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Krupnik L, Avaro J, Liebi M, Anaraki NI, Kohlbrecher J, Sologubenko A, Handschin S, Rzepiela AJ, Appel C, Totu T, Blanchet CE, Alston AEB, Digigow R, Philipp E, Flühmann B, Silva BFB, Neels A, Wick P. Iron-carbohydrate complexes treating iron anaemia: Understanding the nano-structure and interactions with proteins through orthogonal characterisation. J Control Release 2024; 368:566-579. [PMID: 38438093 DOI: 10.1016/j.jconrel.2024.02.044] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2023] [Revised: 02/24/2024] [Accepted: 02/27/2024] [Indexed: 03/06/2024]
Abstract
Intravenous (IV) iron-carbohydrate complexes are widely used nanoparticles (NPs) to treat iron deficiency anaemia, often associated with medical conditions such as chronic kidney disease, heart failure and various inflammatory conditions. Even though a plethora of physicochemical characterisation data and clinical studies are available for these products, evidence-based correlation between physicochemical properties of iron-carbohydrate complexes and clinical outcome has not fully been elucidated yet. Studies on other metal oxide NPs suggest that early interactions between NPs and blood upon IV injection are key to understanding how differences in physicochemical characteristics of iron-carbohydrate complexes cause variance in clinical outcomes. We therefore investigated the core-ligand structure of two clinically relevant iron-carbohydrate complexes, iron sucrose (IS) and ferric carboxymaltose (FCM), and their interactions with two structurally different human plasma proteins, human serum albumin (HSA) and fibrinogen, using a combination of cryo-scanning transmission electron microscopy (cryo-STEM), x-ray diffraction (XRD), small-angle x-ray scattering (SAXS) and small-angle neutron scattering (SANS). Using this orthogonal approach, we defined the nano-structure, individual building blocks and surface morphology for IS and FCM. Importantly, we revealed significant differences in the surface morphology of the iron-carbohydrate complexes. FCM shows a localised carbohydrate shell around its core, in contrast to IS, which is characterised by a diffuse and dynamic layer of carbohydrate ligand surrounding its core. We hypothesised that such differences in carbohydrate morphology determine the interaction between iron-carbohydrate complexes and proteins and therefore investigated the NPs in the presence of HSA and fibrinogen. Intriguingly, IS showed significant interaction with HSA and fibrinogen, forming NP-protein clusters, while FCM only showed significant interaction with fibrinogen. We postulate that these differences could influence bio-response of the two formulations and their clinical outcome. In conclusion, our study provides orthogonal characterisation of two clinically relevant iron-carbohydrate complexes and first hints at their interaction behaviour with proteins in the human bloodstream, setting a prerequisite towards complete understanding of the correlation between physicochemical properties and clinical outcome.
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Affiliation(s)
- Leonard Krupnik
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland; Particles-Biology Interactions Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland; Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
| | - Jonathan Avaro
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland
| | - Marianne Liebi
- Photon Science Division, PSI Paul Scherrer Institute, Villigen CH-5232, Switzerland; Institute of Materials, Ecole Polytechnique Fédérale de Lausanne (EPFL), CH-1015 Lausanne, Switzerland
| | - Neda Iranpour Anaraki
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland; Particles-Biology Interactions Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland; Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland
| | - Joachim Kohlbrecher
- Laboratory for Neutron Scattering, PSI Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - Alla Sologubenko
- Scientific Center for Optical and Electron Microscopy, ScopeM, ETH Zürich, 8093 Zürich, Switzerland
| | - Stephan Handschin
- Scientific Center for Optical and Electron Microscopy, ScopeM, ETH Zürich, 8093 Zürich, Switzerland
| | - Andrzej J Rzepiela
- Scientific Center for Optical and Electron Microscopy, ScopeM, ETH Zürich, 8093 Zürich, Switzerland
| | - Christian Appel
- Photon Science Division, PSI Paul Scherrer Institute, Villigen CH-5232, Switzerland
| | - Tiberiu Totu
- Particles-Biology Interactions Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland; ETH Zurich, Department of Health Sciences and Technology (D-HEST), CH-8093 Zurich, Switzerland; SIB, Swiss Institute of Bioinformatics, CH-1015 Lausanne, Switzerland
| | - Clement E Blanchet
- European Molecular Biology Laboratory, Hamburg Outstation, Notkestrasse 85, Hamburg 22603, Germany
| | | | | | - Erik Philipp
- CSL Vifor, Flughofstrasse 61, CH-8152 Glattbrugg, Switzerland
| | - Beat Flühmann
- CSL Vifor, Flughofstrasse 61, CH-8152 Glattbrugg, Switzerland
| | - Bruno F B Silva
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland
| | - Antonia Neels
- Center for X-ray Analytics, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, St. Gallen 9014, Switzerland; Department of Chemistry, University of Fribourg, Chemin du Musée 9, 1700 Fribourg, Switzerland.
