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Abstract
Pulmonary surfactant is a critical component of lung function in healthy individuals. It functions in part by lowering surface tension in the alveoli, thereby allowing for breathing with minimal effort. The prevailing thinking is that low surface tension is attained by a compression-driven squeeze-out of unsaturated phospholipids during exhalation, forming a film enriched in saturated phospholipids that achieves surface tensions close to zero. A thorough review of past and recent literature suggests that the compression-driven squeeze-out mechanism may be erroneous. Here, we posit that a surfactant film enriched in saturated lipids is formed shortly after birth by an adsorption-driven sorting process and that its composition does not change during normal breathing. We provide biophysical evidence for the rapid formation of an enriched film at high surfactant concentrations, facilitated by adsorption structures containing hydrophobic surfactant proteins. We examine biophysical evidence for and against the compression-driven squeeze-out mechanism and propose a new model for surfactant function. The proposed model is tested against existing physiological and pathophysiological evidence in neonatal and adult lungs, leading to ideas for biophysical research, that should be addressed to establish the physiological relevance of this new perspective on the function of the mighty thin film that surfactant provides.
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Affiliation(s)
- Fred Possmayer
- Department of Biochemistry, Western University, London, Ontario N6A 3K7, Canada
- Department of Obstetrics/Gynaecology, Western University, London, Ontario N6A 3K7, Canada
| | - Yi Y Zuo
- Department of Mechanical Engineering, University of Hawaii at Manon, Honolulu, Hawaii 96822, United States
- Department of Pediatrics, John A. Burns School of Medicine, University of Hawaii, Honolulu, Hawaii 96826, United States
| | - Ruud A W Veldhuizen
- Department of Physiology & Pharmacology, Western University, London, Ontario N6A 5C1, Canada
- Department of Medicine, Western University, London, Ontario N6A 3K7, Canada
- Lawson Health Research Institute, London, Ontario N6A 4V2, Canada
| | - Nils O Petersen
- Department of Chemistry, University of Alberta, Edmonton, Alberta T6G 2G2, Canada
- Department of Chemistry, Western University, London, Ontario N6A 5B7, Canada
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2
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Li J, An Z, Wei L, Xu B, Wang Z, Gao C, Wei L, Qi D, Shi P, Zhang T, Wei D. A New Homotetramer Hemoglobin in the Pulmonary Surfactant of Plateau Zokors (Myospalax Baileyi). Front Genet 2022; 13:824049. [PMID: 35368669 PMCID: PMC8967358 DOI: 10.3389/fgene.2022.824049] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/27/2022] [Indexed: 11/13/2022] Open
Abstract
The plateau zokor (Myospalax baileyi) is a native species to the Qinghai-Tibetan Plateau, inhabiting hypoxia and hypercapnia sealed subterranean burrows that pose several unique physiological challenges. In this study, we observed a novel heme-containing protein in the pulmonary surfactant (PS) of plateau zokor, identified the encoding gene of the protein, predicted its origination and structure, verified its expression in alveolar epithelial cells, and determined the protein’s affinity to oxygen and its effect on the oxygen-dissolving capability in the PS of plateau zokors. The protein is an unusual homotetramer hemoglobin consisting of four γ-like subunits, and the subunit is encoded by a paralog gene of γ, that is γ-like. The divergence time of γ-like from γ is estimated by the molecular clock to be about 2.45 Mya. The generation of γ-like in plateau zokors might well relate to long-time stress of the high land hypoxia. Unlike γ, the γ-like has a hypoxia response element (HRE) and a lung tissue-specific enhancer in its upstream region, and it is expressed specifically in lung tissues and up-regulated by hypoxia. The protein is named as γ4-like which is expressed specifically in Alveolar epithelial type II (ATII) cells and secreted into the alveolar cavities through the osmiophilic multilamellar body (LBs). The γ4-like has a higher affinity to oxygen, and that increases significantly oxygen-dissolving capability in the PS of plateau zokors by its oxygenation function, which might be beneficial for the plateau zokors to obtain oxygen from the severe hypoxia environments by facilitating oxygen diffusion from alveoli to blood.
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Affiliation(s)
- Jimei Li
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
- Research Center for High Altitude Medicine, Qinghai University, Xining, China
| | - Zhifang An
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Linna Wei
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Bo Xu
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
| | - Zhijie Wang
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Conghui Gao
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Lian Wei
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Delin Qi
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
| | - Peng Shi
- State Key Laboratory of Genetic Resources and Evolution, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, China
- *Correspondence: Dengbang Wei, ; Tongzuo Zhang, ; Peng Shi,
| | - Tongzuo Zhang
- Key Laboratory of Adaptation and Evolution of Plateau Biota, Northwest Institute of Plateau Biology, Chinese Academy of Sciences, Xining, China
- *Correspondence: Dengbang Wei, ; Tongzuo Zhang, ; Peng Shi,
| | - Dengbang Wei
- State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University, Xining, China
- Research Center for High Altitude Medicine, Qinghai University, Xining, China
- *Correspondence: Dengbang Wei, ; Tongzuo Zhang, ; Peng Shi,
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3
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Abstract
Purpose The structure of tears has been theoretically considered three tiers with lipids at the air interface, aqueous and proteins in the subphase, and anchored mucins on the corneal epithelial surface. While many lipid and protein species have been identified in tears by mass spectrometry, the localization of the major components within the tear film structure remains speculative. The most controversial components are phospholipids. Although surface active, phospholipids have been presumed to be bound entirely to protein in the aqueous portion of tears or reside at the aqueous-lipid interface. Herein, the possibility that phospholipids are adsorbed at the air-surface interface of tears is interrogated. Methods Polarization-modulated Fourier transform infrared reflective absorption spectroscopy (PM-IRRAS) was used to study the presence of phosphate signals at the tear surface. In order to constrain the depth of signal detection to the surface, an extreme grazing angle of incident radiation was employed. Nulling ellipsometry was used to confirm the presence of monolayers and surface thicknesses when surface active reagents were added to solutions. Results Surface selection of PM-IRRAS was demonstrated by suppression of water and phosphate signals in buffers with monolayers of oleic acid. Phosphate signals were shown to reflect relative concentrations. Absorption peaks attributable to phospholipids were detected by PM-IRRAS on the human tear film surface and were augmented by the addition of phospholipid. Conclusions The data provide strong evidence that phospholipids are present at the surface of tears.
