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Tong P, Xu X, Liu K, Chen H, Gao J. Denatured pre-treatment assisted polyphenol oxidase-catalyzed cross-linking: effects on the cross-linking potential, structure, allergenicity and functional properties of OVA. Food Funct 2021; 12:10083-10096. [PMID: 34518852 DOI: 10.1039/d1fo01809d] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
To evaluate the impacts of denatured pre-treatments (heating and denaturants) on cross-linking and the combined effect of pre-treatment and cross-linking on the structure, allergenicity and functional properties of OVA, OVA was pre-treated in different ways and then cross-linked. Results showed that the cross-linking reaction was obviously promoted with heating at 100 °C for 5 min or 0.5% of SDS as the pretreatment. Due to the coordinated process of pre-treatments and cross-linking, the secondary structure was changed and the gastrointestinal digestion of OVA was promoted. Meanwhile, the emulsifying properties, foaming properties, and antioxidant properties of OVA were remarkably improved. Furthermore, the IgG and IgE binding capacities of OVA, as well as the OVA-induced degranulation capacity of KU812 were all significantly decreased. However, upon comparing the cross-linking assisted by two different pre-treatments, it was seen that heating at 100 °C for 5 min was better than being treated with 0.5% of SDS in reducing the potential allergenicity of OVA. Therefore, we concluded that heat denaturation (at 100 °C for 5 min) assisted enzymatic cross-linking may provide a new cross-linking method to develop hypoallergenic foods with good functional properties.
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Affiliation(s)
- Ping Tong
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P.R. China.
| | - Xiaoqian Xu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P.R. China. .,College of Food Science & Technology, Nanchang University, Nanchang 330031, P R. China.
| | - Ke Liu
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P.R. China. .,College of Food Science & Technology, Nanchang University, Nanchang 330031, P R. China.
| | - Hongbing Chen
- State Key Laboratory of Food Science and Technology, Nanchang University, Nanchang 330047, P.R. China. .,Jiangxi-OAI Joint Research Institute, Nanchang University, Nanchang 330047, P.R. China
| | - Jinyan Gao
- College of Food Science & Technology, Nanchang University, Nanchang 330031, P R. China.
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Hall D, Kinjo AR, Goto Y. A new look at an old view of denaturant induced protein unfolding. Anal Biochem 2018; 542:40-57. [DOI: 10.1016/j.ab.2017.11.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/11/2017] [Accepted: 11/16/2017] [Indexed: 12/15/2022]
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Chen Y, Wedemeyer WJ, Lapidus LJ. A general polymer model of unfolded proteins under folding conditions. J Phys Chem B 2010; 114:15969-75. [PMID: 21077645 DOI: 10.1021/jp104746g] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
There is increasing evidence that a polypeptide chain in solvent conditions that favor folding may have transient structure and is significantly more compact than a fully denatured chain. However, there is no sequence-dependent model to capture such interactions. In this work, we present a simple and computationally inexpensive model based on a wormlike chain with excluded volume. The probability distribution of millions of such chains is reweighted to bias compact conformations in which residues of similar hydrophobicity are located near each other. This model, which has one adjustable parameter, is fit to measured values of intramolecular contact formation, which has been shown to be extremely sensitive to various models of intrachain distances. We show that under various denaturant concentrations, there is good convergence of the model for several different sequences with a wide range of dynamics. We also show that this model quantitatively predicts paramagnetic resonance enhancement (PRE) measurements with no adjustable parameters. Therefore a simple, probabilistic model that accounts for sequence-specific interactions may give a more realistic starting point for predictions of protein folding.
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Affiliation(s)
- Yujie Chen
- Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824, USA
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Abstract
The coil-globule transition, a tenet of the physics of polymers, has been identified in recent years as an important unresolved aspect of the initial stages of the folding of proteins. We describe the basics of the collapse transition, starting with homopolymers and continuing with proteins. Studies of denatured-state collapse under equilibrium are then presented. An emphasis is placed on single-molecule fluorescence experiments, which are particularly useful for measuring properties of the denatured state even under conditions of coexistence with the folded state. Attempts to understand the dynamics of collapse, both theoretically and experimentally, are then described. Only an upper limit for the rate of collapse has been obtained so far. Improvements in experimental and theoretical methodology are likely to continue to push our understanding of the importance of the denatured-state thermodynamics and dynamics for protein folding in the coming years.