| | - Peter Wick
- Particles-Biology Interactions Laboratory, Empa, Swiss Federal Laboratories for Materials Science and Technology, Lerchenfeldstrasse 5, 9014 St. Gallen, Switzerland.
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Stevens MC, Taylor NM, Guo X, Hussain H, Mahmoudi N, Cattoz BN, Leung AHM, Dowding PJ, Vincent B, Briscoe WH. Diblock bottlebrush polymer in a non-polar medium: Self-assembly, surface forces, and superlubricity. J Colloid Interface Sci 2024; 658:639-647. [PMID: 38134672 DOI: 10.1016/j.jcis.2023.12.056] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2023] [Revised: 11/08/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023]
Abstract
Whilst bottlebrush polymers have been studied in aqueous media for their conjectured role in biolubrication, surface forces and friction mediated by bottlebrush polymers in non-polar media have not been previously reported. Here, small-angle neutron scattering (SANS) showed that a diblock bottlebrush copolymer (oligoethyleneglycol acrylate/ethylhexyl acrylate; OEGA/EHA) formed spherical core-shell aggregates in n-dodecane (a model oil) in the polymer concentration range 0.1-2.0 wt%, with a radius of gyration Rg ∼ 7 nm, comprising 40-65 polymer molecules per aggregate. The surface force apparatus (SFA) measurements revealed purely repulsive forces between surfaces bearing inhomogeneous polymer layers of thickness L ∼ 13-23 nm, attributed to adsorption of a mixture of polymer chains and surface-deformed micelles. Despite the surface inhomogeneity, the polymer layers could mediate effective lubrication, demonstrating superlubricity with the friction coefficient as low as µ ∼ 0.003. The analysis of velocity-dependence of friction using the Eyring model shed light on the mechanism of the frictional process. That is, the friction mediation was consistent with the presence of nanoscopic surface aggregates, with possible contributions from a gel-like network formed by the polymer chains on the surface. These unprecedented results, correlating self-assembled polymer micelle structure with the surface forces and friction the polymer layers mediate, highlight the potential of polymers with the diblock bottlebrush architecture widespread in biological living systems, in tailoring desired surface interactions in non-polar media.
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Affiliation(s)
- Michael C Stevens
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Nicholas M Taylor
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK; Syngenta, Jealott's Hill International Research Centre, Bracknell RG42 6EY, UK
| | - Xueying Guo
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Hadeel Hussain
- Diamond Light Source Ltd, I07 Beamline, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0DE, UK
| | - Najet Mahmoudi
- ISIS Neutron and Muon Source, Rutherford Appleton Laboratory, Harwell Science and Innovation Campus, Didcot, Oxfordshire OX11 0QX, UK
| | - Beatrice N Cattoz
- Infineum UK Ltd, Milton Hill Business and Technology Centre, Abingdon, Oxon OX13 6BB, UK
| | - Alice H M Leung
- Infineum UK Ltd, Milton Hill Business and Technology Centre, Abingdon, Oxon OX13 6BB, UK
| | - Peter J Dowding
- Infineum UK Ltd, Milton Hill Business and Technology Centre, Abingdon, Oxon OX13 6BB, UK
| | - Brian Vincent
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - Wuge H Briscoe
- School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK.
