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Zhang Y, Zhang L, Cai C, Zhang J, Lu P, Shi N, Zhu W, He N, Pan X, Wang T, Feng Z. In situ study of structural changes: Exploring the mechanism of protein corona transition from soft to hard. J Colloid Interface Sci 2024; 654:935-944. [PMID: 37898077 DOI: 10.1016/j.jcis.2023.10.095] [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: 06/17/2023] [Revised: 10/12/2023] [Accepted: 10/18/2023] [Indexed: 10/30/2023]
Abstract
HYPOTHESIS The process of protein corona changes has been widely believed to follow the Vroman effect, while protein structural change during the process is rarely reported, due to the lack of analytical methods. In-situ interpretation for protein structural change is critical to processes such as the recognition and transport of nanomaterials. EXPERIMENTS Molecular dynamics (MD) simulation was used to predict the deflection and twist of the protein tertiary structure. The structural changes of the surface protein corona during the interaction of nanoparticles (NPs) with lipid bilayer were probed in situ and real-time by sum frequency generation (SFG) spectroscopy. FINDINGS The ring tertiary structure of the protein corona is altered from vertical to horizontal on particle surface, a process of the soft-to-hard structural transition, which is contributed by the hydrogen bonding force between the protein and water molecules. The negatively charged protein corona can induce the redistribution of interfacial charge, leading to a more stable hydrogen bond network of the interfacial water. Our findings suggest that the structural change from flexible to rigid is a crucial process in the soft-to-hard transition of the protein corona, which will be a beneficial supplement to the Vroman effect of protein adsorption.
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Affiliation(s)
- Yixin Zhang
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Liqiang Zhang
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Chenglong Cai
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Jixiang Zhang
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Pengyu Lu
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Neng Shi
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Weiran Zhu
- SceneRay Co., Ltd., Suzhou 215123, China
| | - Nongyue He
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China
| | - Xuchao Pan
- Nanjing University of Science and Technology, Nanjing 210094, China.
| | - Ting Wang
- State Key Laboratory of Bioelectronics, National Demonstration Center for Experimental Biomedical Engineering Education, School of Biological Science and Medical Engineering, Southeast University, Nanjing 210096, China.
| | - Zhangqi Feng
- Nanjing University of Science and Technology, Nanjing 210094, China
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Gahtori P, Gunwant V, Pandey R. How Does pH Affect the Adsorption of Human Serum Protein in the Presence of Hydrophobic and Hydrophilic Nanoparticles at Air-Water and Lipid-Water Interfaces? LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15487-15498. [PMID: 37878019 DOI: 10.1021/acs.langmuir.3c01755] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
This study investigates interaction between hydrophilic (11-mercaptoundecanoic acid (MUA)) and hydrophobic (1-undecanethiol (UDT)) gold nanoparticles (GNPs) with human serum albumin (HSA) protein on air-water and lipid-water interfaces at pH 3 and 7. Vibrational sum frequency generation (VSFG) spectroscopy is used to analyze changes in the intensity of interfacial water molecules and the C-H group of the protein. At the air-water interface, the hydrophobic interaction between the HSA protein and hydrophobic GNPs at pH 3 leads to their accumulation at the interface, resulting in an increased C-H intensity of the protein with a slight decrease in water intensity. Whereas, at pH 7, where the negative charge of the protein results in the reduced surface activity of the HSA compared to pH 3, the interaction between alkyl chain of the hydrophobic GNPs and alkyl group of the protein results in the adsorption of the protein-capped GNPs at the interface. This leads to an increased intensity of the C-H group of protein and water molecules. However, negatively charged hydrophilic GNPs do not induce significant changes in the interfacial water structure or the C-H group of the protein due to the electrostatic force of repulsion with the negatively charged HSA at pH 7. In contrast, at the lipid-water interface, both hydrophobic and hydrophilic GNPs interact with HSA protein, causing disordering of interfacial water molecules at pH 3 and ordering at pH 7. Interestingly, similar behavior of the protein with both types of GNPs results in comparable ordering/disordering at the interface depending on the pH of solution. Furthermore, the VSFG results obtained with the deuterated lipid suggest that changes in ordering and disorder occur due to increased protein adsorption in the presence of GNPs, causing alterations in the membrane structure. These findings give a better understanding of the mechanisms that govern protein-nanoparticle interaction and their consequential effects on the structure, function, and behavior of molecules at the biological membrane interface, which is crucial for developing safe and effective nanoparticle-based therapeutics.
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Affiliation(s)
- Preeti Gahtori
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Vineet Gunwant
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
| | - Ravindra Pandey
- Department of Chemistry, Indian Institute of Technology Roorkee, Roorkee 247667, Uttarakhand, India
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Yang P, Guo W, Ramamoorthy A, Chen Z. Conformation and Orientation of Antimicrobial Peptides MSI-594 and MSI-594A in a Lipid Membrane. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:5352-5363. [PMID: 37017985 DOI: 10.1021/acs.langmuir.2c03430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
There is significant interest in the development of antimicrobial compounds to overcome the increasing bacterial resistance to conventional antibiotics. Studies have shown that naturally occurring and de novo-designed antimicrobial peptides could be promising candidates. MSI-594 is a synthetic linear, cationic peptide that has been reported to exhibit a broad spectrum of antimicrobial activities. Investigation into how MSI-594 disrupts the cell membrane is important for better understanding the details of this antimicrobial peptide (AMP)'s action against bacterial cells. In this study, we used two different synthetic lipid bilayers: zwitterionic 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) and anionic 7:3 POPC/1-palmitoyl-2-oleoyl-sn-glycero-3-phospho(1'-rac-glycerol) (POPG). Sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) were used to determine the orientations of MSI-594 and its analogue MSI-594A associated with zwitterionic POPC and anionic 7:3 POPC/POPG lipid bilayers. The simulated ATR-FTIR and SFG spectra using nuclear magnetic resonance (NMR)-determined structures were compared with experimental spectra to optimize the bent angle between the N- (1-11) and C- (12-24) termini helices and the membrane orientations of the helices; since the NMR structure of the peptide was determined from lipopolysaccharide (LPS) micelles, the optimization was needed to find the most suitable conformation and orientation in lipid bilayers. The reported experimental results indicate that the optimized MSI-594 helical hairpin structure adopts a complete lipid bilayer surface-bound orientation (denoted "face-on") in both POPC and 7:3 POPC/POPG lipid bilayers. The analogue peptide, MSI-584A, on the other hand, exhibited a larger bent angle between the N- (1-11) and C- (12-24) termini helices with the hydrophobic C-terminal helix inserted into the hydrophobic region of the bilayer (denoted "membrane-inserted") when interacting with both POPC and 7:3 POPC/POPG lipid bilayers. These experimental findings on the membrane orientations suggest that both peptides are likely to disrupt the cell membrane through the carpet mechanism.