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Affiliation(s)
- Ben J Glasgow
- Departments of Pathology and Ophthalmology, UCLA School of Medicine, Jules Stein Eye Institute, Los Angeles, California, United States
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Morozov VN, Mikheev AY, Shlyapnikov YM, Nikolaev AA, Lyadova IV. Non-invasive lung disease diagnostics from exhaled microdroplets of lung fluid: perspectives and technical challenges. J Breath Res 2017; 12:017103. [PMID: 28850044 PMCID: PMC7099678 DOI: 10.1088/1752-7163/aa88e4] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Revised: 08/22/2017] [Accepted: 08/29/2017] [Indexed: 01/27/2023]
Abstract
The combination of ultra-sensitive assay techniques and recent improvements in the instrumentation used to collect microdroplets of lung fluid (MLF) from exhaled breath has enabled the development of non-invasive lung disease diagnostics that are based on MLF analysis. In one example of this approach, electrospun nylon filters were used to collect MLFs from patients with pulmonary tuberculosis. The filters were washed to obtain liquid probes, which were then tested for human immunoglobulin A (h-IgA) and fractions of h-IgA specific to ESAT-6 and Psts-1, two antigens secreted by Mycobacterium tuberculosis. Probes collected for 10 min contained 100-1500 fg of h-IgA and, in patients with pulmonary tuberculosis, a portion of these h-IgA molecules showed specificity to the secreted antigens. Separate MLFs and their dry residues were successfully collected using an electrostatic collector and impactor developed especially for this purpose. Visualization of MLF dry residues by atomic force microscopy made it possible to estimate the lipid content in each MLF and revealed mucin molecules in some MLFs. This exciting new approach will likely make it possible to detect biomarkers in individual MLFs. MLFs emerging from an infection site ('hot' microdroplets) are expected to be enriched with infection biomarkers. This paper discusses possible experimental approaches to detecting biomarkers in single MLFs, as well as certain technological problems that need to be resolved in order to develop new non-invasive diagnostics based on analysing biomarkers in separate MLFs.
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Affiliation(s)
- Victor N Morozov
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia
- National Center for Biodefense and Infectious Diseases, George Mason University, VA, United States of America
| | - Andrey Y Mikheev
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Yuri M Shlyapnikov
- Institute of Theoretical and Experimental Biophysics of the Russian Academy of Sciences, Pushchino, Moscow Region, Russia
| | - Alexander A Nikolaev
- Department of Immunology, Central Tuberculosis Research Institute, Russian Academy of Medical Sciences, Moscow, Russia
| | - Irina V Lyadova
- Department of Immunology, Central Tuberculosis Research Institute, Russian Academy of Medical Sciences, Moscow, Russia
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Boisselier É, Demers É, Cantin L, Salesse C. How to gather useful and valuable information from protein binding measurements using Langmuir lipid monolayers. Adv Colloid Interface Sci 2017; 243:60-76. [PMID: 28372794 DOI: 10.1016/j.cis.2017.03.004] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Revised: 03/14/2017] [Accepted: 03/15/2017] [Indexed: 12/22/2022]
Abstract
This review presents data on the influence of various experimental parameters on the binding of proteins onto Langmuir lipid monolayers. The users of the Langmuir methodology are often unaware of the importance of choosing appropriate experimental conditions to validate the data acquired with this method. The protein Retinitis pigmentosa 2 (RP2) has been used throughout this review to illustrate the influence of these experimental parameters on the data gathered with Langmuir monolayers. The methods detailed in this review include the determination of protein binding parameters from the measurement of adsorption isotherms, infrared spectra of the protein in solution and in monolayers, ellipsometric isotherms and fluorescence micrographs.
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Affiliation(s)
- Élodie Boisselier
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
| | - Éric Demers
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Line Cantin
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada
| | - Christian Salesse
- CUO-Recherche, Hôpital du Saint-Sacrement, Centre de recherche du CHU de Québec and Département d'ophtalmologie, Faculté de médecine, and Regroupement stratégique PROTEO, Université Laval, Québec, Québec, Canada.
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6
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Soranzo T, Cortès S, Gilde F, Kreir M, Picart C, Lenormand JL. Functional characterization of p7 viroporin from hepatitis C virus produced in a cell-free expression system. Protein Expr Purif 2015; 118:83-91. [PMID: 26477501 DOI: 10.1016/j.pep.2015.10.004] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2015] [Revised: 09/21/2015] [Accepted: 10/09/2015] [Indexed: 01/05/2023]
Abstract
Using a cell-free expression system we produced the p7 viroporin embedded into a lipid bilayer in a single-step manner. The protein quality was assessed using different methods. We examined the channel forming activity of p7 and verified its inhibition by 5-(N,N-Hexamethylene) amiloride (HMA). Fourier transformed infrared spectroscopy (FTIR) experiments further showed that when p7 was inserted into synthetic liposomes, the protein displayed a native-like conformation similar to p7 obtained from other sources. Photoactivable amino acid analogs used for p7 protein synthesis enabled oligomerization state analysis in liposomes by cross-linking. Therefore, these findings emphasize the quality of the cell-free produced p7 proteoliposomes which can benefit the field of the hepatitis C virus (HCV) protein production and characterization and also provide tools for the development of new inhibitors to reinforce our therapeutic arsenal against HCV.
