1
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Ashrafi-Kooshk MR, Norouzi F, Zare Karizak A, Ahmadian S, Moosavi-Movahedi AA, Riazi G. Crosstalk between tau protein autoproteolysis and amyloid fibril formation. Int J Biol Macromol 2024; 262:129953. [PMID: 38325678 DOI: 10.1016/j.ijbiomac.2024.129953] [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: 09/15/2023] [Revised: 01/25/2024] [Accepted: 02/01/2024] [Indexed: 02/09/2024]
Abstract
Tau cleavage has been shown to have a significant effect on protein aggregation. Tau truncation results in the formation of aggregation-prone fragments leading to toxic aggregates and also causes the formation of harmful fragments that do not aggregate. Thus, targeting proteolysis of tau would be beneficial for the development of therapeutics for Alzheimer's disease and related tauopathies. In this study, amino-terminal quantification and ThT fluorimetry were respectively used to analyze the kinetics of tau fragmentation and fibril formation. SDS-PAGE analysis of tau protein incubated with a disulfide-reducing agent demonstrated that the cysteines of tau have a crucial role in the fibrillation and autoproteolysis. However, the structures converted to amyloid fibrils were different with conformations that led to autoproteolysis. The quantification of the amino terminal indicated that the double-disulfide parallel structures formed in the presence of heparin did not have protease activity. The survey of possible tau disulfide-mediated dimer configurations suggested that the non-register single disulfide bound conformations were involved in the tau autoproteolysis process. Moreover, the inhibition of autoproteolysis resulted in the increment of aggregation rate; hence it seems that the tau auto-cleavage is the cellular defense mechanism against protein fibrillation.
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Affiliation(s)
| | - Fatemeh Norouzi
- Reproductive Biomedicine Research Center, Royan Institute for Reproductive Biomedicine, Tehran, Iran
| | - Ashkan Zare Karizak
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | - Shahin Ahmadian
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran
| | | | - Gholamhossein Riazi
- Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
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2
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Jiang J, Shi L, Ren Z, Weng W. Preparation and characterization of soy protein isolate films by pretreatment with cysteine. Food Chem X 2023; 18:100735. [PMID: 37397188 PMCID: PMC10314194 DOI: 10.1016/j.fochx.2023.100735] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 05/29/2023] [Accepted: 06/01/2023] [Indexed: 07/04/2023] Open
Abstract
The effect of cysteine concentration on the viscosity of soy protein isolate (SPI)-based film-forming solution (FFS) and physicochemical properties of SPI films was investigated. The apparent viscosity of FFS decreased after adding 1 mmol/L cysteine but did not change after adding 2-8 mmol/L cysteine. After treatment with 1 mmol/L cysteine, the film solubility decreased from 70.40% to 57.60%, but the other physical properties did not change. The water vapor permeability and contact angle of SPI films increased as cysteine concentration increased from 4 mmol/L to 8 mmol/L, whereas the film elongation at break decreased. Based on scanning electron microscopy and X-ray diffraction results, cysteine crystallization could be aggregated on the surface of SPI films treated with 4 or 8 mmol/L cysteine. In conclusion, pretreatment with approximately 2 mmol/L cysteine could reduce the viscosity of SPI-based FFS, but did not change the physicochemical properties of SPI films.
