1
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Nguyen ATP, Weigle AT, Shukla D. Functional regulation of aquaporin dynamics by lipid bilayer composition. Nat Commun 2024; 15:1848. [PMID: 38418487 PMCID: PMC10901782 DOI: 10.1038/s41467-024-46027-y] [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: 07/21/2023] [Accepted: 02/12/2024] [Indexed: 03/01/2024] Open
Abstract
With the diversity of lipid-protein interactions, any observed membrane protein dynamics or functions directly depend on the lipid bilayer selection. However, the implications of lipid bilayer choice are seldom considered unless characteristic lipid-protein interactions have been previously reported. Using molecular dynamics simulation, we characterize the effects of membrane embedding on plant aquaporin SoPIP2;1, which has no reported high-affinity lipid interactions. The regulatory impacts of a realistic lipid bilayer, and nine different homogeneous bilayers, on varying SoPIP2;1 dynamics are examined. We demonstrate that SoPIP2;1's structure, thermodynamics, kinetics, and water transport are altered as a function of each membrane construct's ensemble properties. Notably, the realistic bilayer provides stabilization of non-functional SoPIP2;1 metastable states. Hydrophobic mismatch and lipid order parameter calculations further explain how lipid ensemble properties manipulate SoPIP2;1 behavior. Our results illustrate the importance of careful bilayer selection when studying membrane proteins. To this end, we advise cautionary measures when performing membrane protein molecular dynamics simulations.
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Affiliation(s)
- Anh T P Nguyen
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Austin T Weigle
- Department of Chemistry, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA
| | - Diwakar Shukla
- Department of Chemical and Biomolecular Engineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
- Center for Biophysics and Quantitative Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
- Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
- Department of Plant Biology, University of Illinois Urbana-Champaign, Urbana, IL, 61801, USA.
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2
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Beratto-Ramos A, Dagnino-Leone J, Martínez-Oyanedel J, Fernández M, Aranda M, Bórquez R. Optimization of detergents in solubilization and reconstitution of Aquaporin Z: A structural approach. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184101. [PMID: 36535340 DOI: 10.1016/j.bbamem.2022.184101] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2022] [Revised: 12/03/2022] [Accepted: 12/12/2022] [Indexed: 12/23/2022]
Abstract
BACKGROUND The exceptional capacities of aquaporins in terms of water permeation and selectivity have made them an interesting system for membrane applications. Despite the multiple attempts for immobilizing the aquaporins over a porous substrate, there is a lack of studies related to the purification and reconstitution steps, principally associated with the use of detergents in solubilization and destabilization steps. This study analyzed the effect of detergents in Aquaporin Z solubilization, considering the purity and structural homogeneity of the protein. METHODS The extraction process was optimized by the addition of detergent at the sonication step, which enabled the omission of the ultracentrifugation and resuspension steps. Two detergents, Triton X-100, and octyl-glucoside were also evaluated. Destabilization mediated by detergents was used as reconstitution method. Saturation and solubilization points were defined by detergent concentration and both, liposomes and proteoliposomes, were analyzed by size distribution and permeability assays. Detergent removal with Bio-beads was also analyzed. RESULTS Octyl glucoside ensures structural stability and homogeneity of Aquaporin Z. However, high concentrations of detergents induce the presence of defects in proteoliposomes. While saturated liposomes create homogeneous and functional structures, solubilized liposomes get affected by a reassembly process, creating vesicle defects with anomalous permeability profiles. CONCLUSIONS Detergent concentration affects the structural conformation of proteoliposomes in the reconstitution process. GENERAL SIGNIFICANCE Since the destabilization process is dependent on vesicle, detergent, and buffer composition, optimization of this process should be mandatory for further studies. All these considerations will allow achieving the potential of Aquaporins and any other integral membrane protein in their applications for industrial purposes.
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Affiliation(s)
| | | | - José Martínez-Oyanedel
- Departamento de Bioquímica y Biología Molecular, Facultad de Ciencias Biológicas, Universidad de Concepción, Chile
| | - Marcos Fernández
- Departamento de Farmacia, Facultad de Farmacia, Universidad de Concepción, Chile
| | - Mario Aranda
- Facultad de Química y de Farmacia, Pontificia Universidad Católica de Chile, Chile
| | - Rodrigo Bórquez
- Department of Chemical Engineering, Universidad de Concepción, Chile.