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Affiliation(s)
- Thomas Soranzo
- Synthelis SAS, 5 avenue du Grand Sablon, 38700, La Tronche, France; TheREx Laboratory, TIMC-IMAG, UMR 5525, CNRS /UJF, University Joseph Fourier, UFR de Médecine, 38706, La Tronche, France
| | - Sandra Cortès
- Synthelis SAS, 5 avenue du Grand Sablon, 38700, La Tronche, France
| | - Flora Gilde
- CNRS, UMR 5628 (LMGP), 3 parvis Louis Néel, 38016, Grenoble, France; University of Grenoble Alpes, Grenoble Institute of Technology, 38016, Grenoble, France
| | - Mohamed Kreir
- Nanion Technologies GmbH, Gabrielenstraβe 9, 80636, Munich, Germany
| | - Catherine Picart
- CNRS, UMR 5628 (LMGP), 3 parvis Louis Néel, 38016, Grenoble, France; University of Grenoble Alpes, Grenoble Institute of Technology, 38016, Grenoble, France
| | - Jean-Luc Lenormand
- TheREx Laboratory, TIMC-IMAG, UMR 5525, CNRS /UJF, University Joseph Fourier, UFR de Médecine, 38706, La Tronche, France.
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7
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Composition, structure and mechanical properties define performance of pulmonary surfactant membranes and films. Chem Phys Lipids 2014; 185:153-75. [PMID: 25260665 DOI: 10.1016/j.chemphyslip.2014.09.002] [Citation(s) in RCA: 192] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2014] [Revised: 09/06/2014] [Accepted: 09/11/2014] [Indexed: 12/30/2022]
Abstract
The respiratory surface in the mammalian lung is stabilized by pulmonary surfactant, a membrane-based system composed of multiple lipids and specific proteins, the primary function of which is to minimize the surface tension at the alveolar air-liquid interface, optimizing the mechanics of breathing and avoiding alveolar collapse, especially at the end of expiration. The goal of the present review is to summarize current knowledge regarding the structure, lipid-protein interactions and mechanical features of surfactant membranes and films and how these properties correlate with surfactant biological function inside the lungs. Surfactant mechanical properties can be severely compromised by different agents, which lead to surfactant inhibition and ultimately contributes to the development of pulmonary disorders and pathologies in newborns, children and adults. A detailed comprehension of the unique mechanical and rheological properties of surfactant layers is crucial for the diagnostics and treatment of lung diseases, either by analyzing the contribution of surfactant impairment to the pathophysiology or by improving the formulations in surfactant replacement therapies. Finally, a short review is also included on the most relevant experimental techniques currently employed to evaluate lung surfactant mechanics, rheology, and inhibition and reactivation processes.
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8
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Blume A, Kerth A. Peptide and protein binding to lipid monolayers studied by FT-IRRA spectroscopy. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2013; 1828:2294-305. [PMID: 23816442 DOI: 10.1016/j.bbamem.2013.04.014] [Citation(s) in RCA: 45] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2012] [Accepted: 04/12/2013] [Indexed: 12/30/2022]
Abstract
Lipid monolayers at the air-water interface represent half of a lipid bilayer and are therefore suitable model systems for studying the binding of peripheral proteins and polypeptides as well as proteins containing hydrophobic membrane anchors to membrane interfaces. Infrared reflection-absorption spectroscopy (IRRAS) of these monolayer films at the air-water interface provides information on the state of the lipid monolayers as well as on the conformational and orientational order of the film constituents. We will review shortly the experimental set-up and the possibilities for obtaining structural information before several applications of the method to lipid-protein monolayers will be described. We will focus on examples where the analysis of the protein and peptide bands for pure monolayers of these compounds are combined with experiments where the same compounds are bound to lipid monolayers. Combination of these experiments leads to detailed information about the conformational properties and the orientation of the molecules at the air-water interface in contrast to being bound to the lipid-water interface. This article is part of a Special Issue entitled: FTIR in membrane proteins and peptide studies.
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Affiliation(s)
- Alfred Blume
- Institute of Chemistry, Martin-Luther-University Halle-Wittenberg, von-Danckelmann-Platz 4, D-06120, Halle Saale, Germany.