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Affiliation(s)
- Jialin Jiang
- College of Ocean Food and Biological Engineering, Jimei University, Xiamen 361021, China
| | - Linfan Shi
- College of Ocean Food and Biological Engineering, Jimei University, Xiamen 361021, China
- Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Xiamen 361021, China
| | - Zhongyang Ren
- College of Ocean Food and Biological Engineering, Jimei University, Xiamen 361021, China
- Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Xiamen 361021, China
| | - Wuyin Weng
- College of Ocean Food and Biological Engineering, Jimei University, Xiamen 361021, China
- Fujian Provincial Engineering Technology Research Center of Marine Functional Food, Xiamen 361021, China
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3
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Li C, Paulsen PA, Akıllıoğlu HG, Nielsen SB, Engholm-Keller K, Lund MN. Cysteine residues are responsible for the sulfurous off-flavor formed in heated whey protein solutions. FOOD CHEMISTRY: MOLECULAR SCIENCES 2022; 5:100120. [PMID: 35865714 PMCID: PMC9294045 DOI: 10.1016/j.fochms.2022.100120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/03/2022] [Revised: 05/30/2022] [Accepted: 07/09/2022] [Indexed: 10/25/2022]
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4
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Color and structural modifications of alkaline extracted sunflower protein concentrates and isolates using L-cysteine and glutathione. Food Res Int 2021; 147:110574. [PMID: 34399547 DOI: 10.1016/j.foodres.2021.110574] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2021] [Revised: 06/21/2021] [Accepted: 06/27/2021] [Indexed: 11/22/2022]
Abstract
Alkaline sunflower protein extraction can be performed along with de-phenolization of sunflower seed proteins if greening is unwanted. This greening is promoted at alkaline pH when chlorogenic acid (CGA) oxidizes and reacts with amino acids such as lysine. Thiol-containing dough conditioners: L-cysteine hydrochloride and glutathione (GSH) were investigated as an alternative de-greening strategy to acidification and de-phenolization. Greening and browning inhibition of thiols (GSH and Cysteine) were modeled by a combination of additive and interaction effects of extraction pH (7.0 to 11.0) and thiol concentration (0.00 to 5.60 mM) randomly assigned by Response Surface Methodology (RSM). The powders with the highest greening were the controls (pH 8.9-9.3 and no added thiols) and powders at pH 10.41 with 0.82 mM thiols. From RSM, the maximum greening inhibition was achieved at pH 8.71 and 4.23 mM cysteine, and pH 8.51 and 3.78 mM GSH. However, cysteine caused more browning at alkaline pH than GSH. Furthermore, fluorescence spectroscopy showed that cysteine had a protective effect against alkaline unfolding, whereas GSH quenched fluorescence in a concentration-dependent manner. Overall, de-greening of alkaline extracted sunflower protein was achieved by adding cysteine or glutathione, but the thiols differed in their contribution to the browning and unfolding effect.
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5
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Chen B, Zhou K, Xie Y, Nie W, Li P, Zhou H, Xu B. Glutathione-mediated formation of disulfide bonds modulates the properties of myofibrillar protein gels at different temperatures. Food Chem 2021; 364:130356. [PMID: 34147870 DOI: 10.1016/j.foodchem.2021.130356] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2021] [Revised: 05/24/2021] [Accepted: 06/11/2021] [Indexed: 10/21/2022]
Abstract
The present study illustrated modulation of protein aggregation by affecting disulfide/sulfhydryl exchange reactions by adding different concentrations of free thiol represented by reduced-glutathione (GSH) for modulating myofibrillar protein (MP) gel properties at 75 °C or 95 °C. Gel strength and rheological results showed the effects of GSH were dependent on the concentrations (5, 10, 20, 40, and 80 g/kg) and heating temperatures. SEM results showed that the addition of GSH improved the gel microstructure at 95 °C. AFM and DLS results indicated that protein aggregation was also inhibited. At 75 °C, the addition of GSH influenced both MP aggregation and gel properties. Low concentrations (5, 10 g/kg) of GSH promoted aggregation, whereas high concentrations (20, 40, and 80 g/kg) of GSH inhibited this. By analyzing the protein structure and cross-linking pattern changes of MP and MP/GSH composites, a pathway involving GSH influencing MP gel properties was determined.
