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Gochev GG, Campbell RA, Schneck E, Zawala J, Warszynski P. Exploring proteins at soft interfaces and in thin liquid films - From classical methods to advanced applications of reflectometry. Adv Colloid Interface Sci 2024; 329:103187. [PMID: 38788307 DOI: 10.1016/j.cis.2024.103187] [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: 03/13/2024] [Revised: 05/12/2024] [Accepted: 05/12/2024] [Indexed: 05/26/2024]
Abstract
The history of the topic of proteins at soft interfaces dates back to the 19th century, and until the present day, it has continuously attracted great scientific interest. A multitude of experimental methods and theoretical approaches have been developed to serve the research progress in this large domain of colloid and interface science, including the area of soft colloids such as foams and emulsions. From classical methods like surface tension adsorption isotherms, surface pressure-area measurements for spread layers, and surface rheology probing the dynamics of adsorption, nowadays, advanced surface-sensitive techniques based on spectroscopy, microscopy, and the reflection of light, X-rays and neutrons at liquid/fluid interfaces offers important complementary sources of information. Apart from the fundamental characteristics of protein adsorption layers, i.e., surface tension and surface excess, the nanoscale structure of such layers and the interfacial protein conformations and morphologies are of pivotal importance for extending the depth of understanding on the topic. In this review article, we provide an extensive overview of the application of three methods, namely, ellipsometry, X-ray reflectometry and neutron reflectometry, for adsorption and structural studies on proteins at water/air and water/oil interfaces. The main attention is placed on the development of experimental approaches and on a discussion of the relevant achievements in terms of notable experimental results. We have attempted to cover the whole history of protein studies with these techniques, and thus, we believe the review should serve as a valuable reference to fuel ideas for a wide spectrum of researchers in different scientific fields where proteins at soft interface may be of relevance.
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Affiliation(s)
- Georgi G Gochev
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30239 Krakow, Poland; Institute of Physical Chemistry, Bulgarian Academy of Sciences, 1113 Sofia, Bulgaria.
| | - Richard A Campbell
- Division of Pharmacy and Optometry, University of Manchester, M13 9PT Manchester, UK
| | - Emanuel Schneck
- Physics Department, Technical University Darmstadt, 64289 Darmstadt, Germany
| | - Jan Zawala
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30239 Krakow, Poland
| | - Piotr Warszynski
- Jerzy Haber Institute of Catalysis and Surface Chemistry, Polish Academy of Sciences, 30239 Krakow, Poland
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Chaudhary S, Kaur H, Kaur H, Rana B, Tomar D, Jena KC. Probing the Bovine Hemoglobin Adsorption Process and its Influence on Interfacial Water Structure at the Air-Water Interface. APPLIED SPECTROSCOPY 2021; 75:1497-1509. [PMID: 34346774 DOI: 10.1177/00037028211035157] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
*These authors contributed equally to this work.The molecular-level insight of protein adsorption and its kinetics at interfaces is crucial because of its multifold role in diverse fundamental biological processes and applications. In the present study, the sum frequency generation (SFG) vibrational spectroscopy has been employed to demonstrate the adsorption process of bovine hemoglobin (BHb) protein molecules at the air-water interface at interfacial isoelectric point of the protein. It has been observed that surface coverage of BHb molecules significantly influences the arrangement of the protein molecules at the interface. The time-dependent SFG studies at two different frequencies in the fingerprint region elucidate the kinetics of protein denaturation process and its influence on the hydrogen-bonding network of interfacial water molecules at the air-water interface. The initial growth kinetics suggests the synchronized behavior of protein adsorption process with the structural changes in the interfacial water molecules. Interestingly, both the events carry similar characteristic time constants. However, the conformational changes in the protein structure due to the denaturation process stay for a long time, whereas the changes in water structure reconcile quickly. It is revealed that the protein denaturation process is followed by the advent of strongly hydrogen-bonded water molecules at the interface. In addition, we have also carried out the surface tension kinetics measurements to complement the findings of our SFG spectroscopic results.