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3
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Iwabuchi S, Nomura SIM, Sato Y. Surfactant-Assisted Purification of Hydrophobic DNA Nanostructures. Chembiochem 2023; 24:e202200568. [PMID: 36470849 DOI: 10.1002/cbic.202200568] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 12/04/2022] [Accepted: 12/05/2022] [Indexed: 12/12/2022]
Abstract
Purification of functional DNA nanostructures is an essential step in achieving intended functions because misfolded structures and the remaining free DNA strands in a solution can interact and affect their behavior. However, due to hydrophobicity-mediated aggregation, it is difficult to purify DNA nanostructures modified with hydrophobic molecules by conventional methods. Herein, we report the purification of cholesterol-modified DNA nanostructures by using a novel surfactant-assisted gel extraction. The addition of sodium cholate (SC) to the sample solution before structure folding prevented aggregation; this was confirmed by gel electrophoresis. We also found that adding sodium dodecyl sulfate (SDS) to the sample inhibited structural folding. The cholesterol-modified DNA nanostructures prepared with SC were successfully purified by gel extraction, and their ability to bind to the lipid membrane surfaces was maintained. This method will facilitate the purification of DNA nanostructures modified with hydrophobic molecules and expand their applicability in the construction of artificial cell-like systems.
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Affiliation(s)
- Shoji Iwabuchi
- Department of Robotics, Tohoku University, 6-6-01 Aramaki Aoba-ku, Sendai, 980-0845, Japan
| | - Shin-Ichiro M Nomura
- Department of Robotics, Tohoku University, 6-6-01 Aramaki Aoba-ku, Sendai, 980-0845, Japan
| | - Yusuke Sato
- Department of Intelligent and Control Systems, Kyushu Institute of Technology, 680-4 kawazu, lizuka, 820-8502, Japan
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Optimization of Aquaporin Loading for Performance Enhancement of Aquaporin-Based Biomimetic Thin-Film Composite Membranes. MEMBRANES 2021; 12:membranes12010032. [PMID: 35054558 PMCID: PMC8777877 DOI: 10.3390/membranes12010032] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 12/22/2021] [Accepted: 12/24/2021] [Indexed: 11/17/2022]
Abstract
The aquaporin-based biomimetic thin-film composite membrane (ABM-TFC) has demonstrated superior separation performance and achieved successful commercialization. The larger-scale production of the ABM membrane requires an appropriate balance between the performance and manufacturing cost. This study has systematically investigated the effects of proteoliposome concentration, protein-to-lipid ratio, as well as the additive on the separation performance of ABM for the purpose of finding the optimal preparation conditions for the ABM from the perspective of industrial production. Although increasing the proteoliposome concentration or protein-to-lipid ratio within a certain range could significantly enhance the water permeability of ABMs by increasing the loading of aquaporins in the selective layer, the enhancement effect was marginal or even compromised beyond an optimal point. Alternatively, adding cholesterol in the proteoliposome could further enhance the water flux of the ABM membrane, with minor effects on the salt rejection. The optimized ABM not only achieved a nearly doubled water flux with unchanged salt rejection compared to the control, but also demonstrated satisfactory filtration stability within a wide range of operation temperatures. This study provides a practical strategy for the optimization of ABM-TFC membranes to fit within the scheme of industrial-scale production.
