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Nikfarjam S, Jouravleva EV, Anisimov MA, Woehl TJ. Effects of Protein Unfolding on Aggregation and Gelation in Lysozyme Solutions. Biomolecules 2020; 10:biom10091262. [PMID: 32887233 PMCID: PMC7563771 DOI: 10.3390/biom10091262] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2020] [Accepted: 08/29/2020] [Indexed: 12/15/2022] Open
Abstract
In this work, we investigate the role of folding/unfolding equilibrium in protein aggregation and formation of a gel network. Near the neutral pH and at a low buffer ionic strength, the formation of the gel network around unfolding conditions prevents investigations of protein aggregation. In this study, by deploying the fact that in lysozyme solutions the time of folding/unfolding is much shorter than the characteristic time of gelation, we have prevented gelation by rapidly heating the solution up to the unfolding temperature (~80 °C) for a short time (~30 min.) followed by fast cooling to the room temperature. Dynamic light scattering measurements show that if the gelation is prevented, nanosized irreversible aggregates (about 10–15 nm radius) form over a time scale of 10 days. These small aggregates persist and aggregate further into larger aggregates over several weeks. If gelation is not prevented, the nanosized aggregates become the building blocks for the gel network and define its mesh length scale. These results support our previously published conclusion on the nature of mesoscopic aggregates commonly observed in solutions of lysozyme, namely that aggregates do not form from lysozyme monomers in their native folded state. Only with the emergence of a small fraction of unfolded proteins molecules will the aggregates start to appear and grow.
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Affiliation(s)
- Shakiba Nikfarjam
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA; (S.N.); (T.J.W.)
| | - Elena V. Jouravleva
- Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA;
| | - Mikhail A. Anisimov
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA; (S.N.); (T.J.W.)
- Institute for Physical Science and Technology, University of Maryland, College Park, MD 20742, USA;
- Correspondence:
| | - Taylor J. Woehl
- Department of Chemical and Biomolecular Engineering, University of Maryland, College Park, MD 20742, USA; (S.N.); (T.J.W.)
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Multi-Step Concanavalin A Phase Separation and Early-Stage Nucleation Monitored Via Dynamic and Depolarized Light Scattering. CRYSTALS 2019. [DOI: 10.3390/cryst9120620] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Protein phase separation and protein liquid cluster formation have been observed and analysed in protein crystallization experiments and, in recent years, have been reported more frequently, especially in studies related to membraneless organelles and protein cluster formation in cells. A detailed understanding about the phase separation process preceding liquid dense cluster formation will elucidate what has, so far, been poorly understood—despite intracellular crowding and phase separation being very common processes—and will also provide more insights into the early events of in vitro protein crystallization. In this context, the phase separation and crystallization kinetics of concanavalin A were analysed in detail, which applies simultaneous dynamic light scattering and depolarized dynamic light scattering to obtain insights into metastable intermediate states between the soluble phase and the crystalline form. A multi-step mechanism was identified for ConA phase separation, according to the resultant ACF decay, acquired after an increase in the concentration of the crowding agent until a metastable ConA gel intermediate between the soluble and final crystalline phases was observed. The obtained results also revealed that ConA is trapped in a macromolecular network due to short-range intermolecular protein interactions and is unable to transform back into a non-ergodic solution.