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Liu Y, Xia Y, Rad AT, Aresh W, Fang JM, Nieh MP. Stable Discoidal Bicelles: Formulation, Characterization, and Functions. Methods Mol Biol 2023; 2622:147-57. [PMID: 36781758 DOI: 10.1007/978-1-0716-2954-3_13] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/15/2023]
Abstract
Bicellar mixtures have been used as alignable membrane substrates under a magnetic field applicable for the structural characterization of membrane-associated proteins. Recently, it has shown that bicelles can serve as nanocarriers to effectively deliver hydrophobic therapeutic molecules to cancer cells with a three- to ten-fold enhancement compared to that of liposomes of a chemically identical composition. In this chapter, detailed preparation protocol, common structural characterization methods, the structural stability, the cellular uptake and a few unique functions of bicellar nanodiscs are discussed.
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Sinha NJ, Guo R, Misra R, Fagan J, Faraone A, Kloxin CJ, Saven JG, Jensen GV, Pochan DJ. Colloid-like solution behavior of computationally designed coiled coil bundlemers. J Colloid Interface Sci 2022; 606:1974-82. [PMID: 34749446 DOI: 10.1016/j.jcis.2021.09.184] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 09/23/2021] [Accepted: 09/28/2021] [Indexed: 01/20/2023]
Abstract
The use of isotropic potential models of simple colloids for describing complex protein-protein interactions is a topic of ongoing debate in the biophysical community. This contention stems from the unavailability of synthetic protein-like model particles that are amenable to systematic experimental characterization. In this article, we test the utility of colloidal theory to capture the solution structure, interactions and dynamics of novel globular protein-mimicking, computationally designed peptide assemblies called bundlemers that are programmable model systems at the intersection of colloids and proteins. Small-angle neutron scattering (SANS) measurements of semi-dilute bundlemer solutions in low and high ionic strength solution indicate that bundlemers interact locally via repulsive interactions that can be described by a screened repulsive potential. We also present neutron spin echo (NSE) spectroscopy results that show high-Q freely-diffusive dynamics of bundlemers. Importantly, formation of clusters due to short-range attractive, inter-bundlemer interactions is observed in SANS even at dilute bundlemer concentrations, which is indicative of the complexity of the bundlemer charged surface. The similarities and differences between bundlemers and simple colloidal as well as complex protein-protein interactions is discussed in detail.
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Brunner M, Garvey CJ, Warr GG, Atkin R. Conformation of poly(ethylene glycol) in aqueous cholinium amino acid hybrid solvents. J Colloid Interface Sci 2021; 602:334-343. [PMID: 34139531 DOI: 10.1016/j.jcis.2021.06.015] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2021] [Revised: 05/20/2021] [Accepted: 06/02/2021] [Indexed: 11/30/2022]
Abstract
HYPOTHESIS Hybrid solvents based on cholinium amino acid ionic liquids ([Ch][AA] ILs) mixed with water are environmentally benign solvents with low toxicity. [Ch][AA] ILs are used in biomass pretreatment processes to dissolve targeted (macro)molecules such as lignin from lingnocellulose. Understanding how [Ch][AA] ILs dissolve polymers is therefore of great interest for the rational design of ILs towards industrial application. Variation of the IL anion and the water concentration are hypothesised to change the solvent properties of [Ch][AA] hybrid solvents. Therefore, we probe the solvent quality of [Ch][AA] aqueous solutions with different anions (glycinate, prolinate and argininate) and water concentration for the simple model solute poly(ethylene glycol) (PEG). EXPERIMENTS Partial phase diagrams were produced to probe the salting-out effect of [Ch][AA] ILs towards PEG (Mw = 38 kDa). Small-angle neutron scattering experiments of deuterated PEG in hydrogenous [Ch][AA] aqueous solutions were performed to determine the polymer radius of gyration at infinite dilution (Rg,0) via Zimm-plots. Polymer concentration dependent apparent Rg values were obtained fitting an excluded volume polymer model onto the scattering data. Blends of hydrogenous and deuterated PEG under zero average contrast conditions were analysed to probe Rg at high polymer concentrations. FINDINGS Hydrogen bond capacity of the anion is key to the salting-out effect of [Ch][AA] ILs on PEG. Rg,0 depends on anion species and water concentration. At IL:water = 1:30 (mole:mole) and 37 °C, cholinium argininate and cholinium glycinate are close to theta solvents while cholinium prolinate and dilute cholinium argininate (IL:water = 1:100) are between theta and good solvents.
