1
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Lenard AJ, Mulder FAA, Madl T. Solvent paramagnetic relaxation enhancement as a versatile method for studying structure and dynamics of biomolecular systems. PROGRESS IN NUCLEAR MAGNETIC RESONANCE SPECTROSCOPY 2022; 132-133:113-139. [PMID: 36496256 DOI: 10.1016/j.pnmrs.2022.09.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2022] [Revised: 09/14/2022] [Accepted: 09/15/2022] [Indexed: 06/17/2023]
Abstract
Solvent paramagnetic relaxation enhancement (sPRE) is a versatile nuclear magnetic resonance (NMR)-based method that allows characterization of the structure and dynamics of biomolecular systems through providing quantitative experimental information on solvent accessibility of NMR-active nuclei. Addition of soluble paramagnetic probes to the solution of a biomolecule leads to paramagnetic relaxation enhancement in a concentration-dependent manner. Here we review recent progress in the sPRE-based characterization of structural and dynamic properties of biomolecules and their complexes, and aim to deliver a comprehensive illustration of a growing number of applications of the method to various biological systems. We discuss the physical principles of sPRE measurements and provide an overview of available co-solute paramagnetic probes. We then explore how sPRE, in combination with complementary biophysical techniques, can further advance biomolecular structure determination, identification of interaction surfaces within protein complexes, and probing of conformational changes and low-population transient states, as well as deliver insights into weak, nonspecific, and transient interactions between proteins and co-solutes. In addition, we present examples of how the incorporation of solvent paramagnetic probes can improve the sensitivity of NMR experiments and discuss the prospects of applying sPRE to NMR metabolomics, drug discovery, and the study of intrinsically disordered proteins.
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Affiliation(s)
- Aneta J Lenard
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Ageing, Molecular Biology and Biochemistry, Research Unit Integrative Structural Biology, Medical University of Graz, 8010 Graz, Austria.
| | - Frans A A Mulder
- Interdisciplinary Nanoscience Center and Department of Chemistry, University of Aarhus, DK-8000 Aarhus, Denmark; Institute of Biochemistry, Johannes Kepler Universität Linz, 4040 Linz, Austria.
| | - Tobias Madl
- Gottfried Schatz Research Center for Cell Signaling, Metabolism and Ageing, Molecular Biology and Biochemistry, Research Unit Integrative Structural Biology, Medical University of Graz, 8010 Graz, Austria; BioTechMed-Graz, 8010 Graz, Austria.
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2
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Ribić R, Manček-Keber M, Chain F, Sinnaeve D, Martins JC, Jerala R, Tomić S, Fehér K. Targeted Delivery of Adamantylated Peptidoglycan Immunomodulators in Lipid Nanocarriers: NMR Shows That Cargo Fragments Are Available on the Surface. J Phys Chem B 2020; 124:4132-4145. [PMID: 32283934 DOI: 10.1021/acs.jpcb.0c00029] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
We present an in-depth investigation of the membrane interactions of peptidoglycan (PGN)-based immune adjuvants designed for lipid-based delivery systems using NMR spectroscopy. The derivatives contain a cargo peptidoglycan (PGN) dipeptide fragment and an adamantyl group, which serves as an anchor to the lipid bilayer. Furthermore, derivatives with a mannose group that can actively target cell surface receptors on immune cells are also studied. We showed that the targeting mannose group and the cargo PGN fragment are both available on the lipid bilayer surface, thereby enabling interactions with cognate receptors. We found that the nonmannosylated compounds are incorporated stronger into the lipid assemblies than the mannosylated ones, but the latter compounds penetrate deeper in the bilayer. This might be explained by stronger electrostatic interactions available for zwitterionic nonmannosylated derivatives as opposed to the compounds in which the charged N-terminus is capped by mannose groups. The higher incorporation efficiency of the nonmannosylated compounds correlated with a larger relative enhancement in immune stimulation activities upon lipid incorporation compared to that of the derivatives with the mannose group. The chirality of the adamantyl group also influenced the incorporation efficiency, which in turn correlated with membrane-associated conformations that affect possible intermolecular interactions with lipid molecules. These findings will help in improving the development of PGN-based immune adjuvants suitable for delivery in lipid nanoparticles.