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Yoshida K, Zenin T, Fujiyoshi A, Sanada Y, Yamaguchi T, Murata K, Takata SI, Hiroi K, Takekiyo T, Yoshimura Y. The effect of alkyl ammonium ionic liquids on thermal denaturation aggregation of β-lactoglobulin. J Mol Liq 2019. [DOI: 10.1016/j.molliq.2019.111477] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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4
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Bai H, Sun Y, Xu J, Dong W, Liu X. Rheological and structural characterization of HA/PVA-SbQ composites film-forming solutions and resulting films as affected by UV irradiation time. Carbohydr Polym 2015; 115:422-31. [DOI: 10.1016/j.carbpol.2014.08.103] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2014] [Revised: 08/03/2014] [Accepted: 08/21/2014] [Indexed: 10/24/2022]
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5
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Yoshida K, Fukushima Y, Yamaguchi T. A study of alcohol and temperature effects on aggregation of β-lactoglobulin by viscosity and small-angle X-ray scattering measurements. J Mol Liq 2014. [DOI: 10.1016/j.molliq.2013.06.022] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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6
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Asai H, Nishi K, Hiroi T, Fujii K, Sakai T, Shibayama M. Gelation process of Tetra-PEG ion-gel investigated by time-resolved dynamic light scattering. POLYMER 2013. [DOI: 10.1016/j.polymer.2012.12.053] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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7
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Liu X, Luo S, Ye J, Wu C. Effect of Ca2+ Ion and Temperature on Association of Thermally Sensitive PAA-b-PNIPAM Diblock Chains in Aqueous Solutions. Macromolecules 2012. [DOI: 10.1021/ma300629d] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Xiaobing Liu
- Hefei National Laboratory for
Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei,
China 230026
| | - Shikai Luo
- Institute
of Chemical Materials, China Academy of Engineering Physics, Mianyang, China
621900
| | - Jing Ye
- Hefei National Laboratory for
Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei,
China 230026
| | - Chi Wu
- Hefei National Laboratory for
Physical Sciences at Microscale, Department of Chemical Physics, University of Science and Technology of China, Hefei,
China 230026
- Department of Chemistry, The Chinese University of Hong Kong, Shatin N. T., Hong Kong
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Yoshida K, Vogtt K, Izaola Z, Russina M, Yamaguchi T, Bellissent-Funel MC. Alcohol induced structural and dynamic changes in β-lactoglobulin in aqueous solution: A neutron scattering study. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2012; 1824:502-10. [DOI: 10.1016/j.bbapap.2011.12.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/19/2011] [Revised: 12/24/2011] [Accepted: 12/29/2011] [Indexed: 11/25/2022]
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10
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Inoue H, Katayama K, Iwai K, Miura A, Masuhara H. Conformational relaxation dynamics of a poly(N-isopropylacrylamide) aqueous solution measured using the laser temperature jump transient grating method. Phys Chem Chem Phys 2012; 14:5620-7. [DOI: 10.1039/c2cp40243b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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11
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Vicente-Alique E, Núñez-Ramírez R, Vega JF, Hu P, Martínez-Salazar J. Size and conformational features of ErbB2 and ErbB3 receptors: a TEM and DLS comparative study. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2011; 40:835-42. [PMID: 21476053 DOI: 10.1007/s00249-011-0699-y] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2010] [Revised: 03/11/2011] [Accepted: 03/17/2011] [Indexed: 11/28/2022]
Abstract
ErbB2 and ErbB3 receptors belong to the epidermal growth factor receptor family. The members of this family are able to form homo- and heterodimers that trigger diverse downstream signalling concerned to multiple cellular events. In the absence of a ligand, ErbB3 adopts a characteristic tethered conformation, which differs from ErbB2 extended conformation. In this work, transmission electron microscopy (TEM) and dynamic light scattering (DLS) have been used to characterize the conformational features and the size of ErBb2 and ErbB3 receptors. Two main objectives are presented. The first one is to evaluate the use of TEM as a tool for structural studies for this family of receptors. The low molecular weight of these proteins represents a challenging purpose for TEM studies. The other one is to search for a relationship between the results obtained by TEM and those obtained for the hydrodynamic size measured by DLS. This comparison has allowed us to identify the conformational differences of the receptors and to anticipate the use of these experimental techniques for the study of the ligand activated heterodimerization, a process related to a significant number of human malignancies.
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Affiliation(s)
- Ernesto Vicente-Alique
- Departamento de Física Macromolecular, Instituto de Estructura de la Materia, Madrid, Spain
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12
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Yoshida K, Hosokawa S, Baron AQR, Yamaguchi T. Collective dynamics of hydrated β-lactogloblin by inelastic x-ray scattering. J Chem Phys 2010; 133:134501. [DOI: 10.1063/1.3484238] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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13
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Yoshida K, Yamaguchi T, Osaka N, Endo H, Shibayama M. A study of alcohol-induced gelation of β-lactoglobulin with small-angle neutron scattering, neutron spin echo, and dynamic light scattering measurements. Phys Chem Chem Phys 2010; 12:3260-9. [DOI: 10.1039/b920187d] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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14
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Png GM, Falconer RJ, Fischer BM, Zakaria HA, Mickan SP, Middelberg APJ, Abbott D. Terahertz spectroscopic differentiation of microstructures in protein gels. OPTICS EXPRESS 2009; 17:13102-15. [PMID: 19654715 DOI: 10.1364/oe.17.013102] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
We demonstrate that terahertz (THz) spectroscopy can be used to differentiate soft protein microstructures. Differentiation of soft microstructures in gels has to date been performed using optical imaging techniques (e.g. electron microscope), but a non-destructive differentiation tool is lacking. Particulate and fine-stranded (fibrillar) soft protein microstructures are of interest, particularly to medical researchers, because they form from naturally occurring proteins that are thought to be involved in several human diseases, such as Alzheimer's disease. In this study, globular beta-lactoglobulin structures with diameters of 2 microm, and fibrillar structures with diameters less than 0.03 microm are observed between 0.8 and 1.5 THz. Results show that the globular structures have a decline in THz transmission when compared to the fibrillar ones. The cause of this decline is possibly due to Rayleigh scattering from the globular microstructures.
