics modulates (2)H quadrupolar splittings and introduces ambiguity in the analysis of NMR data. These findings demonstrate that structural descriptions of peptide/membrane complexes are incomplete, and in cases even imprecise, without knowledge of dynamics.
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Affiliation(s)
- Santi Esteban-Martín
- Instituto de Ciencia Molecular (Universitat de València), Paterna (Valencia), Spain
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31
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Reuther G, Tan KT, Vogel A, Nowak C, Arnold K, Kuhlmann J, Waldmann H, Huster D. The lipidated membrane anchor of full length N-Ras protein shows an extensive dynamics as revealed by solid-state NMR spectroscopy. J Am Chem Soc 2007; 128:13840-6. [PMID: 17044712 DOI: 10.1021/ja063635s] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Many proteins involved in signal transduction are equipped with covalently attached lipid chains providing a hydrophobic anchor targeting these molecules to membranes. Despite the considerable biological significance of this membrane binding mechanism for 5-10% of all cellular proteins, to date very little is known about structural and dynamical features of lipidated membrane binding domains. Here we report the first comprehensive study of the molecular dynamics of the C-terminus of membrane-associated full-length lipidated Ras protein determined by solid-state NMR. Fully functional lipid-modified N-Ras protein was obtained by chemical-biological synthesis ligating the expressed water soluble N-terminus with a chemically synthesized (2)H or (13)C labeled lipidated heptapeptide. Dynamical parameters for the lipid chain modification at Cys 181 were determined from static (2)H NMR order parameter and relaxation measurements. Order parameters describing the amplitude of motion in the protein backbone and the side chain were determined from site-specific measurements of (1)H-(13)C dipolar couplings for all seven amino acids in the membrane anchor of Ras. Finally, the correlation times of motion were determined from temperature dependent relaxation time measurements and analyzed using a modified Lipari Szabo approach. Overall, the C-terminus of Ras shows a versatile dynamics with segmental fluctuations and axially symmetric overall motions on the membrane surface. In particular, the lipid chain modifications are highly flexible in the membrane.
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Affiliation(s)
- Guido Reuther
- Institute of Biotechnology, Junior Research Group Structural Biology of Membrane Proteins, Martin Luther University Halle-Wittenberg, Kurt-Mothes-Str. 3, D-06120 Halle, Germany
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32
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Chen JH, Sambol EB, Decarolis P, O'Connor R, Geha RC, Wu YV, Singer S. High-resolution MAS NMR spectroscopy detection of the spin magnetization exchange by cross-relaxation and chemical exchange in intact cell lines and human tissue specimens. Magn Reson Med 2006; 55:1246-56. [PMID: 16676334 DOI: 10.1002/mrm.20889] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
High-resolution magic-angle-spinning (HR-MAS) NMR spectroscopy detects resolved signals from membrane phospholipids and proteins in intact cell and tissue samples. MAS has the additional advantage of quenching spin-diffusion through a mutual "flip-flop" of neighbor spins by time-independent dipolar coupling as long as the dipolar coupling is "inhomogeneous." Under MAS, significant magnetization transfer (MT) was observed between water and each proton site in membrane phospholipid and between water and the NMR-observable protein proton signals. The MT rates between water and membrane phospholipids are lower than those between water and protein proton signals. The interaction of water to other small molecules is selective with the observation of MT from water to creatine, lactate, taurine, and glycine, but not to triglyceride, phosphocholine, choline, or myo-inositol. HR-MAS NMR allows the detection of a complete MT network between water and each proton group of creatine. Two creatine pools (one motion-restricted and one motion-free) were identified in skeletal muscle.
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Affiliation(s)
- Jin-Hong Chen
- Sarcoma Disease Management Program, Memorial Sloan-Kettering Cancer Center, New York, NY 10021, USA
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33
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Zhang W, Sato T, Smith SO. NMR spectroscopy of basic/aromatic amino acid clusters in membrane proteins. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2006. [PMCID: PMC7112282 DOI: 10.1016/j.pnmrs.2006.04.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Affiliation(s)
| | | | - Steven O. Smith
- Corresponding author. Tel.: +1 631 632 1210; fax: +1 631 632 8575.