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5
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Photophysical Properties of BADAN Revealed in the Study of GGBP Structural Transitions. Int J Mol Sci 2021; 22:ijms222011113. [PMID: 34681772 PMCID: PMC8540541 DOI: 10.3390/ijms222011113] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 10/06/2021] [Accepted: 10/09/2021] [Indexed: 01/14/2023] Open
Abstract
The fluorescent dye BADAN (6-bromoacetyl-2-dimetylaminonaphtalene) is widely used in various fields of life sciences, however, the photophysical properties of BADAN are not fully understood. The study of the spectral properties of BADAN attached to a number of mutant forms of GGBP, as well as changes in its spectral characteristics during structural changes in proteins, allowed to shed light on the photophysical properties of BADAN. It was shown that spectral properties of BADAN are determined by at least one non-fluorescent and two fluorescent isomers with overlapping absorbing bands. It was found that BADAN fluorescence is determined by the unsolvated "PICT" (planar intramolecular charge transfer state) and solvated "TICT" (twisted intramolecular charge transfer state) excited states. While "TICT" state can be formed both as a result of the "PICT" state solvation and as a result of light absorption by the solvated ground state of the dye. BADAN fluorescence linked to GGBP/H152C apoform is quenched by Trp 183, but this effect is inhibited by glucose intercalation. New details of the changes in the spectral characteristics of BADAN during the unfolding of the protein apo and holoforms have been obtained.
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6
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Liang Z, Yun Y, Wang M, Liu G, Lu P, Yang W, Li C. Performance evaluation of interfacial polymerisation-fabricated aquaporin-based biomimetic membranes in forward osmosis. RSC Adv 2019; 9:10715-10726. [PMID: 35515303 PMCID: PMC9062497 DOI: 10.1039/c9ra00787c] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2019] [Revised: 06/18/2019] [Accepted: 03/22/2019] [Indexed: 12/24/2022] Open
Abstract
Aquaporins play a promising role in the fabrication of high-performance biomimetic membranes. Interfacial polymerisation is a promising strategy for synthesizing aquaporin-based membranes. In this study, robust and high-performance aquaporin-based biomimetic membranes were successfully fabricated by interfacial polymerisation, and the membrane separation performance and interfacial polymerisation method were systematically evaluated. The effects of modification methods on the performance of aquaporins-based biomimetic membranes, including sodium hypochlorite and thermal post-treatment, protein-to-lipid ratio, liposome concentration and the addition arrangement of aquaporins were also investigated. Morphological observation suggested that the introduced proteoliposomes were completely embedded in the polyamide layer and that their spherical shape was preserved. Sodium hypochlorite post-treatment and thermal treatment were beneficial in improving the water flux and salt rejection of the resultant membrane without sacrificing the aquaporin activity. The biomimetic membranes had a high water flux and salt rejection, which were almost twice that of the control membranes, after aquaporin-based proteoliposomes were incorporated with an appropriated protein-to-lipid ratio and liposome concentration. The addition arrangement of aquaporins during the interfacial polymerisation procedure significantly influence the obtained membrane's structure. Lastly, this article introduces valuable and systematic research on interfacial polymerisation fabricated aquaporin-based biomimetic membranes with outstanding separation performance. Aquaporins play a promising role in the fabrication of high-performance biomimetic membranes.![]()
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Affiliation(s)
- Zhixia Liang
- School of Environmental Science and Engineering
- Beijing Forestry University
- Beijing 100083
- China
| | - Yanbin Yun
- School of Environmental Science and Engineering
- Beijing Forestry University
- Beijing 100083
- China
| | - Manxiang Wang
- Center for Energy Storage Research
- Green City Research Institute
- Korea Institute of Science and Technology (KIST)
- Seoul 02792
- Republic of Korea
| | - Guicheng Liu
- Department of Physics
- Dongguk University
- Seoul 04620
- Republic of Korea
| | - Peng Lu