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Affiliation(s)
- Bo Chen
- Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230601, China; School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Kai Zhou
- Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230601, China; School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China; Anhui QiangWang Flavouring Food CO., LTD, China
| | - Yong Xie
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Wen Nie
- School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Peijun Li
- Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230601, China; School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China
| | - Hui Zhou
- Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230601, China; School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China; The Key Laboratory for Agriculture Products Processing of Anhui Province, Hefei 230601, China
| | - Baocai Xu
- Engineering Research Center of Bio-process, Ministry of Education, Hefei University of Technology, Hefei 230601, China; School of Food and Biological Engineering, Hefei University of Technology, Hefei 230601, China.
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6
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Yu X, Leconte N, Méjean S, Garric G, Even S, Henry G, Tessier FJ, Howsam M, Croguennec T, Gésan-Guiziou G, Dupont D, Jeantet R, Deglaire A. Semi-industrial production of a minimally processed infant formula powder using membrane filtration. J Dairy Sci 2021; 104:5265-5278. [PMID: 33685709 DOI: 10.3168/jds.2020-19529] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2020] [Accepted: 01/08/2021] [Indexed: 01/07/2023]
Abstract
Infant formula (IF) is submitted to several heat treatments during production, which can lead to denaturation or aggregation of proteins and promote Maillard reaction. The objective of this study was to investigate innovative minimal processing routes for the production of first-age IF powder, thus ensuring microbial safety with minimal level of protein denaturation. Three nutritionally complete IF powders were produced at a semi-industrial scale based on ingredients obtained by fresh bovine milk microfiltration (0.8 and 0.1-µm pore size membranes). Low-temperature vacuum evaporation (50°C) and spray-drying (inlet and outlet temperatures of 160 and 70°C, respectively) were conducted to produce the T- formula with no additional heat treatment. The T+ formula was produced with a moderate heat treatment (75°C for 2 min) applied before spray-drying, whereas the T+++ formula received successive heat treatments (72°C for 30 s on the milk; 90°C for 2-3 s before evaporation; 85°C for 2 min before spray-drying), thus mimicking commercial powdered IF. Protein denaturation and Maillard reaction products were followed throughout the production steps and the physicochemical properties of the powders were characterized. The 3 IF powders presented satisfactory physical properties in terms of aw, free fat content, glass transition temperature, and solubility index, as well as satisfactory bacteriological quality with a total flora <103 cfu/g and an absence of pathogens when a high level of bacteriological quality of the ingredients was ensured. Protein denaturation occurred mostly during the heat treatments of T+ and T+++ and was limited during the spray-drying process. The IF powder produced without heat treatment (T-) presented a protein denaturation extent (6 ± 4%) significantly lower than that in T+++ (58 ± 0%), but not significantly different from that in T+ (10 ± 4%). Although T- tended to contain less Maillard reaction products than T+ and T+++, the Maillard reaction products did not significantly discriminate the infant formulas in the frame of this work. The present study demonstrated the feasibility of producing at a semi-industrial scale an infant formula being bacteriologically safe and containing a high content of native proteins. Application of a moderate heat treatment before spray-drying could further guarantee the microbiological quality of the IF powders while maintaining a low protein denaturation extent. This study opens up new avenues for the production of minimally processed IF powders.
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Affiliation(s)
- X Yu
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - N Leconte
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - S Méjean
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - G Garric
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - S Even
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - G Henry
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - F J Tessier
- University of Lille, Inserm, CHU Lille, Pasteur Institute of Lille, U1167 - RID-AGE, F-59000 Lille, France
| | - M Howsam
- University of Lille, Inserm, CHU Lille, Pasteur Institute of Lille, U1167 - RID-AGE, F-59000 Lille, France
| | - T Croguennec
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | | | - D Dupont
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - R Jeantet
- STLO, INRAE, Institut Agro, 35042, Rennes, France
| | - A Deglaire
- STLO, INRAE, Institut Agro, 35042, Rennes, France.