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34
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Volkov VV, Nuti F, Takaoka Y, Chelli R, Papini AM, Righini R. Hydration and Hydrogen Bonding of Carbonyls in Dimyristoyl-Phosphatidylcholine Bilayer. J Am Chem Soc 2006; 128:9466-71. [PMID: 16848484 DOI: 10.1021/ja0614621] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We combine two-color ultrafast infrared spectroscopy and molecular dynamics simulation to investigate the hydration of carbonyl moieties in a dimyristoyl-phosphatidylcholine bilayer. Excitation with femtosecond infrared pulses of the OD stretching mode of heavy water produces a time dependent change of the absorption band of the phospholipid carbonyl groups. This intermolecular vibrational coupling affects the entire C=O band, thus suggesting that the optical inhomogeneity of the infrared response of carbonyl in phospholipid membranes cannot be attributed to the variance in hydration. Both the experimental and the theoretical results demonstrate that sn-1 carbonyl has a higher propensity to form hydrogen bonds with water in comparison to sn-2. The time-resolved experiment allows following the evolution of the system from a nonequilibrium localization of energy in the OD stretching mode to a thermally equilibrated condition and provides the characteristic time constants of the process. The approach opens a new opportunity for investigation of intermolecular structural relations in complex systems, like membranes, polymers, proteins, and glasses.
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Affiliation(s)
- Victor V Volkov
- European Laboratory for Nonlinear Spectroscopy (LENS), Via Nello Carrara 1, I-50019 Sesto Fiorentino, Italy.
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35
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Prosser RS, Evanics F, Kitevski JL, Al-Abdul-Wahid MS. Current Applications of Bicelles in NMR Studies of Membrane-Associated Amphiphiles and Proteins,. Biochemistry 2006; 45:8453-65. [PMID: 16834319 DOI: 10.1021/bi060615u] [Citation(s) in RCA: 177] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
This review covers current trends in studies of membrane amphiphiles and membrane proteins using both fast tumbling bicelles and magnetically aligned bicelle media for both solution state and solid state NMR. The fast tumbling bicelles provide a versatile biologically mimetic membrane model, which in many cases is preferable to micelles, both because of the range of lipids and amphiphiles that may be combined and because radius of curvature effects and strain effects common with micelles may be avoided. Drug and small molecule binding and partitioning studies should benefit from their application in fast tumbling bicelles, tailored to mimic specific membranes. A wide range of topology and immersion depth studies have been shown to be effective in fast tumbling bicelles, while residual dipolar couplings add another dimension to structure refinement possibilities, particularly for situations in which the peptide is uniformly labeled with 15N and 13C. Solid state NMR studies of polytopic transmembrane proteins demonstrate that it is possible to express, purify, and reconstitute membrane proteins, ranging in size from single transmembrane domains to seven-transmembrane GPCRs, into bicelles. The line widths and quality of the resulting 15NH dipole-15N chemical shift spectra demonstrate that there are no insurmountable obstacles to the study of large membrane proteins in magnetically aligned media.
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Affiliation(s)
- R Scott Prosser
- Department of Chemistry, University of Toronto, UTM, 3359 Mississauga Road, North Mississauga, ON, Canada L5L 1C6.
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Soubias O, Jolibois F, Réat V, Milon A. Understanding sterol-membrane interactions, part II: complete 1H and 13C assignments by solid-state NMR spectroscopy and determination of the hydrogen-bonding partners of cholesterol in a lipid bilayer. Chemistry 2006; 10:6005-14. [PMID: 15497136 DOI: 10.1002/chem.200400246] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The complete assignment of cholesterol 1H and 13C NMR resonances in a lipid bilayer environment (Lalpha-dimyristoylphosphatidylcholine/cholesterol 2:1) has been obtained by a combination of 1D and 2D MAS NMR experiments: 13C spectral editing, ge-HSQC, dipolar HETCOR and J-based HETCOR. Specific chemical shift variations have been observed for the C1-C6 atoms of cholesterol measured in CCl4 solution and in the membrane. Based on previous work (F. Jolibois, O. Soubias, V. Reat, A. Milon, Chem. Eur. J. 2004, 10, preceding paper in this issue: DOI: 10.1002/chem.200400245) these variations were attributed to local changes around the cholesterol hydroxy group, such as the three major rotameric states of the C3-O3 bond and different hydrogen bonding partners (water molecules, carboxy and phosphodiester groups of phosphatidylcholine). Comparison of the experimental and theoretical chemical shifts obtained from quantum-chemistry calculations of various transient molecular complexes has allowed the distributions of hydrogen bonding partners and hydroxy rotameric states to be determined. This is the first time that the probability of hydrogen bonding occurring between cholesterol's hydroxy group and phosphatidylcholine's phosphodiester has been determined experimentally.