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Affiliation(s)
- Rosana Ribić
- University Center Varaždin, University North, Jurja Križanića 31b, HR-42 000 Varaždin, Croatia.,Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Mateja Manček-Keber
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, P.O. Box 660, SI-1001 Ljubljana, Slovenia.,Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany
| | - Fernando Chain
- Department of Organic and Macromolecular Chemistry, Ghent University, Campus Sterre S4, Krijgslaan 281, 9000 Ghent, Belgium
| | - Davy Sinnaeve
- Department of Organic and Macromolecular Chemistry, Ghent University, Campus Sterre S4, Krijgslaan 281, 9000 Ghent, Belgium.,Univ. Lille, Inserm, Institut Pasteur de Lille, CHU Lille, U1167 - Labex DISTALZ - RID-AGE - Risk Factors and Molecular Determinants of Aging-Related Diseases, F-59000 Lille, France.,CNRS, ERL9002 - Integrative Structural Biology, F-59000 Lille, France
| | - José C Martins
- Department of Organic and Macromolecular Chemistry, Ghent University, Campus Sterre S4, Krijgslaan 281, 9000 Ghent, Belgium
| | - Roman Jerala
- Department of Synthetic Biology and Immunology, National Institute of Chemistry, Hajdrihova 19, P.O. Box 660, SI-1001 Ljubljana, Slovenia
| | - Srđanka Tomić
- Department of Chemistry, Faculty of Science, University of Zagreb, Horvatovac 102A, HR-10 000 Zagreb, Croatia
| | - Krisztina Fehér
- Department of Organic and Macromolecular Chemistry, Ghent University, Campus Sterre S4, Krijgslaan 281, 9000 Ghent, Belgium.,Heidelberg Institute for Theoretical Studies, Schloss-Wolfsbrunnenweg 35, 69118 Heidelberg, Germany.,Molecular Recognition and Interaction Research Group, Hungarian Academy of Sciences, Egyetem tér 1, H-4032 Debrecen, Hungary
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3
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Russell AE, Sneider A, Witwer KW, Bergese P, Bhattacharyya SN, Cocks A, Cocucci E, Erdbrügger U, Falcon-Perez JM, Freeman DW, Gallagher TM, Hu S, Huang Y, Jay SM, Kano SI, Lavieu G, Leszczynska A, Llorente AM, Lu Q, Mahairaki V, Muth DC, Noren Hooten N, Ostrowski M, Prada I, Sahoo S, Schøyen TH, Sheng L, Tesch D, Van Niel G, Vandenbroucke RE, Verweij FJ, Villar AV, Wauben M, Wehman AM, Yin H, Carter DRF, Vader P. Biological membranes in EV biogenesis, stability, uptake, and cargo transfer: an ISEV position paper arising from the ISEV membranes and EVs workshop. J Extracell Vesicles 2019; 8:1684862. [PMID: 31762963 PMCID: PMC6853251 DOI: 10.1080/20013078.2019.1684862] [Citation(s) in RCA: 156] [Impact Index Per Article: 31.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2019] [Revised: 08/23/2019] [Accepted: 10/04/2019] [Indexed: 02/07/2023] Open
Abstract
Paracrine and endocrine roles have increasingly been ascribed to extracellular vesicles (EVs) generated by multicellular organisms. Central to the biogenesis, content, and function of EVs are their delimiting lipid bilayer membranes. To evaluate research progress on membranes and EVs, the International Society for Extracellular Vesicles (ISEV) conducted a workshop in March 2018 in Baltimore, Maryland, USA, bringing together key opinion leaders and hands-on researchers who were selected on the basis of submitted applications. The workshop was accompanied by two scientific surveys and covered four broad topics: EV biogenesis and release; EV uptake and fusion; technologies and strategies used to study EV membranes; and EV transfer and functional assays. In this ISEV position paper, we synthesize the results of the workshop and the related surveys to outline important outstanding questions about EV membranes and describe areas of consensus. The workshop discussions and survey responses reveal that while much progress has been made in the field, there are still several concepts that divide opinion. Good consensus exists in some areas, including particular aspects of EV biogenesis, uptake and downstream signalling. Areas with little to no consensus include EV storage and stability, as well as whether and how EVs fuse with target cells. Further research is needed in these key areas, as a better understanding of membrane biology will contribute substantially towards advancing the field of extracellular vesicles.
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Affiliation(s)
- Ashley E. Russell
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Alexandra Sneider
- Department of Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD, USA
| | - Kenneth W. Witwer
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Paolo Bergese
- Department of Molecular and Translational Medicine, Università degli Studi di Brescia, CSGI and INSTM, Brescia, Italy
| | | | | | - Emanuele Cocucci
- Division of Pharmaceutics and Pharmacology, College of Pharmacy, Columbus, OH, USA
- Comprehensive Cancer Center, The Ohio State University, Columbus, OH, USA
| | | | - Juan M. Falcon-Perez
- Exosomes laboratory and Metabolomics Platform, CIC bioGUNE, CIBERehd, Bizkaia, Spain
- IKERBASQUE, Basque Foundation for Science, Bizkaia, Spain
| | - David W. Freeman
- Laboratory of Epidemiology and Population Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Thomas M. Gallagher
- Department of Microbiology and Immunology, Loyola University Chicago, Chicago, IL, USA
| | - Shuaishuai Hu
- School of Biological and Healthy Sciences, Technological University Dublin, Dublin, Ireland
| | - Yiyao Huang