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Affiliation(s)
- Gretel M Png
- Centre for Biomedical Engineering, School of Electrical and Electronic Engineering, University of Adelaide, Adelaide, SA 5005, Australia.
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15
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Mercadé-Prieto R, Gunasekaran S. Alkali cold gelation of whey proteins. Part I: sol-gel-sol(-gel) transitions. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2009; 25:5785-5792. [PMID: 19432494 DOI: 10.1021/la804093d] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The cold gelation of preheated whey protein isolate (WPI) solutions at alkaline conditions (pH>10) has been studied to better understand the effect of NaOH in the formation and destruction of whey protein aggregates and gels. Oscillatory rheology has been used to follow the gelation process, resulting in novel and different gelation profiles with the gelation pH. At low alkaline pH, typical sol-gel transitions are observed, as in many other biopolymers. At pH>11.5, the system gels quickly, after approximately 300 s, followed by a slow degelation step that transforms the gel to a viscous solution. Finally, there is a second gelation step. This results in a surprising sol-gel-sol-gel transition in time at constant gelation conditions. At very high pH (>12.5), the degelation step is very severe, and the second gelation step is not observed, resulting in a sol-gel-sol transition. The first quick gelation step is related to the quick swelling of the WPI aggregates in alkali, as observed from light scattering, which enables the formation of new noncovalent interactions to form a gel network. These interactions are argued to be destroyed in the subsequent degelation step. Disulfide cross-linking is observed only in the second gelation step, not in the first step.
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Affiliation(s)
- Ruben Mercadé-Prieto
- Biological Systems Engineering, University of Wisconsin-Madison, 460 Henry Mall, Madison, Wisconsin 53706, USA.
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16
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Osaka N, Takata SI, Suzuki T, Endo H, Shibayama M. Comparison of heat- and pressure-induced gelation of β-lactoglobulin aqueous solutions studied by small-angle neutron and dynamic light scattering. POLYMER 2008. [DOI: 10.1016/j.polymer.2008.04.055] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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17
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Abstract
β-lactoglobulin is a protein of huge importance to the food industry, and as such it has been extensively studied by the food community sui generis. However, recently there has been an increasing number of studies approaching the protein from a soft matter perspective. Here it is shown how its behaviour can be seen to be generic, in so far as its forms of aggregation are actually typical of many other proteins under comparable conditions, and hence that it is useful to seek unifying mechanisms for its behaviour.
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Affiliation(s)
- Athene M Donald
- Cavendish Laboratory, University of Cambridge, JJ Thomson Avenue, Cambridge, UKCB3 0HE
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18
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Yadav PJP, Ghosh G, Maiti B, Aswal VK, Goyal PS, Maiti P. Thermoreversible Gelation of Poly(Vinylidene Fluoride) in Phthalates: The Influence of Aliphatic Chain Length of Solvents. J Phys Chem B 2008; 112:4594-603. [DOI: 10.1021/jp800001t] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- P. Jaya Prakash Yadav
- School of Materials Science and Technology, Institute of Technology, Department of Chemistry, Banaras Hindu University, Varanasi 221 005, India, and UGC-DAE Consortium for Scientific Research, Solid State Physics Division, Mumbai Centre, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Goutam Ghosh
- School of Materials Science and Technology, Institute of Technology, Department of Chemistry, Banaras Hindu University, Varanasi 221 005, India, and UGC-DAE Consortium for Scientific Research, Solid State Physics Division, Mumbai Centre, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Biswajit Maiti
- School of Materials Science and Technology, Institute of Technology, Department of Chemistry, Banaras Hindu University, Varanasi 221 005, India, and UGC-DAE Consortium for Scientific Research, Solid State Physics Division, Mumbai Centre, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Vinod K. Aswal
- School of Materials Science and Technology, Institute of Technology, Department of Chemistry, Banaras Hindu University, Varanasi 221 005, India, and UGC-DAE Consortium for Scientific Research, Solid State Physics Division, Mumbai Centre, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - P. S. Goyal