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Affiliation(s)
- Olivier Soubias
- Institut de Pharmacologie et de Biologie Structurale, CNRS and University P. Sabatier, 205 rte de Narbonne, Toulouse, France
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Andronesi OC, Becker S, Seidel K, Heise H, Young HS, Baldus M. Determination of Membrane Protein Structure and Dynamics by Magic-Angle-Spinning Solid-State NMR Spectroscopy†. J Am Chem Soc 2005; 127:12965-74. [PMID: 16159291 DOI: 10.1021/ja0530164] [Citation(s) in RCA: 249] [Impact Index Per Article: 13.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
It is shown that molecular structure and dynamics of a uniformly labeled membrane protein can be studied under magic-angle-spinning conditions. For this purpose, dipolar recoupling experiments are combined with novel through-bond correlation schemes that probe mobile protein segments. These NMR schemes are demonstrated on a uniformly [13C,15N] variant of the 52-residue polypeptide phospholamban. When reconstituted in lipid bilayers, the NMR data are consistent with an alpha-helical trans-membrane segment and a cytoplasmic domain that exhibits a high degree of structural disorder.
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Affiliation(s)
- Ovidiu C Andronesi
- Department of NMR-based Structural Biology, Max-Planck-Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
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Carravetta M, Murata Y, Murata M, Heinmaa I, Stern R, Tontcheva A, Samoson A, Rubin Y, Komatsu K, Levitt MH. Solid-State NMR Spectroscopy of Molecular Hydrogen Trapped Inside an Open-Cage Fullerene. J Am Chem Soc 2004; 126:4092-3. [PMID: 15053583 DOI: 10.1021/ja031536y] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Solid-state 1H experiments were performed an open-cage fullerene hosting molecular hydrogen. The anisotropy of the molecular hydrogen rotation was studied by double-quantum magic-angle-spinning NMR. The time scale of the molecular hydrogen rotation was estimated by spin-lattice relaxation measurements as a function of temperature.
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Affiliation(s)
- Marina Carravetta
- School of Chemistry, University of Southampton, SO17 1BJ Southampton, UK
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Cruciani O, Mannina L, Sobolev AP, Segre A, Luisi P. Multilamellar liposomes formed by phosphatidyl nucleosides: an NMR-HR-MAS characterization. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:1144-1151. [PMID: 15803689 DOI: 10.1021/la035804h] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present an NMR investigation of multilamellar vesicles (MLVs) obtained from phosphatidyl nucleosides, 5'-(1-palmitoyl-2-oleoyl-sn-glycero(3)phospho)cytidine (1), 5'-(1-palmitoyl-2-oleoyl-sn-glycero(3)phospho)inosine (2), and their mixtures. Because of the lower stability of liposomes obtained from 2, studies have been preferentially performed in this case with mixed liposomes 2/POPC (4:1). The investigation is conducted mostly via the HR-MAS technique and the general observation is that the resolution achieved in this way is superior to that obtained in the past with small unilamellar vesicles (SUVs). A full assignment is now possible, which includes the spectral region of the ribose ring and part of the glycerol moiety. Also in the case of MLVs, both for 1 and 2, a stacking between the aromatic bases of the same liposome layer seems to be ruled out, although in both cases the nucleobases appear to be exposed to the aqueous phase. The splitting of both aromatic H-5cyt and H-6cyt is ascribed to the presence of two aggregate populations that may correspond to the two syn and anti conformations observed for cytidine monophosphate in aqueous solution. On the basis of NOESY cross-peaks, it is not always possible to discriminate between inter- and intramolecular interactions; however, the distances found for 1 appear to be compatible with the intramolecular contacts in the anti conformation of the cytidine and also with intermolecular interactions between neighboring molecules of 1. We also find that the glycerol moiety does not seem to interact with the cytidine; however, part of the ribose ring seems to be close to the glycerol moiety. More generally, the interaction of one base with the sugar moiety of a neighboring base, previously observed for SUVs, still appears to be true for MLVs. Studies have been performed also for mixed liposomes obtained from the mixture of 1 and 2, where it is observed that the HR-MAS spectra of the corresponding MLVs are not simply the sum of the spectra of the two isolated components. In particular, there is the presence of a NOESY cross-peak between the aromatic protons H-6cyt and H-2ino, and this permits us to rule out large patchwork domains containing only one nucleoside components in the mixed liposomes. Finally, a study is performed on the time evolution of the system obtained by mixing the previously prepared liposomes of 1 and 2. No interaction is obtained in this case, i.e., the spectra are constitutive, which is consistent with the general picture of liposomes as kinetic traps that are not fusing with each other.