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Affiliation(s)
- Shilpi Chaudhary
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, India
- Department of Applied Sciences, Punjab Engineering College (Deemed to be University), Chandigarh, India
| | - Harsharan Kaur
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar, India
| | - Harpreet Kaur
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, India
| | - Bhawna Rana
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, India
| | - Deepak Tomar
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, India
| | - Kailash C Jena
- Department of Physics, Indian Institute of Technology Ropar, Rupnagar, India
- Department of Biomedical Engineering, Indian Institute of Technology Ropar, Rupnagar, India
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3
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β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 5. Adsorption Isotherm and Equation of State Revisited, Impact of pH. COLLOIDS AND INTERFACES 2021. [DOI: 10.3390/colloids5010014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The theoretical description of the adsorption of proteins at liquid/fluid interfaces suffers from the inapplicability of classical formalisms, which soundly calls for the development of more complicated adsorption models. A Frumkin-type thermodynamic 2-d solution model that accounts for nonidealities of interface enthalpy and entropy was proposed about two decades ago and has been continuously developed in the course of comparisons with experimental data. In a previous paper we investigated the adsorption of the globular protein β-lactoglobulin at the water/air interface and used such a model to analyze the experimental isotherms of the surface pressure, Π(c), and the frequency-, f-, dependent surface dilational viscoelasticity modulus, E(c)f, in a wide range of protein concentrations, c, and at pH 7. However, the best fit between theory and experiment proposed in that paper appeared incompatible with new data on the surface excess, Γ, obtained from direct measurements with neutron reflectometry. Therefore, in this work, the same model is simultaneously applied to a larger set of experimental dependences, e.g., Π(c), Γ(c), E(Π)f, etc., with E-values measured strictly in the linear viscoelasticity regime. Despite this ambitious complication, a best global fit was elaborated using a single set of parameter values, which well describes all experimental dependencies, thus corroborating the validity of the chosen thermodynamic model. Furthermore, we applied the model in the same manner to experimental results obtained at pH 3 and pH 5 in order to explain the well-pronounced effect of pH on the interfacial behavior of β-lactoglobulin. The results revealed that the propensity of β-lactoglobulin globules to unfold upon adsorption and stretch at the interface decreases in the order pH 3 > pH 7 > pH 5, i.e., with decreasing protein net charge. Finally, we discuss advantages and limitations in the current state of the model.
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Gochev GG, Scoppola E, Campbell RA, Noskov BA, Miller R, Schneck E. β-Lactoglobulin Adsorption Layers at the Water/Air Surface: 3. Neutron Reflectometry Study on the Effect of pH. J Phys Chem B 2019; 123:10877-10889. [PMID: 31725291 DOI: 10.1021/acs.jpcb.9b07733] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Several characteristics of β-lactoglobulin (BLG) layers adsorbed at the air/water interface exhibit a strong pH dependence, but our knowledge on the underlying structure-property relations is still fragmental. Here, we therefore extend our recent studies by neutron reflectometry (NR) and provide a comprehensive overview through direct measurements of the surface excess Γ and the layers' molecular structure. This enables comparison with available literature data to draw general conclusions. The NR experiments were performed at various pH values and within a wide range of protein concentrations, CBLG. Adsorption kinetics measurements in air-contrast-matched-water and over a narrow Qz range enabled direct quantification of the dynamic surface excess Γ(t) and are found to be consistent with ellipsometry data. Near the isoelectric point, pI, the rates of adsorption and Γ are maximal but only at sufficiently high CBLG. NR data collected over a wider Qz range and in two aqueous isotopic contrasts revealed the structure of adsorbed BLG layers at a steady state close to equilibrium. Independent of the pH, BLG was found to form dense monolayers with average thicknesses of 1.1 nm, suggesting flattening of the BLG globules upon adsorption as compared with their bulk dimensions (≈3.5 nm). Near pI and at sufficiently high CBLG, a thick (≈5.5 nm) but looser secondary sublayer is additionally formed adjacent to the dense primary monolayer. The thickness of this sublayer can be interpreted in terms of disordered BLG dimers. The results obtained and notably the specific interfacial structuring of BLG near pI complement previous observations relating the impact of solution pH and CBLG on other interfacial characteristics such as surface pressure and surface dilational viscoelasticity modulus.
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Affiliation(s)
- Georgi G Gochev
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany.,Institute of Physical Chemistry , Bulgarian Academy of Sciences , 1113 Sofia , Bulgaria
| | - Ernesto Scoppola
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany
| | - Richard A Campbell
- Institut Laue-Langevin , 71 Avenue des Martyrs, CS20156 , 38042 Grenoble , France.,Division of Pharmacy and Optometry , University of Manchester , M13 9PT Manchester , U.K
| | - Boris A Noskov
- Institute of Chemistry , St. Petersburg State University , 198504 Saint-Petersburg , Russia
| | - Reinhard Miller
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany
| | - Emanuel Schneck
- Max Planck Institute of Colloids and Interfaces , 14476 Potsdam , Germany
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Molecular simulation of protein adsorption and conformation at gas-liquid, liquid–liquid and solid–liquid interfaces. Curr Opin Colloid Interface Sci 2019. [DOI: 10.1016/j.cocis.2018.11.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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Devineau S, Inoue KI, Kusaka R, Urashima SH, Nihonyanagi S, Baigl D, Tsuneshige A, Tahara T. Change of the isoelectric point of hemoglobin at the air/water interface probed by the orientational flip-flop of water molecules. Phys Chem Chem Phys 2017; 19:10292-10300. [DOI: 10.1039/c6cp08854f] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Nonlinear vibrational spectroscopy reveals that the isoelectric point of proteins can largely change when the proteins are adsorbed at the air/water interface.