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- Department of Clinical Laboratory Medicine, Nanfang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Steven M. Jay
- Fischell Department of Bioengineering, University of Maryland, College Park, MD, USA
| | - Shin-ichi Kano
- Department of Psychiatry and Behavioral Neurobiology, The University of Alabama at Birmingham School of Medicine, Birmingham, AL, USA
| | - Gregory Lavieu
- INSERM U932, Institut Curie, PSL Research University, France
| | | | - Alicia M. Llorente
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, Oslo, Norway
| | - Quan Lu
- Program in Molecular and Integrative Physiological Sciences Departments of Environmental Health, Genetics & Complex Diseases Harvard T.H. Chan School of Public Health, Boston, MA, USA
| | - Vasiliki Mahairaki
- Department of Neurology, Johns Hopkins School of Medicine, Baltimore, MD, USA
| | - Dillon C. Muth
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Nicole Noren Hooten
- Laboratory of Epidemiology and Population Science, National Institute on Aging, National Institutes of Health, Baltimore, MD, USA
| | - Matias Ostrowski
- INBIRS Institute, UBA-CONICET School of Medicine University of Buenos Aires, Buenos Aires, Argentina
| | | | - Susmita Sahoo
- Cardiovascular Research Center, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Tine Hiorth Schøyen
- Department of Molecular and Comparative Pathobiology, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
- K. G. Jebsen - Thrombosis Research and Expertise Center (TREC), Department of Clinical Medicine, UiT - The Arctic University of Norway, Tromsø, Norway
| | - Lifu Sheng
- Department of Pathology, University of Washington School of Medicine, Seattle, WA, USA
| | - Deanna Tesch
- Department of Chemistry, Shaw University, Raleigh, NC, USA
| | - Guillaume Van Niel
- Institute for Psychiatry and Neuroscience of Paris, INSERM U1266, Hopital Saint-Anne, Université Descartes, Paris, France
| | - Roosmarijn E. Vandenbroucke
- VIB Center for Inflammation Research, Ghent, Belgium
- Department of Biomedical Molecular Biology, Ghent University, Ghent, Belgium
| | - Frederik J. Verweij
- Institute for Psychiatry and Neuroscience of Paris, INSERM U1266, Hopital Saint-Anne, Université Descartes, Paris, France
| | - Ana V. Villar
- Instituto de Biomedicina y Biotecnología de Cantabria (IBBTEC) CSIC-Universidad de Cantabria and Departamento de Fisiología y Farmacología, Universidad de Cantabria, Santander, Spain
| | - Marca Wauben
- Department of Biochemistry and Cell Biology, Faculty of Veterinary Medicine, Utrecht University, Utrecht, The Netherlands
| | - Ann M. Wehman
- Rudolf Virchow Center, Julius-Maximilians-Universität Würzburg, Würzburg, Germany
| | - Hang Yin
- School of Pharmaceutical Sciences, Tsinghua University-Peking University Joint Center for Life Sciences, Tsinghua University, Beijing, China
| | | | - Pieter Vader
- Laboratory of Clinical Chemistry and Haematology & Department of Experimental Cardiology, University Medical Center Utrecht, Utrecht, The Netherlands
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Subramaniam R, Lynch S, Cen Y, Balaz S. Polarity of Hydrated Phosphatidylcholine Headgroups. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:8460-8471. [PMID: 31244216 PMCID: PMC6853183 DOI: 10.1021/acs.langmuir.8b03992] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
The headgroup (H) stratum (sometimes called the polar region) of membrane bilayers is a relevant yet poorly understood solvation phase for small molecules and macromolecules interacting with the membranes. Solvation of compounds in bilayer strata is characterized experimentally by wide- and small-angle X-ray scattering, neutron diffraction, and various NMR techniques. The quantification is tedious and only available for a limited set of small molecules. Our recently published model of liposome partitioning of small molecules shows that solvation of compounds in the H-stratum of fluid phosphatidylcholine (PC) bilayers correlates well with their solvation in hydrated diacetyl phosphatidylcholine (DAcPC), and solvation in the core (C) depends in a similar way on that in n-hexadecane. These two correlations became a basis for a model describing the location of compounds in the H- and C-strata and at the connecting interface as a nonlinear function of the fragment solvation characteristics of the compounds. In this study, refractivity of hydrated DAcPC phases with varying water contents was measured and polarity was determined using the steady-state fluorescence of indole and Nile Red. The results were compared with the published data obtained by other techniques for PC bilayers in liposomes or on solid supports. The demonstrated qualitative agreement, as well as the polarity and refractivity dependencies on the DAcPC concentration, supports the suitability of hydrated DAcPC as the H-stratum surrogate. Interestingly, depending on hydrations typical for the H-strata of fluid PC bilayers, the dielectric constant could decrease significantly from 31.0 to 7.3 for 16 and 8 water molecules per headgroup, respectively. Although additional experiments are needed for confirmation, this observation could help set proper dielectric constant magnitudes in continuum-based computational models of accumulation and crossing of the PC bilayers with varying hydration levels thanks to the temperature or the structure of fatty acid chains.
