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Ongey EL, Banerjee A. In vitro reconstitution of transition metal transporters. J Biol Chem 2024; 300:107589. [PMID: 39032653 PMCID: PMC11381811 DOI: 10.1016/j.jbc.2024.107589] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2024] [Revised: 06/28/2024] [Accepted: 07/03/2024] [Indexed: 07/23/2024] Open
Abstract
Transition metal ions are critically important across all kingdoms of life. The chemical properties of iron, copper, zinc, manganese, cobalt, and nickel make them very attractive for use as cofactors in metalloenzymes and/or metalloproteins. Their versatile chemistry in aqueous solution enables them to function both as electron donors and acceptors, and thus participate in both reduction and oxidation reactions respectively. Transition metal ions can also function as nonredox multidentate coordination sites that play essential roles in macromolecular structure and function. Malfunction in transition metal transport and homeostasis has been linked to a wide number of human diseases including cancer, diabetes, and neurodegenerative disorders. Transition metal transporters are central players in the physiology of transition metals whereby they move transition metals in and out of cellular compartments. In this review, we provide a comprehensive overview of in vitro reconstitution of the activity of integral membrane transition metal transporters and discuss strategies that have been successfully implemented to overcome the challenges. We also discuss recent advances in our understanding of transition metal transport mechanisms and the techniques that are currently used to decipher the molecular basis of transport activities of these proteins. Deep mechanistic insights into transition metal transport systems will be essential to understand their malfunction in human diseases and target them for potential therapeutic strategies.
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Affiliation(s)
- Elvis L Ongey
- Cell Biology and Neurobiology Branch, National Institutes of Child Health and Human, Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Anirban Banerjee
- Cell Biology and Neurobiology Branch, National Institutes of Child Health and Human, Development, National Institutes of Health, Bethesda, Maryland, USA.
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2
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Pashirova T, Salah-Tazdaït R, Tazdaït D, Masson P. Applications of Microbial Organophosphate-Degrading Enzymes to Detoxification of Organophosphorous Compounds for Medical Countermeasures against Poisoning and Environmental Remediation. Int J Mol Sci 2024; 25:7822. [PMID: 39063063 PMCID: PMC11277490 DOI: 10.3390/ijms25147822] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2024] [Revised: 07/13/2024] [Accepted: 07/15/2024] [Indexed: 07/28/2024] Open
Abstract
Mining of organophosphorous (OPs)-degrading bacterial enzymes in collections of known bacterial strains and in natural biotopes are important research fields that lead to the isolation of novel OP-degrading enzymes. Then, implementation of strategies and methods of protein engineering and nanobiotechnology allow large-scale production of enzymes, displaying improved catalytic properties for medical uses and protection of the environment. For medical applications, the enzyme formulations must be stable in the bloodstream and upon storage and not susceptible to induce iatrogenic effects. This, in particular, includes the nanoencapsulation of bioscavengers of bacterial origin. In the application field of bioremediation, these enzymes play a crucial role in environmental cleanup by initiating the degradation of OPs, such as pesticides, in contaminated environments. In microbial cell configuration, these enzymes can break down chemical bonds of OPs and usually convert them into less toxic metabolites through a biotransformation process or contribute to their complete mineralization. In their purified state, they exhibit higher pollutant degradation efficiencies and the ability to operate under different environmental conditions. Thus, this review provides a clear overview of the current knowledge about applications of OP-reacting enzymes. It presents research works focusing on the use of these enzymes in various bioremediation strategies to mitigate environmental pollution and in medicine as alternative therapeutic means against OP poisoning.
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Affiliation(s)
- Tatiana Pashirova
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia;
- Arbuzov Institute of Organic and Physical Chemistry, FRC Kazan Scientific Center of RAS, Arbuzov Str. 8, 420088 Kazan, Russia
| | - Rym Salah-Tazdaït
- Bioengineering and Process Engineering Laboratory (BIOGEP), National Polytechnic School, 10 Rue des Frères Oudek, El Harrach, Algiers 16200, Algeria; (R.S.-T.); (D.T.)
| | - Djaber Tazdaït
- Bioengineering and Process Engineering Laboratory (BIOGEP), National Polytechnic School, 10 Rue des Frères Oudek, El Harrach, Algiers 16200, Algeria; (R.S.-T.); (D.T.)