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Affiliation(s)
- Pei Yang
- Department of Chemistry, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Wen Guo
- Department of Chemistry, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Ayyalusamy Ramamoorthy
- Department of Chemistry, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
- Department of Biophysics, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
| | - Zhan Chen
- Department of Chemistry, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
- Department of Biophysics, The University of Michigan, 930 North University Avenue, Ann Arbor, Michigan 48109-1055, United States
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Guo W, Lu T, Gandhi Z, Chen Z. Probing Orientations and Conformations of Peptides and Proteins at Buried Interfaces. J Phys Chem Lett 2021; 12:10144-10155. [PMID: 34637311 DOI: 10.1021/acs.jpclett.1c02956] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Molecular structures of peptides/proteins at interfaces determine their interfacial properties, which play important roles in many applications. It is difficult to probe interfacial peptide/protein structures because of the lack of appropriate tools. Sum frequency generation (SFG) vibrational spectroscopy has been developed into a powerful technique to elucidate molecular structures of peptides/proteins at buried solid/liquid and liquid/liquid interfaces. SFG has been successfully applied to study molecular interactions between model cell membranes and antimicrobial peptides/membrane proteins, surface-immobilized peptides/enzymes, and physically adsorbed peptides/proteins on polymers and 2D materials. A variety of other analytical techniques and computational simulations provide supporting information to SFG studies, leading to more complete understanding of structure-function relationships of interfacial peptides/proteins. With the advance of SFG techniques and data analysis methods, along with newly developed supplemental tools and simulation methodology, SFG research on interfacial peptides/proteins will further impact research in fields like chemistry, biology, biophysics, engineering, and beyond.
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Affiliation(s)
- Wen Guo
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Tieyi Lu
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zahra Gandhi
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan 48109, United States
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5
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Golbek TW, Otto SC, Roeters SJ, Weidner T, Johnson CP, Baio JE. Direct Evidence That Mutations within Dysferlin's C2A Domain Inhibit Lipid Clustering. J Phys Chem B 2021; 125:148-157. [PMID: 33355462 DOI: 10.1021/acs.jpcb.0c07143] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Mechanical stress on sarcolemma can create small tears in the muscle cell membrane. Within the sarcolemma resides the multidomain dysferlin protein. Mutations in this protein render it unable to repair the sarcolemma and have been linked to muscular dystrophy. A key step in dysferlin-regulated repair is the binding of the C2A domain to the lipid membrane upon increased intracellular calcium. Mutations mapped to this domain cause loss of binding ability of the C2A domain. There is a crucial need to understand the geometry of dysferlin C2A at a membrane interface as well as cell membrane lipid reorientation when compared to that of a mutant. Here, we describe a comparison between the wild-type dysferlin C2A and a mutation to the conserved aspartic acids in the domain binding loops. To identify both the geometry and the cell membrane lipid reorientation, we applied sum frequency generation (SFG) vibrational spectroscopy and coupled it with simulated SFG spectra to observe and quantify the interaction with a model cell membrane composed of phosphotidylserine and phosphotidylcholine. Observed changes in surface pressure demonstrate that calcium-bridged electrostatic interactions govern the initial interaction of the C2A domains docking with a lipid membrane. SFG spectra taken from the amide-I region for the wild type and variant contain features near 1642, 1663, and 1675 cm-1 related to the C2A domain β-sandwich secondary structure, indicating that the domain binds in a specific orientation. Mapping simulated SFG spectra to the experimentally collected spectra indicated that both wild-type and variant domains have nearly the same orientation to the membrane surface. However, examining the ordering of the lipids that make up a model membrane using SFG, we find that the wild type clusters the lipids as seen by the increase in the ratio of the CD3 and CD2 symmetric intensities by 170% for the wild type and by 120% for the variant. This study highlights the capabilities of SFG to probe with great detail biological mutations in proteins at cell membrane interfaces.
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Affiliation(s)
| | - Shauna C Otto
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Steven J Roeters
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - Tobias Weidner
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
| | - Colin P Johnson
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon 97331, United States
| | - Joe E Baio
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon 97331, United States
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6
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Hosseinpour S, Roeters SJ, Bonn M, Peukert W, Woutersen S, Weidner T. Structure and Dynamics of Interfacial Peptides and Proteins from Vibrational Sum-Frequency Generation Spectroscopy. Chem Rev 2020; 120:3420-3465. [DOI: 10.1021/acs.chemrev.9b00410] [Citation(s) in RCA: 75] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Saman Hosseinpour
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | | | - Mischa Bonn
- Molecular Spectroscopy Department, Max Planck Institute for Polymer Research, 55128 Mainz, Germany
| | - Wolfgang Peukert
- Institute of Particle Technology (LFG), Friedrich-Alexander-University Erlangen-Nürnberg (FAU), 91058 Erlangen, Germany
| | - Sander Woutersen
- Van’t Hoff Institute for Molecular Sciences, University of Amsterdam, 1098 EP Amsterdam, The Netherlands
| | - Tobias Weidner
- Department of Chemistry, Aarhus University, 8000 Aarhus C, Denmark
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7
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Golbek TW, Padmanarayana M, Roeters SJ, Weidner T, Johnson CP, Baio JE. Otoferlin C2F Domain-Induced Changes in Membrane Structure Observed by Sum Frequency Generation. Biophys J 2019; 117:1820-1830. [PMID: 31587832 DOI: 10.1016/j.bpj.2019.09.010] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2019] [Revised: 08/16/2019] [Accepted: 09/10/2019] [Indexed: 12/30/2022] Open
Abstract
Proteins that contain C2 domains are involved in a variety of biological processes, including encoding of sound, cell signaling, and cell membrane repair. Of particular importance is the interface activity of the C-terminal C2F domain of otoferlin due to the pathological mutations known to significantly disrupt the protein's lipid membrane interface binding activity, resulting in hearing loss. Therefore, there is a critical need to define the geometry and positions of functionally important sites and structures at the otoferlin-lipid membrane interface. Here, we describe the first in situ probe of the protein orientation of otoferlin's C2F domain interacting with a cell membrane surface. To identify this protein's orientation at the lipid interface, we applied sum frequency generation (SFG) vibrational spectroscopy and coupled it with simulated SFG spectra to observe and quantify the otoferlin C2F domain interacting with model lipid membranes. A model cell membrane was built with equal amounts of phosphatidylserine and phosphatidylcholine. SFG measurements of the lipids that make up the model membrane indicate a 62% increase in amplitude from the SFG signal near 2075 cm-1 upon protein interaction, suggesting domain-induced changes in the orientation of the lipids and possible membrane curvature. This increase is related to lipid ordering caused by the docking interaction of the otoferlin C2F domain. SFG spectra taken from the amide-I region contain features near 1630 and 1670 cm-1 related to the C2F domains beta-sandwich secondary structure, thus indicating that the domain binds in a specific orientation. By mapping the simulated SFG spectra to the experimentally collected SFG spectra, we found the C2F domain of otoferlin orients 22° normal to the lipid surface. This information allows us to map what portion of the domain directly interacts with the lipid membrane.
