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Jazani AM, Murata H, Cvek M, Lewandowska-Andralojc A, Bernat R, Kapil K, Hu X, De Luca Bossa F, Szczepaniak G, Matyjaszewski K. Aqueous photo-RAFT polymerization under ambient conditions: synthesis of protein-polymer hybrids in open air. Chem Sci 2024; 15:9742-9755. [PMID: 38939137 PMCID: PMC11206215 DOI: 10.1039/d4sc01409j] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2024] [Accepted: 05/01/2024] [Indexed: 06/29/2024] Open
Abstract
A photoinduced reversible addition-fragmentation chain-transfer (photo-RAFT) polymerization technique in the presence of sodium pyruvate (SP) and pyruvic acid derivatives was developed. Depending on the wavelength of light used, SP acted as a biocompatible photoinitiator or promoter for polymerization, allowing rapid open-to-air polymerization in aqueous media. Under UV irradiation (370 nm), SP decomposes to generate CO2 and radicals, initiating polymerization. Under blue (450 nm) or green (525 nm) irradiation, SP enhances the polymerization rate via interaction with the excited state RAFT agent. This method enabled the polymerization of a range of hydrophilic monomers in reaction volumes up to 250 mL, eliminating the need to remove radical inhibitors from the monomers. In addition, photo-RAFT polymerization using SP allowed for the facile synthesis of protein-polymer hybrids in short reaction times (<1 h), low organic content (≤16%), and without rigorous deoxygenation and the use of transition metal photocatalysts. Enzymatic studies of a model protein (chymotrypsin) showed that despite a significant loss of protein activity after conjugation with RAFT chain transfer agents, the grafting polymers from proteins resulted in a 3-4-fold recovery of protein activity.
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Affiliation(s)
- Arman Moini Jazani
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
| | - Hironobu Murata
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
| | - Martin Cvek
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
- Centre of Polymer Systems, Tomas Bata University in Zlin Trida T. Bati 5678 76001 Zlin Czech Republic
| | - Anna Lewandowska-Andralojc
- Faculty of Chemistry, Adam Mickiewicz University Uniwersytetu Poznanskiego 8 61-614 Poznan Poland
- Center for Advanced Technology, Adam Mickiewicz University Uniwersytetu Poznanskiego 10 61-614 Poznan Poland
| | - Roksana Bernat
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
- Institute of Materials Engineering, University of Silesia 75 Pulku Piechoty 1A 41-500 Chorzow Poland
| | - Kriti Kapil
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
| | - Xiaolei Hu
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
| | | | - Grzegorz Szczepaniak
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
- Faculty of Chemistry, University of Warsaw Pasteura 1 02-093 Warsaw Poland
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh PA 15213 USA
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Pavlyuk E, Yungerman I, Bliznyuk A, Moskovitz Y. Studying the Effects of Dissolved Noble Gases and High Hydrostatic Pressure on the Spherical DOPC Bilayer Using Molecular Dynamic Simulations. MEMBRANES 2024; 14:89. [PMID: 38668117 PMCID: PMC11052037 DOI: 10.3390/membranes14040089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/15/2024] [Revised: 04/04/2024] [Accepted: 04/10/2024] [Indexed: 04/28/2024]
Abstract
Fine-grained molecular dynamics simulations have been conducted to depict lipid objects enclosed in water and interacting with a series of noble gases dissolved in the medium. The simple point-charge (SPC) water system, featuring a boundary composed of 1,2-Dioleoyl-sn-glycero-3-phosphocholine (DOPC) molecules, maintained stability throughout the simulation under standard conditions. This allowed for the accurate modeling of the effects of hydrostatic pressure at an ambient pressure of 25 bar. The chosen pressure references the 240 m depth of seawater: the horizon frequently used by commercial divers, who comprise the primary patient population of the neurological complication of inert gas narcosis and the consequences of high-pressure neurological syndrome. To quantify and validate the neurological effects of noble gases and discriminate them from high hydrostatic pressure, we reduced the dissolved gas molar concentration to 1.5%, three times smaller than what we previously tested for the planar bilayer (3.5%). The nucleation and growth of xenon, argon and neon nanobubbles proved consistent with the data from the planar bilayer simulations. On the other hand, hyperbaric helium induces only a residual distorting effect on the liposome, with no significant condensed gas fraction observed within the hydrophobic core. The bubbles were distributed over a large volume-both in the bulk solvent and in the lipid phase-thereby causing substantial membrane distortion. This finding serves as evidence of the validity of the multisite distortion hypothesis for the neurological effect of inert gases at high pressure.