- Department of Nature and Life Sciences, University of Algiers, Benyoucef Benkhedda, 2 Rue Didouche Mourad, Algiers 16000, Algeria
| | - Patrick Masson
- Institute of Fundamental Medicine and Biology, Kazan Federal University, 18 Kremlyovskaya St., 420008 Kazan, Russia;
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Veit S, Paweletz LC, Günther Pomorski T. Determination of membrane protein orientation upon liposomal reconstitution down to the single vesicle level. Biol Chem 2023; 404:647-661. [PMID: 36857289 DOI: 10.1515/hsz-2022-0325] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Accepted: 02/07/2023] [Indexed: 03/02/2023]
Abstract
Reconstitution of membrane proteins into liposomal membranes represents a key technique in enabling functional analysis under well-defined conditions. In this review, we provide a brief introduction to selected methods that have been developed to determine membrane protein orientation after reconstitution in liposomes, including approaches based on proteolytic digestion with proteases, site-specific labeling, fluorescence quenching and activity assays. In addition, we briefly highlight new strategies based on single vesicle analysis to address the problem of sample heterogeneity.
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Affiliation(s)
- Sarina Veit
- Department of Molecular Biochemistry , Faculty of Chemistry and Biochemistry , NC 7/174, Ruhr University Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
| | - Laura Charlotte Paweletz
- Department of Molecular Biochemistry , Faculty of Chemistry and Biochemistry , NC 7/174, Ruhr University Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
| | - Thomas Günther Pomorski
- Department of Molecular Biochemistry , Faculty of Chemistry and Biochemistry , NC 7/174, Ruhr University Bochum, Universitätsstraße 150, D-44780 Bochum, Germany
- Department of Plant and Environmental Sciences, University of Copenhagen, Thorvaldsensvej 40, DK-1871, Frederiksberg C, Denmark
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Irwin MJ, Wang X, Cote RH. Reconstitution of Membrane-associated Components of a G-protein Signaling Pathway on Membrane-coated Nanoparticles (Lipobeads). Bio Protoc 2022; 12:e4303. [PMID: 35127993 PMCID: PMC8799665 DOI: 10.21769/bioprotoc.4303] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2021] [Revised: 11/28/2021] [Accepted: 11/30/2021] [Indexed: 11/01/2023] Open
Abstract
G-protein coupled signaling pathways are organized into multi-protein complexes called signalosomes that are located within and on cellular membranes. We describe the use of silica nanoparticles coated with a unilamellar phospholipid bilayer (lipobeads) to reconstitute the activated photoreceptor G-protein α-subunit (Gtα*) with its cognate effector (phosphodiesterase-6; PDE6) for biochemical and structural studies of the activation mechanism regulating this GPCR signaling pathway. Lipobeads are prepared by resuspending dried-down phospholipid mixtures with monodisperse 70 nm silica particles, followed by extrusion through a 100 nm membrane filter. This uniform and supported liposomal preparation is easily sedimented, permitting the separation of soluble from membrane-associated proteins. Upon loading lipobeads with Gtα* and PDE6, we find that activation of PDE6 catalysis by Gtα* occurs much more efficiently than in the absence of membranes. Chemical cross-linking of membrane-confined proteins allows detection of changes in protein-protein interactions, resulting from G-protein activation of PDE6. The advantages of using lipobeads over partially purified membrane preparations or traditional liposomal preparations are generally applicable to the study of other membrane-confined signal transduction pathways.
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Affiliation(s)
- Michael J. Irwin
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Xin Wang
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
| | - Rick H. Cote
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, Durham, NH 03824, USA
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5
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Current problems and future avenues in proteoliposome research. Biochem Soc Trans 2021; 48:1473-1492. [PMID: 32830854 DOI: 10.1042/bst20190966] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2020] [Revised: 07/10/2020] [Accepted: 07/14/2020] [Indexed: 12/11/2022]
Abstract
Membrane proteins (MPs) are the gatekeepers between different biological compartments separated by lipid bilayers. Being receptors, channels, transporters, or primary pumps, they fulfill a wide variety of cellular functions and their importance is reflected in the increasing number of drugs that target MPs. Functional studies of MPs within a native cellular context, however, is difficult due to the innate complexity of the densely packed membranes. Over the past decades, detergent-based extraction and purification of MPs and their reconstitution into lipid mimetic systems has been a very powerful tool to simplify the experimental system. In this review, we focus on proteoliposomes that have become an indispensable experimental system for enzymes with a vectorial function, including many of the here described energy transducing MPs. We first address long standing questions on the difficulty of successful reconstitution and controlled orientation of MPs into liposomes. A special emphasis is given on coreconstitution of several MPs into the same bilayer. Second, we discuss recent progress in the development of fluorescent dyes that offer sensitive detection with high temporal resolution. Finally, we briefly cover the use of giant unilamellar vesicles for the investigation of complex enzymatic cascades, a very promising experimental tool considering our increasing knowledge of the interplay of different cellular components.