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Affiliation(s)
| | | | | | - Stefan Balaz
- Corresponding author: Stefan Balaz, Albany College of Pharmacy and Health Sciences, Vermont Campus, Department of Pharmaceutical Sciences, 261 Mountain View Road, Colchester, VT 05446, United States, phone 802-735-2615,
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5
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Rodriguez-Muñiz GM, Gomez-Mendoza M, Nuin E, Andreu I, Marin ML, Miranda MA. "Snorkelling" vs. "diving" in mixed micelles probed by means of a molecular bathymeter. Org Biomol Chem 2017; 15:10281-10288. [PMID: 29186227 DOI: 10.1039/c7ob02595e] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
A photoactive bathymeter based on a carboxylic acid moiety covalently linked to a signalling methoxynaphthalene (MNP) fluorophore has been designed to prove the concept of "snorkelling" vs. "diving" in mixed micelles (MM). The carboxylic acid "floats" on the MM surface, while the MNP unit sinks deep in MM. The rate constants of MNP fluorescence quenching by iodide, which remains basically in water, consistently decrease with increasing spacer length, revealing different regions. This is associated with the distance MNP should "dive" in MM to achieve protection from aqueous reactants. Unequivocal proof of the exergonic photoinduced electron transfer was obtained from the UV-visible spectral signature of I3- upon steady-state photolysis. The applicability of the bathymeter was examined upon testing a family of MNP derivatives. The obtained results were validated by comparison with different lipophilicity tests: (i) a modified version of the Kow partition coefficient and (ii) the retention factor on thin layer chromatography. This concept could potentially be extended to test drugs or pharmacophores exhibiting any photoactive moiety.
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Affiliation(s)
- Gemma M Rodriguez-Muñiz
- Instituto Universitario Mixto de Tecnología Química (UPV-CSIC) Universitat Politècnica de València, Avda de los Naranjos s/n, 46022 Valencia, Spain
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6
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Liebau J, Mäler L. Immersion Depths of Lipid Carbons in Bicelles Measured by Paramagnetic Relaxation Enhancement. J Phys Chem B 2017; 121:7660-7670. [DOI: 10.1021/acs.jpcb.7b05822] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Affiliation(s)
- Jobst Liebau
- Department of Biochemistry
and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
| | - Lena Mäler
- Department of Biochemistry
and Biophysics, Stockholm University, SE-106 91 Stockholm, Sweden
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7
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Koroloff SN, Tesch DM, Awosanya EO, Nevzorov AA. Sensitivity enhancement for membrane proteins reconstituted in parallel and perpendicular oriented bicelles obtained by using repetitive cross-polarization and membrane-incorporated free radicals. JOURNAL OF BIOMOLECULAR NMR 2017; 67:135-144. [PMID: 28205016 DOI: 10.1007/s10858-017-0090-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Accepted: 01/19/2017] [Indexed: 06/06/2023]
Abstract
Multidimensional separated local-field and spin-exchange experiments employed by oriented-sample solid-state NMR are essential for structure determination and spectroscopic assignment of membrane proteins reconstituted in macroscopically aligned lipid bilayers. However, these experiments typically require a large number of scans in order to establish interspin correlations. Here we have shown that a combination of optimized repetitive cross polarization (REP-CP) and membrane-embedded free radicals allows one to enhance the signal-to-noise ratio by factors 2.4-3.0 in the case of Pf1 coat protein reconstituted in magnetically aligned bicelles with their normals being either parallel or perpendicular to the main magnetic field. Notably, spectral resolution is not affected at the 2:1 radical-to-protein ratio. Spectroscopic assignment of Pf1 coat protein in the parallel bicelles has been established as an illustration of the method. The proposed methodology will advance applications of oriented-sample NMR technique when applied to samples containing smaller quantities of proteins and three-dimensional experiments.
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Affiliation(s)
- Sophie N Koroloff
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA
| | - Deanna M Tesch
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA
- Shaw University, 118 E. South Street, Raleigh, NC, 27601, USA
| | - Emmanuel O Awosanya
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA
| | - Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC, 27695-8204, USA.
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8
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Natesan S, Lukacova V, Peng M, Subramaniam R, Lynch S, Wang Z, Tandlich R, Balaz S. Structure-based prediction of drug distribution across the headgroup and core strata of a phospholipid bilayer using surrogate phases. Mol Pharm 2014; 11:3577-95. [PMID: 25179490 PMCID: PMC4186683 DOI: 10.1021/mp5003366] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
![]()
Solvation of drugs in the core (C)
and headgroup (H) strata of
phospholipid bilayers affects their physiological transport rates
and accumulation. These characteristics, especially a complete drug
distribution profile across the bilayer strata, are tedious to obtain
experimentally, to the point that even simplified preferred locations
are only available for a few dozen compounds. Recently, we showed
that the partition coefficient (P) values in the
system of hydrated diacetyl phosphatidylcholine (DAcPC) and n-hexadecane (C16), as surrogates of the H- and C-strata
of the bilayer composed of the most abundant mammalian phospholipid,
PC, agree well with the preferred bilayer location of compounds. High P values are typical for lipophiles accumulating in the
core, and low P values are characteristic of cephalophiles
preferring the headgroups. This simple pattern does not hold for most
compounds, which usually have more even distribution and may also
accumulate at the H/C interface. To model complete distribution, the
correlates of solvation energies are needed for each drug state in
the bilayer: (1) for the H-stratum it is the DAcPC/W P value, calculated as the ratio of the C16/W and C16/DAcPC (W for
water) P values; (2) for the C-stratum, the C16/W P value; (3) for the H/C interface, the P values for all plausible molecular poses are characterized using
the fragment DAcPC/W and C16/W solvation parameters for the parts
of the molecule embedded in the H- and C-strata, respectively. The
correlates, each scaled by two Collander coefficients, were used in
a nonlinear, mass-balance based model of intrabilayer distribution,
which was applied to the easily measurable overall P values of compounds in the DMPC (M = myristoyl) bilayers and monolayers
as the dependent variables. The calibrated model for 107 neutral compounds
explains 94% of experimental variance, achieves similar cross-validation
levels, and agrees well with the nontrivial, experimentally determined
bilayer locations for 27 compounds. The resulting structure-based
prediction system for intrabilayer distribution will facilitate more
realistic modeling of passive transport and drug interactions with
those integral membrane proteins, which have the binding sites located
in the bilayer, such as some enzymes, influx and efflux transporters,
and receptors. If only overall bilayer accumulation is of interest,
the 1-octanol/W P values suffice to model the studied
set.