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Affiliation(s)
- Eugeny Pavlyuk
- Laboratory of Multi-Scale Mathematical Modeling, Ural Federal University, Ekaterinburg 620002, Russia
| | - Irena Yungerman
- Department of Chemical Engineering, Technion—Israel Technological Institute, Technion City, Haifa 3200003, Israel
| | - Alice Bliznyuk
- Ilse Katz Institute for Nanoscale Science and Technology (IKI), Ben Gurion University of the Negev, Beer Sheva 8410501, Israel
| | - Yevgeny Moskovitz
- Laboratory of Multi-Scale Mathematical Modeling, Ural Federal University, Ekaterinburg 620002, Russia
- Department of Chemical Engineering, Technion—Israel Technological Institute, Technion City, Haifa 3200003, Israel
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3
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Zhang T, Wu Z, Ng G, Boyer C. Design of an Oxygen-Tolerant Photo-RAFT System for Protein-Polymer Conjugation Achieving High Bioactivity. Angew Chem Int Ed Engl 2023; 62:e202309582. [PMID: 37591792 DOI: 10.1002/anie.202309582] [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: 07/09/2023] [Revised: 08/15/2023] [Accepted: 08/17/2023] [Indexed: 08/19/2023]
Abstract
Protein-polymer conjugates have significant potential in pharmaceutical and biomedical applications. To enable their widespread use, robust conjugation techniques are crucial. This study introduces a photo-initiated reversible addition-fragmentation chain-transfer (Photo-RAFT) polymerization system that exhibits excellent oxygen tolerance. This system allows for the synthesis of protein-polymer conjugates with high bioactivity under mild and aerobic conditions. Three photocatalytic systems utilizing Eosin Y (EY) as the photocatalyst with two different cocatalysts (ascorbic acid and triethanolamine) were investigated, each generating distinct reactive oxygen species (ROS) such as singlet oxygen, superoxide, hydrogen peroxide, and hydroxyl radicals. The impact of these ROS on three model proteins (lysozyme, albumin, and myoglobin) was evaluated, demonstrating varying bioactivities based on the ROS produced. The EY/TEOA system was identified as the optimal photo-RAFT initiating system, enabling the preparation of protein-polymer conjugates under aerobic conditions while maintaining high protein enzymatic activity. To showcase the potential of this approach, lysozyme-poly(dimethylaminoethyl acrylate) conjugates were successfully prepared and exhibited enhanced antimicrobial property against Gram-positive and Gram-negative bacteria.
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Affiliation(s)
- Tong Zhang
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Zilong Wu
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Gervase Ng
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
| | - Cyrille Boyer
- Cluster for Advanced Macromolecular Design and UNSW RNA Institute, School of Chemical Engineering, The University of New South Wales, 2052, Sydney, NSW, Australia
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4
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Voutyritsa E, Gryparis C, Theodorou A, Velonia K. Synthesis of Multifunctional Protein-Polymer Conjugates via Oxygen-tolerant, Aqueous Copper-Mediated Polymerization, and Bioorthogonal Click Chemistry. Macromol Rapid Commun 2023; 44:e2200976. [PMID: 37002553 DOI: 10.1002/marc.202200976] [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: 12/27/2022] [Revised: 03/07/2023] [Indexed: 04/04/2023]
Abstract
Oxygen-tolerant, aqueous copper-mediated polymerization approaches are combined with click chemistry in either a sequential or a simultaneous manner, to enable the synthesis of multifunctional protein-polymer conjugates. Propargyl acrylate (PgA) and propargyl methacrylate (PgMA) grafting from a bovine serum albumin (BSA) macroinitiator is thoroughly optimized to synthesize chemically addressable BSA-poly(propargyl acrylate) and BSA-poly(propargyl methacrylate) respectively. The produced multifunctional bioconjugates bear pendant terminal 1-alkynes which can be readily post-functionalized via both [3+2] Huisgen cycloaddition and thiol-yne click chemistry under mild reaction conditions. Simultaneous oxygen-tolerant, aqueous copper-catalyzed polymerization, and click chemistry mediate the in situ multiple chemical tailoring of biomacromolecules in excellent yields.
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Affiliation(s)
- Errika Voutyritsa
- Department of Materials Science and Technology, University of Crete, Heraklion, Crete, 70013, Greece
| | - Charis Gryparis
- Department of Materials Science and Technology, University of Crete, Heraklion, Crete, 70013, Greece
| | - Alexis Theodorou
- Department of Materials Science and Technology, University of Crete, Heraklion, Crete, 70013, Greece
| | - Kelly Velonia
- Department of Materials Science and Technology, University of Crete, Heraklion, Crete, 70013, Greece
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5
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He J, Dmochowski IJ. Local Xenon-Protein Interaction Produces Global Conformational Change and Allosteric Inhibition in Lysozyme. Biochemistry 2023; 62:1659-1669. [PMID: 37192381 PMCID: PMC10821772 DOI: 10.1021/acs.biochem.3c00046] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Noble gases have well-established biological effects, yet their molecular mechanisms remain poorly understood. Here, we investigated, both experimentally and computationally, the molecular modes of xenon (Xe) action in bacteriophage T4 lysozyme (T4L). By combining indirect gassing methods with a colorimetric lysozyme activity assay, a reversible, Xe-specific (20 ± 3)% inhibition effect was observed. Accelerated molecular dynamic simulations revealed that Xe exerts allosteric inhibition on the protein by expanding a C-terminal hydrophobic cavity. Xe-induced cavity expansion results in global conformational changes, with long-range transduction distorting the active site where peptidoglycan binds. Interestingly, the peptide substrate binding site that enables lysozyme specificity does not change conformation. Two T4L mutants designed to reshape the C-terminal Xe cavity established a correlation between cavity expansion and enzyme inhibition. This work also highlights the use of Xe flooding simulations to identify new cryptic binding pockets. These results enrich our understanding of Xe-protein interactions at the molecular level and inspire further biochemical investigations with noble gases.