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9
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Pollard GF, Shaw A, Sowa M, Rand T, Thliveris JA, Scott JE. <i>Stachybotrys chartarum</i> (<i>atra</i>) spore extract alters surfactant protein expression and surfactant function in isolated fetal rat lung epithelial cells, fibroblasts and human A549 cells. ACTA ACUST UNITED AC 2013. [DOI: 10.4236/ojped.2013.33043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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10
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Gilde F, Maniti O, Guillot R, Mano JF, Logeart-Avramoglou D, Sailhan F, Picart C. Secondary structure of rhBMP-2 in a protective biopolymeric carrier material. Biomacromolecules 2012; 13:3620-6. [PMID: 22967015 DOI: 10.1021/bm3010808] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Efficient delivery of growth factors is one of the great challenges of tissue engineering. Polyelectrolyte multilayer films (PEM) made of biopolymers have recently emerged as an interesting carrier for delivering recombinant human bone morphogenetic protein 2 (rhBMP-2 noted here BMP-2) to cells in a matrix-bound manner. We recently showed that PEM made of poly(l-lysine) and hyaluronan (PLL/HA) can retain high and tunable quantities of BMP-2 and can deliver it to cells to induce their differentiation in osteoblasts. Here, we investigate quantitatively by Fourier transform infrared spectroscopy (FTIR) the secondary structure of BMP-2 in solution as well as trapped in a biopolymeric thin film. We reveal that the major structural elements of BMP-2 in solution are intramolecular β-sheets and unordered structures as well as α-helices. Furthermore, we studied the secondary structure of rhBMP-2 trapped in hydrated films and in dry films since drying is an important step for future applications of these bioactive films onto orthopedic biomaterials. We demonstrate that the structural elements were preserved when BMP-2 was trapped in the biopolymeric film in hydrated conditions and, to a lesser extent, in dry state. Importantly, its bioactivity was maintained after drying of the film. Our results appear highly promising for future applications of these films as coatings of biomedical materials, to deliver bioactive proteins while preserving their bioactivity upon storage in dry state.
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Affiliation(s)
- Flora Gilde
- CNRS UMR 5628 (LMGP), Grenoble Institute of Technology and CNRS, 3 parvis Louis Néel, F-38016 Grenoble Cedex, France
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11
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Wang X, Huang X, Xin Y, Du X. Myoglobin-directed assemblies of binary monolayers functionalized with iminodiacetic acid ligands at the air-water interface through metal coordination for multivalent protein binding. Phys Chem Chem Phys 2012; 14:5470-8. [PMID: 22415292 DOI: 10.1039/c2cp40104e] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Myoglobin binding to the binary monolayers composed of sodium hexadecylimino diacetate and hexadecanol at the air-water interface by means of metal coordination has been investigated using infrared reflection absorption spectroscopy (IRRAS). In the absence of Cu(2+), no myoglobin binding to the binary monolayers was observed. In the presence of Cu(2+), remarkable myoglobin binding to the binary monolayers resulted from the formation of ternary complexes of iminodiacetate (IDA)-Cu(2+)-surface histidine. Myoglobin-directed assemblies of the binary monolayers facilitated multivalent protein binding through lateral rearrangements of the IDA ligands and reorientations of the alkyl chains for enhanced protein binding. Myoglobin binding to and desorption from the binary monolayers could be readily controlled through metal coordination.
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Affiliation(s)
- Xiaoyu Wang
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, PR China
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12
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Kong X, Du X. In Situ IRRAS Studies of Molecular Recognition of Barbituric Acid Lipids to Melamine at the Air–Water Interface. J Phys Chem B 2011; 115:13191-8. [DOI: 10.1021/jp207863x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Affiliation(s)
- Xianming Kong
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
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13
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Wang H, Miao W, Liu H, Zhang X, Du X. Molecular Assemblies of 4-(Hexadecyloxy)-N-(pyridinylmethylene)anilines at the Air−Water Interface and Cu(II)-Promoted Vesicle Formation via Metal Coordination. J Phys Chem B 2010; 114:11069-75. [DOI: 10.1021/jp1059352] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Haibo Wang
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Wangen Miao
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Huijin Liu
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Xianfeng Zhang
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
| | - Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China, and School of Chemistry and Technology, Zhanjiang Normal University, Zhanjiang 524048, P. R. China
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Mendelsohn R, Mao G, Flach CR. Infrared reflection-absorption spectroscopy: principles and applications to lipid-protein interaction in Langmuir films. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2010; 1798:788-800. [PMID: 20004639 DOI: 10.1016/j.bbamem.2009.11.024] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/25/2009] [Revised: 11/19/2009] [Accepted: 11/24/2009] [Indexed: 01/08/2023]
Abstract
Infrared reflection-absorption spectroscopy (IRRAS) of lipid/protein monolayer films in situ at the air/water interface provides unique molecular structure and orientation information from the film constituents. The technique is thus well suited for studies of lipid/protein interaction in a physiologically relevant environment. Initially, the nature of the IRRAS experiment is described and the molecular structure information that may be obtained is recapitulated. Subsequently, several types of applications, including the determination of lipid chain conformation and tilt as well as elucidation of protein secondary structure are reviewed. The current article attempts to provide the reader with an understanding of the current capabilities of IRRAS instrumentation and the type of results that have been achieved to date from IRRAS studies of lipids, proteins, and lipid/protein films of progressively increasing complexity. Finally, possible extensions of the technology are briefly considered.
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Affiliation(s)
- Richard Mendelsohn
- Department of Chemistry, Newark College, Rutgers University, 73 Warren Street, Newark, NJ 07102, USA.