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Affiliation(s)
- Thaddeus W Golbek
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon; Department of Chemistry, Aarhus University, Aarhus, Denmark
| | | | | | - Tobias Weidner
- Department of Chemistry, Aarhus University, Aarhus, Denmark
| | - Colin P Johnson
- Department of Biochemistry and Biophysics, Oregon State University, Corvallis, Oregon.
| | - Joe E Baio
- School of Chemical, Biological, and Environmental Engineering, Oregon State University, Corvallis, Oregon.
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8
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Lux S, Baldauf‐Sommerbauer G, Siebenhofer M. Hydrogenation of Inorganic Metal Carbonates: A Review on Its Potential for Carbon Dioxide Utilization and Emission Reduction. CHEMSUSCHEM 2018; 11:3357-3375. [PMID: 30098275 PMCID: PMC6221144 DOI: 10.1002/cssc.201801356] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/18/2018] [Indexed: 06/08/2023]
Abstract
Carbonaceous minerals represent a valuable and abundant resource. Their exploitation is based on decarboxylation at elevated temperature and under oxidizing conditions, which inevitably release carbon dioxide into the atmosphere. Hydrogenation of inorganic metal carbonates opens up a new pathway for processing several metal carbonates. Preliminary experimental studies revealed significant advantages over conventional isolation technologies. Under a reducing hydrogen atmosphere, the temperature of decarboxylation is significantly lower. Carbon dioxide is not directly released into the atmosphere, but may be reduced to carbon monoxide, methane, and higher hydrocarbons, which adds value to the overall process. Apart from metal oxides in different oxidation states, metals in their elemental form may also be obtained if transition-metal carbonates are processed under a hydrogen atmosphere. This review summarizes the most important findings and fields of the application of metal carbonate hydrogenation to elucidate the need for a detailed investigation into optimized process conditions for large-scale applications.
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Affiliation(s)
- Susanne Lux
- Institute of Chemical Engineering and Environmental TechnologyGraz University of TechnologyInffeldgasse 25C/II8010GrazAustria
| | - Georg Baldauf‐Sommerbauer
- Institute of Chemical Engineering and Environmental TechnologyGraz University of TechnologyInffeldgasse 25C/II8010GrazAustria
| | - Matthäus Siebenhofer
- Institute of Chemical Engineering and Environmental TechnologyGraz University of TechnologyInffeldgasse 25C/II8010GrazAustria
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9
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Wang T, Feng Z, Wang C, He N. Real-time investigation of interactions between nanoparticles and cell membrane model. Colloids Surf B Biointerfaces 2018; 164:70-77. [DOI: 10.1016/j.colsurfb.2018.01.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2017] [Revised: 12/07/2017] [Accepted: 01/09/2018] [Indexed: 12/12/2022]
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10
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Han X, Zheng J, Lin F, Kuroda K, Chen Z. Interactions between Surface-Immobilized Antimicrobial Peptides and Model Bacterial Cell Membranes. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:512-520. [PMID: 29232144 DOI: 10.1021/acs.langmuir.7b03411] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Sum frequency generation (SFG) vibrational spectroscopy was used to study surface immobilization effects on the interactions between antimicrobial peptide cecropin P1 (CP1) and model cell membranes. While free CP1 in solution interacted with a model cell membrane composed of a phosphatidylglycerol (PG) bilayer, electrostatic interaction led to the attachment of CP1 molecules onto the PG surface and the hydrophobic domain in the lipid bilayer enabled the peptides to insert into the bilayer and form α-helices from random coil structures. While CP1 molecules immobilized on a self-assembled monolayer interacted with PG lipid vesicles, the intensity of the SFG peak for the peptide α-helix decreased as the PG vesicle concentration increased. It was believed that when surface-immobilized CP1 molecules interacted with lipid vesicles, they lay down on the surface or became random coils. When the immobilized CP1 interacted with a PG lipid monolayer on water, the strong interaction led to the lying-down orientation of all of the surface-immobilized peptides as well. Differently, no significant interactions between surface-immobilized CP1 with the mammalian cell membrane model 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer were observed. Our results suggest that, instead of membrane insertion, the electrostatic interactions between the surface cationic charges of CP1 and anionic bacterial membranes may play an important role in the antimicrobial activity of the surface-immobilized CP1 peptide.