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Affiliation(s)
- Stéphanie Devineau
- Molecular Spectroscopy Laboratory
- RIKEN
- Saitama 351-0198
- Japan
- Ecole Normale Supérieure
| | - Ken-ichi Inoue
- Molecular Spectroscopy Laboratory
- RIKEN
- Saitama 351-0198
- Japan
| | - Ryoji Kusaka
- Molecular Spectroscopy Laboratory
- RIKEN
- Saitama 351-0198
- Japan
| | | | - Satoshi Nihonyanagi
- Molecular Spectroscopy Laboratory
- RIKEN
- Saitama 351-0198
- Japan
- Ultrafast Spectroscopy Research Team
| | - Damien Baigl
- Ecole Normale Supérieure
- PSL Research University
- UPMC Univ Paris 06
- CNRS
- PASTEUR
| | | | - Tahei Tahara
- Molecular Spectroscopy Laboratory
- RIKEN
- Saitama 351-0198
- Japan
- Ultrafast Spectroscopy Research Team
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Cheung DL. Conformations of Myoglobin-Derived Peptides at the Air-Water Interface. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2016; 32:4405-4414. [PMID: 27077474 DOI: 10.1021/acs.langmuir.5b04619] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The conformational change exhibited by proteins at liquid interfaces, such as the air-water and oil-water interfaces, has long been of interest both for understanding protein structure outside of native environments and for applications in areas including food technology and pharmaceuticals. Using molecular simulation, this article studies the conformations of two peptides derived from myoglobin, for which the emulsification behavior has been studied. Both peptides were found to readily adsorb onto the air-water interface, with one of these (experimentally, the more effective stabilizer) adopting a flat, extended conformation and the other peptide remaining close to its solution conformation.
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Affiliation(s)
- David L Cheung
- School of Chemistry, National University of Ireland Galway , Galway, Ireland
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Dennison AJC, Jones RAL, Staniforth RA, Parnell AJ. Interaction of partially denatured insulin with a DSPC floating lipid bilayer. SOFT MATTER 2016; 12:824-829. [PMID: 26540006 DOI: 10.1039/c5sm02502h] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The carefully controlled permeability of cellular membranes to biological molecules is key to life. In degenerative diseases associated with protein misfolding and aggregation, protein molecules or their aggregates are believed to permeate these barriers and threaten membrane integrity. We used neutron reflectivity to study the interaction of insulin, a model amyloidogenic protein, with a DSPC floating lipid bilayer. Structural changes consistent with protein partitioning to the membrane interior and adsorption to a gel phase model lipid bilayer were observed under conditions where the native fold of the protein is significantly destabilised. We propose that the perturbation of the membrane by misfolded proteins involves long term occupation of the membrane by these proteins, rather than transient perforation events.
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Affiliation(s)
- A J C Dennison
- University Grenoble Alpes, IBS, F-38044 Grenoble, France.
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Day L, Zhai J, Xu M, Jones NC, Hoffmann SV, Wooster TJ. Conformational changes of globular proteins adsorbed at oil-in-water emulsion interfaces examined by Synchrotron Radiation Circular Dichroism. Food Hydrocoll 2014. [DOI: 10.1016/j.foodhyd.2012.12.015] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Ang JC, Henderson MJ, Campbell RA, Lin JM, Yaron PN, Nelson A, Faunce T, White JW. Human serum albumin binding to silica nanoparticles – effect of protein fatty acid ligand. Phys Chem Chem Phys 2014; 16:10157-68. [DOI: 10.1039/c4cp00293h] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Fat containing and defatted human serum albumin adsorption to silica nanoparticles have different structures and time dependence to form.