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15
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Zheng H, Du X. Protein-Directed Spatial Rearrangement of Glycolipids at the Air−Water Interface for Bivalent Protein Binding: In Situ Infrared Reflection Absorption Spectroscopy. J Phys Chem B 2009; 114:577-84. [DOI: 10.1021/jp908559n] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Haifu Zheng
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
| | - Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People’s Republic of China
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Liu H, Zheng H, Miao W, Du X. In situ studies of metal coordinations and molecular orientations in monolayers of amino-acid-derived Schiff bases at the air-water interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:2941-2948. [PMID: 19437705 DOI: 10.1021/la803976c] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The surface behaviors of monolayers of amino-acid-derived Schiff bases, namely, 4-(4-(hexadecyloxy)benzylideneamino)benzoic acid (HBA), at the air-water interface on pure water and ion-containing subphases (Cu2+, Ca2+, and Ba2+) have been clarified by a combination of surface pressure-area isotherms and surface plasmon resonance (SPR) technique, and the metal coordinations and molecular orientations in the monolayers have been investigated using in situ infrared reflection absorption spectroscopy (IRRAS). The presence of metal ions gives rise to condensation of the monolayers (Cu2+, pH 6.1; Ca2+, pH 11; Ba2+, pH 10), even leading to the formation of three-dimensional structures of the compressed monolayer in the case of Ba2+ (pH 12). The metal coordinations with the carboxyl groups at the interface depend on the type of metal ions and pH of the aqueous subphase. The orientations of the aromatic Schiff base segments with surface pressure are elaborately described. The spectral behaviors of the Schiff base segments with incidence angle in the case of Ba2+ (pH 12) have so far presented an excellent example for the selection rule of IRRAS at the air-water interface for p-polarization with vibrational transition moments perpendicular to the water surface. The chain orientations in the monolayers are quantitatively determined on the assumption that the thicknesses of the HBA monolayers at the air-water interface are composed of the sublayers of alkyl chains and Schiff base segments.
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Affiliation(s)
- Huijin Liu
- MOE Key Laboratory of Mesoscopic Chemistry, State Key Laboratory of Coordination Chemistry, and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People's Republic of China
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17
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Wang L, Brauner JW, Mao G, Crouch E, Seaton B, Head J, Smith K, Flach CR, Mendelsohn R. Interaction of recombinant surfactant protein D with lipopolysaccharide: conformation and orientation of bound protein by IRRAS and simulations. Biochemistry 2008; 47:8103-13. [PMID: 18620419 DOI: 10.1021/bi800626h] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Effective innate host defense requires early recognition of pathogens. Surfactant protein D (SP-D), shown to play a role in host defense, binds to the lipopolysaccharide (LPS) component of Gram-negative bacterial membranes. Binding takes place via the carbohydrate recognition domain (CRD) of SP-D. Recombinant trimeric neck+CRDs (NCRD) have proven valuable in biophysical studies of specific interactions. Although X-ray crystallography has provided atomic level information on NCRD binding to carbohydrates and other ligands, molecular level information about interactions between SP-D and biological ligands under physiologically relevant conditions is lacking. Infrared reflection-absorption spectroscopy (IRRAS) provides molecular structure information from films at the air/water interface where protein adsorption to LPS monolayers serves as a model for protein-lipid interaction. In the current studies, we examine the adsorption of NCRDs to Rd 1 LPS monolayers using surface pressure measurements and IRRAS. Measurements of surface pressure, Amide I band intensities, and LPS acyl chain conformational ordering, along with the introduction of EDTA, permit discrimination of Ca (2+)-mediated binding from nonspecific protein adsorption. The findings support the concept of specific binding between the CRD and heptoses in the core region of LPS. In addition, a novel simulation method that accurately predicts the IR Amide I contour from X-ray coordinates of NCRD SP-D is applied and coupled to quantitative IRRAS equations providing information on protein orientation. Marked differences in orientation are found when the NCRD binds to LPS compared to nonspecific adsorption. The geometry suggests that all three CRDs are simultaneously bound to LPS under conditions that support the Ca (2+)-mediated interaction.
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Affiliation(s)
- Lin Wang
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, Newark, New Jersey 07102, USA
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18
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Liu H, Miao W, Du X. Determination of chain orientation in the monolayers of amino-acid-derived schiff base at the air-water interface using in situ infrared reflection absorption spectroscopy. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:11034-41. [PMID: 17902721 DOI: 10.1021/la702017p] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
The chain orientation in the monolayers of amino-acid-derived Schiff base, 4-(4-dodecyloxy)-2-hydroxybenzylideneamino)benzoic acid (DSA), at the air-water interface has been determined using infrared reflection absorption spectroscopy (IRRAS). On pure water, a condensed monolayer is formed with the long axes of Schiff base segments almost perpendicular to the water surface. In the presence of metal ions (Ca2+, Co2+, Zn2+, Ni2+, and Cu2+) in the subphase, the monolayer is expanded and the long axes of the Schiff base segments are inclined with respect to the monolayer normal depending on metal ion. The monolayer thickness, which is an important parameter for quantitative determination of orientation of hydrocarbon chains, is composed of alkyl chains and salicylideneaniline portions for the DSA monolayers. The effective thickness of the Schiff base portions is roughly estimated in the combination of the IRRAS results and surface pressure-area isotherms for computer simulation, since the only two observable p- and s-polarized reflectance-absorbance (RA) values can be obtained. The alkyl chains with almost all-trans conformations are oriented at an angle of about 10 degrees for H2O, 15 degrees for Ca2+, 30 degrees for Co2+, 35 degrees -40 degrees for Zn2+, and 35 degrees -40 degrees for Ni2+ with respect to the monolayer normal. The chain segments linked with gauche conformers in the case of Cu2+ are estimated to be 40 degrees -50 degrees away from the normal.