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Affiliation(s)
- Oscar Cruciani
- Istituto di Metodologie Chimiche, CNR, Area della Ricerca di Roma, CP 10, I-00016 Monterotondo Stazione, Rome, Italy
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Sizun C, Aussenac F, Grelard A, Dufourc EJ. NMR methods for studying the structure and dynamics of oncogenic and antihistaminic peptides in biomembranes. MAGNETIC RESONANCE IN CHEMISTRY : MRC 2004; 42:180-186. [PMID: 14745798 DOI: 10.1002/mrc.1336] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We present several applications of both wide-line and magic angle spinning (MAS) solid-state NMR of bicelles in which are embedded fragments of a tyrosine kinase receptor or enkephalins. The magnetically orientable bicelle membranes are shown to be of particular interest for studying the functional properties of lipids and proteins in a state that is very close to their natural environment. Quadrupolar, dipolar and chemical shielding interactions can be used to determine minute alterations of internal membrane dynamics and the orientation of peptides with respect to the membrane plane. MAS of bicelles can in turn lead to high-resolution proton spectra of hydrated membranes. Using deuterium-proton contrast methods one can then obtain pseudo-high-resolution proton spectra of peptides or proteins embedded in deuterated membranes and determine their atomic 3D structure using quasi-conventional liquid-state NMR methods.
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Affiliation(s)
- Christina Sizun
- Institut Européen de Chimie et Biologie, Ecole Polytechnique, 2 rue Robert Escarpit, 33607 Pessac, France
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Soubias O, Piotto M, Saurel O, Assemat O, Réat V, Milon A. Detection of natural abundance 1H-13C correlations of cholesterol in its membrane environment using a gradient enhanced HSQC experiment under high resolution magic angle spinning. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2003; 165:303-308. [PMID: 14643713 DOI: 10.1016/j.jmr.2003.08.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The quality and signal to noise ratio of a J-based HETCOR performed on a standard MAS probe have been compared with a gradient enhanced HSQC performed on a HR-MAS probe at 500 MHz. The sample selected was cholesterol, inserted at 30 mol% in acyl chain deuterated phospholipids (DMPC-d54), at a temperature where the bilayer is in a liquid crystalline phase (310 K). It is representative of any rigid molecule undergoing fast axial diffusion in a bilayer as the main movement. After optimization of the spinning rate and carbon decoupling conditions, it is shown that the ge-HSQC/MAS approach is far superior to the more conventional J-HETCOR/MAS in terms of signal to noise ratio, and that it allows the detection of all the natural abundance cross peaks of cholesterol in a membrane environment. Clear differences between the 1H and 13C chemical shifts of cholesterol in a membrane and in chloroform solution were thus revealed.