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Affiliation(s)
- Manuel Brunner
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia.
| | - Christopher J Garvey
- Lund Institute for Advanced Neutron and X-ray Science, 223 70 Lund, Sweden; Heinz Maier-Leibnitz Zentrum (MLZ), Technische Universität München, Lichtenbergstraße 1, 85748 Garching, Germany.
| | - Gregory G Warr
- School of Chemistry and University of Sydney Nano Institute, The University of Sydney, Sydney, NSW 2006, Australia.
| | - Rob Atkin
- School of Molecular Sciences, The University of Western Australia, 35 Stirling Highway, Perth, WA 6009, Australia.
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Abstract
Small-angle neutron scattering (SANS) provides structural information on biomacromolecules and their complexes in dilute solutions at the nanometer length scale. The overall dimensions, shapes, and interactions can be probed and compared to information obtained by complementary structural biology techniques such as crystallography, NMR, and EM. SANS, in combination with solvent H2O/D2O exchange and/or deuteration, is particularly well suited to probe the internal structure of RNA-protein (RNP) complexes since neutrons are more sensitive than X-rays to the difference in scattering length densities of proteins and RNA, with respect to an aqueous solvent. In this book chapter we provide a practical guide on how to carry out SANS experiments on RNP complexes, as well as possibilities of data analysis and interpretation.
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Affiliation(s)
- Audrone Lapinaite
- Department of Molecular and Cell Biology, University of California, Berkeley, CA, USA
| | - Teresa Carlomagno
- Centre for Biomolecular Drug Research, Leibniz University Hannover, Hannover, Germany.,Helmholtz Centre for Infection Research, Group of Structural Chemistry, Braunschweig, Germany
| | - Frank Gabel
- Univ. Grenoble Alpes, CEA, CNRS, IBS, Grenoble, France.
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Ardyani T, Mohamed A, Bakar SA, Sagisaka M, Umetsu Y, Mamat MH, Ahmad MK, Khalil HPSA, King S, Rogers SE, Eastoe J. Surfactants with aromatic headgroups for optimizing properties of graphene/natural rubber latex composites (NRL): Surfactants with aromatic amine polar heads. J Colloid Interface Sci 2019; 545:184-94. [PMID: 30878784 DOI: 10.1016/j.jcis.2019.03.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 03/04/2019] [Accepted: 03/05/2019] [Indexed: 11/20/2022]
Abstract
HYPOTHESIS The compatibility of surfactants and graphene surfaces can be improved by increasing the number of aromatic groups in the surfactants. Including aniline in the structure may improve the compatibility between surfactant and graphene further still. Surfactants can be modified by incorporating aromatic groups in the hydrophobic chains or hydrophilic headgroups. Therefore, it is of interest to investigate the effects of employing anilinium based surfactants to disperse graphene nanoplatelets (GNPs) in natural rubber latex (NRL) for the fabrication of electrically conductive nanocomposites. EXPERIMENTS New graphene-philic surfactants carrying aromatic moieties in the hydrophilic headgroups and hydrophobic tails were synthesized by swapping the traditional sodium counterion with anilinium. 1H NMR spectroscopy was used to characterize the surfactants. These custom-made surfactants were used to assist the dispersion of GNPs in natural rubber latex matrices for the preparation of conductive nanocomposites. The properties of nanocomposites with the new anilinium surfactants were compared with commercial sodium surfactant sodium dodecylsulfate (SDS), sodium dodecylbenzenesulfonate (SDBS), and the previously synthesized aromatic tri-chain sodium surfactant TC3Ph3 (sodium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate). Structural properties of the nanocomposites were studied using Raman spectroscopy, field emission scanning electron microscopy (FESEM), and high-resolution transmission electron microscopy (HRTEM). Electrical conductivity measurements and Zeta potential measurements were used to assess the relationships between total number of aromatic groups in the surfactant molecular structure and nanocomposite properties. The self-assembly structure of surfactants in aqueous systems and GNP dispersions was assessed using small-angle neutron scattering (SANS). FINDINGS Among these different surfactants, the anilinium version of TC3Ph3 namely TC3Ph3-AN (anilinium 1,5-dioxo-1,5-bis(3-phenylpropoxy)-3-((3phenylpropoxy)carbonyl) pentane-2-sulfonate) was shown to be highly efficient for dispersing GNPs in the NRL matrices, increasing electrical conductivity eleven orders of magnitude higher than the neat rubber latex. Comparisons between the sodium and anilinium surfactants show significant differences in the final properties of the nanocomposites. In general, the strategy of increasing the number of surfactant-borne aromatic groups by incorporating anilinium ions in surfactant headgroups appears to be effective.