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Affiliation(s)
- Senthil Natesan
- Department of Pharmaceutical Sciences, Albany College of Pharmacy and Health Sciences , Vermont Campus, Colchester, Vermont 05446, United States
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9
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Alvares R, Gupta S, Macdonald PM, Prosser RS. Temperature and Pressure Based NMR Studies of Detergent Micelle Phase Equilibria. J Phys Chem B 2014; 118:5698-706. [DOI: 10.1021/jp500139p] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Affiliation(s)
- Rohan Alvares
- Department
of Chemistry, University of Toronto, UTM Campus, 3359 Mississauga
Road North, Mississauga, Ontario, Canada L5L 1C6
| | - Shaan Gupta
- Department
of Chemistry, University of Toronto, UTM Campus, 3359 Mississauga
Road North, Mississauga, Ontario, Canada L5L 1C6
| | - Peter M. Macdonald
- Department
of Chemistry, University of Toronto, UTM Campus, 3359 Mississauga
Road North, Mississauga, Ontario, Canada L5L 1C6
| | - R. Scott Prosser
- Department
of Chemistry, University of Toronto, UTM Campus, 3359 Mississauga
Road North, Mississauga, Ontario, Canada L5L 1C6
- Department
of Biochemistry, University of Toronto, Toronto, Ontario, Canada M5S 1A8
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10
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Ladokhin AS. Measuring membrane penetration with depth-dependent fluorescence quenching: distribution analysis is coming of age. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1838:2289-95. [PMID: 24593994 DOI: 10.1016/j.bbamem.2014.02.019] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2014] [Accepted: 02/21/2014] [Indexed: 10/25/2022]
Abstract
Depth-dependent fluorescence quenching by lipid-attached quenchers (e.g., bromine atoms and doxyl groups) is an important tool for determining the penetration of proteins and peptides into lipid bilayers. Extracting quantitative information and accurate calculations of the depth of the fluorophore are complicated by thermal disorder, resulting in broad distributions of the transverse positions of both quenchers and fluorophores. Twenty-one years ago a methodology called distribution analysis (DA) was introduced, based on the emerging view of the complexity of the transverse organization of lipid bilayer structure. The method is aimed at extracting quantitative information on membrane penetration, such as position and width of fluorophore's distribution along the depth coordinate and its exposure to the lipid phase. Here we review recent progress in refining the DA method and illustrate its applications to protein-membrane interactions. We demonstrate how basic assumptions of the DA approach can be validated using molecular dynamics simulations and how the precision of depth determination is improved by applying a new protocol based on a combination of steady-state and time-resolved fluorescence quenching. Using the example of the MPER fragment of the membrane-spanning domain of the HIV-1 gp41 fusion protein, we illustrate how DA applications and computer simulations can be used together to reveal the molecular organization of a protein-membrane complex. This article is part of a Special Issue entitled: Interfacially Active Peptides and Proteins. Guest Editors: William C. Wimley and Kalina Hristova.
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Affiliation(s)
- Alexey S Ladokhin
- Department of Biochemistry and Molecular Biology, The University of Kansas Medical Center, Kansas City, KS 66160-7421, USA.
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11
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Tesch DM, Nevzorov AA. Sensitivity enhancement and contrasting information provided by free radicals in oriented-sample NMR of bicelle-reconstituted membrane proteins. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2014; 239:9-15. [PMID: 24355622 DOI: 10.1016/j.jmr.2013.11.010] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Revised: 11/13/2013] [Accepted: 11/18/2013] [Indexed: 06/03/2023]
Abstract
Elucidating structure and topology of membrane proteins (MPs) is essential for unveiling functionality of these important biological constituents. Oriented-sample solid-state NMR (OS-NMR) is capable of providing such information on MPs under nearly physiological conditions. However, two dimensional OS-NMR experiments can take several days to complete due to long longitudinal relaxation times combined with the large number of scans to achieve sufficient signal sensitivity in biological samples. Here, free radicals 5-DOXYL stearic acid, TEMPOL, and CAT-1 were added to uniformly (15)N-labeled Pf1 coat protein reconstituted in DMPC/DHPC bicelles, and their effect on the longitudinal relaxation times (T1Z) was investigated. The dramatically shortened T1Z's allowed for the signal gain per unit time to be used for either: (i) up to a threefold reduction of the total experimental time at 99% magnetization recovery or (ii) obtaining up to 74% signal enhancement between the control and radical samples during constant experimental time at "optimal" relaxation delays. In addition, through OS-NMR and high-field EPR studies, free radicals were able to provide positional constraints in the bicelle system, which provide a description of the location of each residue in Pf1 coat protein within the bicellar membranes. This information can be useful in the determination of oligomerization states and immersion depths of larger membrane proteins.