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Affiliation(s)
- Jiayi He
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
| | - Ivan J Dmochowski
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania 19104-6323, United States
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Kapil K, Jazani AM, Szczepaniak G, Murata H, Olszewski M, Matyjaszewski K. Fully Oxygen-Tolerant Visible-Light-Induced ATRP of Acrylates in Water: Toward Synthesis of Protein-Polymer Hybrids. Macromolecules 2023; 56:2017-2026. [PMID: 36938511 PMCID: PMC10019465 DOI: 10.1021/acs.macromol.2c02537] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2022] [Revised: 02/05/2023] [Indexed: 02/22/2023]
Abstract
Over the last decade, photoinduced ATRP techniques have been developed to harness the energy of light to generate radicals. Most of these methods require the use of UV light to initiate polymerization. However, UV light has several disadvantages: it can degrade proteins, damage DNA, cause undesirable side reactions, and has low penetration depth in reaction media. Recently, we demonstrated green-light-induced ATRP with dual catalysis, where eosin Y (EYH2) was used as an organic photoredox catalyst in conjunction with a copper complex. This dual catalysis proved to be highly efficient, allowing rapid and well-controlled aqueous polymerization of oligo(ethylene oxide) methyl ether methacrylate without the need for deoxygenation. Herein, we expanded this system to synthesize polyacrylates under biologically relevant conditions using CuII/Me6TREN (Me6TREN = tris[2-(dimethylamino)ethyl]amine) and EYH2 at ppm levels. Water-soluble oligo(ethylene oxide) methyl ether acrylate (average M n = 480, OEOA480) was polymerized in open reaction vessels under green light irradiation (520 nm). Despite continuous oxygen diffusion, high monomer conversions were achieved within 40 min, yielding polymers with narrow molecular weight distributions (1.17 ≤ D̵ ≤ 1.23) for a wide targeted DP range (50-800). In situ chain extension and block copolymerization confirmed the preserved chain end functionality. In addition, polymerization was triggered/halted by turning on/off a green light, showing temporal control. The optimized conditions also enabled controlled polymerization of various hydrophilic acrylate monomers, such as 2-hydroxyethyl acrylate, 2-(methylsulfinyl)ethyl acrylate), and zwitterionic carboxy betaine acrylate. Notably, the method allowed the synthesis of well-defined acrylate-based protein-polymer hybrids using a straightforward reaction setup without rigorous deoxygenation.
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7
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Khodia S, Jarupula R, Maity S. Accurate measurement of sequential Ar desorption energies from the dispersion-dominated Ar 1-3 complexes of aromatic molecules. Phys Chem Chem Phys 2023; 25:2510-2516. [PMID: 36602110 DOI: 10.1039/d2cp04676h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
We present experimental determination of the energies associated with the gradual desorption of Ar atoms from the aromatic molecular surface. Non-covalently bound 2,2'-pyridylbenzimidazole-Ar1-3 complexes were produced in the gas phase and characterized using resonant two-photon ionization (R2PI) spectroscopy. The single Ar desorption from the PBI-Ar, PBI-Ar2 and PBI-Ar3 complexes were measured as 581 ± 18, 656 ± 30 and 537 ± 31 cm-1, respectively. The energies were bracketed between the last observed band in the respective R2PI spectra and the disappeared intramolecular modes of PBI. The Arn dissociation energies in the S1 state were measured as 581 ± 18, 1237 ± 48 and 1774 ± 79 cm-1, respectively, for n = 1, 2 and 3. The calculated dissociation energies of the respective complexes, obtained using three computational methods, show excellent agreement with the experimental data. The ground state dissociation energies were estimated by subtracting the Δν shift of the origin band, and the respective values are 541 ± 18, 1160 ± 48 and 1634 ± 79 cm-1. Overall, the calculated values resulted in scaling factors ranging from 0.956 to 1.017, which depict the predictive power of the methods to determine dispersion energies. The current investigation describes a unique methodology to accurately determine the dissociation and desorption energies of Ar atoms from the surfaces of bio-relevant aromatic molecules.
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Affiliation(s)
- Saurabh Khodia
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, India.
| | - Ramesh Jarupula
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, India.
| | - Surajit Maity
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, India.
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8
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Zhao Z, Rudman NA, He J, Dmochowski IJ. Programming xenon diffusion in maltose-binding protein. Biophys J 2022; 121:4635-4643. [PMID: 36271622 PMCID: PMC9748359 DOI: 10.1016/j.bpj.2022.10.025] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Revised: 10/12/2022] [Accepted: 10/17/2022] [Indexed: 12/15/2022] Open
Abstract
Protein interiors contain void space that can bind small gas molecules. Determination of gas pathways and kinetics in proteins has been an intriguing and challenging task. Here, we combined computational methods and the hyperpolarized xenon-129 chemical exchange saturation transfer (hyper-CEST) NMR technique to investigate xenon (Xe) exchange kinetics in maltose-binding protein (MBP). A salt bridge ∼9 Å from the Xe-binding site formed upon maltose binding and slowed the Xe exchange rate, leading to a hyper-CEST 129Xe signal from maltose-bound MBP. Xe dissociation occurred faster than dissociation of the salt bridge, as shown by 13C NMR spectroscopy and variable-B1 hyper-CEST experiments. "Xe flooding" molecular dynamics simulations identified a surface hydrophobic site, V23, that has good Xe binding affinity. Mutations at this site confirmed its role as a secondary exchange pathway in modulating Xe diffusion. This shows the possibility for site-specifically controlling xenon protein-solvent exchange. Analysis of the available MBP structures suggests a biological role of MBP's large hydrophobic cavity to accommodate structural changes associated with ligand binding and protein-protein interactions.
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Affiliation(s)
- Zhuangyu Zhao
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Nathan A Rudman
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Jiayi He
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Ivan J Dmochowski
- Department of Chemistry, University of Pennsylvania, Philadelphia, Pennsylvania.