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Affiliation(s)
- Huijin Liu
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), and School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, People's Republic of China
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19
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Du X, Wang Y, Ding Y, Guo R. Protein-directed assembly of binary monolayers at the interface and surface patterns of protein on the monolayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2007; 23:8142-9. [PMID: 17583923 DOI: 10.1021/la700955f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/15/2023]
Abstract
Ferritin-directed assembly of binary monolayers of zwitterionic dipalmitoylphosphatidylcholine and cationic dioctadecyldimethylammonium bromide (DOMA) at the interface and surface patterns of ferritin on the monolayers have been investigated using a combination of infrared reflection absorption spectroscopy, surface plasmon resonance, and atomic force microscopy. Ferritin binding to the binary monolayers at the air-water interface at the surface pressure 30 mN/m, primarily driven by the electrostatic interaction, gives rise to a change in tilt angle of hydrocarbon chains from 15 degrees +/- 1 degrees to 10 degrees +/- 1 degrees with respect to the normal of the monolayer at the mole fraction of DOMA (XDOMA) of 0.1. The chains at XDOMA = 0.3 are oriented vertical to the water surface before and after protein binding. A new mechanism for protein binding to the binary monolayers is proposed. The secondary structures of the adsorbed ferritin are prevented from changing to some extent due to the existence of the monolayers. The amounts of the bound protein on the monolayers at the air-water interface are increased in comparison with those on the pre-immobilized monolayers at low XDOMA. The increased amounts and different patterns of the adsorbed protein at the monolayers are mostly attributed to the formation of multiple binding sites available for ferritin, which is due to the lateral reorganization of the lipid components in the monolayers induced by the protein in the subphase. The created multiple binding sites on the monolayer surfaces through the protein-directed assembly can be preserved for subsequent protein binding.
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Affiliation(s)
- Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210093, P. R. China.
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20
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Du X, Wang Y. Directed Assembly of Binary Monolayers with a High Protein Affinity: Infrared Reflection Absorption Spectroscopy (IRRAS) and Surface Plasmon Resonance (SPR). J Phys Chem B 2007; 111:2347-56. [PMID: 17286427 DOI: 10.1021/jp0653196] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Infrared reflection absorption spectroscopy (IRRAS) and surface plasmon resonance (SPR) techniques have been employed to investigate human serum albumin (HSA) binding to binary monolayers of zwitterionic dipalmitoylphosphatidylcholine (DPPC) and cationic dioctadecyldimethylammonium bromide (DOMA). At the air-water interface, the favorable electrostatic interaction between DPPC and DOMA leads to a dense chain packing. The tilt angle of the hydrocarbon chains decreases with increasing mole fraction of DOMA (X(DOMA)) in the monolayers at the surface pressure 30 mN/m: DPPC ( approximately 30 degrees ), X(DOMA) = 0.1 ( approximately 15 degrees ), and X(DOMA) = 0.3 ( approximately 0 degrees ). Negligible protein binding to the DPPC monolayer is observed in contrast to a significant binding to the binary monolayers. After HSA binding, the hydrocarbon chains at X(DOMA) = 0.1 undergo an increase in tilt angle from 15 degrees to 25 approximately 30 degrees , and the chains at X(DOMA) = 0.3 remain almost unchanged. The two components in the monolayers deliver through lateral reorganization, induced by the protein in the subphase, to form multiple interaction sites favorable for protein binding. The surfaces with a high protein affinity are created through the directed assembly of binary monolayers for use in biosensing.
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Affiliation(s)
- Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Ministry of Education), State Key Laboratory of Coordination Chemistry, Nanjing University, Nanjing 210093, People's Republic of China.
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21
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Influence of metal ions on phosphatidylcholine–bovine serum albumin model membrane, an FTIR study. J Mol Struct 2006. [DOI: 10.1016/j.molstruc.2006.01.021] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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22
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Serrano AG, Pérez-Gil J. Protein-lipid interactions and surface activity in the pulmonary surfactant system. Chem Phys Lipids 2006; 141:105-18. [PMID: 16600200 DOI: 10.1016/j.chemphyslip.2006.02.017] [Citation(s) in RCA: 208] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2005] [Accepted: 02/20/2006] [Indexed: 11/30/2022]
Abstract
Pulmonary surfactant is a lipid-protein complex, synthesized and secreted by the respiratory epithelium of lungs to the alveolar spaces, whose main function is to reduce the surface tension at the air-liquid interface to minimize the work of breathing. The activity of surfactant at the alveoli involves three main processes: (i) transfer of surface active molecules from the aqueous hypophase into the interface, (ii) surface tension reduction to values close to 0 mN/m during compression at expiration and (iii) re-extension of the surface active film upon expansion at inspiration. Phospholipids are the main surface active components of pulmonary surfactant, but the dynamic behaviour of phospholipids along the breathing cycle requires the necessary participation of some specific surfactant associated proteins. The present review summarizes the current knowledge on the structure, disposition and lipid-protein interactions of the hydrophobic surfactant proteins SP-B and SP-C, the two main actors participating in the surface properties of pulmonary surfactant. Some of the methodologies currently used to evaluate the surface activity of the proteins in lipid-protein surfactant preparations are also revised. Working models for the potential molecular mechanism of SP-B and SP-C are finally discussed. SP-B might act in surfactant as a sort of amphipathic tag, directing the lipid-protein complexes to insert and re-insert very efficiently into the air-liquid interface along successive breathing cycles. SP-C could be essential to maintain association of lipid-protein complexes with the interface at the highest compressed states, at the end of exhalation. The understanding of the mechanisms of action of these proteins is critical to approach the design and development of new clinical surfactant preparations for therapeutical applications.