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Affiliation(s)
- O Soubias
- Institut de Pharmacologie et de Biologie Structurale, CNRS and UPS, UMR 5089 205 rte de Narbonne, 31077 Toulouse, Cedex 4, France
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Zhang W, Crocker E, McLaughlin S, Smith SO. Binding of peptides with basic and aromatic residues to bilayer membranes: phenylalanine in the myristoylated alanine-rich C kinase substrate effector domain penetrates into the hydrophobic core of the bilayer. J Biol Chem 2003; 278:21459-66. [PMID: 12670959 DOI: 10.1074/jbc.m301652200] [Citation(s) in RCA: 98] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Electrostatic interactions with positively charged regions of membrane-associated proteins such as myristoylated alanine-rich C kinase substrate (MARCKS) may have a role in regulating the level of free phosphatidylinositol 4,5-bisphosphate (PI(4,5)P2) in plasma membranes. Both the MARCKS protein and a peptide corresponding to the effector domain (an unstructured region that contains 13 basic residues and 5 phenylalanines), MARCKS-(151-175), laterally sequester the polyvalent lipid PI(4,5)P2 in the plane of a bilayer membrane with high affinity. We used high resolution magic angle spinning NMR to establish the location of MARCKS-(151-175) in membrane bilayers, which is necessary to understand the sequestration mechanism. Measurements of cross-relaxation rates in two-dimensional nuclear Overhauser enhancement spectroscopy NMR experiments show that the five Phe rings of MARCKS-(151-175) penetrate into the acyl chain region of phosphatidylcholine bilayers containing phosphatidylglycerol or PI(4,5)P2. Specifically, we observed strong cross-peaks between the aromatic protons of the Phe rings and the acyl chain protons of the lipids, even for very short (50 ms) mixing times. The position of the Phe rings implies that the adjacent positively charged amino acids in the peptide are close to the level of the negatively charged lipid phosphates. The deep location of the MARCKS peptide in the polar head group region should enhance its electrostatic sequestration of PI(4,5)P2 by an "image charge" mechanism. Moreover, this location has interesting implications for membrane curvature and local surface pressure effects and may be relevant to a wide variety of other proteins with basic-aromatic clusters, such as phospholipase D, GAP43, SCAMP2, and the N-methyl-d-aspartate receptor.
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Affiliation(s)
- Wenyi Zhang
- Department of Biochemistry and Cell Biology, Center for Structural Biology, State University of New York, Stony Brook, NY 11794-5115, USA
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Huster D, Vogel A, Katzka C, Scheidt HA, Binder H, Dante S, Gutberlet T, Zschörnig O, Waldmann H, Arnold K. Membrane insertion of a lipidated ras peptide studied by FTIR, solid-state NMR, and neutron diffraction spectroscopy. J Am Chem Soc 2003; 125:4070-9. [PMID: 12670227 DOI: 10.1021/ja0289245] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Membrane binding of a doubly lipid modified heptapeptide from the C-terminus of the human N-ras protein was studied by Fourier transform infrared, solid-state NMR, and neutron diffraction spectroscopy. The 16:0 peptide chains insert well into the 1,2-dimyristoyl-sn-glycero-3-phosphocholine phospholipid matrix. This is indicated by a common main phase transition temperature of 21.5 degrees C for both the lipid and peptide chains as revealed by FTIR measurements. Further, (2)H NMR reveals that peptide and lipid chains have approximately the same chain length in the liquid crystalline state. This is achieved by a much lower order parameter of the 16:0 peptide chains compared to the 14:0 phospholipid chains. Finally, proton/deuterium contrast variation of neutron diffraction experiments indicates that peptide chains are localized in the membrane interior analogous to the phospholipid chains. In agreement with this model of peptide chain insertion, the peptide part is localized at the lipid-water interface of the membrane. This is revealed by (1)H nuclear Overhauser enhancement spectra recorded under magic angle spinning conditions. Quantitative cross-peak analysis allows the examination of the average location of the peptide backbone and side chains with respect to the membrane. While the backbone shows the strongest cross-relaxation rates with the phospholipid glycerol, the hydrophobic side chains of the peptide insert deeper into the membrane interior. This is supported by neutron diffraction experiments that reveal a peptide distribution in the lipid-water interface of the membrane. Concurring with these experimental findings, the amide protons of the peptide show strong water exchange as seen in NMR and FTIR measurements. No indications for a hydrogen-bonded secondary structure of the peptide backbone are found. Therefore, membrane binding of the C-terminus of the N-ras protein is mainly due to lipid chain insertion but also supported by interactions between hydrophobic side chains and the lipid membrane. The peptide assumes a mobile and disordered conformation in the membrane. Since the C-terminus of the soluble part of the ras protein is also disordered, we hypothesize that our model for membrane binding of the ras peptide realistically describes the membrane binding of the lipidated C-terminus of the active ras protein.