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Schlachet I, Trousil J, Rak D, Knudsen KD, Pavlova E, Nyström B, Sosnik A. Chitosan-graft-poly(methyl methacrylate) amphiphilic nanoparticles: Self-association and physicochemical characterization. Carbohydr Polym 2019; 212:412-420. [PMID: 30832875 DOI: 10.1016/j.carbpol.2019.02.022] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2018] [Revised: 02/03/2019] [Accepted: 02/08/2019] [Indexed: 02/09/2023]
Abstract
In this work, we synthesized and characterized the self-assembly behavior of a chitosan-poly(methyl methacrylate) graft copolymer and the properties of the formed nanoparticles by static and dynamic light scattering, small-angle neutron scattering, and transmission electron microscopy. Overall, our results indicate that the hydrophobization of the chitosan side-chain with PMMA leads to a complex array of small unimolecular and/or small-aggregation number "building blocks" that further self-assemble into larger amphiphilic nanoparticles.
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Affiliation(s)
- Inbar Schlachet
- Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion-Israel Institute of Technology, 320003 Haifa, Israel
| | - Jiří Trousil
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského náměstí 2, 162 06 Prague 6, Czechia; Department of Analytical Chemistry, Charles University, Faculty of Science, Hlavova 8, 128 43 Prague 2, Czechia
| | - Dmytro Rak
- Institute of Experimental Physics, Slovak Academy of Sciences, Watsonova 47, 040 01 Košice, Slovakia
| | - Kenneth D Knudsen
- Department of Physics, Institute for Energy Technology, P. O. Box 40, N-2027 Kjeller, Norway
| | - Ewa Pavlova
- Institute of Macromolecular Chemistry, Czech Academy of Sciences, Heyrovského náměstí 2, 162 06 Prague 6, Czechia
| | - Bo Nyström
- Department of Chemistry, University of Oslo, P.O. Box 1033, Blindern, N-0315 Oslo, Norway
| | - Alejandro Sosnik
- Laboratory of Pharmaceutical Nanomaterials Science, Department of Materials Science and Engineering, Technion-Israel Institute of Technology, 320003 Haifa, Israel.
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Abstract
Methods to characterize the nanostructure and molecular organization of aggregates of peptides such as amyloid or amphiphilic peptide assemblies are reviewed. We discuss techniques to characterize conformation and secondary structure including circular and linear dichroism and FTIR and Raman spectroscopies, as well as fluorescence methods to detect aggregation. NMR spectroscopy methods, especially solid-state NMR measurements to probe beta-sheet packing motifs, are also briefly outlined. Also discussed are scattering methods including X-ray diffraction and small-angle scattering techniques including SAXS (small-angle X-ray scattering) and SANS (small-angle neutron scattering) and dynamic light scattering. Imaging methods are direct methods to uncover features of peptide nanostructures, and we provide a summary of electron microscopy and atomic force microscopy techniques. Selected examples are highlighted showing data obtained using these techniques, which provide a powerful suite of methods to probe ordering from the molecular scale to the aggregate superstructure.