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Affiliation(s)
- Xiaofeng Han
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, National Demonstration Center for Experimental Biomedical Engineering Education, Southeast University , Nanjing 210096, China
| | - Jingguo Zheng
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, National Demonstration Center for Experimental Biomedical Engineering Education, Southeast University , Nanjing 210096, China
| | - Fengming Lin
- State Key Laboratory of Bioelectronics, School of Biological Science and Medical Engineering, National Demonstration Center for Experimental Biomedical Engineering Education, Southeast University , Nanjing 210096, China
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11
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Identifying the selectivity of antimicrobial peptides to cell membranes by sum frequency generation spectroscopy. Biointerphases 2017; 12:02D406. [PMID: 28476090 DOI: 10.1116/1.4982710] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Cationic amphiphilic peptides have been engineered to target both Gram-positive and Gram-negative bacteria while avoiding damage to other cell types. However, the exact mechanism of how these peptides target, bind, and disrupt bacterial cell membranes is not understood. One specific peptide that has been engineered to selectively capture bacteria is WLBU2 (sequence: RRWVRRVRRWVRRVVRVVRRWVRR). It has been suggested that WLBU2 activity stems from the fact that when interacting with bacterial cell membranes the peptide assumes an α-helical structure and inserts itself into the membrane. Alternatively, in the presence of mammalian cell membranes, the peptide assumes an inert β-sheet structure. To test this hypothesis, the authors applied sum frequency generation (SFG) spectroscopy and surface tensiometry to identify the structure of WLBU2 as it interacts with model lipid monolayers that mimic mammalian and bacterial cell membranes. Model mammalian cell membranes were built upon zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphocholine lipids while bacterial cell membranes were constructed with negatively charged 1,2-dimyristoyl-sn-glycero-3-phospho-(1'-rac-glycerol) lipids. Observed changes in surface pressure at the peptide-lipid-air interface demonstrate that the peptide has a clear binding preference toward negatively charged bacteria-like lipids. The structure of both the lipids and peptides were characterized by SFG spectra collected at the monolayer interface. Changes in monolayer structure as the peptide binds were observed by tracking the intensities of SFG vibrational modes related to the acyl chains within the lipids. Peptide structures when bound to both types of lipids were determined by SFG spectra collected within the amide I vibrational band. The SFG spectra of WLBU2 interacting with the model mammalian lipid monolayer contain two peaks near 1642 and 1678 cm-1 indicative of an inactive β-sheet structure. SFG spectra collected from the peptide bound to a bacteria-like lipid monolayer contains just a single peak near 1651 cm-1 which corresponds to an active α-helix structure. Combined, the tensiometry and SFG results demonstrate that WLBU2 both possesses a higher binding affinity toward and is in an active α-helix structure when bound to bacterial cell membranes.
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12
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Xiao M, Joglekar S, Zhang X, Jasensky J, Ma J, Cui Q, Guo LJ, Chen Z. Effect of Interfacial Molecular Orientation on Power Conversion Efficiency of Perovskite Solar Cells. J Am Chem Soc 2017; 139:3378-3386. [DOI: 10.1021/jacs.6b10651] [Citation(s) in RCA: 47] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
| | | | - Xiaoxian Zhang
- CAS
Key laboratory of Standardization and Measurement for Nanotechnology,
Chinese Academy of Sciences Center for Excellence in Nanoscience, National Center for Nanoscience and Technology, Beijing 100190, China
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13
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Yu T, Zhou G, Hu X, Ye S. Transport and Organization of Cholesterol in a Planar Solid-Supported Lipid Bilayer Depend on the Phospholipid Flip-Flop Rate. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:11681-11689. [PMID: 27756133 DOI: 10.1021/acs.langmuir.6b02560] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
Understanding the transport behavior of the cholesterol molecules within a cell membrane is a key challenge in cell biology at present. Here, we have applied sum frequency generation vibrational spectroscopy to characterize the transport and organization of cholesterol in different kinds of planar solid-supported lipid bilayers by combining achiral- and chiral-sensitive polarization measurements. This method allows us to distinguish the organization of cholesterol in tail-to-tail, head-to-tail, head-to-head, and side-by-side manners. It is found that the movement of cholesterol in the lipid bilayer largely depends on the flip-flop rate of the phospholipid. The flip-flop dynamics of the phospholipid and cholesterol are synchronous. In the solid-supported zwitterionic phosphocholine lipid bilayer, the cholesterol molecules flip quickly from the distal leaflet to the neutral proximal leaflet of the bilayer and form tail-to-tail organization on both leaflets. The phosphocholine lipid and cholesterol show the same flip-flop rate. However, when the proximal leaflet is prepared using negative glycerol phospholipids, cholesterol organizes itself by mainly forming an α-β structure on the distal leaflet. Because of the strong interaction between the glycerol phospholipid and the substrate, no or only partial cholesterol molecules flip from the distal leaflet to the negatively charged proximal leaflet. However, the cholesterol molecules undergo flip-flop in the presence of salt solution because the ions weaken the interaction between the negative phospholipid and the substrate.
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Affiliation(s)
- Ting Yu
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Guangnan Zhou
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Xia Hu
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
| | - Shuji Ye
- Hefei National Laboratory for Physical Sciences at the Microscale, and Department of Chemical Physics and ‡Synergetic Innovation Center of Quantum Information & Quantum Physics, University of Science and Technology of China , Hefei, Anhui 230026, China
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14
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Franz J, Lelle M, Peneva K, Bonn M, Weidner T. SAP(E) – A cell-penetrating polyproline helix at lipid interfaces. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:2028-2034. [DOI: 10.1016/j.bbamem.2016.05.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/25/2016] [Revised: 05/09/2016] [Accepted: 05/24/2016] [Indexed: 12/19/2022]
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15
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Hankett JM, Collin WR, Yang P, Chen Z, Duhaime M. Low-Volatility Model Demonstrates Humidity Affects Environmental Toxin Deposition on Plastics at a Molecular Level. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2016; 50:1304-1312. [PMID: 26752114 DOI: 10.1021/acs.est.5b05598] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Despite the ever-increasing prevalence of plastic debris and endocrine disrupting toxins in aquatic ecosystems, few studies describe their interactions in freshwater environments. We present a model system to investigate the deposition/desorption behaviors of low-volatility lake ecosystem toxins on microplastics in situ and in real time. Molecular interactions of gas-phase nonylphenols (NPs) with the surfaces of two common plastics, poly(styrene) and poly(ethylene terephthalate), were studied using quartz crystal microbalance and sum frequency generation vibrational spectroscopy. NP point sources were generated under two model environments: plastic on land and plastic on a freshwater surface. We found the headspace above calm water provides an excellent environment for NP deposition and demonstrate significant NP deposition on plastic within minutes at relevant concentrations. Further, NP deposits and orders differently on both plastics under humid versus dry environments. We attributed the unique deposition behaviors to surface energy changes from increased water content during the humid deposition. Lastly, nanograms of NP remained on microplastic surfaces hours after initial NP introduction and agitating conditions, illustrating feasibility for plastic-bound NPs to interact with biota and surrounding matter. Our model studies reveal important interactions between low-volatility environmental toxins and microplastics and hold potential to correlate the environmental fate of endocrine disrupting toxins in the Great Lakes with molecular behaviors.