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Affiliation(s)
- Daniel Huster
- Junior Research Group Solid-state NMR Studies of Membrane-associated Proteins, University of Leipzig, Liebigstrasse 27, D-04103 Leipzig, Germany.
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Farès C, Sharom FJ, Davis JH. 15N,(1)H Heteronuclear correlation NMR of gramicidin A in DMPC-d(67). J Am Chem Soc 2002; 124:11232-3. [PMID: 12236713 DOI: 10.1021/ja0264549] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We have studied gramicidin A, an environmentally sensitive polymorphic pentadecapeptide, fully 15N-labelled and dispersed in a highly deuterated phospholipid bilayer system. By submitting the sample to fast magic angle spinning, we were able to reduce the polypeptide amide hydrogen linewidths to 160 Hz, and hence to partially resolve them. By correlating these resonances with the 40 Hz wide dipolar coupled 15N in a 2D-CROPSY (cross-polarization spectroscopy) experiment, it was possible to observe the 20 partially overlapping 1H-15N signal pairs from the polypeptide backbone and sidechains. Both chemical shift distributions closely match those of the same peptide in SDS micelles, but only poorly match those of conformationally different gramicidin A in trifluoroethanol, dimethylsulfoxide, or methanol/chloroform mixture. Our results are indicative of the N-to-N right-handed beta6.3-helix conformation of gramicidin A and offer sufficient resolution to encourage development of experiments to measure orientational or distance restraints using through-space dipolar couplings.
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Affiliation(s)
- Christophe Farès
- Department of Physics, University of Guelph, Guelph, Ontario, N1G 2W1, Canada
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Soubias O, Réat V, Saurel O, Milon A. High resolution 2D 1H-13C correlation of cholesterol in model membrane. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2002; 158:143-148. [PMID: 12419679 DOI: 10.1016/s1090-7807(02)00067-8] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
High resolution 2D NMR MAS spectra of liposomes, in particular 1H-13C chemical shifts correlations have been obtained on fluid lipid bilayers made of pure phospholipids for several years. We have investigated herein the possibility to obtain high resolution 2D MAS spectra of cholesterol embedded in membranes, i.e. on a rigid molecule whose dynamics is characterized mainly by axial diffusion without internal segmental mobility. The efficiency of various pulse sequences for heteronuclear HETCOR has been compared in terms of resolution, sensitivity and selectivity, using either cross polarization or INEPT for coherence transfer, and with or without MREV-8 homonuclear decoupling during t1. At moderately high spinning speed (9 kHz), a similar resolution is obtained in all cases (0.2 ppm for 1H(3,4), 0.15 ppm for 13C(3,4) cholesterol resonances), while sensitivity increases in the order: INEPT < CP(x4) < CP + MREV. At reduced spinning speed (5 kHz), the homonuclear dipolar coupling between the two geminal protons attached to C(4) gives rise to spinning sidebands from which one can estimate a H-H dipolar coupling of 10 kHz which is in good agreement with the known dynamics of cholesterol in membranes.
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Affiliation(s)
- Olivier Soubias
- Institut de Pharmacologie et de Biologie Structurale, CNRS et Univ P Sabatier, 205 rte de Narbonne, Toulouse, France
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Carlotti C, Aussenac F, Dufourc EJ. Towards high-resolution 1H-NMR in biological membranes: magic angle spinning of bicelles. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1564:156-64. [PMID: 12101008 DOI: 10.1016/s0005-2736(02)00446-7] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Proton line narrowing in biomembranes spun at the magic angle, for spinning speeds greater than 7 kHz, was investigated in two ways: increasing the field strength from 200 to 800 MHz and changing the membrane fluidity. The resolution that one can obtain on natural lipid membranes under the form of liposomes is 0.019 ppm at 800 MHz. On the other hand, spinning bicelles (disk-like model membranes made of synthetic long and short chain lipids) at the magic angle decreases the line width by an additional factor of 3 provided the bicelle is subjected to large orientational disorder. This leads to proton line widths of the order of 6 Hz at 500 MHz. The conjunction of high field, magic angle spinning and use of bicelle membranes should prove to be useful to solve membrane protein structure in a membrane environment.