- School of Materials Science and Technology, Institute of Technology, Department of Chemistry, Banaras Hindu University, Varanasi 221 005, India, and UGC-DAE Consortium for Scientific Research, Solid State Physics Division, Mumbai Centre, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Pralay Maiti
- School of Materials Science and Technology, Institute of Technology, Department of Chemistry, Banaras Hindu University, Varanasi 221 005, India, and UGC-DAE Consortium for Scientific Research, Solid State Physics Division, Mumbai Centre, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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Ozbas B, Rajagopal K, Haines-Butterick L, Schneider JP, Pochan DJ. Reversible stiffening transition in beta-hairpin hydrogels induced by ion complexation. J Phys Chem B 2007; 111:13901-8. [PMID: 18044866 DOI: 10.1021/jp075117p] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
We have previously shown that properly designed lysine and valine-rich peptides undergo a random coil to beta-hairpin transition followed by intermolecular self-assembly into a fibrillar hydrogel network only after the peptide solutions are heated above the intramolecular folding transition temperature. Here we report that these hydrogels also undergo a stiffening transition as they are cooled below a critical temperature only when boric acid is used to buffer the peptide solution. This stiffening transition is characterized by rheology, dynamic light scattering, and small angle neutron scattering. Rheological measurements show that the stiffening transition causes an increase in the hydrogel storage modulus (G') by as much as 1 order of magnitude and is completely reversible on subsequently raising the temperature. Although this reversible transition exhibits rheological properties that are similar to polyol/borax solutions, the underlying mechanism does not involve hydroxyl-borate complexation. The stiffening transition is mainly caused by the interactions between lysine and boric acid/borate anion and is not driven by the changes in the secondary structure of the beta-hairpin peptide. Addition of glucose to boric acid and peptide solution disrupts the stiffening transition due to competitive glucose-borate complexation.
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Affiliation(s)
- Bulent Ozbas
- Department of Materials Science and Engineering, Delaware Biotechnology Institute, Newark, Delaware 19716, USA
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20
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KONDO A, SATO T. Structure of Aggregates Formed by a Thermally Denatured Protein after Quench. KOBUNSHI RONBUNSHU 2007. [DOI: 10.1295/koron.64.452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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21
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Shibayama M. Universality and Specificity of Polymer Gels Viewed by Scattering Methods. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2006. [DOI: 10.1246/bcsj.79.1799] [Citation(s) in RCA: 95] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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22
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Liu R, Gao X, Oppermann W. Dynamic light scattering studies on random cross-linking of polystyrene in semi-dilute solution. POLYMER 2006. [DOI: 10.1016/j.polymer.2006.10.020] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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23
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Nagao M, Okabe S, Shibayama M. Small-angle neutron-scattering study on a structure of microemulsion mixed with polymer networks. J Chem Phys 2005; 123:144909. [PMID: 16238426 DOI: 10.1063/1.2013211] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The structure of a microemulsion mixed with polymer networks was investigated by means of small-angle neutron scattering (SANS). The system consists of nonionic surfactant, polymer network, oil, and water. The microemulsion and the polymer network employed in this work are known to undergo temperature-induced structural transition and volume phase transition, respectively. Polymer solutions and gels were made by polymerizing monomer solutions in the presence of microemulsion droplets. In the case of a mixture of an N-isopropylacrylamide (NIPA) monomer solution and a microemulsion, the NIPA monomer was found to behave as a cosurfactant. However, polymerization resulted in a phase separation to polymer-rich and -poor phases. Interestingly, SANS results indicated that a well-developed ordered structure of oil domains was formed in polymer network and the structure was very different from its parent systems. Furthermore, the system underwent two different types of structural transitions with respect to temperature. One was originated from the structural transition of microemulsion due to the change of the spontaneous curvature and the other from the volume phase transition of the NIPA gel.
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Affiliation(s)
- Michihiro Nagao
- Institute for Solid State Physics, The University of Tokyo, 106-1 Shirakata, Tokai 319-1106, Japan.