- College of Material Science and Chemical Engineering
- Ningbo University
- Zhejiang 315211
- China
| | - Woochul Yang
- Department of Physics
- Dongguk University
- Seoul 04620
- Republic of Korea
| | - Chunli Li
- College of Material Science and Chemical Engineering
- Ningbo University
- Zhejiang 315211
- China
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7
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Abdelrasoul A, Doan H, Lohi A, Cheng CH. Aquaporin-Based Biomimetic and Bioinspired Membranes for New Frontiers in Sustainable Water Treatment Technology: Approaches and Challenges. POLYMER SCIENCE SERIES A 2018. [DOI: 10.1134/s0965545x18040016] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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8
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Li X, Chou S, Wang R, Shi L, Fang W, Chaitra G, Tang CY, Torres J, Hu X, Fane AG. Nature gives the best solution for desalination: Aquaporin-based hollow fiber composite membrane with superior performance. J Memb Sci 2015. [DOI: 10.1016/j.memsci.2015.07.040] [Citation(s) in RCA: 113] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
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9
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Habel J, Hansen M, Kynde S, Larsen N, Midtgaard SR, Jensen GV, Bomholt J, Ogbonna A, Almdal K, Schulz A, Hélix-Nielsen C. Aquaporin-Based Biomimetic Polymeric Membranes: Approaches and Challenges. MEMBRANES 2015; 5:307-51. [PMID: 26264033 PMCID: PMC4584284 DOI: 10.3390/membranes5030307] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/08/2015] [Accepted: 07/22/2015] [Indexed: 12/12/2022]
Abstract
In recent years, aquaporin biomimetic membranes (ABMs) for water separation have gained considerable interest. Although the first ABMs are commercially available, there are still many challenges associated with further ABM development. Here, we discuss the interplay of the main components of ABMs: aquaporin proteins (AQPs), block copolymers for AQP reconstitution, and polymer-based supporting structures. First, we briefly cover challenges and review recent developments in understanding the interplay between AQP and block copolymers. Second, we review some experimental characterization methods for investigating AQP incorporation including freeze-fracture transmission electron microscopy, fluorescence correlation spectroscopy, stopped-flow light scattering, and small-angle X-ray scattering. Third, we focus on recent efforts in embedding reconstituted AQPs in membrane designs that are based on conventional thin film interfacial polymerization techniques. Finally, we describe some new developments in interfacial polymerization using polyhedral oligomeric silsesquioxane cages for increasing the physical and chemical durability of thin film composite membranes.
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Affiliation(s)
- Joachim Habel
- Technical University of Denmark, Department of Environmental Engineering, Miljøvej, Building 113, 2800 Kgs. Lyngby, Denmark.
- Aquaporin A/S, Ole Maaløes Vej 3, 2200 Copenhagen, Denmark.
| | - Michael Hansen
- University of Copenhagen, Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark.
| | - Søren Kynde
- University of Copenhagen, Copenhagen Biocenter, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark.
| | - Nanna Larsen
- University of Copenhagen, Niels Bohr Institute, Hans Christian Ørsted building D, Universitetsparken, 5, 2100 Copenhagen, Denmark.
| | - Søren Roi Midtgaard
- University of Copenhagen, Copenhagen Biocenter, Ole Maaløes Vej 5, 2200 Copenhagen, Denmark.
| | | | - Julie Bomholt
- Aquaporin A/S, Ole Maaløes Vej 3, 2200 Copenhagen, Denmark.
| | - Anayo Ogbonna
- Aquaporin A/S, Ole Maaløes Vej 3, 2200 Copenhagen, Denmark.
| | - Kristoffer Almdal
- Technical University of Denmark, Department of Micro- and Nanotechnology, Produktionstorvet, Building 423, 2800 Kgs. Lyngby.
| | - Alexander Schulz
- University of Copenhagen, Department of Plant and Environmental Sciences, Thorvaldsensvej 40, 1871 Frederiksberg, Denmark.
| | - Claus Hélix-Nielsen
- Technical University of Denmark, Department of Environmental Engineering, Miljøvej, Building 113, 2800 Kgs. Lyngby, Denmark.
- Aquaporin A/S, Ole Maaløes Vej 3, 2200 Copenhagen, Denmark.
- University of Maribor, Laboratory for Water Biophysics and Membrane Processes, Faculty of Chemistry and Chemical Engineering, Smetanova ulica 17, 2000 Maribor, Slovenia.