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Affiliation(s)
- Deanna M Tesch
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States
| | - Alexander A Nevzorov
- Department of Chemistry, North Carolina State University, 2620 Yarbrough Drive, Raleigh, NC 27695-8204, United States.
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12
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Hocking HG, Zangger K, Madl T. Studying the structure and dynamics of biomolecules by using soluble paramagnetic probes. Chemphyschem 2013; 14:3082-94. [PMID: 23836693 PMCID: PMC4171756 DOI: 10.1002/cphc.201300219] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2013] [Indexed: 12/20/2022]
Abstract
Characterisation of the structure and dynamics of large biomolecules and biomolecular complexes by NMR spectroscopy is hampered by increasing overlap and severe broadening of NMR signals. As a consequence, the number of available NMR spectroscopy data is often sparse and new approaches to provide complementary NMR spectroscopy data are needed. Paramagnetic relaxation enhancements (PREs) obtained from inert and soluble paramagnetic probes (solvent PREs) provide detailed quantitative information about the solvent accessibility of NMR-active nuclei. Solvent PREs can be easily measured without modification of the biomolecule; are sensitive to molecular structure and dynamics; and are therefore becoming increasingly powerful for the study of biomolecules, such as proteins, nucleic acids, ligands and their complexes in solution. In this Minireview, we give an overview of the available solvent PRE probes and discuss their applications for structural and dynamic characterisation of biomolecules and biomolecular complexes.
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Affiliation(s)
- Henry G Hocking
- Chair of Biomolecular NMR, Department Chemie, Technische Universität München, 85747 Garching (Germany); Institute of Structural Biology, Helmholtz Zentrum München, 85764 Neuherberg (Germany)
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Kyrychenko A, Ladokhin AS. Molecular dynamics simulations of depth distribution of spin-labeled phospholipids within lipid bilayer. J Phys Chem B 2013; 117:5875-85. [PMID: 23614631 DOI: 10.1021/jp4026706] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spin-labeled lipids are commonly used as fluorescence quenchers in studies of membrane penetration of dye-labeled proteins and peptides using depth-dependent quenching. Accurate calculations of depth of the fluorophore rely on the use of several spin labels placed in the membrane at various positions. The depth of the quenchers (spin probes) has to be determined independently; however, experimental determination of transverse distributions of spin probe depths is difficult. In this Article, we use molecular dynamics (MD) simulations to study the membrane behavior and depth distributions of spin-labeled phospholipids in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) bilayer. To probe different depths within the bilayer, a series containing five Doxyl-labeled lipids (n-Doxyl PC) has been studied, in which a spin moiety was covalently attached to nth carbon atoms (where n = 5, 7, 10, 12, and 14) of the sn-2 stearoyl chain of the host phospholipid. Our results demonstrate that the chain-attached spin labels are broadly distributed across the model membrane and their environment is characterized by a high degree of mobility and structural heterogeneity. Despite the high thermal disorder, the depth distributions of the Doxyl labels were found to correlate well with their attachment positions, indicating that the distribution of the spin label within the model membrane is dictated by the depth of the nth lipid carbon atom and not by intrinsic properties of the label. In contrast, a much broader and heterogeneous distribution was observed for a headgroup-attached Tempo spin label of Tempo-PC lipids. MD simulations reveal that, due to the hydrophobic nature, a Tempo moiety favors partitioning from the headgroup region deeper into the membrane. Depending on the concentration of Tempo-PC lipids, the probable depth of the Tempo moiety could span a range from 14.4 to 18.2 Å from the membrane center. Comparison of the MD-estimated immersion depths of Tempo and n-Doxyl labels with their suggested experimental depth positions allows us to review critically the possible sources of error in depth-dependent fluorescence quenching studies.
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Affiliation(s)
- Alexander Kyrychenko
- Department of Biochemistry and Molecular Biology, Kansas University Medical Center, Kansas City, Kansas 66160-7421, USA.
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Al-Abdul-Wahid MS, Verardi R, Veglia G, Prosser RS. Topology and immersion depth of an integral membrane protein by paramagnetic rates from dissolved oxygen. JOURNAL OF BIOMOLECULAR NMR 2011; 51:173-183. [PMID: 21947925 DOI: 10.1007/s10858-011-9551-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/19/2011] [Accepted: 06/30/2011] [Indexed: 05/31/2023]
Abstract
In studies of membrane proteins, knowledge of protein topology can provide useful insight into both structure and function. In this work, we present a solution NMR method for the measurement the tilt angle and average immersion depth of alpha helices in membrane proteins, from analysis of the paramagnetic relaxation rate enhancements arising from dissolved oxygen. No modification to the micelle or protein is necessary, and the topology of both transmembrane and amphipathic helices are readily determined. We apply this method to the measure the topology of a monomeric mutant of phospholamban (AFA-PLN), a 52-residue membrane protein containing both an amphipathic and a transmembrane alpha helix. In dodecylphosphocholine micelles, the amphipathic helix of AFA-PLN was found to have a tilt angle of 87° ± 1° and an average immersion depth of 13.2 Å. The transmembrane helix was found to have an average immersion depth of 5.4 Å, indicating residues 41 and 42 are closest to the micelle centre. The resolution of paramagnetic relaxation rate enhancements from dissolved oxygen compares favourably to those from Ni (II), a hydrophilic paramagnetic species.