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Parker R, Noel TR, Brownsey GJ, Laos K, Ring SG. The nonequilibrium phase and glass transition behavior of beta-lactoglobulin. Biophys J 2005; 89:1227-36. [PMID: 15923230 PMCID: PMC1366607 DOI: 10.1529/biophysj.105.064246] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2005] [Accepted: 05/25/2005] [Indexed: 11/18/2022] Open
Abstract
Concentrated solutions of bovine beta-lactoglobulin were studied using osmotic stress and rheological techniques. At pH 6.0 and 8.0, the osmotic pressure was largely independent of NaCl concentration and could be described by a hard sphere equation of state. At pH 5.1, close to the isoelectric point, the osmotic pressure was lower at the lower NaCl concentrations (0 mM, 100 mM) and was fitted by an adhesive hard sphere model. Liquid-liquid phase separation was observed at pH 5.1 at ionic strengths of 13 mM and below. Comparison of the liquid-liquid and literature solid-liquid coexistence curves showed these solutions to be supersaturated and the phase separation to be nonequilibrium in nature. In steady shear, the zero shear viscosity of concentrated solutions at pH 5.1 was observed at shear rates above 50 s(-1). With increasing concentration, the solution viscosity showed a progressive increase, a behavior interpreted as the approach to a colloidlike glass transition at approximately 60% w/w. In oscillatory shear experiments, the storage modulus crossed the loss modulus at concentrations of 54% w/w, an indication of the approaching glass transition. Comparison of the viscous behavior with predictions from the Krieger-Dougherty equation indicates the hydrodynamic size of the protein decreases with increasing concentration, resulting in a slower approach to the glass transition than a hard sphere system.
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Affiliation(s)
- Roger Parker
- Institute of Food Research, Norwich Research Park, UK
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25
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Eissa AS, Khan SA. Acid-induced gelation of enzymatically modified, preheated whey proteins. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2005; 53:5010-7. [PMID: 15941349 DOI: 10.1021/jf047957w] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
Low-pH whey protein gels are formulated using a sequential protocol of heat treatment, enzyme incubation, and cold-set acidification. The heat-induced disulfide and enzyme-catalyzed epsilon-(gamma-glutamyl)lysine linkages, both at neutral pH, produce a polymerized protein solution. The molecular weights of these samples show an exponential increase with protein concentration. The additional enzyme-catalyzed cross-links cause little change in molecular weight from that of heat-treated samples at low protein concentrations, indicating predominant intramolecular cross-linking. Enzyme treatment at higher protein concentration however causes increase in molecular weight, possibly due to formation of intermolecular cross-links. Acidification of the polymerized protein solutions through glucono-delta-lactone acid leads to gel formation at pH 4. The elastic (G') and viscous (G' ') moduli of gels with and without enzyme treatment show similar frequency dependence, indicating comparable microstructures, consistent with all samples exhibiting similar fractal dimensions of approximately 2 obtained independently using rheology and confocal microscopy. A substantial increase in fracture strain and stress of the gel is achieved by enzyme treatment. However, the elastic modulus (G') is only slightly larger after enzyme treatment compared with heat-treated samples. These results indicate that factors responsible for fracture properties may not be apparent in the gel microstructure and linear viscoelastic properties.
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Affiliation(s)
- Ahmed S Eissa
- Department of Chemical and Biomolecular Engineering, North Carolina State University, Raleigh, North Carolina 27695-7905, USA
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Mongondry P, Tassin JF, Nicolai T. Revised state diagram of Laponite dispersions. J Colloid Interface Sci 2005; 283:397-405. [PMID: 15721911 DOI: 10.1016/j.jcis.2004.09.043] [Citation(s) in RCA: 163] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2004] [Accepted: 09/14/2004] [Indexed: 10/26/2022]
Abstract
We propose a state diagram of charged disk-like mineral particle (Laponite) dispersions as a function of the Laponite concentration (C) and the concentration of added salt (C(s)), based on simple observation and light-scattering measurements. At low C or high C(s) the dispersions separate into two domains due to sedimentation of Laponite aggregates, while at high C and low C(s) they form homogeneous gels that do not flow upon tube reversal. The aggregation rate and the structure factor of the Laponite dispersions is determined with light scattering as a function of C and C(s). We discuss in detail the controversy on the origin of gelation of Laponite dispersions in the absence of added salt. We argue that aggregation rather than glass formation causes gelation.
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Affiliation(s)
- Philippe Mongondry
- Polymères Colloïdes Interfaces, UMR CNRS 6120, Université du Maine, 72085 Le Mans Cedex 9, France
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28
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Bromley EH, Krebs MRH, Donald AM. Aggregation across the length-scales in β-lactoglobulin. Faraday Discuss 2005; 128:13-27. [PMID: 15658764 DOI: 10.1039/b403014a] [Citation(s) in RCA: 140] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The protein beta-lactoglobulin (BLG) has been widely studied, in large part because of its importance to the food industry. Following denaturation during heating, under different conditions of pH it has been found to form either particulate (around the isoelectric point at pH 5.1) or fibrillar gels. The nature of the fibrils has recently been suggested to be the same as that identified with amyloid fibrils known for a wide-range of different proteins and implicated in many disease states. We confirm that the BLG fibrils show all the classical signatures of amyloid fibrils. In addition, the fibrils are capable themselves of aggregating further to form large-scale (many microns in size) spherulites. Polarized light microscopy and Environmental scanning electron microscopy (ESEM) have been used to explore the internal structure of these spherulites under conditions in which the solvent has not been dried off. The factors which determine whether or not the spherulites form have also been considered, together with implications for other amyloid-containing systems.