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Hayes DG, Ye R, Dunlap RN, Cuneo MJ, Pingali SV, O'Neill HM, Urban VS. Protein extraction into the bicontinuous microemulsion phase of a Water/SDS/pentanol/dodecane winsor-III system: Effect on nanostructure and protein conformation. Colloids Surf B Biointerfaces 2017; 160:144-153. [PMID: 28922633 DOI: 10.1016/j.colsurfb.2017.09.005] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2017] [Revised: 08/22/2017] [Accepted: 09/04/2017] [Indexed: 02/04/2023]
Abstract
Bicontinuous microemulsions (BμEs), consisting of water and oil nanodomains separated by surfactant monolayers of near-zero curvature, are potentially valuable systems for purification and delivery of biomolecules, for hosting multiphasic biochemical reactions, and as templating media for preparing nanomaterials. We formed Winsor-III systems by mixing aqueous protein and sodium dodecyl sulfate (SDS) solutions with dodecane and 1-pentanol (cosurfactant) to efficiently extract proteins into the middle (BμE) phase. Bovine serum albumin (BSA) and cytochrome c partitioned to the BμE phase at 64% and 81% efficiency, respectively, producing highly concentrated protein solutions (32 and 44gL-1, respectively), through release of water and oil from the BμEs. Circular dichroism spectroscopic analysis demonstrated that BSA underwent minor secondary structural changes upon incorporation into BμEs, while the secondary structure of cytochrome c and pepsin underwent major changes. Small-angle x-ray scattering (SAXS) results show that proteins promoted an increase of the interfacial fluidity and surface area per volume for the BμE surfactant monolayers, and that each protein uniquely altered self-assembly in the Winsor-III systems. Cytochrome c partitioned via electrostatic attractions between SDS and the protein's positively-charged groups, residing near the surfactant head groups of BμE monolayers, where it decreased surfactant packing efficiency. BSA partitioned through formation of SDS-BSA complexes via hydrophobic and electrostatic attractive interactions. As the BSA-SDS ratio increased, complexes' partitioning favored BμEs over the oil excess phase due to the increased hydrophilicity of the complexes. This study demonstrates the potential utility of BμEs to purify proteins and prepare nanostructured fluids possessing high protein concentration.
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Affiliation(s)
- Douglas G Hayes
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996-4531 USA.
| | - Ran Ye
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996-4531 USA
| | - Rachel N Dunlap
- Department of Biosystems Engineering and Soil Science, University of Tennessee, Knoxville, TN 37996-4531 USA; Biology & Soft Matter Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6475, USA
| | - Matthew J Cuneo
- Biology & Soft Matter Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6475, USA
| | - Sai Venkatesh Pingali
- Biology & Soft Matter Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6475, USA
| | - Hugh M O'Neill
- Biology & Soft Matter Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6475, USA
| | - Volker S Urban
- Biology & Soft Matter Division, Oak Ridge National Laboratory, P.O. Box 2008, Oak Ridge, TN 37831-6475, USA
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Poznar M, Hołubowicz R, Wojtas M, Gapiński J, Banachowicz E, Patkowski A, Ożyhar A, Dobryszycki P. Structural properties of the intrinsically disordered, multiple calcium ion-binding otolith matrix macromolecule-64 (OMM-64). Biochim Biophys Acta Proteins Proteom 2017; 1865:1358-1371. [PMID: 28866388 DOI: 10.1016/j.bbapap.2017.08.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 08/28/2017] [Indexed: 01/28/2023]
Abstract
Fish otoliths are calcium carbonate biominerals that are involved in hearing and balance sensing. An organic matrix plays a crucial role in their formation. Otolith matrix macromolecule-64 (OMM-64) is a highly acidic, calcium-binding protein (CBP) found in rainbow trout otoliths. It is a component of high-molecular-weight aggregates, which influence the size, shape and polymorph of calcium carbonate in vitro. In this study, a protocol for the efficient expression and purification of OMM-64 was developed. For the first time, the complete structural characteristics of OMM-64 were described. Various biophysical methods were combined to show that OMM-64 occurs as an intrinsically disordered monomer. Under denaturing conditions (pH, temperature) OMM-64 exhibits folding propensity. It was determined that OMM-64 binds approximately 61 calcium ions with millimolar affinity. The folding-unfolding experiments showed that calcium ions induced the collapse of OMM-64. The effect of other counter ions present in trout endolymph on OMM-64 conformational changes was studied. The significance of disordered properties of OMM-64 and the possible function of this protein is discussed.