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Affiliation(s)
- Guy Ziv
- Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot, Israel. E-mail:
| | - D. Thirumalai
- Biophysics Program, Institute for Physical Science and Technology and Department of Chemistry and Biochemistry, University of Maryland, College Park, MD 20742, USA
| | - Gilad Haran
- Chemical Physics Department, Weizmann Institute of Science, 76100 Rehovot, Israel. E-mail:
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5
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Lopez CF, Darst RK, Rossky PJ. Mechanistic elements of protein cold denaturation. J Phys Chem B 2008; 112:5961-7. [PMID: 18181599 DOI: 10.1021/jp075928t] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Globular proteins undergo structural transitions to denatured states when sufficient thermodynamic state or chemical perturbations are introduced to their native environment. Cold denaturation is a somewhat counterintuitive phenomenon whereby proteins lose their compact folded structure as a result of a temperature drop. The currently accepted explanation for cold denaturation is based on an associated favorable change in the contact free energy between water and nonpolar groups at colder temperatures which would weaken the hydrophobic interaction and is thought to eventually allow polymer entropy to disrupt protein tertiary structure. In this paper we explore how this environmental perturbation leads to changes in the protein hydration and local motions in apomyoglobin. We do this by analyzing changes in protein hydration and protein motion from molecular dynamics simulation trajectories initially at 310 K, followed by a temperature drop to 278 K. We observe an increase in the number of solvent contacts around the protein and, in particular, distinctly around nonpolar atoms. Further analysis shows that the fluctuations of some protein atoms increase with decreasing temperature. This is accompanied by an observed increase in the isothermal compressibility of the protein, indicating an increase in the protein interior interstitial space. Closer inspection reveals that atoms with increased compressibility and larger-than-expected fluctuations are localized within the protein core regions. These results provide insight into a description of the mechanism of cold denaturation. That is, the lower temperature leads to solvent-induced packing defects at the protein surface, and this more favorable water-protein interaction in turn destabilizes the overall protein structure.
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Affiliation(s)
- Carlos F Lopez
- Center for Computational Molecular Sciences, Institute for Computational Engineering and Science, and Department of Chemistry and Biochemistry, The University of Texas at Austin, Austin, Texas 78712-1167, USA
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Cheema MA, Taboada P, Barbosa S, Castro E, Siddiq M, Mosquera V. Modification of the Thermal Unfolding Pathways of Myoglobin upon Drug Interaction in Different Aqueous Media. J Phys Chem B 2007; 111:13851-7. [DOI: 10.1021/jp075006q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Mohammad Arif Cheema
- Grupo de Física de Coloides y Polímeros, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782, Santiago de Compostela, Spain, and Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Pablo Taboada
- Grupo de Física de Coloides y Polímeros, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782, Santiago de Compostela, Spain, and Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Silvia Barbosa
- Grupo de Física de Coloides y Polímeros, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782, Santiago de Compostela, Spain, and Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Emilio Castro
- Grupo de Física de Coloides y Polímeros, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782, Santiago de Compostela, Spain, and Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Mohammad Siddiq
- Grupo de Física de Coloides y Polímeros, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782, Santiago de Compostela, Spain, and Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Víctor Mosquera
- Grupo de Física de Coloides y Polímeros, Departamento de Física de la Materia Condensada, Facultad de Física, Universidad de Santiago de Compostela, E-15782, Santiago de Compostela, Spain, and Department of Chemistry, Quaid-i-Azam University, Islamabad 45320, Pakistan
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Blanco E, Ruso JM, Prieto G, Sarmiento F. Different thermal unfolding pathways of catalase in the presence of cationic surfactants. J Phys Chem B 2007; 111:2113-8. [PMID: 17284066 DOI: 10.1021/jp066343m] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this paper we have corroborated the usefulness of spectroscopic techniques, such as UV-visible, in the study and thermodynamic characterization of the thermal unfolding of catalase as a function of the concentration and alkyl chain length of n-alkyltrimethylammonium bromides (CnTAB, n = 8, 10, and 12). For this reason, a thermodynamic model was used which included experimental data corresponding to the pre- and posttransition into the observable transition. It has been found that n-alkyltrimethylammonium bromides play two opposite roles in the folding and stability of catalase. They act as a structure stabilizer at a low molar concentration and as a destabilizer at a higher concentration. The maximum of the unfolding temperature has been found to decrease with the alkyl chain. The reason for this difference has been suggested to be the side chains involved. In the presence of C8TAB and C10TAB, Gibbs energies of unfolding (DeltaG(T)) decrease with concentration, whereas for C12TAB an increase has been observed. These findings can be explained by the fact that when differences in the hydrophobic nature of the surfactants exist, different pathways of unfolding may occur. Also, the presence of surfactants has been observed to affect the cold denaturation of catalase. Thermodynamic results suggest that the thermal denaturation of catalase in the presence of n-alkyltrimethylammonium bromides is a perfect transition between two states.
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Affiliation(s)
- Elena Blanco
- Group of Biophysics and Interfaces, Department of Applied Physics, Faculty of Physics, University of Santiago de Compostela, E-15782 Santiago de Compostela, Spain
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