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Affiliation(s)
- Jeanne M Hankett
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States
| | - William R Collin
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States
| | - Pei Yang
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States
| | - Zhan Chen
- Department of Chemistry, University of Michigan , 930 North University Avenue, Ann Arbor, Michigan 48109 United States
| | - Melissa Duhaime
- Department of Ecology and Evolutionary Biology, University of Michigan , 830 North University Ave, Ann Arbor, Michigan 48109 United States
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16
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Duarte AA, Botelho do Rego AM, Salerno M, Ribeiro PA, El Bari N, Bouchikhi B, Raposo M. DPPG Liposomes Adsorbed on Polymer Cushions: Effect of Roughness on Amount, Surface Composition and Topography. J Phys Chem B 2015; 119:8544-52. [PMID: 26076391 DOI: 10.1021/acs.jpcb.5b02384] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The adsorption of intact liposomes onto solid supports is a fundamental issue when preparing systems with encapsulated biological molecules. In this work, the adsorption kinetic of 1,2-dipalmitoyl-sn-glycero-3-[phospho-rac-(1-glycerol)] (sodium salt) liposomes onto cushions prepared from commom polyelectrolytes by the layer-by-layer technique was investigated with the main objective of finding the surface conditions leading to the adsorption of intact liposomes. For this purpose, different cushion surface roughnesses were obtained by changing the number of cushion bilayers. The adsorbed amount per unit area was measured through quartz crystal microbalance, surface morphology was characterized by atomic force microscopy, and the surface composition was assessed by X-ray photoelectron spectroscopy. The results show that (1) the amount of adsorbed lipids depends on the number of cushion bilayers, (2) the cushions are uniformly covered by the adsorbed lipids, and (3) the surface morphology of polymer cushions tunes liposome rupture and its adsorption kinetics. The fraction of ruptured liposomes, calculated from the measured amount of adsorbed lipids, is a function of surface roughness together with other surface morphology parameters, namely the dominating in-plane spatial feature size, the fractal dimension, and other textural features as well as amplitude and hybrid parameters.
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Affiliation(s)
- Andreia A Duarte
- †CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Ana M Botelho do Rego
- ‡Centro de Química-Física Molecular and IN, Complexo Interdisciplinar, Instituto Superior Técnico, University of Lisbon, 1049-001 Lisboa, Portugal
| | - Marco Salerno
- §Istituto Italiano di Tecnologia, via Morego 30, 16163 Genova, Italy
| | - Paulo A Ribeiro
- †CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
| | - Nezha El Bari
- ∥Biotechnology Agroalimentary and Biomedical Analysis Group, Moulay Ismaïl University, Faculty of Sciences, Biology Department, B.P. 11201, Zitoune, Meknes, Morocco
| | | | - Maria Raposo
- †CEFITEC, Departamento de Física, Faculdade de Ciências e Tecnologia, FCT, Universidade Nova de Lisboa, 2829-516 Caparica, Portugal
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17
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Volpati D, Aoki PHB, Alessio P, Pavinatto FJ, Miranda PB, Constantino CJL, Oliveira ON. Vibrational spectroscopy for probing molecular-level interactions in organic films mimicking biointerfaces. Adv Colloid Interface Sci 2014; 207:199-215. [PMID: 24530000 DOI: 10.1016/j.cis.2014.01.014] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2013] [Revised: 11/28/2013] [Accepted: 01/13/2014] [Indexed: 01/26/2023]
Abstract
Investigation into nanostructured organic films has served many purposes, including the design of functionalized surfaces that may be applied in biomedical devices and tissue engineering and for studying physiological processes depending on the interaction with cell membranes. Of particular relevance are Langmuir monolayers, Langmuir-Blodgett (LB) and layer-by-layer (LbL) films used to simulate biological interfaces. In this review, we shall focus on the use of vibrational spectroscopy methods to probe molecular-level interactions at biomimetic interfaces, with special emphasis on three surface-specific techniques, namely sum frequency generation (SFG), polarization-modulated infrared reflection absorption spectroscopy (PM-IRRAS) and surface-enhanced Raman scattering (SERS). The two types of systems selected for exemplifying the potential of the methods are the cell membrane models and the functionalized surfaces with biomolecules. Examples will be given on how SFG and PM-IRRAS can be combined to determine the effects from biomolecules on cell membrane models, which include determination of the orientation and preservation of secondary structure. Crucial information for the action of biomolecules on model membranes has also been obtained with PM-IRRAS, as is the case of chitosan removing proteins from the membrane. SERS will be shown as promising for enabling detection limits down to the single-molecule level. The strengths and limitations of these methods will also be discussed, in addition to the prospects for the near future.
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Affiliation(s)
- Diogo Volpati
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | - Pedro H B Aoki
- Faculty of Science and Technology, UNESP, Presidente Prudente, CEP 19060-900 SP,Brazil
| | - Priscila Alessio
- Faculty of Science and Technology, UNESP, Presidente Prudente, CEP 19060-900 SP,Brazil
| | - Felippe J Pavinatto
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | - Paulo B Miranda
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil
| | | | - Osvaldo N Oliveira
- São Carlos Institute of Physics, University of São Paulo, CP 369, São Carlos, SP 13560-970, Brazil.
