High-Density Reconstitution of Functional Water Channels into Vesicular and Planar Block Copolymer Membranes

Kumar, Manish; Habel, Joachim Erich Otto; Shen, Yue; Meier, Wolfgang; Walz, Thomas

doi:10.1021/ja304721r

Cited by 113 publications

(174 citation statements)

References 54 publications

(118 reference statements)

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“…While not all of the AQP0 proteins were integrated, this sevenfold growth in osmotic response values is relatively consistent with the high-packing density parameters and low permeability of AQP0 [22]. In this experimental run, the integration occurred through the process of mixing detergent-solubilized polymers with the detergent-solubilized AQP0, and then dialyzing the detergent out of the mixture [8,23]. In this case, the vesicle's shape continued to show substantially greater densities at block copolymers, when correlated to standard types of lipids such as the 1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE).…”

Section: Figures 1 and 2)supporting

confidence: 62%

“…In comparison to PB-PEO, PMOXA-PDMS-PMOXA has a signiicantly broader PDI [81] range, since its bilayer is water impermeable [7] and generally does not collapse in its dried form [82]. On the other hand, PB-PEO is noticeably more lipid-like because of its capacity to collapse easier and its greater water permeability potential [8]. Research suggests that these polymers that could not atain functional AQP incorporation are mostly PB-PEO polymers featuring small M n and PDI values.…”

Section: Figures 1 and 2)mentioning

confidence: 98%

“…It is quite fascinating that the membrane proteins may be functionally incorporated into polymeric bilayers (e.g., based on PMOXA-PDMS-PMOXA) that occur up to 10 times thicker than their lipidic counterparts [7]. Moreover, researchers have observed proteopolymersomes with protein density values that drastically surpassed those of proteoliposomes [8]. Research on these phenomena has helped to establish a theoretical approach for generalized membrane protein incorporation into the amphiphilic structures.…”

Section: Assessing Aquaporin Proteins and Block Copolymer Matrixes Inmentioning

confidence: 99%

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Interactions between Aquaporin Proteins and Block Copolymer Matrixes

Abdelrasoul¹,

Doan²,

Lohi³

2017

Biomimetic and Bioinspired Membranes for New Frontiers in Sustainable Water Treatment Technology

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This chapter continues to further expand its focus on aquaporins (AQPs) by ofering a general outline on how the AQPs block copolymers, and polymer support structures can interrelate and such connections can be comprehensively classiied and deined. The irst section of the overview will consider the relationship between block copolymers and AQPs. It will also examine the general membrane protein integration into block copolymers, since this can cause AQP-block copolymer complexes in vesicular (proteopolymersomes) as well as in planar forms. The majority of considerations taken into account during AQP incorporation come from the research conducted in relation to the process of incorporating other types of membrane proteins. This chapter includes an overview of the various characterization methodologies needed for the study of proteopolymersomes, as well as freeze-fracture transmission electron microscopy (FF-TEM), luorescence correlation spectroscopy (FCS), small-angle X-ray scatering (SAXS), and stopped-low light scatering (SFLS). The research data presented in this chapter emphasizes the fact that a successful process of membrane fabrication requires the integration of reconstituted AQPs into a suitable supporting matrix formation.Keywords: aquaporin proteins, block copolymer, matrix, vesicular, membrane protein Assessing aquaporin proteins and block copolymer matrixes interactionsMost research performed on membrane protein inclusion has been conducted primarily with lipids as the host matrix components (original proteoliposomes publication on the subject came out in 1971) [1]. Since then, polymer-based incorporation process has received increased atention and the earliest proteopolymersomes publication emerged in 2000 [2]. The initial work stages in this research area concentrated on the inclusion of membranespanning proteins, such as membrane-bound ion channels (ATPases) and bacteriorhodopsin incorporation into polymethyloxazoline-polydimethylsiloxane-polymethyloxazoline (PMOXA-PDMS-PMOXA) triblock copolymer bilayers occurring in planar [3] or vesicular forms [4][5][6]. It is quite fascinating that the membrane proteins may be functionally incorporated into polymeric bilayers (e.g., based on PMOXA-PDMS-PMOXA) that occur up to 10 times thicker than their lipidic counterparts [7]. Moreover, researchers have observed proteopolymersomes with protein density values that drastically surpassed those of proteoliposomes [8]. Research on these phenomena has helped to establish a theoretical approach for generalized membrane protein incorporation into the amphiphilic structures. This methodology is based on the notion that the eiciency of the membrane protein incorporation process relies on its hydrophobicity potential and its coupling capacity to the host membrane is directly connected to the hydrophobic mismatch parameters. In order to reduce this mismatch dynamic, the method calls for the host membrane to be deformed in such a way that it matches the hydrophobic length parameter of the membrane protein's transm...