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Norisuye T, Tran-Cong-Miyata Q, Shibayama M. Dynamic Inhomogeneities in Polymer Gels Investigated by Dynamic Light Scattering. Macromolecules 2004. [DOI: 10.1021/ma035246d] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Tomohisa Norisuye
- Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Qui Tran-Cong-Miyata
- Department of Polymer Science and Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mitsuhiro Shibayama
- Neutron Science Laboratory, Institute for Solid State Physics, 106-1 Shirakata, The University of Tokyo, Tokai, Naka-gun, Ibaraki 319-1106, Japan
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30
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Okabe S, Ando K, Hanabusa K, Shibayama M. Dynamic light scattering and small-angle neutron scattering studies on organogels formed with a gelator. ACTA ACUST UNITED AC 2004. [DOI: 10.1002/polb.20067] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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31
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Gun'ko VM, Klyueva AV, Levchuk YN, Leboda R. Photon correlation spectroscopy investigations of proteins. Adv Colloid Interface Sci 2003; 105:201-328. [PMID: 12969646 DOI: 10.1016/s0001-8686(03)00091-5] [Citation(s) in RCA: 72] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Physical principles of photon correlation spectroscopy (PCS), mathematical treatment of the PCS data (converting autocorrelation functions to distribution functions or average characteristics), and PCS applications to study proteins and other biomacromolecules in aqueous media are described and analysed. The PCS investigations of conformational changes in protein molecules, their aggregation itself or in consequence of interaction with other molecules or organic (polymers) and inorganic (e.g. fumed silica) fine particles as well as the influence of low molecular compounds (surfactants, drugs, salts, metal ions, etc.) reveal unique capability of the PCS techniques for elucidation of important native functions of proteins and other biomacromolecules (DNA, RNA, etc.) or microorganisms (Escherichia coli, Pseudomonas putida, Dunaliella viridis, etc.). Special attention is paid to the interaction of proteins with fumed oxides and the impact of polymers and fine oxide particles on the motion of living flagellar microorganisms analysed by means of PCS.
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Affiliation(s)
- Vladimir M Gun'ko
- Institute of Surface Chemistry, 17 General Naumov Street, Kiev 03164, Ukraine.
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32
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Peng S, Wu C. Influence of initial chain conformation on the formation of mesoglobule phase in a dilute heteropolymer solution. POLYMER 2003. [DOI: 10.1016/s0032-3861(02)00860-1] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Lin W, Zhou Y, Zhao Y, Zhu Q, Wu C. Cr3+/COO- Complexation Induced Aggregation of Gelatin in Dilute Solution. Macromolecules 2002. [DOI: 10.1021/ma020372n] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wei Lin
- Laboratory of Bond-Selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, Anhui, China; Institute of Biomass Engineering, The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, Sichuan, China; and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
| | - Yunshen Zhou
- Laboratory of Bond-Selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, Anhui, China; Institute of Biomass Engineering, The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, Sichuan, China; and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
| | - Yuer Zhao
- Laboratory of Bond-Selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, Anhui, China; Institute of Biomass Engineering, The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, Sichuan, China; and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
| | - Qingshi Zhu
- Laboratory of Bond-Selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, Anhui, China; Institute of Biomass Engineering, The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, Sichuan, China; and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
| | - Chi Wu
- Laboratory of Bond-Selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Chinese Academy of Sciences, Hefei, 230026, Anhui, China; Institute of Biomass Engineering, The Key Laboratory of Leather Chemistry and Engineering of Ministry of Education, Sichuan University, Chengdu, 610065, Sichuan, China; and Department of Chemistry, The Chinese University of Hong Kong, Shatin, N.T., Hong Kong
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34
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Weijers M, Visschers RW, Nicolai T. Light Scattering Study of Heat-Induced Aggregation and Gelation of Ovalbumin. Macromolecules 2002. [DOI: 10.1021/ma0120198] [Citation(s) in RCA: 77] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mireille Weijers
- Wageningen Centre for Food Science and NIZO Food Research, PO Box 20, 61710 Ede, The Netherlands
| | - Ronald W. Visschers
- Wageningen Centre for Food Science and NIZO Food Research, PO Box 20, 61710 Ede, The Netherlands