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18
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Roy S, Covert PA, FitzGerald WR, Hore DK. Biomolecular Structure at Solid–Liquid Interfaces As Revealed by Nonlinear Optical Spectroscopy. Chem Rev 2014; 114:8388-415. [DOI: 10.1021/cr400418b] [Citation(s) in RCA: 93] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Affiliation(s)
- Sandra Roy
- Department
of Chemistry, University of Victoria, Victoria, British Columbia, V8W 3V6 Canada
| | - Paul A. Covert
- Department
of Chemistry, University of Victoria, Victoria, British Columbia, V8W 3V6 Canada
| | - William R. FitzGerald
- Department
of Chemistry, University of Victoria, Victoria, British Columbia, V8W 3V6 Canada
| | - Dennis K. Hore
- Department
of Chemistry, University of Victoria, Victoria, British Columbia, V8W 3V6 Canada
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19
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Liu W, Wang Z, Fu L, Leblanc RM, Yan ECY. Lipid compositions modulate fluidity and stability of bilayers: characterization by surface pressure and sum frequency generation spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:15022-31. [PMID: 24245525 DOI: 10.1021/la4036453] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Abstract
Cell membranes are crucial to many biological processes. Because of their complexity, however, lipid bilayers are often used as model systems. Lipid structures influence the physical properties of bilayers, but their interplay, especially in multiple-component lipid bilayers, has not been fully explored. Here, we used the Langmuir-Blodgett method to make mono- and bilayers of 1,2-dihexadecanoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (DPPG), 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) (POPG), and 1-hexadecanoyl-2-(9Z-octadecenoyl)-sn-glycero-3-phospho-L-serine (POPS) as well as their 1:1 binary mixtures. We studied the fluidity, stability, and rigidity of these structures using sum frequency generation (SFG) spectroscopy combined with analyses of surface pressure-area isotherms, compression modulus, and stability. Our results show that single-component bilayers, both saturated and unsaturated, may not be ideal membrane mimics because of their low fluidity and/or stability. However, the binary saturated and unsaturated DPPG/POPG and DPPG/POPS systems show not only high stability and fluidity but also high resistance to changes in surface pressure, especially in the range of 25-35 mN/m, the range typical of cell membranes. Because the ratio of saturated to unsaturated lipids is highly regulated in cells, our results underline the possibility of modulating biological properties using lipid compositions. Also, our use of flat optical windows as solid substrates in SFG experiments should make the SFG method more compatible with other techniques, enabling more comprehensive future surface characterizations of bilayers.
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Affiliation(s)
- Wei Liu
- Department of Chemistry, Yale University , 225 Prospect Street, New Haven, Connecticut 06520, United States
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20
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Yang P, Glukhova A, Tesmer JJG, Chen Z. Membrane orientation and binding determinants of G protein-coupled receptor kinase 5 as assessed by combined vibrational spectroscopic studies. PLoS One 2013; 8:e82072. [PMID: 24278472 PMCID: PMC3838385 DOI: 10.1371/journal.pone.0082072] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2013] [Accepted: 10/20/2013] [Indexed: 11/18/2022] Open
Abstract
G-protein coupled receptors (GPCRs) are integral membrane proteins involved in a wide variety of biological processes in eukaryotic cells, and are targeted by a large fraction of marketed drugs. GPCR kinases (GRKs) play important roles in feedback regulation of GPCRs, such as of β-adrenergic receptors in the heart, where GRK2 and GRK5 are the major isoforms expressed. Membrane targeting is essential for GRK function in cells. Whereas GRK2 is recruited to the membrane by heterotrimeric Gβγ subunits, the mechanism of membrane binding by GRK5 is not fully understood. It has been proposed that GRK5 is constitutively associated with membranes through elements located at its N-terminus, its C-terminus, or both. The membrane orientation of GRK5 is also a matter of speculation. In this work, we combined sum frequency generation (SFG) vibrational spectroscopy and attenuated total reflectance-Fourier transform infrared spectroscopy (ATR-FTIR) to help determine the membrane orientation of GRK5 and a C-terminally truncated mutant (GRK51-531) on membrane lipid bilayers. It was found that GRK5 and GRK51-531 adopt a similar orientation on model cell membranes in the presence of PIP2 that is similar to that predicted for GRK2 in prior studies. Mutation of the N-terminal membrane binding site of GRK5 did not eliminate membrane binding, but prevented observation of this discrete orientation. The C-terminus of GRK5 does not have substantial impact on either membrane binding or orientation in this model system. Thus, the C-terminus of GRK5 may drive membrane binding in cells via interactions with other proteins at the plasma membrane or bind in an unstructured manner to negatively charged membranes.
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Affiliation(s)
- Pei Yang
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
| | - Alisa Glukhova
- Departments of Pharmacology and Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- Program in Chemical Biology, University of Michigan, Ann Arbor, Michigan, United States of America
| | - John J. G. Tesmer
- Departments of Pharmacology and Biological Chemistry, Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (ZC); (JJGT)
| | - Zhan Chen
- Department of Chemistry, University of Michigan, Ann Arbor, Michigan, United States of America
- * E-mail: (ZC); (JJGT)
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21
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Khan MS, Dosoky NS, Williams JD. Engineering lipid bilayer membranes for protein studies. Int J Mol Sci 2013; 14:21561-97. [PMID: 24185908 PMCID: PMC3856022 DOI: 10.3390/ijms141121561] [Citation(s) in RCA: 81] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2013] [Revised: 10/13/2013] [Accepted: 10/21/2013] [Indexed: 01/05/2023] Open
Abstract
Lipid membranes regulate the flow of nutrients and communication signaling between cells and protect the sub-cellular structures. Recent attempts to fabricate artificial systems using nanostructures that mimic the physiological properties of natural lipid bilayer membranes (LBM) fused with transmembrane proteins have helped demonstrate the importance of temperature, pH, ionic strength, adsorption behavior, conformational reorientation and surface density in cellular membranes which all affect the incorporation of proteins on solid surfaces. Much of this work is performed on artificial templates made of polymer sponges or porous materials based on alumina, mica, and porous silicon (PSi) surfaces. For example, porous silicon materials have high biocompatibility, biodegradability, and photoluminescence, which allow them to be used both as a support structure for lipid bilayers or a template to measure the electrochemical functionality of living cells grown over the surface as in vivo. The variety of these media, coupled with the complex physiological conditions present in living systems, warrant a summary and prospectus detailing which artificial systems provide the most promise for different biological conditions. This study summarizes the use of electrochemical impedance spectroscopy (EIS) data on artificial biological membranes that are closely matched with previously published biological systems using both black lipid membrane and patch clamp techniques.