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10
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Fonin A, Kuznetsova I, Turoverov K. Spectral properties of BADAN in solutions with different polarities. J Mol Struct 2015. [DOI: 10.1016/j.molstruc.2015.01.038] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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11
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Folding energetics and oligomerization of polytopic α-helical transmembrane proteins. Arch Biochem Biophys 2014; 564:281-96. [DOI: 10.1016/j.abb.2014.07.017] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2014] [Revised: 06/26/2014] [Accepted: 07/14/2014] [Indexed: 01/06/2023]
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12
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Klein N, Neumann J, O'Neil JD, Schneider D. Folding and stability of the aquaglyceroporin GlpF: Implications for human aqua(glycero)porin diseases. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2014; 1848:622-33. [PMID: 25462169 DOI: 10.1016/j.bbamem.2014.11.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/12/2014] [Revised: 11/12/2014] [Accepted: 11/14/2014] [Indexed: 01/22/2023]
Abstract
Aquaporins are highly selective polytopic transmembrane channel proteins that facilitate the permeation of water across cellular membranes in a large diversity of organisms. Defects in aquaporin function are associated with common diseases, such as nephrogenic diabetes insipidus, congenital cataract and certain types of cancer. In general, aquaporins have a highly conserved structure; from prokaryotes to humans. The conserved structure, together with structural dynamics and the structural framework for substrate selectivity is discussed. The folding pathway of aquaporins has been a topic of several studies in recent years. These studies revealed that a conserved protein structure can be reached by following different folding pathways. Based on the available data, we suggest a complex folding pathway for aquaporins, starting from the insertion of individual helices up to the formation of the tetrameric aquaporin structure. The consequences of some known mutations in human aquaporin-encoding genes, which most likely affect the folding and stability of human aquaporins, are discussed.
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Affiliation(s)
- Noreen Klein
- Department of Pharmacy and Biochemistry, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - Jennifer Neumann
- Department of Pharmacy and Biochemistry, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany
| | - Joe D O'Neil
- Department of Chemistry, University of Manitoba, Winnipeg, Manitoba R3T 2N2, Canada
| | - Dirk Schneider
- Department of Pharmacy and Biochemistry, Johannes Gutenberg-University Mainz, 55128 Mainz, Germany.
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13
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14
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Zhao Y, Li X. Detecting the micellization of anionic surfactants by a colorimetric and fluorescent probe based on electrostatic attraction. Colloid Polym Sci 2014. [DOI: 10.1007/s00396-014-3209-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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15
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Kong X, Li Z, Lu D, Liu Z, Wu J. Multiscale simulation of surfactant–aquaporin complex formation and water permeability. RSC Adv 2014. [DOI: 10.1039/c4ra03759f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
Abstract
Molecular dynamics simulation reveals distinctive roles of electrostatic and hydrophobic interactions in surfactant (SDS)–protein (AqpZ) complex formation and functionality.
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Affiliation(s)
- Xian Kong
- Department of Chemical Engineering
- Tsinghua University
- Beijing, China
- Department of Chemical & Environmental Engineering
- University of California
| | - Zhixian Li
- Department of Chemical Engineering
- Tsinghua University
- Beijing, China
| | - Diannan Lu
- Department of Chemical Engineering
- Tsinghua University
- Beijing, China
| | - Zheng Liu
- Department of Chemical Engineering
- Tsinghua University
- Beijing, China
| | - Jianzhong Wu
- Department of Chemical & Environmental Engineering
- University of California
- Riverside, USA
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16
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Zhao Y, Vararattanavech A, Li X, Hélixnielsen C, Vissing T, Torres J, Wang R, Fane AG, Tang CY. Effects of proteoliposome composition and draw solution types on separation performance of aquaporin-based proteoliposomes: implications for seawater desalination using aquaporin-based biomimetic membranes. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2013; 47:1496-1503. [PMID: 23311686 DOI: 10.1021/es304306t] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Aquaporins are a large family of water transport proteins in cell membranes. Their high water permeability and solute rejection make them potential building blocks for high-performance biomimetic membranes for desalination. In the current study, proteoliposomes were prepared using AquaporinZ from Escherichia coli cells, and their separation properties were characterized by stopped-flow measurements. The current study systematically investigated the effect of proteoliposome composition (lipid type, protein-to-lipid ratio (PLR), and the addition of cholesterol) on water permeability and NaCl retention. Among the various lipids investigated, 1,2-dioleoyl-sn-glycero-3-phosphocholine (DOPC)-based proteoliposomes were found to have excellent osmotic water permeability and NaCl reflection coefficient values. Increasing the PLR of DOPC proteoliposomes up to 1:200 increased their osmotic water permeability. However, further increase in the PLR reduced the osmotic water permeability probably due to the occurrence of defects in the proteoliposomes, whereas the addition of cholesterol improved their osmotic water permeation likely due to defects sealing. The current study also investigated the effect of major dissolved ions in seawater (e.g., Mg(2+) and SO(4)(2-)) on the stability of proteoliposomes, and design criteria for aquaporin-based biomimetic membranes are proposed in the context of desalination.