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7
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Matsuyama K, Sunagawa N, Igarashi K. Mutation of cysteine residues increases heterologous expression of peach expansin in the methylotrophic yeast Pichia pastoris. PLANT BIOTECHNOLOGY (TOKYO, JAPAN) 2020; 37:397-403. [PMID: 33850426 PMCID: PMC8034678 DOI: 10.5511/plantbiotechnology.20.0713a] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/13/2020] [Indexed: 05/25/2023]
Abstract
The study of Carbohydrate-Active enZymes (CAZymes) associated with plant cell wall metabolism is important for elucidating the developmental mechanisms of plants and also for the utilization of plants as a biomass resource. The use of recombinant proteins is common in this context, but heterologous expression of plant proteins is particularly difficult, in part because the presence of many cysteine residues promotes denaturation, aggregation and/or protein misfolding. In this study, we evaluated two phenotypes of methylotrophic yeast Pichia pastoris as expression hosts for expansin from peach (Prunus persica (L.) Batsch, PpEXP1), which is one of the most challenging targets for heterologous expression. cDNAs encoding wild-type expansin (PpEXP1_WT) and a mutant in which all cysteine residues were replaced with serine (PpEXP1_CS) were each inserted into expression vectors, and the protein expression levels were compared. The total amount of secreted protein in PpEXP1_WT culture was approximately twice that of PpEXP1_CS. However, the amounts of recombinant expansin were 0.58 and 4.3 mg l-1, corresponding to 0.18% and 2.37% of total expressed protein, respectively. This 13-fold increase in production of the mutant in P. pastoris indicates that the replacement of cysteine residues stabilizes recombinant PpEXP1.
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Affiliation(s)
- Kaori Matsuyama
- Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Naoki Sunagawa
- Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
| | - Kiyohiko Igarashi
- Department of Biomaterial Sciences, Graduate School of Agricultural and Life Sciences, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo 113-8657, Japan
- VTT Technical Research Centre of Finland, PO Box 1000, Tietotie 2, Espoo FI-02044 VTT, Finland
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8
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Jiang S, Carroll L, Rasmussen LM, Davies MJ. Oxidation of protein disulfide bonds by singlet oxygen gives rise to glutathionylated proteins. Redox Biol 2020; 38:101822. [PMID: 33338920 PMCID: PMC7750407 DOI: 10.1016/j.redox.2020.101822] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2020] [Revised: 11/20/2020] [Accepted: 11/27/2020] [Indexed: 02/06/2023] Open
Abstract
Disulfide bonds play a key function in determining the structure of proteins, and are the most strongly conserved compositional feature across proteomes. They are particularly common in extracellular environments, such as the extracellular matrix and plasma, and in proteins that have structural (e.g. matrix) or binding functions (e.g. receptors). Recent data indicate that disulfides vary markedly with regard to their rate of reaction with two-electron oxidants (e.g. HOCl, ONOOH), with some species being rapidly and readily oxidized. These reactions yielding thiosulfinates that can react further with a thiol to give thiolated products (e.g. glutathionylated proteins with glutathione, GSH). Here we show that these ‘oxidant-mediated thiol-disulfide exchange reactions’ also occur during photo-oxidation reactions involving singlet oxygen (1O2). Reaction of protein disulfides with 1O2 (generated by multiple sensitizers in the presence of visible light and O2), yields reactive intermediates, probably zwitterionic peroxyl adducts or thiosulfinates. Subsequent exposure to GSH, at concentrations down to 2 μM, yields thiolated adducts which have been characterized by both immunoblotting and mass spectrometry. The yield of GSH adducts is enhanced in D2O buffers, and requires the presence of the disulfide bond. This glutathionylation can be diminished by non-enzymatic (e.g. tris-(2-carboxyethyl)phosphine) and enzymatic (glutaredoxin) reducing systems. Photo-oxidation of human plasma and subsequent incubation with GSH yields similar glutathionylated products with these formed primarily on serum albumin and immunoglobulin chains, demonstrating potential in vivo relevance. These reactions provide a novel pathway to the formation of glutathionylated proteins, which are widely recognized as key signaling molecules, via photo-oxidation reactions. Disulfide bonds (DSBs) are critical to protein structure and function. DSBs are rapidly oxidized by singlet oxygen and other oxidants to reactive species. These DSB-derived intermediates react with GSH to give glutathionylated proteins. Glutathionylation can be diminished by reductants, but does not repair DSB damage. Oxidation of human plasma DSBs gives glutathionylated albumin and immunoglobulins.