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Affiliation(s)
- Alicia G Serrano
- Departamento de Bioquímica y Biología Molecular I, Facultad de Biología, Universidad Complutense, Jose Antonio Novais 2, Madrid, Spain
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23
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Wu YZ, Manevich Y, Baldwin JL, Dodia C, Yu K, Feinstein SI, Fisher AB. Interaction of Surfactant Protein A with Peroxiredoxin 6 Regulates Phospholipase A2 Activity. J Biol Chem 2006; 281:7515-25. [PMID: 16330552 DOI: 10.1074/jbc.m504525200] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Peroxiredoxin 6 (Prdx6) is a "moonlighting" protein with both GSH peroxidase and phospholipase A(2) (PLA(2)) activities. This protein is responsible for degradation of internalized dipalmitoylphosphatidylcholine, the major phospholipid component of lung surfactant. The PLA(2) activity is inhibited by surfactant protein A (SP-A). We postulate that SP-A regulates the PLA(2) activity of Prdx6 through direct protein-protein interaction. Recombinant human Prdx6 and SP-A isolated from human alveolar proteinosis fluid were studied. Measurement of kinetic constants at pH 4.0 (maximal PLA(2) activity) showed K(m)0.35 mm and V(max) 138 nmol/min/mg of protein. SP-A inhibited PLA(2) activity non-competitively with K(i) 10 mug/ml and was Ca(2+) -independent. Activity at pH 7.4 was approximately 50% less, and inhibition by SP-A was partially dependent on Ca(2+). Interaction of SP-A and Prdx6 at pH 7.4 was shown by Prdx6-mediated inhibition of SP-A binding to agarose beads, a pull-down assay using His-tagged Prdx6 and Ni(2) -chelating beads, co-immunoprecipitation from lung epithelial cells and from a binary mixture of the two proteins, binding after treatment with a trifunctional cross-linker, and size-exclusion chromatography. Analysis by static light scattering and surface plasmon resonance showed calcium-independent SP-A binding to Prdx6 at pH 4.0 and partial Ca(2+) dependence of binding at pH 7.4. These results indicate a direct interaction between SP-A and Prdx6, which provides a mechanism for regulation of the PLA(2) activity of Prdx6 by SP-A.
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Affiliation(s)
- Yong-Zheng Wu
- Institute for Environmental Medicine, University of Pennsylvania, One John Morgan Building, 3620 Hamilton Walk, Philadelphia, PA 19104-6068, USA
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24
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Wüstneck R, Perez-Gil J, Wüstneck N, Cruz A, Fainerman VB, Pison U. Interfacial properties of pulmonary surfactant layers. Adv Colloid Interface Sci 2005; 117:33-58. [PMID: 16120435 DOI: 10.1016/j.cis.2005.05.001] [Citation(s) in RCA: 145] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2004] [Revised: 02/16/2005] [Accepted: 05/20/2005] [Indexed: 11/25/2022]
Abstract
The composition of the pulmonary surfactant and the border conditions of normal human breathing are relevant to characterize the interfacial behavior of pulmonary layers. Based on experimental data methods are reviewed to investigate interfacial properties of artificial pulmonary layers and to explain the behavior and interfacial structures of the main components during compression and expansion of the layers observed by epifluorescence and scanning force microscopy. Terms like over-compression, collapse, and formation of the surfactant reservoir are discussed. Consequences for the viscoelastic surface rheological behavior of such layers are elucidated by surface pressure relaxation and harmonic oscillation experiments. Based on a generalized Volmer isotherm the interfacial phase transition is discussed for the hydrophobic surfactant proteins, SP-B and SP-C, as well as for the mixtures of dipalmitoylphosphatidylcholine (DPPC) with these proteins. The behavior of the layers depends on both the oligomerisation state and the secondary structure of the hydrophobic surfactant proteins, which are controlled by the preparation of the proteins. An example for the surface properties of bronchoalveolar porcine lung washings of uninjured, injured, and Curosurf treated lavage is discussed in the light of surface behavior. An outlook summarizes the present knowledge and the main future development in this field of surface science.
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Affiliation(s)
- R Wüstneck
- Charité, Campus Virchow-Klinikum, Universitätsmedizin Berlin, Klinik für Anästhesiologie und operative Intensivmedizin, Spandauer Damm 130, 14050 Berlin, Germany.
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25
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Campbell RA, Day JPR, Bain CD. External reflection Fourier transform infrared spectroscopy of surfactants at the air-water interface: separation of bulk and adsorbed surfactant signals. APPLIED SPECTROSCOPY 2005; 59:993-1001. [PMID: 16105207 DOI: 10.1366/0003702054615241] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/04/2023]
Abstract
External reflection Fourier transform infrared spectroscopy (ERFTIRS) has been used to obtain spectra of monolayers of the hydrocarbon surfactant octaethylene glycol monodecyl ether (C(10)E(8)) and the fluorocarbon surfactant ammonium perfluorononanoate (APFN) at the expanding liquid surface of an overflowing cylinder. The use of target factor analysis (TFA) to separate out the contributions of water, adsorbed surfactant, and dissolved surfactant is demonstrated. For both surfactants, there is a linear relationship between the component weight of the adsorbed surfactant, obtained by TFA, and the surface excess determined independently by ellipsometry or neutron reflection. This linear relationship suggests that the monolayers behave like isotropic films with a constant density. A sensitivity of less than 10% of a monolayer is demonstrated. The benefits of using a multivariate curve fitting procedure to analyze sets of ER-FTIR spectra are discussed and some potential pitfalls are identified. This technique is also applicable to static interfaces.