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Affiliation(s)
- Claire Carlotti
- Institut Européen de Chimie et Biologie, Ecole Polytechnique, Pessac, France
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Gawrisch K, Eldho NV, Polozov IV. Novel NMR tools to study structure and dynamics of biomembranes. Chem Phys Lipids 2002; 116:135-51. [PMID: 12093539 DOI: 10.1016/s0009-3084(02)00024-5] [Citation(s) in RCA: 66] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Nuclear magnetic resonance (NMR) studies on biomembranes have benefited greatly from introduction of magic angle spinning (MAS) NMR techniques. Improvements in MAS probe technology, combined with the higher magnetic field strength of modern instruments, enables almost liquid-like resolution of lipid resonances. The cross-relaxation rates measured by nuclear Overhauser enhancement spectroscopy (NOESY) provide new insights into conformation and dynamics of lipids with atomic-scale resolution. The data reflect the tremendous motional disorder in the lipid matrix. Transfer of magnetization by spin diffusion along the proton network of lipids is of secondary relevance, even at a long NOESY mixing time of 300 ms. MAS experiments with re-coupling of anisotropic interactions, like the 13C-(1)H dipolar couplings, benefit from the excellent resolution of 13C shifts that enables assignment of the couplings to specific carbon atoms. The traditional 2H NMR experiments on deuterated lipids have higher sensitivity when conducted on oriented samples at higher magnetic field strength. A very large number of NMR parameters from lipid bilayers is now accessible, providing information about conformation and dynamics for every lipid segment. The NMR methods have the sensitivity and resolution to study lipid-protein interaction, lateral lipid organization, and the location of solvents and drugs in the lipid matrix.
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Affiliation(s)
- Klaus Gawrisch
- Laboratory of Membrane Biochemistry and Biophysics, NIAAA, NIH, 12420 Parklawn Drive, Room 150, Rockville, MD 20852, USA.
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Huster D, Yao X, Hong M. Membrane protein topology probed by (1)H spin diffusion from lipids using solid-state NMR spectroscopy. J Am Chem Soc 2002; 124:874-83. [PMID: 11817963 DOI: 10.1021/ja017001r] [Citation(s) in RCA: 145] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We describe a two-dimensional solid-state NMR technique to investigate membrane protein topology under magic-angle spinning conditions. The experiment detects the rate of (1)H spin diffusion from the mobile lipids to the rigid protein. While spin diffusion within the rigid protein is fast, magnetization transfer in the mobile lipids is an inefficient and slow process. Qualitative analysis of (1)H spin-diffusion build-up curves from the lipid chain-end methyl groups to the protein allows the identification of membrane-embedded domains in the protein. Numerical simulations of spin-diffusion build-up curves yield the approximate insertion depth of protein segments in the membrane. The experiment is demonstrated on the selectively (13)C labeled colicin Ia channel domain, known to have a membrane-embedded domain, and on DNA/cationic lipid complexes where the DNA rods are bound to the membrane surface. The experiment is designed for X-nucleus detection, which could be (13)C or (15)N in the protein and (31)P for the DNA. Finally, we show that a qualitative distinction between membrane proteins with and without a membrane-embedded domain can be made even by using an unlabeled protein, by detection of lipid signals. This spin-diffusion experiment is simple to perform and requires no oriented bilayer preparations and only standard NMR hardware.
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Affiliation(s)
- Daniel Huster
- Department of Chemistry, Iowa State University, Gilman Hall 0108, Ames, Iowa 50011, USA
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Mikros E, Benaki D, Humpfer E, Spraul M, Loukas S, Stassinopoulou CI, Pelecanou M. High-Resolution NMR Spectroscopy of theβ-Amyloid(1-28) Fibril Typical for Alzheimer's Disease. Angew Chem Int Ed Engl 2001. [DOI: 10.1002/1521-3757(20011001)113:19<3715::aid-ange3715>3.0.co;2-b] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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