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Nieh MP, Raghunathan VA, Pabst G, Harroun T, Nagashima K, Morales H, Katsaras J, Macdonald P. Temperature driven annealing of perforations in bicellar model membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2011; 27:4838-4847. [PMID: 21438512 DOI: 10.1021/la104750x] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Bicellar model membranes composed of 1,2-dimyristoylphosphatidylcholine (DMPC) and 1,2-dihexanoylphosphatidylcholine (DHPC), with a DMPC/DHPC molar ratio of 5, and doped with the negatively charged lipid 1,2-dimyristoylphosphatidylglycerol (DMPG), at DMPG/DMPC molar ratios of 0.02 or 0.1, were examined using small angle neutron scattering (SANS), (31)P NMR, and (1)H pulsed field gradient (PFG) diffusion NMR with the goal of understanding temperature effects on the DHPC-dependent perforations in these self-assembled membrane mimetics. Over the temperature range studied via SANS (300-330 K), these bicellar lipid mixtures exhibited a well-ordered lamellar phase. The interlamellar spacing d increased with increasing temperature, in direct contrast to the decrease in d observed upon increasing temperature with otherwise identical lipid mixtures lacking DHPC. (31)P NMR measurements on magnetically aligned bicellar mixtures of identical composition indicated a progressive migration of DHPC from regions of high curvature into planar regions with increasing temperature, and in accord with the "mixed bicelle model" (Triba, M. N.; Warschawski, D. E.; Devaux, P. E. Biophys. J.2005, 88, 1887-1901). Parallel PFG diffusion NMR measurements of transbilayer water diffusion, where the observed diffusion is dependent on the fractional surface area of lamellar perforations, showed that transbilayer water diffusion decreased with increasing temperature. A model is proposed consistent with the SANS, (31)P NMR, and PFG diffusion NMR data, wherein increasing temperature drives the progressive migration of DHPC out of high-curvature regions, consequently decreasing the fractional volume of lamellar perforations, so that water occupying these perforations redistributes into the interlamellar volume, thereby increasing the interlamellar spacing.
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Affiliation(s)
- Mu-Ping Nieh
- Chemical, Materials and Biomolecular Engineering Department, Institute of Material Sciences, University of Connecticut, 97 North Eagleville Road, Storrs, Connecticut 06269-3136, USA
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Lomize AL, Pogozheva ID, Mosberg HI. Anisotropic solvent model of the lipid bilayer. 2. Energetics of insertion of small molecules, peptides, and proteins in membranes. J Chem Inf Model 2011; 51:930-46. [PMID: 21438606 DOI: 10.1021/ci200020k] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
A new computational approach to calculating binding energies and spatial positions of small molecules, peptides, and proteins in the lipid bilayer has been developed. The method combines an anisotropic solvent representation of the lipid bilayer and universal solvation model, which predicts transfer energies of molecules from water to an arbitrary medium with defined polarity properties. The universal solvation model accounts for hydrophobic, van der Waals, hydrogen-bonding, and electrostatic solute-solvent interactions. The lipid bilayer is represented as a fluid anisotropic environment described by profiles of dielectric constant (ε), solvatochromic dipolarity parameter (π*), and hydrogen bonding acidity and basicity parameters (α and β). The polarity profiles were calculated using published distributions of quasi-molecular segments of lipids determined by neutron and X-ray scattering for DOPC bilayer and spin-labeling data that define concentration of water in the lipid acyl chain region. The model also accounts for the preferential solvation of charges and polar groups by water and includes the effect of the hydrophobic mismatch for transmembrane proteins. The method was tested on calculations of binding energies and preferential positions in membranes for small-molecules, peptides and peripheral membrane proteins that have been experimentally studied. The new theoretical approach was implemented in a new version (2.0) of our PPM program and applied for the large-scale calculations of spatial positions in membranes of more than 1000 peripheral and integral proteins. The results of calculations are deposited in the updated OPM database ( http://opm.phar.umich.edu ).
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Affiliation(s)
- Andrei L Lomize
- Department of Medicinal Chemistry, College of Pharmacy, University of Michigan , 428 Church St., Ann Arbor, Michigan 48109-1065, USA.