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Affiliation(s)
- Muhammad Shuja Khan
- Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA; E-Mail:
| | - Noura Sayed Dosoky
- Biological Sciences Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA; E-Mail:
| | - John Dalton Williams
- Electrical and Computer Engineering Department, University of Alabama in Huntsville, Huntsville, AL 35899, USA; E-Mail:
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22
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Balhara V, Schmidt R, Gorr SU, DeWolf C. Membrane selectivity and biophysical studies of the antimicrobial peptide GL13K. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2193-203. [DOI: 10.1016/j.bbamem.2013.05.027] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/03/2013] [Revised: 05/24/2013] [Accepted: 05/27/2013] [Indexed: 01/27/2023]
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23
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Yang P, Wu FG, Chen Z. Lipid Fluid-Gel Phase Transition Induced Alamethicin Orientational Change Probed by Sum Frequency Generation Vibrational Spectroscopy. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2013; 117:17039-17049. [PMID: 24124624 PMCID: PMC3792402 DOI: 10.1021/jp4047215] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Alamethicin has been extensively studied as an antimicrobial peptide (AMP) and is widely used as a simple model for ion channel proteins. It has been shown that the antimicrobial activity of AMPs is related to their cell membrane orientation, which may be influenced by the phase of the lipid molecules in the cell membrane. The "healthy" cell membranes contain fluid phase lipids, while gel phase lipids can be found in injured or aged cells or in some phase separated membrane regions. Thus, investigations on how the phase of the lipids influences the membrane orientation of AMPs are important to understand more details regarding the AMP's action on cell membranes. In this study, we determined the orientational changes of alamethicin molecules associated with planar substrate supported single lipid bilayers (serving as model cell membranes) with different phases (fluid or gel) as a function of peptide concentration using sum frequency generation (SFG) vibrational spectroscopy. The phase changes of the lipid bilayers were realized by varying the sample temperature. Our SFG results indicated that alamethicin lies down on the surface of fluid and gel phase 1,2-dimyristoyl(d54)-sn-glycero-3-phosphocholine (d-DMPC) lipid bilayers when the lipid bilayers are in contact with a peptide solution with a low concentration of 0.84 μM. However, at a medium peptide concentration of 10.80 μM, alamethicin inserts into the fluid phase lipid bilayer. Its orientation switches from a transmembrane to an in-plane (or lying down) orientation when the phase of the lipid bilayer changes from a fluid state to a gel state. At a high peptide concentration of 21.60 μM, alamethicin adopts a transmembrane orientation while associated with both fluid and gel phase lipid bilayers. We also studied the structural changes of the fluid and gel phase lipid bilayers upon their interactions with alamethicin molecules at different peptide concentrations.
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Affiliation(s)
| | | | - Zhan Chen
- To whom correspondence should be addressed. Fax: 734-647-4865;
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24
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Keszthelyi T, Hill K, Kiss É. Interaction of Phospholipid Langmuir Monolayers with an Antibiotic Peptide Conjugate. J Phys Chem B 2013; 117:6969-79. [DOI: 10.1021/jp401533c] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Tamás Keszthelyi
- Institute of Molecular Pharmacology,
Research Centre for Natural Sciences, Hungarian Academy of Sciences, H-1025 Budapest, Pusztaszeri út
59-67, Hungary
| | - Katalin Hill
- Laboratory
of Interfaces and
Nanostructures, Institute of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518 Budapest
112, Hungary
| | - Éva Kiss
- Laboratory
of Interfaces and
Nanostructures, Institute of Chemistry, Eötvös Loránd University, P.O. Box 32, H-1518 Budapest
112, Hungary
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25
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Kett PJN, Casford MTL, Davies PB. Sum Frequency Generation Vibrational Spectroscopy of Cholesterol in Hybrid Bilayer Membranes. J Phys Chem B 2013; 117:6455-65. [DOI: 10.1021/jp403584j] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Affiliation(s)
- Peter J. N. Kett
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Michael T. L. Casford
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
| | - Paul B. Davies
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge CB2 1EW, U.K
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26
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Yang P, Boughton A, Homan KT, Tesmer JJG, Chen Z. Membrane orientation of Gα(i)β(1)γ(2) and Gβ(1)γ(2) determined via combined vibrational spectroscopic studies. J Am Chem Soc 2013; 135:5044-51. [PMID: 23461393 DOI: 10.1021/ja3116026] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The manner in which the heterotrimeric G protein complexes Gβ1γ2 and Gαiβ1γ2 interact with membranes is likely related to their biological function. We combined complementary measurements from sum frequency generation (SFG) vibrational and attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy to determine the possible membrane orientations of Gβ1γ2 and the Gαiβ1γ2 heterotrimer more precisely than could be achieved using SFG alone. The most likely orientations of Gβ1γ2 and the Gαiβ1γ2 heterotrimer were both determined to fall within a similar narrow range of twist and tilt angles, suggesting that Gβ1γ2 may bind to Gαi without a significant change in orientation. This "basal" orientation seems to depend primarily on the geranylgeranylated C-terminus of Gγ2 along with basic residues at the N-terminus of Gαi, and suggests that activated G protein-coupled receptors (GPCRs) must reorient G protein heterotrimers at lipid bilayers to catalyze nucleotide exchange. The innovative methodologies developed in this paper can be widely applied to study the membrane orientation of other proteins in situ.
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Affiliation(s)
- Pei Yang
- Department of Chemistry, University of Michiga n, 930 North University Avenue, Ann Arbor, Michigan 48109, United States
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27
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Yang P, Wu FG, Chen Z. Dependence of Alamethicin Membrane Orientation on the Solution Concentration. THE JOURNAL OF PHYSICAL CHEMISTRY. C, NANOMATERIALS AND INTERFACES 2013; 117:3358-3365. [PMID: 23565299 PMCID: PMC3613978 DOI: 10.1021/jp3099522] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Alamethicin has been extensively studied as an antimicrobial peptide and is widely used as a simple model for ion channel proteins. It has been shown that the antimicrobial activity of peptides is related to their membrane orientation. In this study, we determined the relationship between the solution concentration of alamethicin and its membrane orientation in lipid bilayers using sum frequency generation (SFG) vibrational spectroscopy. Our SFG results indicated that the alamethicin molecules more or less lay down on the surface of 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) lipid bilayers at a low peptide concentration of 0.84 μM; the α-helix segment tilts at about 88°, and 310-helix segment tilts at about 58° versus the surface normal. However, when the peptide concentration was increased to 15.6 μM, we observed that alamethicin molecules further inserted into the lipid bilayers: the α-helical component changes its orientation to make a 37° tilt from the lipid bilayer normal, and the 310-helical component tilts at about 50° versus the surface normal. This is in agreement with the barrel-stave mode for the alamethicin-cell membrane interaction as reported previously. Additionally, we have also studied membrane orientation of alamethicin as a function of peptide concentration with SFG. Our results showed that the membrane orientation of the alamethicin α-helical component changed substantially with the increase of the alamethicin concentration, while the membrane orientation of the 310-helical component remained more or less the same.