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Affiliation(s)
- Shuwen Jiang
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Luke Carroll
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Lars M Rasmussen
- Center for Individualized Medicine in Arterial Diseases (CIMA), Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, University of Southern Denmark, Odense, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, 2200, Denmark.
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9
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Carroll L, Jiang S, Irnstorfer J, Beneyto S, Ignasiak MT, Rasmussen LM, Rogowska-Wrzesinska A, Davies MJ. Oxidant-induced glutathionylation at protein disulfide bonds. Free Radic Biol Med 2020; 160:513-525. [PMID: 32877736 DOI: 10.1016/j.freeradbiomed.2020.08.018] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/18/2020] [Accepted: 08/19/2020] [Indexed: 01/13/2023]
Abstract
Disulfide bonds are a key determinant of protein structure and function, and highly conserved across proteomes. They are particularly abundant in extracellular proteins, including those with critical structural, ligand binding or receptor function. We demonstrate that oxidation of protein disulfides induces polymerization, and results in oxygen incorporation into the former disulfide via thiosulfinate generation. These intermediates, which have half-lives of several hours in vitro, undergo secondary reactions that cleave the disulfide bond, by irreversible hydrolysis to sulfinic and sulfonic acids, or reaction with thiols in a process that yields thiolated proteins (e.g. glutathionylated species in the case of reaction with glutathione). The adducts have been characterized by mass spectrometry (as ions corresponding to the addition of 306 and 712 Da for addition of one and two glutathione molecules, respectively) and immunoblotting. These modifications can be induced by multiple biologically-important oxidants, including HOCl, ONOOH, and H2O2, and on multiple proteins, demonstrating that this is a common disulfide modification pathway. Addition of glutathione to give glutathionylated proteins, can be reversed by reducing systems (e.g. tris(2-carboxyethyl)phosphine), but this does not repair the original disulfide bond. Exposure of human plasma to these modifying agents increases protein glutathionylation, demonstrating potential in vivo relevance. Overall these data provide evidence for a novel and facile route to glutathionylated proteins involving initial oxidation of a disulfide to a thiosulfinate followed by rapid reaction with GSH ('oxidant-mediated thiol-disulfide exchange'). These data elucidate a novel pathway for protein glutathionylation that may have significant implications for redox biology and cell signaling.
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Affiliation(s)
- Luke Carroll
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Shuwen Jiang
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Johanna Irnstorfer
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Sergi Beneyto
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Marta T Ignasiak
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark; Faculty of Chemistry, Adam Mickiewicz University, and Wielkopolska Center for Advanced Technologies, Poznan, Poland
| | - Lars M Rasmussen
- Center for Individualized Medicine in Arterial Diseases (CIMA), Department of Clinical Biochemistry and Pharmacology, Odense University Hospital, University of Southern Denmark, Odense, Denmark
| | - Adelina Rogowska-Wrzesinska
- Department of Biochemistry and Molecular Biology and VILLUM Center for Bioanalytical Sciences, University of Southern Denmark, Odense, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark.