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Why Do Tethered-Bilayer Lipid Membranes Suit for Functional Membrane Protein Reincorporation? APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11114876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Membrane proteins (MPs) are essential for cellular functions. Understanding the functions of MPs is crucial as they constitute an important class of drug targets. However, MPs are a challenging class of biomolecules to analyze because they cannot be studied outside their native environment. Their structure, function and activity are highly dependent on the local lipid environment, and these properties are compromised when the protein does not reside in the cell membrane. Mammalian cell membranes are complex and composed of different lipid species. Model membranes have been developed to provide an adequate environment to envisage MP reconstitution. Among them, tethered-Bilayer Lipid Membranes (tBLMs) appear as the best model because they allow the lipid bilayer to be decoupled from the support. Thus, they provide a sufficient aqueous space to envisage the proper accommodation of large extra-membranous domains of MPs, extending outside. Additionally, as the bilayer remains attached to tethers covalently fixed to the solid support, they can be investigated by a wide variety of surface-sensitive analytical techniques. This review provides an overview of the different approaches developed over the last two decades to achieve sophisticated tBLMs, with a more and more complex lipid composition and adapted for functional MP reconstitution.
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Wang X, Clément R, Roger M, Bauzan M, Mazurenko I, Poulpiquet AD, Ilbert M, Lojou E. Bacterial Respiratory Chain Diversity Reveals a Cytochrome c Oxidase Reducing O 2 at Low Overpotentials. J Am Chem Soc 2019; 141:11093-11102. [PMID: 31274287 DOI: 10.1021/jacs.9b03268] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Cytochrome c oxidases (CcOs) are the terminal enzymes in energy-converting chains of microorganisms, where they reduce oxygen into water. Their affinity for O2 makes them attractive biocatalysts for technological devices in which O2 concentration is limited, but the high overpotentials they display on electrodes severely limit their applicative use. Here, the CcO of the acidophilic bacterium Acidithiobacillus ferrooxidans is studied on various carbon materials by direct protein electrochemistry and mediated one with redox mediators either diffusing or co-immobilized at the electrode surface. The entrapment of the CcO in a network of hydrophobic carbon nanofibers permits a direct electrochemical communication between the enzyme and the electrode. We demonstrate that the CcO displays a μM affinity for O2 and reduces O2 at exceptionally high electrode potentials in the range of +700 to +540 mV vs NHE over a pH range of 4-6. The kinetics of interactions between the enzyme and its physiological partners are fully quantified. Based on these results, an electron transfer pathway allowing O2 reduction in the acidic metabolic chain is proposed.