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Section: Figures 1 and 2)supporting

confidence: 62%

Section: Figures 1 and 2)mentioning

confidence: 98%

Section: Assessing Aquaporin Proteins and Block Copolymer Matrixes Inmentioning

confidence: 99%

See 1 more Smart Citation

Interactions between Aquaporin Proteins and Block Copolymer Matrixes

Abdelrasoul¹,

Doan²,

Lohi³

2017

Biomimetic and Bioinspired Membranes for New Frontiers in Sustainable Water Treatment Technology

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show abstract

“…which the PAP channel-lipid aggregates transition from curved to flat membranes was close to 0.5, compared with a range of 0.02-0.125 for most membrane protein-lipid aggregates (45). The transition at a lower mCLR for PAP channel-lipid aggregates can be explained by the cross-sectional area of the PAP channel, which is smaller than that of most membrane proteins.…”

Section: Simulationsmentioning

confidence: 79%

“…S18). This will offset the high water permeability of AQPs, even if a membrane is very densely packed with AQPs, such as in 2D crystals (1,45). Taking into account the crosssectional areas of the PAP channel (3.0 nm 2 ), AQP1 (9.0 nm 2 ) (50), and CNTs (2.1 nm 2 ) (12, 51), the single-channel permeability of the PAP channel per cross-sectional area is similar to that of the most water-permeable AQPs and CNTs (SI Appendix, Fig.…”

Section: Comparison Of Pap Channels With Aqps and Cntsmentioning

confidence: 99%

Highly permeable artificial water channels that can self-assemble into two-dimensional arrays

Shen

Wen

Erbakan

et al. 2015

Proc. Natl. Acad. Sci. U.S.A.

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159

246

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Bioinspired artificial water channels aim to combine the high permeability and selectivity of biological aquaporin (AQP) water channels with chemical stability. Here, we carefully characterized a class of artificial water channels, peptide-appended pillar [5]arenes (PAPs). The average single-channel osmotic water permeability for PAPs is 1.0(±0.3) × 10 −14 cm 3 /s or 3.5(±1.0) × 10 8 water molecules per s, which is in the range of AQPs (3.4∼40.3 × 10 8 water molecules per s) and their current synthetic analogs, carbon nanotubes (CNTs, 9.0 × 10 8 water molecules per s). This permeability is an order of magnitude higher than first-generation artificial water channels (20 to ∼10 7 water molecules per s). Furthermore, within lipid bilayers, PAP channels can self-assemble into 2D arrays. Relevant to permeable membrane design, the pore density of PAP channel arrays (∼2.6 × 10 5 pores per μm 2 ) is two orders of magnitude higher than that of CNT membranes (0.1∼2.5 × 10 3 pores per μm 2 ). PAP channels thus combine the advantages of biological channels and CNTs and improve upon them through their relatively simple synthesis, chemical stability, and propensity to form arrays.artificial aquaporins | artificial water channels | peptide-appended pillar [5]arene | single-channel water permeability | two-dimensional arrays T he discovery of the high water and gas permeability of aquaporins (AQPs) and the development of artificial analogs, carbon nanotubes (CNTs), have led to an explosion in studies aimed at incorporating such channels into materials and devices for applications that use their unique transport properties (1-9). Areas of application include liquid and gas separations (10-13), drug delivery and screening (14), DNA recognition (15), and sensors (16). CNTs are promising channels because they conduct water and gas three to four orders of magnitude faster than predicted by conventional Hagen-Poiseuille flow theory (11). However, their use in large-scale applications has been hampered by difficulties in producing CNTs with subnanometer pore diameters and fabricating membranes in which the CNTs are vertically aligned (4). AQPs also efficiently conduct water across membranes (∼3 billion molecules per second) (17) and are therefore being studied intensively for their use in biomimetic membranes for water purification and other applications (1, 2, 18). The largescale applications of AQPs is complicated by the high cost of membrane protein production, their low stability, and challenges in membrane fabrication (1).Artificial water channels, bioinspired analogs of AQPs created using synthetic chemistry (19), ideally have a structure that forms a water-permeable channel in the center and an outer surface that is compatible with a lipid membrane environment (1). Interest in artificial water channels has grown in recent years, following decades of research and focus on synthetic ion channels (19). However, two fundamental questions remain: (i) Can artificial channels approach the permeability and selectivity of AQP water chan...

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Membrane Protein Insertion into and Compatibility with Biomimetic Membranes

et al. 2017

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Membrane protein and membrane protein–mimic functionalized materials are rapidly gaining interest across a wide range of applications, including drug screening, DNA sequencing, drug delivery, sensors, water desalination, and bioelectronics. In these applications, material performance is highly dependent on activity‐per‐protein and protein packing density in bilayer and bilayer‐like structures collectively known as biomimetic membranes. However, a clear understanding of, and accurate tools to study these properties of biomimetic membranes does not exist. This paper presents methods to evaluate membrane protein compatibility with biomimetic membrane materials. The methods utilized provide average single protein activity, and for the first time, provide experimentally quantifiable measures of the chemical and physical compatibility between proteins (and their mimics) and membrane materials. Water transport proteins, rhodopsins, and artificial water channels are reconstituted into the full range of current biomimetic membrane matrices to evaluate the proposed platform. Compatibility measurement results show that both biological and artificial water channels tested largely preserve their single protein water transport rates in biomimetic membranes, while their reconstitution density is variable, leading to different overall membrane permeabilities. It is also shown that membrane protein insertion efficiency inversely correlates with both chemical and physical hydrophobicity mismatch between membrane protein and the membrane matrix.

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High-Density Reconstitution of Functional Water Channels into Vesicular and Planar Block Copolymer Membranes

Cited by 113 publications

References 54 publications

Interactions between Aquaporin Proteins and Block Copolymer Matrixes

Interactions between Aquaporin Proteins and Block Copolymer Matrixes

Highly permeable artificial water channels that can self-assemble into two-dimensional arrays

Membrane Protein Insertion into and Compatibility with Biomimetic Membranes

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