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Lee Y, Kwon Y, Kim Y, Yu C, Feng S, Park J, Doh J, Wannemacher R, Koo B, Gierschner J, Kwon MS. A Water-Soluble Organic Photocatalyst Discovered for Highly Efficient Additive-Free Visible-Light-Driven Grafting of Polymers from Proteins at Ambient and Aqueous Environments. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2022; 34:e2108446. [PMID: 35032043 DOI: 10.1002/adma.202108446] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2021] [Revised: 01/11/2022] [Indexed: 06/14/2023]
Abstract
Since the pioneering discovery of a protein bound to poly(ethylene glycol), the utility of protein-polymer conjugates (PPCs) is rapidly expanding to currently emerging applications. Photoinduced energy/electron-transfer reversible addition-fragmentation chain-transfer (PET-RAFT) polymerization is a very promising method to prepare structurally well-defined PPCs, as it eliminates high-cost and time-consuming deoxygenation processes due to its oxygen tolerance. However, the oxygen-tolerance behavior of PET-RAFT polymerization is not well-investigated in aqueous environments, and thereby the preparation of PPCs using PET-RAFT polymerization needs a substantial amount of sacrificial reducing agents or inert-gas purging processes. Herein a novel water-soluble and biocompatible organic photocatalyst (PC) is reported, which enables visible-light-driven additive-free "grafting-from" polymerizations of a protein in ambient and aqueous environments. Interestingly, the developed PC shows unconventional "oxygen-acceleration" behavior for a variety of acrylic and acrylamide monomers in aqueous conditions without any additives, which are apparently distinct from previously reported systems. With such a PC, "grafting-from" polymerizations are successfully performed from protein in ambient buffer conditions under green light-emitting diode (LED) irradiation, which result in various PPCs that have neutral, anionic, cationic, and zwitterionic polyacrylates, and polyacrylamides. It is believed that this PC will be widely employed for a variety of photocatalysis processes in aqueous environments, including the living cell system.
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Affiliation(s)
- Yungyeong Lee
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Yonghwan Kwon
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Youngmu Kim
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Department of Materials Science and Engineering, Ulsan National Institute of Science and Technology (UNIST), Ulsan, 44919, Republic of Korea
| | - Changhoon Yu
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
| | - Siyang Feng
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Calle Faraday 9, Campus Cantoblanco, Madrid, 28049, Spain
| | - Jeehun Park
- Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Junsang Doh
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
| | - Reinhold Wannemacher
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Calle Faraday 9, Campus Cantoblanco, Madrid, 28049, Spain
| | - Byungjin Koo
- Department of Polymer Science and Engineering, Dankook University, Gyeonggi-do, 16890, Republic of Korea
| | - Johannes Gierschner
- Madrid Institute for Advanced Studies, IMDEA Nanoscience, Calle Faraday 9, Campus Cantoblanco, Madrid, 28049, Spain
| | - Min Sang Kwon
- Department of Materials Science and Engineering, Seoul National University, Seoul, 08826, Republic of Korea
- Research Institute of Advanced Materials, Seoul National University, Seoul, 08826, Republic of Korea
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Szczepaniak G, Jeong J, Kapil K, Dadashi-Silab S, Yerneni SS, Ratajczyk P, Lathwal S, Schild DJ, Das SR, Matyjaszewski K. Open-air green-light-driven ATRP enabled by dual photoredox/copper catalysis. Chem Sci 2022; 13:11540-11550. [PMID: 36320395 PMCID: PMC9557244 DOI: 10.1039/d2sc04210j] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 09/19/2022] [Indexed: 11/24/2022] Open
Abstract
Photoinduced atom transfer radical polymerization (photo-ATRP) has risen to the forefront of modern polymer chemistry as a powerful tool giving access to well-defined materials with complex architecture. However, most photo-ATRP systems can only generate radicals under biocidal UV light and are oxygen-sensitive, hindering their practical use in the synthesis of polymer biohybrids. Herein, inspired by the photoinduced electron transfer-reversible addition–fragmentation chain transfer (PET-RAFT) polymerization, we demonstrate a dual photoredox/copper catalysis that allows open-air ATRP under green light irradiation. Eosin Y was used as an organic photoredox catalyst (PC) in combination with a copper complex (X–CuII/L). The role of PC was to trigger and drive the polymerization, while X–CuII/L acted as a deactivator, providing a well-controlled polymerization. The excited PC was oxidatively quenched by X–CuII/L, generating CuI/L activator and PC˙+. The ATRP ligand (L) used in excess then reduced the PC˙+, closing the photocatalytic cycle. The continuous reduction of X–CuII/L back to CuI/L by excited PC provided high oxygen tolerance. As a result, a well-controlled and rapid ATRP could proceed even in an open vessel despite continuous oxygen diffusion. This method allowed the synthesis of polymers with narrow molecular weight distributions and controlled molecular weights using Cu catalyst and PC at ppm levels in both aqueous and organic media. A detailed comparison of photo-ATRP with PET-RAFT polymerization revealed the superiority of dual photoredox/copper catalysis under biologically relevant conditions. The kinetic studies and fluorescence measurements indicated that in the absence of the X–CuII/L complex, green light irradiation caused faster photobleaching of eosin Y, leading to inhibition of PET-RAFT polymerization. Importantly, PET-RAFT polymerizations showed significantly higher dispersity values (1.14 ≤ Đ ≤ 4.01) in contrast to photo-ATRP (1.15 ≤ Đ ≤ 1.22) under identical conditions. Fully oxygen-tolerant photoinduced atom transfer radical polymerization (photo-ATRP) allowed the synthesis of well-defined polymers using a Cu catalyst and eosin Y at ppm levels in both aqueous and organic media.![]()
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Affiliation(s)
- Grzegorz Szczepaniak
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
- Faculty of Chemistry, University of Warsaw, Pasteura 1, 02-093 Warsaw, Poland
| | - Jaepil Jeong
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Kriti Kapil
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Sajjad Dadashi-Silab
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | | | - Paulina Ratajczyk
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
- Faculty of Chemistry, Adam Mickiewicz University, Uniwersytetu Poznańskiego 8, 61-614 Poznań, Poland
| | - Sushil Lathwal