| | - Taco Nicolai
- Polymères, Colloïdes, Interfaces, UMR-CNRS, Université du Maine, 72085 Le Mans Cedex 9, France
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35
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Ikkai F, Naito S. Dynamic light scattering and circular dichroism studies on heat-induced gelation of hard-keratin protein aqueous solutions. Biomacromolecules 2002; 3:482-7. [PMID: 12005518 DOI: 10.1021/bm010160i] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Animal hairs consist of aggregates of dead cells filled with keratin protein gel. We succeeded in preparing water-soluble hard-keratin proteins and reconstructing the keratin gels by heat-induced disulfide linkages in vitro. Here, the roles of intermolecular hydrophobic interaction and disulfide bonding between the proteins in the gel were discussed. Water-soluble keratin proteins consisting of mixtures of type I ( approximately 48 kDa) and type II ( approximately 61 kDa) were prepared from wool fibers as S-carboxymethyl alanyl disulfide keratin (CMADK). The gelation was achieved by heating an aqueous solution containing at least 0.8 wt % CMADK at 100 degrees C. CMADK solutions with different urea or N-ethylmaleimide concentrations or pH were exposed to dynamic light scattering (DLS) and circular dichroism (CD). DLS clarified the gelation point of CMADK solutions and provided information on the changes in keratin cluster size. DLS suggested two types of gelation mechanism. One was the regenerated chemical disulfide bonding between keratins from CMAD parts of chains. After the gel formed, this bond became important to maintain the gel structure. The other was the physical assembly due to hydrophobic interaction between alpha-helix parts of keratin chains. This hydrophobic assembly also played an important role during gelation. CD confirmed a conformational change in the keratin protein, resulting heat-induced gelation. CD clarified the relationship between keratin protein conformation and gelation, i.e., a rodlike conformation with many alpha-helix structures was necessary to associate keratin chains and form a gel network.
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Affiliation(s)
- Fumiyoshi Ikkai
- The Institute of Advanced Science Research, L'OREAL Tsukuba Center, 5-5 Tokodai, Tsukuba, Ibaraki 300-2635, Japan.
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36
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Shibayama M, Norisuye T. Gel Formation Analyses by Dynamic Light Scattering. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 2002. [DOI: 10.1246/bcsj.75.641] [Citation(s) in RCA: 136] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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37
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Ikeda S, Nishinari K, Foegeding EA. Mechanical characterization of network formation during heat-induced gelation of whey protein dispersions. Biopolymers 2002; 56:109-19. [PMID: 11592057 DOI: 10.1002/1097-0282(2000)56:2<109::aid-bip1056>3.0.co;2-u] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The formation of gel network structures during isothermal heating of whey protein aqueous dispersions was probed by mechanical spectroscopy. It was anticipated that the pathway of the sol-to-gel transition of whey protein dispersions is quite different from that of ordinary cross-linking polymers (e.g., percolation-type transition), since aqueous solutions of native whey proteins have been shown to be highly structured even before gelation, in our previous study. At 20 degrees C, aqueous dispersions of beta-lactoglobulin, the major whey protein, and those of whey protein isolate (WPI), a mixture of whey proteins, exhibited solid-like mechanical spectra, i.e., the predominant storage modulus G' over the loss modulus G", in a certain range of the frequency omega (1-100 rad/s), regardless of the presence or absence of added NaCl. The existence of the added salt was, however, a critical factor for determining transitions in mechanical spectra during gelation at 70 degrees C. beta-Lactoglobulin dispersions in 0.1 mol/dm(3) NaCl maintained the solid-like nature during the entire gelation process and, after passing through the gelation point, satisfied parallel power laws (G' approximately G" approximately omega(n)) that have been proposed for a critical gel (i.e., the gel at the gelation point) that possesses a self-similar or fractal network structure. In contrast, beta-lactoglobulin dispersions without added salt exhibited a transition from solid-like [G'(omega) > G"(omega)] to liquid-like [G'(omega) < G"(omega)] mechanical spectra before gelation, but no parallel power law behavior was recognized at the gelation point. During extended heating time (aging), beta-lactoglobulin gels with 0.1 mol/dm(3) NaCl showed deviations from the parallel power laws, while spectra of gels without added NaCl approached the parallel power laws, suggesting that post-gelation reactions also significantly affect gel network structures. A percolation-type sol-to-gel transition was found only for WPI dispersions without added salt.