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Affiliation(s)
- Xie Wang
- Aix-Marseille Univ , CNRS, BIP UMR 7281, 31 Chemin Aiguier , CS 70071, 13402 Marseille Cedex 09 , France
| | - Romain Clément
- Aix-Marseille Univ , CNRS, BIP UMR 7281, 31 Chemin Aiguier , CS 70071, 13402 Marseille Cedex 09 , France
| | - Magali Roger
- School of Natural and Environmental Sciences , Newcastle University , Devonshire Building , NE1 7RX , Newcastle upon Tyne , England
| | - Marielle Bauzan
- Aix-Marseille Univ , CNRS, IMM FR 3479, 31 Chemin Aiguier , 13009 Marseille , France
| | - Ievgen Mazurenko
- Aix-Marseille Univ , CNRS, BIP UMR 7281, 31 Chemin Aiguier , CS 70071, 13402 Marseille Cedex 09 , France
| | - Anne de Poulpiquet
- Aix-Marseille Univ , CNRS, BIP UMR 7281, 31 Chemin Aiguier , CS 70071, 13402 Marseille Cedex 09 , France
| | - Marianne Ilbert
- Aix-Marseille Univ , CNRS, BIP UMR 7281, 31 Chemin Aiguier , CS 70071, 13402 Marseille Cedex 09 , France
| | - Elisabeth Lojou
- Aix-Marseille Univ , CNRS, BIP UMR 7281, 31 Chemin Aiguier , CS 70071, 13402 Marseille Cedex 09 , France
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Spherical-supported membranes as platforms for screening against membrane protein targets. Anal Biochem 2018; 549:58-65. [PMID: 29545094 PMCID: PMC5948183 DOI: 10.1016/j.ab.2018.03.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2018] [Revised: 03/09/2018] [Accepted: 03/12/2018] [Indexed: 11/23/2022]
Abstract
Screening assays performed against membrane protein targets (e.g. phage display) are hampered by issues arising from protein expression and purification, protein stability in detergent solutions and epitope concealment by detergent micelles. Here, we have studied a fast and simple method to improve screening against membrane proteins: spherical-supported bilayer lipid membranes (“SSBLM”). SSBLMs can be quickly isolated via low-speed centrifugation and redispersed in liquid solutions while presenting the target protein in a native-like lipid environment. To provide proof-of-concept, SSBLMs embedding the polytopic bacterial nucleoside transporter NupC were assembled on 100- and 200 nm silica particles. To test specific binding of antibodies, NupC was tagged with a poly-histidine epitope in one of its central loops between two transmembrane helices. Fluorescent labelling, small angle X-ray scattering (SAXS) and cryo-electron microscopy (cryo-EM) were used to monitor formation of the SSBLMs. Specific binding of an anti-his antibody and a gold-nitrilotriacetic acid (NTA) conjugate probe was confirmed with ELISAs and cryo-EM. SSBLMs for screening could be made with purified and lipid reconstituted NupC, as well as crude bacterial membrane extracts. We conclude that SSBLMs are a promising new means of presenting membrane protein targets for (biomimetic) antibody screening in a native-like lipid environment.
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Alipour E, Halverson D, McWhirter S, Walker GC. Phospholipid Bilayers: Stability and Encapsulation of Nanoparticles. Annu Rev Phys Chem 2017; 68:261-283. [DOI: 10.1146/annurev-physchem-040215-112634] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Affiliation(s)
- Elnaz Alipour
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada;, , ,
| | - Duncan Halverson
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada;, , ,
| | - Samantha McWhirter
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada;, , ,
| | - Gilbert C. Walker
- Department of Chemistry, University of Toronto, Toronto, Ontario M5S 3H6, Canada;, , ,
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Geiss AF, Bliem C, Frank P, Reiner-Rozman C, Kewney J, Boersch M, Naumann RLC. Proteo-lipobeads to encapsulate cytochrome c oxidase from Paracoccus denitrificans. J Colloid Interface Sci 2017; 500:119-125. [PMID: 28407595 DOI: 10.1016/j.jcis.2017.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2017] [Revised: 04/01/2017] [Accepted: 04/04/2017] [Indexed: 01/08/2023]
Abstract
Proteo-lipobeads (PLBs) are investigated as cell-free model systems to encapsulate membrane proteins such as ion channels and transporters. PLBs are based on nickel nitrile tri-acetic acid (Ni-NTA)-functionalized agarose beads, onto which membrane proteins (MP) are bound via histidine(his)-tag. Composite beads thus obtained (subsequently called proteobeads) are dialyzed in the presence of lipid micelles to form PLBs. As an example we employed cytochrome c oxidase from P. denitrificans with a his-tag fused to the C-terminus of subunitI. In this orientation the P side of CcO faces the outside of the PLB and hence protons are released to the outer aqueous phase, when electron transfer is initiated by light excitation of Ru complexes. Proton release kinetics was probed by fluorescence microscopy using the pH-sensitive sensor molecule fluorescein DHPE inserted into the lipid layer. In order to monitor the generation of membrane potentials we performed a FLIPR assay on the CcO embedded in PLBs using the FRET pair CC2-DMPE/DiSBAC2(3). The combined results show that PLBs can be used as a model system designed to quantify the kinetic parameters of membrane proteins. In addition, the FLIPR assay demonstrates the feasibility of PLBs for high throughput screening applications.