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Affiliation(s)
| | | | - Zhan Chen
- To whom correspondence should be addressed. Fax: 734-647-4865.
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28
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Prudovsky I, Kumar TKS, Sterling S, Neivandt D. Protein-phospholipid interactions in nonclassical protein secretion: problem and methods of study. Int J Mol Sci 2013; 14:3734-72. [PMID: 23396106 PMCID: PMC3588068 DOI: 10.3390/ijms14023734] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2012] [Revised: 01/24/2013] [Accepted: 01/25/2013] [Indexed: 12/30/2022] Open
Abstract
Extracellular proteins devoid of signal peptides use nonclassical secretion mechanisms for their export. These mechanisms are independent of the endoplasmic reticulum and Golgi. Some nonclassically released proteins, particularly fibroblast growth factors (FGF) 1 and 2, are exported as a result of their direct translocation through the cell membrane. This process requires specific interactions of released proteins with membrane phospholipids. In this review written by a cell biologist, a structural biologist and two membrane engineers, we discuss the following subjects: (i) Phenomenon of nonclassical protein release and its biological significance; (ii) Composition of the FGF1 multiprotein release complex (MRC); (iii) The relationship between FGF1 export and acidic phospholipid externalization; (iv) Interactions of FGF1 MRC components with acidic phospholipids; (v) Methods to study the transmembrane translocation of proteins; (vi) Membrane models to study nonclassical protein release.
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Affiliation(s)
- Igor Prudovsky
- Maine Medical Center Research Institute, 81 Research Drive, Scarborough, ME 04074, USA
| | | | - Sarah Sterling
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
| | - David Neivandt
- Department of Chemical and Biological Engineering, University of Maine, Orono, ME 04469, USA; E-Mails: (S.S.); (D.N.)
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29
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Barth C, Jakubczyk D, Kubas A, Anastassacos F, Brenner-Weiss G, Fink K, Schepers U, Bräse S, Koelsch P. Interkingdom signaling: integration, conformation, and orientation of N-acyl-L-homoserine lactones in supported lipid bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2012; 28:8456-62. [PMID: 22568488 PMCID: PMC3388113 DOI: 10.1021/la301241s] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/03/2023]
Abstract
N-Acyl-L-homoserine lactones (AHLs) are small cell-to-cell signaling molecules involved in the regulation of population density and local gene expression in microbial communities. Recent evidence shows that contact of this signaling system, usually referred to as quorum sensing, to living eukaryotes results in interactions of AHL with host cells in a process termed "interkingdom signaling". So far details of this process and the binding site of the AHLs remain unknown; both an intracellular and a membrane-bound receptor seem possible, the first of which requires passage through the cell membrane. Here, we used sum-frequency-generation (SFG) spectroscopy to investigate the integration, conformation, orientation, and translocation of deuterated N-acyl-L-homoserine lactones (AHL-d(n)) with varying chain length (8, 12, and 14 C atoms) in lipid bilayers consisting of a 1:1 mixture of POPC:POPG supported on SiO(2) substrates (prepared by vesicle fusion). We found that all AHL-d(n) derivatives are well-ordered within the supported lipid bilayer (SLB) in a preferentially all-trans conformation of the deuterated alkyl chain and integrated into the upper leaflet of the SLB with the methyl terminal groups pointing downward. For the bilayer system described above, no flip-flop of AHL-d(n) from the upper leaflet to the lower one could be observed. Spectral assignments and interpretations were further supported by Fourier transform infrared and Raman spectroscopy.
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Affiliation(s)
- Christoph Barth
- Institute for Toxicology and Genetics, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Dorota Jakubczyk
- Institute for Functional Interfaces, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Adam Kubas
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Frances Anastassacos
- Institute for Toxicology and Genetics, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Gerald Brenner-Weiss
- Institute for Functional Interfaces, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Karin Fink
- Institute of Nanotechnology, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Ute Schepers
- Institute for Toxicology and Genetics, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Stefan Bräse
- Institute of Organic Chemistry, Karlsruhe Institute of Technology, Postfach 3640, 76021 Karlsruhe, Germany
| | - Patrick Koelsch
- National ESCA and Surface Analysis Center for Biomedical Problems, Department of Bioengineering, University of Washington, Box 35170, Seattle, WA 98195-1750
- Corresponding author.
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Padermshoke A, Konishi S, Ara M, Tada H, Ishibashi TA. Novel SiO2-deposited CaF2 substrate for vibrational sum-frequency generation (SFG) measurements of chemisorbed monolayers in an aqueous environment. APPLIED SPECTROSCOPY 2012; 66:711-718. [PMID: 22732544 DOI: 10.1366/11-06583] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
A novel SiO(2)-deposited CaF(2) (SiO(2)/CaF(2)) substrate for measuring vibrational sum-frequency generation (SFG) spectra of silane-based chemisorbed monolayers in aqueous media has been developed. The substrate is suitable for silanization and transparent over a broad range of the infrared (IR) probe. The present work demonstrates the practical application of the SiO(2)/CaF(2) substrate and, to our knowledge, the first SFG spectrum at the solid/water interface of a silanized monolayer observed over the IR fingerprint region (1780-1400 cm(-1)) using a back-side probing geometry. This new substrate can be very useful for SFG studies of various chemisorbed organic molecules, particularly biological compounds, in aqueous environments.
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Affiliation(s)
- Adchara Padermshoke
- Center for Quantum Life Sciences, Hiroshima University, Higashi-Hiroshima, Japan
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31
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Sanderson JM. Resolving the kinetics of lipid, protein and peptide diffusion in membranes. Mol Membr Biol 2012; 29:118-43. [DOI: 10.3109/09687688.2012.678018] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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