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Dirk J. Schild
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Subha R. Das
- Department of Chemistry, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
- Center for Nucleic Acids Science & Technology, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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11
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Khodia S, Maity S. A combined spectroscopic and computational investigation on dispersion-controlled docking of Ar atoms on 2-(2'-pyridyl)benzimidazole. Phys Chem Chem Phys 2021; 23:17992-18000. [PMID: 34382618 DOI: 10.1039/d1cp02184b] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The dispersion-controlled docking of inert Ar atoms on the face of polycyclic 2-(2'-pyridyl)-benzimidazole (PBI) was studied experimentally aided by computational findings. The PBI-Arn (n = 1-3) complexes were produced in a supersonically jet-cooled molecular beam and probed using resonant two-photon ionization coupled with a time-of-flight mass spectrometric detection scheme and laser-induced fluorescence spectroscopy. The ground state vibrational frequencies were obtained from single vibronic level fluorescence spectroscopy. The formation of multiple isomers was verified using UV-UV hole-burning spectroscopy. The geometries of PBI-Arn (n = 1-3) complexes were derived by mutual agreement between experimental findings and computational results such as vibrational frequencies in the ground and excited electronic states, Franck-Condon factors and spectral shift of the S1← S0 transitions. All the above analyses provided good agreement between the experimental and simulated spectrum with the most stable PBI-Arn (n = 1-3) clusters. The highest intermolecular interaction between PBI and Ar was obtained with the Ar atom positioned above the imidazolyl ring. A second Ar atom was preferably docking on the other side of the imidazolyl ring than the pyridyl ring. The subsequent addition of the third Ar atom preferred the position above the pyridyl ring. The current investigation can be useful to investigate the preferential docking of dispersion-controlled interacting partners in multifunctional aromatic side chains present in biological systems.
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Affiliation(s)
- Saurabh Khodia
- Department of Chemistry, Indian Institute of Technology Hyderabad, Kandi, Sangareddy, 502285, India.
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12
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Petrov E, Verkhovskiy A. Xenon as a transdermal enhancer for niacinamide in Strat-M™ membranes. Med Gas Res 2021; 12:24-27. [PMID: 34472499 PMCID: PMC8447954 DOI: 10.4103/2045-9912.320704] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Xenon is confirmed to diffuse readily through membranes and has properties of transdermal enhancer. In this study, the ability of xenon to regulate the transdermal diffusion of niacinamide was investigated using a model of an artificial skin analogue of Strat-M™ membranes in Franz cells. Based on the data obtained, we found that in the simplified biophysical model of Strat-M™ membranes xenon exerts its enhancer effect based on the heterogeneous nucleation of xenon at the interfaces in the microporous structures of Strat-M™ membranes.
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Affiliation(s)
- Evgeny Petrov
- Laboratory of Biochemistry of Transport Systems, Faculty of Innovative Technologies, National Research Tomsk State University, Tomsk, Russian Federation
| | - Alexander Verkhovskiy
- Laboratory of Biochemistry of Transport Systems, Faculty of Innovative Technologies, National Research Tomsk State University, Tomsk, Russian Federation
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Szczepaniak G, Fu L, Jafari H, Kapil K, Matyjaszewski K. Making ATRP More Practical: Oxygen Tolerance. Acc Chem Res 2021; 54:1779-1790. [PMID: 33751886 DOI: 10.1021/acs.accounts.1c00032] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Atom-transfer radical polymerization (ATRP) is a well-known technique for the controlled polymerization of vinyl monomers under mild conditions. However, as with any other radical polymerization, ATRP typically requires rigorous oxygen exclusion, making it time-consuming and challenging to use by nonexperts. In this Account, we discuss various approaches to achieving oxygen tolerance in ATRP, presenting the overall progress in the field.Copper-mediated ATRP, which we first discovered in the late 1990s, uses a CuI/L activator that reversibly reacts with the dormant C(sp3)-X polymer chain end, forming a X-CuII/L deactivator and a propagating radical. Oxygen interferes with activation and chain propagation by quenching the radicals and oxidizing the activator. At ATRP equilibrium, the activator is present at a much higher concentration than the propagating radicals. Thus, oxidation of the activator is the dominant inhibition pathway. In conventional ATRP, this reaction is irreversible, so oxygen must be strictly excluded to achieve good results.Over the last two decades, our group has developed several ATRP techniques based on the concept of regenerating the activator. When the oxidized activator is continuously converted back to its active reduced form, then the catalytic system itself can act as an oxygen scavenger. Regeneration can be accomplished by reducing agents and photo-, electro-, and mechanochemical stimuli. This family of methods offers a degree of oxygen tolerance, but most of them can tolerate only a limited amount of oxygen and do not allow polymerization in an open vessel.More recently, we discovered that enzymes can be used in auxiliary catalytic systems that directly deoxygenate the reaction medium and protect the polymerization process. We developed a method that uses glucose oxidase (GOx), glucose, and sodium pyruvate to very effectively scavenge oxygen and enable open-vessel ATRP. By adding a second enzyme, horseradish peroxidase (HPR), we managed to extend the role of the auxiliary enzymatic system to generating carbon-based radicals and changed ATRP from an oxygen-sensitive to an oxygen-fueled reaction.While performing control experiments for the enzymatic methods, we noticed that using sodium pyruvate under UV irradiation triggers polymerization without the presence of GOx. This serendipitous discovery allowed us to develop the first oxygen-proof, small-molecule-based, photoinduced ATRP system. It has oxygen tolerance similar to that of the enzymatic methods, exhibits superior compatibility with both aqueous media and organic solvents, and avoids problems associated with purifying polymers from enzymes. The system was able to rapidly polymerize N-isopropylacrylamide, a challenging monomer, with a high degree of control.These contributions have substantially simplified the use of ATRP, making it more practical and accessible to everyone.