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Chu S, Maltsev S, Emwas AH, Lorigan GA. Solid-state NMR paramagnetic relaxation enhancement immersion depth studies in phospholipid bilayers. JOURNAL OF MAGNETIC RESONANCE (SAN DIEGO, CALIF. : 1997) 2010; 207:89-94. [PMID: 20851650 PMCID: PMC2978330 DOI: 10.1016/j.jmr.2010.08.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/26/2010] [Revised: 08/11/2010] [Accepted: 08/18/2010] [Indexed: 05/20/2023]
Abstract
A new approach for determining the membrane immersion depth of a spin-labeled probe has been developed using paramagnetic relaxation enhancement (PRE) in solid-state NMR spectroscopy. A DOXYL spin label was placed at different sites of 1-palmitoyl-2-stearoyl-sn-glycero-3-phosphocholine (PSPC) phospholipid bilayers as paramagnetic moieties and the resulting enhancements of the longitudinal relaxation (T₁) times of ³¹P nuclei on the surface of the bilayers were measured by a standard inversion recovery pulse sequence. The ³¹P NMR spin-lattice relaxation times decrease steadily as the DOXYL spin label moves closer to the surface as well as the concentration of the spin-labeled lipids increase. The enhanced relaxation vs. the position and concentration of spin-labels indicate that PRE induced by the DOXYL spin label are significant to determine longer distances over the whole range of the membrane depths. When these data were combined with estimated correlation times τ(c), the r⁻⁶-weighted, time-averaged distances between the spin-labels and the ³¹P nuclei on the membrane surface were estimated. The application of using this solid-state NMR PRE approach coupled with site-directed spin labeling (SDSL) may be a powerful method for measuring membrane protein immersion depth.
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Affiliation(s)
- Shidong Chu
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
| | - Sergey Maltsev
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
| | - A-H Emwas
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
| | - Gary A. Lorigan
- Department of Chemistry and Biochemistry, Miami University, Oxford, OH, USA 45056
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Demarco ML, Woods RJ, Prestegard JH, Tian F. Presentation of membrane-anchored glycosphingolipids determined from molecular dynamics simulations and NMR paramagnetic relaxation rate enhancement. J Am Chem Soc 2010; 132:1334-8. [PMID: 20058858 DOI: 10.1021/ja907518x] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Challenges for structural characterization of membrane-bound glycosphingolipids include their high internal dynamic motions and their physical proximity to membrane surfaces. Here we demonstrate that NMR paramagnetic relaxation enhancement can be used, alongside independent molecular dynamics simulations and an outer-sphere relaxation model, to quantitatively characterize the presentation (insertion depth and orientation relative to a membrane surface) of ganglioside GM1 in biologically relevant membrane environments. Longitudinal and transverse paramagnetic relaxation enhancement effects were measured for GM1, anchored to phospholipid bicelles, using both water-soluble and membrane-anchored paramagnetic probes, respectively. A method was developed to rapidly calculate paramagnetic relaxation enhancement effects from thousands of structures taken from a simulation of GM1 in a phospholipid bilayer. The combined computational and experimental approach yielded experimentally verified atomic-resolution 3D models of a highly plastic membrane-bound biomolecule.
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Affiliation(s)
- Mari L Demarco
- Complex Carbohydrate Research Center, University of Georgia, 315 Riverbend Road, Athens, Georgia 30602, USA
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Affiliation(s)
- Gottfried Otting
- Australian National University, Research School of Chemistry, Canberra, ACT 0200, Australia;
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Matsumori N, Murata M. 3D structures of membrane-associated small molecules as determined in isotropic bicelles. Nat Prod Rep 2010; 27:1480-92. [DOI: 10.1039/c0np00002g] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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Van Horn WD, Beel AJ, Kang C, Sanders CR. The impact of window functions on NMR-based paramagnetic relaxation enhancement measurements in membrane proteins. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2009; 1798:140-9. [PMID: 19751702 DOI: 10.1016/j.bbamem.2009.08.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2009] [Revised: 08/25/2009] [Accepted: 08/31/2009] [Indexed: 11/24/2022]
Abstract
Though challenging, solution NMR spectroscopy allows fundamental interrogation of the structure and dynamics of membrane proteins. One major technical hurdle in studies of helical membrane proteins by NMR is the difficulty of obtaining sufficient long range NOEs to determine tertiary structure. For this reason, long range distance information is sometimes sought through measurement of paramagnetic relaxation enhancements (PRE) of NMR nuclei as a function of distance from an introduced paramagnetic probe. Current PRE interpretation is based on the assumption of Lorentzian resonance lineshapes. However, in order to optimize spectral resolution, modern multidimensional NMR spectra are almost always subjected to resolution-enhancement, leading to distortions in the Lorentizian peak shape. Here it is shown that when PREs are derived using peak intensities (i.e., peak height) and linewidths from both real and simulated spectra that were produced using a wide range of apodization/window functions, that there is little variation in the distances determined (<1 A at the extremes). This indicates that the high degree of resolution enhancement required to obtain well-resolved spectra from helical membrane proteins is compatible with the use of PRE data as a source of distance restraints. While these conclusions are particularly important for helical membrane proteins, they are generally applicable to all PRE measurements made using resolution-enhanced data.
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Affiliation(s)
- Wade D Van Horn
- Department of Biochemistry and Center for Structural Biology, Vanderbilt University School of Medicine, Nashville, TN 37232-8725, USA
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