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Affiliation(s)
- Joo Chuan Ang
- Research School of Chemistry
- Australian National University
- Canberra, Australia
| | - Mark J. Henderson
- Research School of Chemistry
- Australian National University
- Canberra, Australia
| | | | - Jhih-Min Lin
- Research School of Chemistry
- Australian National University
- Canberra, Australia
| | - Peter N. Yaron
- Research School of Chemistry
- Australian National University
- Canberra, Australia
| | - Andrew Nelson
- Bragg Institute
- Australian Nuclear Science and Technology Organization
- Menai, Australia
| | - Thomas Faunce
- College of Law
- Australian National University
- ACT 0200, Australia
| | - John W. White
- Research School of Chemistry
- Australian National University
- Canberra, Australia
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Yano YF. Kinetics of protein unfolding at interfaces. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2012; 24:503101. [PMID: 23164927 DOI: 10.1088/0953-8984/24/50/503101] [Citation(s) in RCA: 66] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
The conformation of protein molecules is determined by a balance of various forces, including van der Waals attraction, electrostatic interaction, hydrogen bonding, and conformational entropy. When protein molecules encounter an interface, they are often adsorbed on the interface. The conformation of an adsorbed protein molecule strongly depends on the interaction between the protein and the interface. Recent time-resolved investigations have revealed that protein conformation changes during the adsorption process due to the protein-protein interaction increasing with increasing interface coverage. External conditions also affect the protein conformation. This review considers recent dynamic observations of protein adsorption at various interfaces and their implications for the kinetics of protein unfolding at interfaces.
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Affiliation(s)
- Yohko F Yano
- Department of Physics, Kinki University, Higashiosaka City, Osaka, Japan.
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Zhao X, Pan F, Lu JR. Interfacial assembly of proteins and peptides: recent examples studied by neutron reflection. J R Soc Interface 2009; 6 Suppl 5:S659-70. [PMID: 19656822 PMCID: PMC2843974 DOI: 10.1098/rsif.2009.0168.focus] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2009] [Accepted: 07/08/2009] [Indexed: 01/31/2023] Open
Abstract
Through reviewing a number of recent neutron reflection studies of interfacial adsorption of peptides and proteins, this paper aims to demonstrate the significance of this technique in studying interfacial biomolecular processes by illustrating the typical structural details that can be derived. The review will start with the introduction of relevant theoretical background, followed by an outline of representative biomolecular systems that have recently been studied to indicate the technical strengths of neutron reflection.
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Affiliation(s)
| | | | - Jian R. Lu
- Biological Physics Group, University of Manchester, Schuster Building, Oxford Road, Manchester M13 9PL, UK
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Perriman AW, Henderson MJ, Evenhuis CR, McGillivray DJ, White JW. Effect of the Air−Water Interface on the Structure of Lysozyme in the Presence of Guanidinium Chloride. J Phys Chem B 2008; 112:9532-9. [DOI: 10.1021/jp800354r] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Adam W. Perriman
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - Mark J. Henderson
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - Christian R. Evenhuis
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - Duncan J. McGillivray
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
| | - John W. White
- Research School of Chemistry, The Australian National University, Canberra, ACT 0200, Australia
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Perriman AW, Apponyi MA, Buntine MA, Jackway RJ, Rutland MW, White JW, Bowie JH. Surface movement in water of splendipherin, the aquatic male sex pheromone of the tree frog Litoria splendida. FEBS J 2008; 275:3362-74. [PMID: 18494800 DOI: 10.1111/j.1742-4658.2008.06483.x] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The aquatic sex pheromone splendipherin (GLVSSIGKALGGLLADVVKSKGQPA-OH) of the male green tree frog Litoria splendida moves across the surface of water to reach the female. Surface pressure and X-ray reflectometry measurements confirm that splendipherin is a surface-active molecule, and are consistent with it having an ordered structure, whereby the hydrophilic portion of the peptide interacts with the underlying water and the hydrophobic region is adjacent to the vapour phase. The movement of splendipherin over the surface of water is caused by a surface pressure gradient. In order to better define the structure of splendipherin at the water/air interface we used 2D NMR studies of the pheromone with the solvent system trifluoroethanol/water (1 : 1 v/v). In this solvent system, splendipherin adopts a bent alpha helix from residues V3 to K21. The bending of the helix occurs in the centre of the peptide in the vicinity of G11 and G12. The region of splendipherin from V3 to G11 has well-defined amphipathicity, whereas the amphipathicity from G12 to A25 is reduced by K19 and P24 intruding into the hydrophobic and hydrophilic regions respectively. A helical structure is consistent with X-ray reflectometry data.