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Affiliation(s)
- Grzegorz Szczepaniak
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
- Faculty of Chemistry, University of Warsaw, Żwirki i Wigury 101, 02-089 Warsaw, Poland
| | - Liye Fu
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Hossein Jafari
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Kriti Kapil
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University, 4400 Fifth Avenue, Pittsburgh, Pennsylvania 15213, United States
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Wang Y, Guo Z, Tan T, Ji Y, Hu J, Zhang Y. The effects of nanobubbles on the assembly of glucagon amyloid fibrils. SOFT MATTER 2021; 17:3486-3493. [PMID: 33657201 DOI: 10.1039/d0sm02279a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Some recent studies have shown that the surface and interface play an important role in the assembly and aggregation of amyloid proteins. However, it is unclear how the gas-liquid interface affects the protein assembly at the nanometer scale although the presence of gas-liquid interfaces is very common in in vitro experiments. Nanobubbles have a large specific surface area, which provides a stage for interactions with various proteins and peptides on the nanometer scale. In this work, nanobubbles produced in solution were employed for studying the effects of the gas-liquid interface on the assembly of glucagon proteins. Atomic force microscopy (AFM) studies showed that nanobubble-treated glucagon solution formed fibrils with an apparent height of 4.02 ± 0.71 nm, in contrast to the fibrils formed with a height of 2.14 ± 0.53 nm in the control. Transmission electron microscopy (TEM) results also showed that nanobubbles promoted the assembly of glucagon to form more fibrils. Thioflavin T (ThT) fluorescence and Fourier transform infrared (FTIR) analyses indicated that the nanobubbles induced the change of the glucagon conformation to a β-sheet structure. A mechanism that explains how nanobubbles affect the assembly of glucagon amyloid fibrils was proposed based on the above-mentioned experimental results. Given the fact that there are a considerable amount of nanobubbles existing in protein solutions, our results indicate that nanobubbles should be considered for fully understanding the protein aggregation events in vitro.
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Affiliation(s)
- Yujiao Wang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
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Wang J, Yuan K, Wang X, Zhang L, Hu J. Influence of Krypton Gas Nanobubbles on the Activity of Pepsin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2020; 36:14070-14075. [PMID: 33179933 DOI: 10.1021/acs.langmuir.0c02635] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
The fact that biologically inert gases can significantly affect the biological function of proteins still lacks a full understanding because they are usually chemically stable and weakly absorbed by biological molecules. Recently, nanobubbles were proposed to play an important role in the activity of a protein (Scientific reports 2013, 3; Scientific reports 2017, 7, 10176). In this study, we developed a controllable method to produce high-concentration krypton (Kr) gas nanobubbles in pure water and measured the concentration influence of those Kr nanobubbles on pepsin protein activity. By combining high-sensitivity synchrotron radiation X-ray fluorescence techniques with a nanoparticle tracking analysis technology, we provided strong evidence that the observed "nanoparticles" were indeed Kr nanobubbles. Activity measurements showed that the activity would be inhibited by the existence of Kr nanobubbles and could be recovered by degassing. More importantly, the inhibition extent of pepsin activity was dominated by the number of nanobubbles in solution. More nanobubbles would cause more inhibition of pepsin activity. Furthermore, the structures of pepsin could be changed by nanobubbles, which might be the reason for inhabitation of activity. Our results would provide a further understanding of the mechanisms of the biological effects of inert gases.