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Affiliation(s)
- S Ikeda
- Department of Food and Nutrition, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan
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38
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39
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Okamoto M, Norisuye T, Shibayama M. Time-Resolved Dynamic Light Scattering Study on Gelation and Gel-Melting Processes of Gelatin Gels. Macromolecules 2001. [DOI: 10.1021/ma010734b] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Masahiko Okamoto
- Department of Polymer Science & Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Tomohisa Norisuye
- Department of Polymer Science & Engineering, Kyoto Institute of Technology, Matsugasaki, Sakyo-ku, Kyoto 606-8585, Japan
| | - Mitsuhiro Shibayama
- Neutron Scattering Laboratory, Institute for Solid State Physics, The University of Tokyo, Tokai, Naka-gun, Ibaraki 319-1106, Japan
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40
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Abstract
Macroscopic and molecular structural changes during heat-induced gelation of beta-lactoglobulin, bovine serum albumin, ovalbumin, and alpha-lactalbumin aqueous dispersions were probed by the mechanical and CD spectroscopy, respectively. Aqueous solutions of the native globular proteins, except for alpha-lactalbumin, exhibited solid-like mechanical spectra-namely, the predominant storage modulus G' over the loss modulus G" in the entire frequency range examined (0.1-100 rad/s), suggesting that these protein solutions were highly structured even before gelation, possibly due to strong repulsions among protein molecules. Such solid-like structures were susceptible to nonlinearly large shear but recovered almost immediately at rest. During gelation by isothermal heating, major changes in the secondary structure of the globular proteins completed within a few minutes, while values of the modulus continued to develop for hours with maintaining values of tandelta (= G"/G') less than unity. As a result, a conventional criterion for mechanically defining the gelation point, such as a crossover between G' and G", was inapplicable to these globular protein systems. beta-Lactoglobulin gels that had passed the gelation point satisfied power laws (G' approximately G" approximately omega(n)) believed to be valid only at the gelation point, suggesting that fractal gel networks, similar to those of critical gels (i.e., gels at the gelation point), were formed.
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Affiliation(s)
- S Ikeda
- Department of Food and Nutrition, Osaka City University, 3-3-138 Sugimoto, Sumiyoshi-ku, Osaka 558-8585, Japan.
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41
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Nicolai T, Urban C, Schurtenberger P. Light Scattering Study of Turbid Heat-Set Globular Protein Gels Using Cross-Correlation Dynamic Light Scattering. J Colloid Interface Sci 2001; 240:419-424. [PMID: 11482949 DOI: 10.1006/jcis.2001.7672] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The structure factor of aqueous solutions of the globular protein beta-lactoglobulin was determined as a function of heating time at 76 degrees C. We show how the effect of multiple scattering on the scattered light intensity can be effectively corrected using cross-correlation dynamic light scattering even if the transmission is only 1%. The structure factor of aggregated and gelled proteins can be described by the Ornstein-Zernike equation. The system is characterized by a correlation length that increases with heating time and stabilizes some time after the gel is formed. The correlation length of the protein gels decreases with decreasing concentration. Measurements after progressive dilution of a sample close to the gel point showed that the protein aggregates are initially interpenetrated and disinterpenetrate upon dilution. Copyright 2001 Academic Press.
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Affiliation(s)
- Taco Nicolai
- Polyméres, Colloides, Interfaces, UMR-CNRS, Université du Maine, Le Mans Cedex 9, 72085, France
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42
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Peng S, Wu C. Comparison of the Ca2+/COO- Complexation Induced Controllable Aggregation of P(VCL-co-NaA) Spherical Microgels and Linear Chains. Macromolecules 2001. [DOI: 10.1021/ma010376c] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Shufu Peng
- The Open Laboratory of Bond-selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, China, and Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong
| | - Chi Wu
- The Open Laboratory of Bond-selective Chemistry, Department of Chemical Physics, University of Science and Technology of China, Hefei, Anhui, China, and Department of Chemistry, The Chinese University of Hong Kong, Shatin, Hong Kong
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43
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Annaka M, Shibayama M, Ikkai F, Sugiyama M, Hara K, Nakahira T, Tanaka T. Multiple-phase behavior and its microscopic implication for 4-acrylamidosalicylic acid gel. J Chem Phys 2001. [DOI: 10.1063/1.1357201] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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