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Affiliation(s)
- Richard A Campbell
- Department of Chemistry, University of Oxford, Chemistry Research Laboratory, UK
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26
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Casals C, García-Verdugo I. Molecular and Functional Properties of Surfactant Protein A. LUNG BIOLOGY IN HEALTH AND DISEASE 2005. [DOI: 10.1201/b14169-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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27
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Du X, Miao W, Liang Y. IRRAS Studies on Chain Orientation in the Monolayers of Amino Acid Amphiphiles at the Air−Water Interface Depending on Metal Complex and Hydrogen Bond Formation with the Headgroups. J Phys Chem B 2005; 109:7428-34. [PMID: 16851851 DOI: 10.1021/jp0441700] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Monolayers of N-octadecanoyl-L-alanine at the air-water interface on pure water and metal ion containing subphases have been studied using polarized infrared reflection-absorption spectroscopy (IRRAS). The metal complex and hydrogen bond formation with the headgroups give rise to a change in chain order depending on metal ion in the subphase. On pure water and Ag(+)-/Pb(2+)-containing subphase, the antisymmetric CH(2) stretching band intensity [nu(a)(CH(2))] undergoes a slower increase than the symmetric one [nu(s)(CH(2))] below the Brewster angle, so the intensity ratios of nu(a)(CH(2))/nu(s)(CH(2)) are less than 1 in the cases of Ag(+) and Pb(2+). Beyond the Brewster angle, the nu(a)(CH(2)) band intensities are substantially reduced in comparison with the nu(s)(CH(2)) ones in the cases of pure water and Ag(+), but the nu(a)(CH(2)) bands still remain negative-oriented in the presence of Pb(2+). These unusual spectral features indicate that the alkyl chains take a preferential orientation with their C-C-C planes parallel to the water surface. The parallel packing of the alkyl chains results from the intermolecular hydrogen bonds C=O...H-N between the neighboring amide groups, strengthened by the metal complex of covalent interaction. On the Ca(2+)-/Cu(2+)-containing subphase, the corresponding polarized spectra display a usual behavior. The alkyl chains are roughly estimated to be inclined around 35-40 degrees from the surface normal on the assumption of chain segment orientation for the monolayers in the liquid-expanded phase. The chain conformation and tilt are closely related to the formation of intramolecular hydrogen bonds and the ionic interaction of the metal complex in the cases of Ca(2+) and Cu(2+).
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Affiliation(s)
- Xuezhong Du
- Key Laboratory of Mesoscopic Chemistry (Nanjing University), Ministry of Education, and Department of Chemistry, Nanjing University, Nanjing 210093, People's Republic of China.
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28
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Hussain H, Kerth A, Blume A, Kressler J. Amphiphilic Block Copolymers of Poly(ethylene oxide) and Poly(perfluorohexylethyl methacrylate) at the Water Surface and Their Penetration into the Lipid Monolayer. J Phys Chem B 2004. [DOI: 10.1021/jp0495702] [Citation(s) in RCA: 61] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- H. Hussain
- Department of Engineering Science and Department of Chemistry, Martin-Luther-University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - A. Kerth
- Department of Engineering Science and Department of Chemistry, Martin-Luther-University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - A. Blume
- Department of Engineering Science and Department of Chemistry, Martin-Luther-University Halle-Wittenberg, D-06099 Halle (Saale), Germany
| | - J. Kressler
- Department of Engineering Science and Department of Chemistry, Martin-Luther-University Halle-Wittenberg, D-06099 Halle (Saale), Germany
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29
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Xu Z, Brauner JW, Flach CR, Mendelsohn R. Orientation of peptides in aqueous monolayer films. Infrared reflection-absorption spectroscopy studies of a synthetic amphipathic beta-sheet. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2004; 20:3730-3. [PMID: 15875407 DOI: 10.1021/la0304316] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Infrared reflection-absorption spectroscopy (IRRAS) intensities of the Amide I vibration are used to develop a quantitative approach for determining the Euler angles that describe the orientation of protein beta-sheets in aqueous monolayer films. A synthetic amphipathic peptide, Val-Glu-Val-Orn-Val-Glu-Val-Orn-Val-Glu-Val-Orn-Val-OH is used as a test case. The pattern of Amide I frequencies suggests that the molecule is organized as an antiparallel beta-sheet at the air/water interface. The model used to simulate the Amide I intensities reveals that the beta-sheet has a slight preferential alignment parallel to the direction of compression; i.e., deviation from uniaxial symmetry is observed. In addition, the sheet is found to lie flat on the aqueous surface, with (presumably) the polar side chains interacting with the aqueous subphase. Limitations and advantages of the theoretical approach are discussed.
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Affiliation(s)
- Zhi Xu
- Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102, USA
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30
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Brauner JW, Flach CR, Xu Z, Bi X, Lewis RNAH, McElhaney RN, Gericke A, Mendelsohn R. Quantitative Functional Group Orientation in Langmuir Films by Infrared Reflection−Absorption Spectroscopy: CO Groups in Behenic Acid Methyl Ester and sn2-13C-DSPC. J Phys Chem B 2003. [DOI: 10.1021/jp030066r] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Joseph W. Brauner
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Carol R. Flach
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Zhi Xu
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Xiaohong Bi
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Ruthven N. A. H. Lewis
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Ronald N. McElhaney
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Arne Gericke
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
| | - Richard Mendelsohn
- Department of Biochemistry, University of Alberta, Edmonton, Alberta, Canada T6G2H7, Department of Chemistry, Kent State University, Kent, Ohio 44242, and Department of Chemistry, Newark College of Arts and Science, Rutgers University, 73 Warren Street, Newark, New Jersey 07102
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31
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Abstract
Pulmonary surfactant functions by first flowing rapidly into the alveolar air/water interface, but then resisting collapse from the surface when the adsorbed interfacial film is compressed during exhalation. Widely accepted models emphasize the importance of phase behavior in both processes. Recent studies show, however, that fluidity is a relatively minor determinant of adsorption and that solid films, which resist collapse, can form by kinetic processes unrelated to equilibrium phase behavior.
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Affiliation(s)
- Barbora Piknova
- Molecular Medicine, Mail Code NRC-3, Oregon Health & Science University, Portland 97201-3098, USA.
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