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Affiliation(s)
- Jing Wang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Kaiwei Yuan
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- University of Chinese Academy of Sciences, Beijing 100049, China
| | - Xingya Wang
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Lijuan Zhang
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
| | - Jun Hu
- Key Laboratory of Interfacial Physics and Technology, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Shanghai 201800, China
- Shanghai Synchrotron Radiation Facility, Shanghai Advanced Research Institute, Chinese Academy of Sciences, Shanghai 201204, China
- School of Physical Science and Technology, ShanghaiTech University, Shanghai 201204, China
- University of Chinese Academy of Sciences, Beijing 100049, China
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Szczepaniak G, Łagodzińska M, Dadashi-Silab S, Gorczyński A, Matyjaszewski K. Fully oxygen-tolerant atom transfer radical polymerization triggered by sodium pyruvate. Chem Sci 2020; 11:8809-8816. [PMID: 34123134 PMCID: PMC8163335 DOI: 10.1039/d0sc03179h] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 08/06/2020] [Indexed: 01/01/2023] Open
Abstract
ATRP (atom transfer radical polymerization) is one of the most robust reversible deactivation radical polymerization (RDRP) systems. However, the limited oxygen tolerance of conventional ATRP impedes its practical use in an ambient atmosphere. In this work, we developed a fully oxygen-tolerant PICAR (photoinduced initiators for continuous activator regeneration) ATRP process occurring in both water and organic solvents in an open reaction vessel. Continuous regeneration of the oxidized form of the copper catalyst with sodium pyruvate through UV excitation allowed the chemical removal of oxygen from the reaction mixture while maintaining a well-controlled polymerization of N-isopropylacrylamide (NIPAM) or methyl acrylate (MA) monomers. The polymerizations of NIPAM were conducted with 250 ppm (with respect to the monomer) or lower concentrations of CuBr2 and a tris[2-(dimethylamino)ethyl]amine ligand. The polymers were synthesized to nearly quantitative monomer conversions (>99%), high molecular weights (M n > 270 000), and low dispersities (1.16 < Đ < 1.44) in less than 30 min under biologically relevant conditions. The reported method provided a well-controlled ATRP (Đ = 1.16) of MA in dimethyl sulfoxide despite oxygen diffusion from the atmosphere into the reaction system.
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Affiliation(s)
- Grzegorz Szczepaniak
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
- Faculty of Chemistry, University of Warsaw Żwirki i Wigury 101 02-089 Warsaw Poland
| | - Matylda Łagodzińska
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
- Department of Chemistry, University of Oxford South Parks Road Oxford OX13QZ UK
| | - Sajjad Dadashi-Silab
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
| | - Adam Gorczyński
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
- Faculty of Chemistry, Adam Mickiewicz University Uniwersytetu Poznańskiego 8 61-614 Poznań Poland
| | - Krzysztof Matyjaszewski
- Department of Chemistry, Carnegie Mellon University 4400 Fifth Avenue Pittsburgh Pennsylvania 15213 USA
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Hydrogen molecules can modulate enzymatic activity and structural properties of pepsin in vitro. Colloids Surf B Biointerfaces 2020; 189:110856. [DOI: 10.1016/j.colsurfb.2020.110856] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2019] [Revised: 02/03/2020] [Accepted: 02/07/2020] [Indexed: 01/19/2023]
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Theodorou A, Liarou E, Haddleton DM, Stavrakaki IG, Skordalidis P, Whitfield R, Anastasaki A, Velonia K. Protein-polymer bioconjugates via a versatile oxygen tolerant photoinduced controlled radical polymerization approach. Nat Commun 2020; 11:1486. [PMID: 32198365 PMCID: PMC7083936 DOI: 10.1038/s41467-020-15259-z] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2019] [Accepted: 02/19/2020] [Indexed: 12/25/2022] Open
Abstract
The immense application potential of amphiphilic protein-polymer conjugates remains largely unexplored, as established "grafting from" synthetic protocols involve time-consuming, harsh and disruptive deoxygenation methods, while "grafting to" approaches result in low yields. Here we report an oxygen tolerant, photoinduced CRP approach which readily affords quantitative yields of protein-polymer conjugates within 2 h, avoiding damage to the secondary structure of the protein and providing easily accessible means to produce biomacromolecular assemblies. Importantly, our methodology is compatible with multiple proteins (e.g. BSA, HSA, GOx, beta-galactosidase) and monomer classes including acrylates, methacrylates, styrenics and acrylamides. The polymerizations are conveniently conducted in plastic syringes and in the absence of any additives or external deoxygenation procedures using low-organic content media and ppm levels of copper. The robustness of the protocol is further exemplified by its implementation under UV, blue light or even sunlight irradiation as well as in buffer, nanopure, tap or even sea water.
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Affiliation(s)
- Alexis Theodorou
- Department of Materials Science and Technology, University of Crete, Heraklion, 70013, Greece
| | - Evelina Liarou
- Chemistry Department, University of Warwick, Coventry, CV4 7AL, UK
| | | | - Iren Georgia Stavrakaki
- Department of Materials Science and Technology, University of Crete, Heraklion, 70013, Greece
| | - Panagiotis Skordalidis
- Department of Materials Science and Technology, University of Crete, Heraklion, 70013, Greece
| | | | | | - Kelly Velonia
- Department of Materials Science and Technology, University of Crete, Heraklion, 70013, Greece.
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The effect of high pressure on the NMDA receptor: molecular dynamics simulations. Sci Rep 2019; 9:10814. [PMID: 31346207 PMCID: PMC6658662 DOI: 10.1038/s41598-019-47102-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2018] [Accepted: 07/09/2019] [Indexed: 12/18/2022] Open
Abstract
Professional divers exposed to ambient pressures above 11 bar develop the high pressure neurological syndrome (HPNS), manifesting as central nervous system (CNS) hyperexcitability, motor disturbances, sensory impairment, and cognitive deficits. The glutamate-type N-methyl-D-aspartate receptor (NMDAR) has been implicated in the CNS hyperexcitability of HPNS. NMDARs containing different subunits exhibited varying degrees of increased/decreased current at high pressure. The mechanisms underlying this phenomenon remain unclear. We performed 100 ns molecular dynamics (MD) simulations of the NMDAR structure embedded in a dioleoylphosphatidylcholine (DOPC) lipid bilayer solvated in water at 1 bar, hydrostatic 25 bar, and in helium at 25 bar. MD simulations showed that in contrast to hydrostatic pressure, high pressure helium causes substantial distortion of the DOPC membrane due to its accumulation between the two monolayers: reduction of the Sn-1 and Sn-2 DOPC chains and helium-dependent dehydration of the NMDAR pore. Further analysis of important regions of the NMDAR protein such as pore surface (M2 α-helix), Mg2+ binding site, and TMD-M4 α-helix revealed significant effects of helium. In contrast with previous models, these and our earlier results suggest that high pressure helium, not hydrostatic pressure per se, alters the receptor tertiary structure via protein-lipid interactions. Helium in divers’ breathing mixtures may partially contribute to HPNS symptoms.