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Affiliation(s)
- Adam W Perriman
- Research School of Chemistry, Australian National University, Canberra, Australia
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Perriman AW, Henderson MJ, Holt SA, White JW. Effect of the Air−Water Interface on the Stability of β-Lactoglobulin. J Phys Chem B 2007; 111:13527-37. [DOI: 10.1021/jp074777r] [Citation(s) in RCA: 46] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Adam W. Perriman
- Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia, and ISIS, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon UKO X110 QX
| | - Mark J. Henderson
- Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia, and ISIS, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon UKO X110 QX
| | - Stephen A. Holt
- Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia, and ISIS, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon UKO X110 QX
| | - John W. White
- Research School of Chemistry, Australian National University, Canberra ACT 0200, Australia, and ISIS, CCLRC Rutherford Appleton Laboratory, Chilton, Didcot, Oxon UKO X110 QX
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Henderson MJ, Perriman AW, Robson-Marsden H, White JW. Protein-poly(silicic) acid interactions at the air/solution interface. J Phys Chem B 2007; 109:20878-86. [PMID: 16853707 DOI: 10.1021/jp051908k] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The structure of the interface generated by a spread layer of beta-casein on an aqueous colloidal poly(silicic) acid subphase is described. The results are compared with data for the protein alone spread at the air/water interface and the silicate solution. Films develop at the air-solution interface and a strong pH dependence of the interaction causing this is demonstrated. Reflectometry with X-rays and neutrons was used to probe the interaction as a function of subphase pH and film compression. Film thickness, tau/A, scattering length density, rho/A(-2), water volume fraction, phi(w), and surface coverage, Gamma/mg m(-2), were used to quantify the interfacial structure. Where possible, the X-ray and neutron data sets were co-refined enabling phi(w) to be evaluated without assumption regarding the protein density. At pH 5-7, strong protein-silicate interaction occurred, the interface comprising three regions: a discrete protein upper layer on top of a 15 +/- 2 A layer of silicated material followed by a diffuse layer that extended into the subphase.
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Affiliation(s)
- Mark J Henderson
- Research School of Chemistry, Australian National University, Canberra 0200, Australia
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Biasco A, Pisignano D, Krebs B, Pompa PP, Persano L, Cingolani R, Rinaldi R. Conformation of microcontact-printed proteins by atomic force microscopy molecular sizing. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2005; 21:5154-8. [PMID: 15896064 DOI: 10.1021/la050010j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
We investigated the structural changes occurring in proteins patterned via microcontact printing. This was done by molecular sizing using atomic force microscopy to observe the structure of printed individual metalloprotein molecules in the unlabeled and untreated states. We observed that the size of the printed proteins were more than 2-fold smaller than the native shape, which indicates that some deformations take place upon the contact-assisted adsorption on silanized silicon dioxide. This can be attributed to simultaneously occurring effects, and particularly to the sandwiching between surfaces of very different hydrophilic/hydrophobic properties during contact lithography.
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Affiliation(s)
- Adriana Biasco
- National Nanotechnology Laboratory of Istituto Nazionale di Fisica della Materia, c/o Dipartimento di Ingegneria dell'Innovazione, Università di Lecce, via Arnesano, I-73100 Lecce, Italy.
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Fullagar WK, Aberdeen KA, Bucknall DG, Kroon PA, Gentle IR. Conformational changes in SP-B as a function of surface pressure. Biophys J 2004; 85:2624-32. [PMID: 14507725 PMCID: PMC1303486 DOI: 10.1016/s0006-3495(03)74685-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
X-ray reflectivity of bovine and sheep surfactant-associated protein B (SP-B) monolayers is used in conjunction with pressure-area isotherms and protein models to suggest that the protein undergoes changes in its tertiary structure at the air/water interface under the influence of surface pressure, indicating the likely importance of such changes to the phenomena of protein squeeze out as well as lipid exchange between the air-water interface and subphase structures. We describe an algorithm based on the well-established box- or layer-models that greatly assists the fitting of such unknown scattering-length density profiles, and which takes the available instrumental resolution into account. Scattering-length density profiles from neutron reflectivity of bovine SP-B monolayers on aqueous subphases are shown to be consistent with the exchange of a large number of labile protons as well as the inclusion of a significant amount of water, which is partly squeezed out of the protein monolayer at elevated surface pressures.
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Affiliation(s)
- Wilfred K Fullagar
- School of Molecular and Microbial Sciences, The University of Queensland, Brisbane, Queensland 4072, Australia
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Surface-sensitive X-ray and neutron scattering characterization of planar lipid model membranes and lipid/peptide interactions. PEPTIDE-LIPID INTERACTIONS 2002. [DOI: 10.1016/s1063-5823(02)52007-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
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