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Affiliation(s)
- Yang Zhao
- Singapore Membrane Technology Centre, Nanyang Technological University, Singapore 639798
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17
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Synthesis of robust and high-performance aquaporin-based biomimetic membranes by interfacial polymerization-membrane preparation and RO performance characterization. J Memb Sci 2012. [DOI: 10.1016/j.memsci.2012.08.039] [Citation(s) in RCA: 159] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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18
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Hansen JS, Vararattanavech A, Vissing T, Torres J, Emnéus J, Hélix-Nielsen C. Formation of giant protein vesicles by a lipid cosolvent method. Chembiochem 2011; 12:2856-62. [PMID: 22069223 DOI: 10.1002/cbic.201100537] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2011] [Indexed: 12/18/2022]
Abstract
This paper describes a method to create giant protein vesicles (GPVs) of ≥10 μm by solvent-driven fusion of large vesicles (0.1-0.2 μm) with reconstituted membrane proteins. We found that formation of GPVs proceeded from rotational mixing of protein-reconstituted large unilamellar vesicles (LUVs) with a lipid-containing solvent phase. We made GPVs by using n-decane and squalene as solvents, and applied generalized polarization (GP) imaging to monitor the polarity around the protein transmembrane region of aquaporins labeled with the polarity-sensitive probe Badan. Specifically, we created GPVs of spinach SoPIP2;1 and E. coli AqpZ aquaporins. Our findings show that hydrophobic interactions within the bilayer of formed GPVs are influenced not only by the solvent partitioning propensity, but also by lipid composition and membrane protein isoform.
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Affiliation(s)
- Jesper S Hansen
- Research Department, Aquaporin A/S, Ole Maaloes Vej 3, 2200 Copenhagen, Denmark.
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19
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An epifluorescence microscopy method for generalized polarization imaging. Biochem Biophys Res Commun 2011; 415:686-90. [PMID: 22079294 DOI: 10.1016/j.bbrc.2011.10.138] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2011] [Accepted: 10/28/2011] [Indexed: 12/17/2022]
Abstract
Generalized polarization (GP) microscopy represents an excellent tool to study lipid-lipid and lipid-protein interactions in situ and in vitro. Here, we present an efficient and cost effective method to perform GP microscopy using a standard light-emitting diode (LED) epifluorescence microscope equipped with a digital color camera.
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20
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Veerappan A, Cymer F, Klein N, Schneider D. The Tetrameric α-Helical Membrane Protein GlpF Unfolds via a Dimeric Folding Intermediate. Biochemistry 2011; 50:10223-30. [DOI: 10.1021/bi201266m] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Anbazhagan Veerappan
- Institut für Pharmazie
und Biochemie, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, 55128 Mainz, Germany
- Institut für Biochemie
und Molekularbiologie, ZBMZ, Albert-Ludwigs-Universität, Stefan-Meier-Strasse 17, 79104 Freiburg, Germany
| | - Florian Cymer
- Institut für Pharmazie
und Biochemie, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, 55128 Mainz, Germany
- Institut für Biochemie
und Molekularbiologie, ZBMZ, Albert-Ludwigs-Universität, Stefan-Meier-Strasse 17, 79104 Freiburg, Germany
| | - Noreen Klein
- Institut für Pharmazie
und Biochemie, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, 55128 Mainz, Germany
| | - Dirk Schneider
- Institut für Pharmazie
und Biochemie, Johannes Gutenberg-Universität Mainz, Johann-Joachim-Becher-Weg 30, 55128 Mainz, Germany
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