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Bull DS, Kienle DF, Chaparro Sosa AF, Nelson N, Roy S, Cha JN, Schwartz DK, Kaar JL, Goodwin AP. Surface-Templated Nanobubbles Protect Proteins from Surface-Mediated Denaturation. J Phys Chem Lett 2019; 10:2641-2647. [PMID: 31067058 PMCID: PMC8051143 DOI: 10.1021/acs.jpclett.9b00806] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
In this Letter, we report that surface-bound nanobubbles reduce protein denaturation on methylated glass by irreversible protein shell formation. Single-molecule total internal reflection fluorescence (SM-TIRF) microscopy was combined with intramolecular Förster resonance energy transfer (FRET) to study the conformational dynamics of nitroreductase (NfsB) on nanobubble-laden methylated glass surfaces, using reflection brightfield microscopy to register nanobubble locations with NfsB adsorption. First, NfsB adsorbed irreversibly to nanobubbles with no apparent desorption after 5 h. Moreover, virtually all (96%) of the NfsB molecules that interacted with nanobubbles remained folded, whereas less than 50% of NfsB molecules remained folded in the absence of nanobubbles on unmodified silica or methylated glass surfaces. This trend was confirmed by ensemble-average fluorometer TIRF experiments. We hypothesize that nanobubbles reduce protein damage by passivating strongly denaturing topographical surface defects. Thus, nanobubble stabilization on surfaces may have important implications for antifouling surfaces and improving therapeutic protein storage.
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Munsch-Alatossava P, Ibarra D, Youbi-Idrissi M, Alatossava T. N2 Gas-Flushing Prevents Bacteria-Promoted Lipolysis and Proteolysis and Alleviates Auto-Oxidation in Bovine Raw Milk During Cold-Storage. FRONTIERS IN SUSTAINABLE FOOD SYSTEMS 2019. [DOI: 10.3389/fsufs.2019.00041] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Ke S, Xiao W, Quan N, Dong Y, Zhang L, Hu J. Formation and Stability of Bulk Nanobubbles in Different Solutions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2019; 35:5250-5256. [PMID: 30909695 DOI: 10.1021/acs.langmuir.9b00144] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
The existence of bulk nanobubbles is still controversial in spite of their significance in a large range of applications. Here, we developed a new method of compression-decompression to produce controllably bulk nanobubbles. Then, we further investigated the generation of bulk nanobubbles in pure water, acid, alkaline, and salt solutions using nanoparticle tracking analysis. The results indicated that the concentration of bulk nanobubbles depends on the decompression time and would reach a maximum value when the decompression time is about 30 min for the pure water system. More importantly, we gave a relatively direct evidence of the existence of bulk nanobubbles by measuring the X-ray fluorescence intensity of Kr in acid, alkaline, and salt solutions. It is shown that the decrease tendency in intensity of Kr in alkaline solution is similar to that in the concentration of bulk nanobubbles with the deposited time, indicating that the bulk nanobubbles produced indeed have gas inside. Furthermore, the concentration and stability of bulk nanobubbles in an alkaline solution are greatest compared with other two solutions regardless of gas types. The concentration of bulk nanobubbles will decrease in the order alkaline > acid/pure water > salt solutions. We believe that our results should be very helpful in understanding the formation and stability of bulk nanobubbles in different solutions.
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Affiliation(s)
- Shuo Ke
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Wei Xiao
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- School of Resources Engineering , Xi'an University of Architecture and Technology , Xi'an 710055 , China
| | - Nannan Quan
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Yaming Dong
- Life and Environment Science College , Shanghai Normal University , Shanghai 200234 , China
| | - Lijuan Zhang
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
| | - Jun Hu
- Shanghai Synchrotron Radiation Facility , Shanghai Advanced Research Institute, Chinese Academy of Sciences , Shanghai 201204 , China
- Shanghai Institute of Applied Physics, Chinese Academy of Sciences , Shanghai 201800 , China
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Roose BW, Zemerov SD, Dmochowski IJ. Xenon-Protein Interactions: Characterization by X-Ray Crystallography and Hyper-CEST NMR. Methods Enzymol 2018; 602:249-272. [PMID: 29588032 DOI: 10.1016/bs.mie.2018.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The physiological activity of xenon has long been recognized, though the exact nature of its interactions with biomolecules remains poorly understood. Xe is an inert noble gas, but can act as a general anesthetic, most likely by binding internal hydrophobic cavities within proteins. Understanding Xe-protein interactions, therefore, can provide crucial insight regarding the mechanism of Xe anesthesia and potentially other general anesthetic agents. Historically, Xe-protein interactions have been studied primarily through X-ray crystallography and nuclear magnetic resonance (NMR). In this chapter, we first describe our methods for preparing Xe derivatives of protein crystals and identifying Xe-binding sites. Second, we detail our procedure for 129Xe hyper-CEST NMR spectroscopy, a versatile NMR technique well suited for characterizing the weak, transient nature of Xe-protein interactions.
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