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Affiliation(s)
- Monika Poznar
- Wrocław University of Science and Technology, Faculty of Chemistry, Department of Biochemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Rafał Hołubowicz
- Wrocław University of Science and Technology, Faculty of Chemistry, Department of Biochemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Magdalena Wojtas
- Wrocław University of Science and Technology, Faculty of Chemistry, Department of Biochemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Jacek Gapiński
- A. Mickiewicz University, Faculty of Physics, Molecular Biophysics Division, Umultowska 85, 61-614, Poznań, Poland
| | - Ewa Banachowicz
- A. Mickiewicz University, Faculty of Physics, Molecular Biophysics Division, Umultowska 85, 61-614, Poznań, Poland
| | - Adam Patkowski
- A. Mickiewicz University, Faculty of Physics, Molecular Biophysics Division, Umultowska 85, 61-614, Poznań, Poland
| | - Andrzej Ożyhar
- Wrocław University of Science and Technology, Faculty of Chemistry, Department of Biochemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland
| | - Piotr Dobryszycki
- Wrocław University of Science and Technology, Faculty of Chemistry, Department of Biochemistry, Wybrzeże Wyspiańskiego 27, 50-370 Wrocław, Poland.
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Ünnep R, Zsiros O, Hörcsik Z, Markó M, Jajoo A, Kohlbrecher J, Garab G, Nagy G. Low-pH induced reversible reorganizations of chloroplast thylakoid membranes - As revealed by small-angle neutron scattering. Biochim Biophys Acta Bioenerg 2017; 1858:360-365. [PMID: 28237493 DOI: 10.1016/j.bbabio.2017.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2016] [Revised: 02/13/2017] [Accepted: 02/15/2017] [Indexed: 12/20/2022]
Abstract
Energization of thylakoid membranes brings about the acidification of the lumenal aqueous phase, which activates important regulatory mechanisms. Earlier Jajoo and coworkers (2014 FEBS Lett. 588:970) have shown that low pH in isolated plant thylakoid membranes induces changes in the excitation energy distribution between the two photosystems. In order to elucidate the structural background of these changes, we used small-angle neutron scattering on thylakoid membranes exposed to low p2H (pD) and show that gradually lowering the p2H from 8.0 to 5.0 causes small but well discernible reversible diminishment of the periodic order and the lamellar repeat distance and an increased mosaicity - similar to the effects elicited by light-induced acidification of the lumen. Our data strongly suggest that thylakoids dynamically respond to the membrane energization and actively participate in different regulatory mechanisms.
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Affiliation(s)
- Renáta Ünnep
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1121 Budapest, Hungary; Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, 5232 Villigen PSI, Switzerland
| | - Ottó Zsiros
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, H-6701 Szeged, Hungary
| | - Zsolt Hörcsik
- College of Nyíregyháza, Institute of Environmental Science, H-4400 Nyíregyháza, Hungary
| | - Márton Markó
- Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1121 Budapest, Hungary
| | - Anjana Jajoo
- School of Life Science, Devi Ahilya University, Khandwa Road, Indore 452 001, India
| | - Joachim Kohlbrecher
- Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, 5232 Villigen PSI, Switzerland
| | - Győző Garab
- Institute of Plant Biology, Biological Research Center, Hungarian Academy of Sciences, POB 521, H-6701 Szeged, Hungary; Department of Physics, Faculty of Science, Ostrava University, Chittussiho 10, CZ-710 0 Ostrava - Slezská Ostrava, Czech Republic.
| | - Gergely Nagy
- Paul Scherrer Institute, Laboratory for Neutron Scattering and Imaging, 5232 Villigen PSI, Switzerland; Wigner Research Centre for Physics, Institute for Solid State Physics and Optics, Hungarian Academy of Sciences, H-1121 Budapest, Hungary.
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