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Affiliation(s)
- Andreas F Geiss
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria; University of Natural Resources and Life Sciences, Gregor-Mendel-Straβe 33, 1180 Wien, Austria.
| | - Christina Bliem
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria; Center of Electrochemical Surface Technology, CEST, Viktor-Kaplan-Str. 2, 2700 Wiener Neustadt, Austria.
| | - Pinar Frank
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria.
| | - Ciril Reiner-Rozman
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria; Center of Electrochemical Surface Technology, CEST, Viktor-Kaplan-Str. 2, 2700 Wiener Neustadt, Austria.
| | - Justin Kewney
- Telford Pavilion, Todd Campus, West of Scotland Science Park, Glasgow G20 OXA, Scotland, UK.
| | - Michael Boersch
- Single-Molecule Microscopy Group, Jena University Hospital, Nonnenplan 2-4, 07743 Jena, Germany.
| | - Renate L C Naumann
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria.
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Geiss AF, Khandelwal R, Baurecht D, Bliem C, Reiner-Rozman C, Boersch M, Ullmann GM, Loew LM, Naumann RLC. pH and Potential Transients of the bc 1 Complex Co-Reconstituted in Proteo-Lipobeads with the Reaction Center from Rb. sphaeroides. J Phys Chem B 2017; 121:143-152. [PMID: 27992230 DOI: 10.1021/acs.jpcb.6b11116] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
His-tag technology is employed to bind membrane proteins, such as the bc1 complex and the reaction center (RC) from Rhodobacter sphaeroides, to spherical as well as planar surfaces in a strict orientation. Subsequently, the spherical and planar surfaces are subjected to in situ dialysis to form proteo-lipobeads (PLBs) and protein-tethered bilayer membranes, respectively. PLBs based on Ni-nitrileotriacetic acid-functionalized agarose beads that have diameters ranging from 50 to 150 μm are used to assess proton release and membrane potential parameters by confocal laser-scanning microscopy. The pH and potential transients are thus obtained from bc1 activated by the RC. To assess the turnover of bc1 excited by the RC in a similar setting, we used the planar surface of an attenuated total reflection crystal modified with a thin gold layer to carry out time-resolved surface-enhanced IR absorption spectroscopy triggered by flash lamp excitation. The experiments suggest that both proteins interact in a cyclic manner in both environments. The activity of the proteins seems to be preserved in the same manner as that in chromatophores or reconstituted in liposomes.
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Affiliation(s)
- Andreas F Geiss
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT , Donau-City Street 1, 1220 Vienna, Austria.,University of Natural Resources and Life Sciences , Gregor-Mendel-Straße 33, 1180 Wien, Austria
| | - Raghav Khandelwal
- Indian Institute of Technology Kanpur , Kalyanpur, Kanpur, Uttar Pradesh 208016, India
| | - Dieter Baurecht
- Faculty of Chemistry, Department of Physical Chemistry, University of Vienna , Währinger Straße 42, 1090 Vienna, Austria
| | - Christina Bliem
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT , Donau-City Street 1, 1220 Vienna, Austria.,Center of Electrochemical Surface Technology, CEST , Viktor-Kaplan-Str. 2, 2700 Wiener Neustadt, Austria
| | - Ciril Reiner-Rozman
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT , Donau-City Street 1, 1220 Vienna, Austria.,Center of Electrochemical Surface Technology, CEST , Viktor-Kaplan-Str. 2, 2700 Wiener Neustadt, Austria
| | - Michael Boersch
- Single-Molecule Microscopy Group, Jena University Hospital , Nonnenplan 2-4, 07743 Jena, Germany
| | - G Matthias Ullmann
- Computational Biochemistry Group, University of Bayreuth , Universitätsstraße 30, NWI, 95447 Bayreuth, Germany
| | - Leslie M Loew
- R. D. Berlin Center for Cell Analysis and Modeling, University of Connecticut Health Center , Farmington, Connecticut 06030, United States
| | - Renate L C Naumann
- Biosensor Technologies, Austrian Institute of Technology GmbH, AIT , Donau-City Street 1, 1220 Vienna, Austria
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Naumann RLC, Geiss AF, Steininger C, Knoll W. Biomimetic Membranes for Multi-Redox Center Proteins. Int J Mol Sci 2016; 17:330. [PMID: 26950120 PMCID: PMC4813192 DOI: 10.3390/ijms17030330] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2015] [Revised: 11/27/2015] [Accepted: 02/17/2016] [Indexed: 11/22/2022] Open
Abstract
His-tag technology was applied for biosensing purposes involving multi-redox center proteins (MRPs). An overview is presented on various surfaces ranging from flat to spherical and modified with linker molecules with nitrile-tri-acetic acid (NTA) terminal groups to bind his-tagged proteins in a strict orientation. The bound proteins are submitted to in situ dialysis in the presence of lipid micelles to form a so-called protein-tethered bilayer lipid membrane (ptBLM). MRPs, such as the cytochrome c oxidase (CcO) from R. sphaeroides and P. denitrificans, as well as photosynthetic reactions centers (RCs) from R. sphaeroides, were thus investigated. Electrochemical and surface-sensitive optical techniques, such as surface plasmon resonance, surface plasmon-enhanced fluorescence, surface-enhanced infrared absorption spectroscopy (SEIRAS) and surface-enhanced resonance Raman spectroscopy (SERRS), were employed in the case of the ptBLM structure on flat surfaces. Spherical particles ranging from µm size agarose gel beads to nm size nanoparticles modified in a similar fashion were called proteo-lipobeads (PLBs). The particles were investigated by laser-scanning confocal fluorescence microscopy (LSM) and UV/Vis spectroscopy. Electron and proton transfer through the proteins were demonstrated to take place, which was strongly affected by the membrane potential. MRPs can thus be used for biosensing purposes under quasi-physiological conditions.
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Affiliation(s)
- Renate L C Naumann
- Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria.
| | - Andreas F Geiss
- Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria.
| | - Christoph Steininger
- Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria.
| | - Wolfgang Knoll
- Austrian Institute of Technology GmbH, AIT, Donau-City-Str. 1, 1220 Vienna, Austria.
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Grossutti M, Seenath R, Lipkowski J. Infrared and Fluorescence Spectroscopic Investigations of the Acyl Surface Modification of Hydrogel Beads for the Deposition of a Phospholipid Coating. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2015; 31:11598-11604. [PMID: 26429738 DOI: 10.1021/acs.langmuir.5b02813] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The scaffolded vesicle has been employed as an alternative means of developing natural model membranes and envisioned as a potential nutraceutical transporter. Furthering the research of the scaffolded vesicle system, a nucleophilic substitution reaction was implemented to form an ester linkage between palmitate and terminal hydroxyl groups of dextran in order to hydrophobically modify the hydrogel scaffold. An average tilt angle of 38° of the hydrophobic palmitate modifying layer on the surface of the hydrogel was determined from dichroic ratios obtained from infrared spectra collected in the attenuated total reflection (ATR) configuration. ATR-IR studies of the DMPC-coated acylated hydrogel demonstrated that the hydrocarbon chains of the DMPC coating was similar to those of the DMPC bilayers and that the underlying palmitate layer had a negligible effect on the average tilt angle (26°) of the DMPC coating. The permeability of this acylated hydrogel was investigated with fluorescence spectroscopy and the terbium/dipicolinic acid assay. The hydrophobic modification on the surface of the hydrogel bead allowed for an efficient deposition of a DMPC layer that served as an impermeable barrier to terbium efflux. About 72% of DMPC-coated acylated hydrogel beads showed ideal barrier properties. The remaining 28% were leaking, but the half-life of terbium efflux of the DMPC-coated acylated hydrogel was increasing, and the total amount of leaked terbium was decreasing with the incubation time. The half-life time and the retention were considered a marked improvement relative to past scaffolded vesicle preparations. The process of acylating hydrogel beads for efficient DMPC deposition has been identified as another viable method for controlling the permeability of the scaffolded vesicle.
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Affiliation(s)
- Michael Grossutti
- Department of Chemistry, University of Guelph , Guelph, ON, Canada N1G 2W1
| | - Ryan Seenath
- Department of Chemistry, University of Guelph , Guelph, ON, Canada N1G 2W1
| | - Jacek Lipkowski
- Department of Chemistry, University of Guelph , Guelph, ON, Canada N1G 2W1
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