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Halabi A, Deglaire A, Hennetier M, Violleau F, Burel A, Bouhallab S, Dupont D, Croguennec T. Structural characterization of heat-induced protein aggregates in model infant milk formulas. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.105928] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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11
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Zhao Z, Poojary MM, Skibsted LH, Lund MN. Cleavage of Disulfide Bonds in Cystine by UV-B Illumination Mediated by Tryptophan or Tyrosine as Photosensitizers. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:6900-6909. [PMID: 32437144 DOI: 10.1021/acs.jafc.0c01760] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Photolytic cleavage of disulfide bonds in proteins by UV light will influence their structure and functionality. The present study aimed to investigate the efficiency of disulfide cleavage by UV-B light in a system without a protein backbone consisting of combinations of cystine (a disulfide) and tryptophan (Trp) or tyrosine (Tyr) under anaerobic and aerobic conditions and to identify oxidation products formed by UV-B light. Cystine was reduced to cysteine (Cys) almost with a 1:1 stoichiometry by photoexcited Trp for anaerobic equimolar aqueous solutions (each 200 μM; pH 7.0), while photoexcited Tyr provided lower concentrations of Cys. The calculation of apparent quantum yields allowed for a comparison between the efficiency of reactions and showed that formation of Cys from disulfide cleavage of cystine was more efficient by photoexcited Trp than by photoexcited Tyr and of cystine alone and that Trp was more sensitive to photodegradation than Tyr and cystine under both aerobic and anaerobic conditions. Increasing the ratio between cystine and Trp to a 1:2 ratio did not increase the efficiency of free thiol formation but caused a more efficient photodegradation of Trp. The free thiol formed from disulfide cleavage of cystine was further oxidized to other unidentified compounds. Trp oxidation products (3-hydroxykynurenine (3-OH-Kyn) and tryptamine) were only identified in minor concentrations following light exposure of cystine and Trp in 1:1 and 1:2 ratios under both aerobic and anaerobic conditions, indicating further photodegradation to unidentified compounds. 3,4-Dihydroxyphenylalanine (DOPA) was formed from the oxidation of Tyr in the illuminated samples of cystine and Tyr in a 1:1 ratio under both aerobic and anaerobic conditions.
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Affiliation(s)
- Zichen Zhao
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Denmark
| | - Mahesha M Poojary
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Denmark
| | - Leif H Skibsted
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Denmark
| | - Marianne N Lund
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
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12
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Zhao Z, Engholm-Keller K, Poojary MM, Boelt SG, Rogowska-Wrzesinska A, Skibsted LH, Davies MJ, Lund MN. Generation of Aggregates of α-Lactalbumin by UV-B Light Exposure. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:6701-6714. [PMID: 32396720 DOI: 10.1021/acs.jafc.0c00757] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Whey proteins are widely used as ingredients in the form of aggregates to obtain certain functionalities in food applications. The aim of this study was to understand how UV illumination generates aggregates of α-lactalbumin (α-LA) as an alternative to heat treatments traditionally used for industrial production of protein aggregates. Absorption of UV light by α-LA caused cleavage of disulfide bonds and release of thiol groups, which resulted in primarily disulfide-mediated aggregation. This process mediated efficient aggregation with up to 98% monomer conversion into aggregates through formation of intermolecular disulfide bonds, while only minor levels of nonreducible cross-links were observed. SDS-PAGE analysis revealed that illumination led to formation of dimeric, trimeric, and oligomeric forms of α-LA. LC-MS/MS analysis showed that all of the four native disulfide bonds in α-LA were cleaved by UV illumination but to different extents, and the extent of cleavage was found to be higher in the absence of calcium. Seventeen different non-native disulfides were formed after 24 h of UV illumination. Two dityrosine bonds were identified (Tyr103-Tyr103 and Tyr36-Tyr103) alongside ditryptophan (Trp118-Trp118) and tyrosine-tryptophan (Tyr50-Trp60) cross-links. In addition, Trp60, Trp118, Cys73, Cys91, Cys120, Phe80, Met90, His68, and His107 were found to be oxidized up to 12% as compared to a nonilluminated control. Our work illustrates that light exposure can be used for generation of α-LA aggregates, but optimization of the illumination conditions is required to reduce oxidative damage to Trp, Cys, Phe, Met, and His residues.
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Affiliation(s)
- Zichen Zhao
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark
| | - Kasper Engholm-Keller
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark
| | - Mahesha M Poojary
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark
| | - Sanne G Boelt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | | | - Leif H Skibsted
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
| | - Marianne N Lund
- Department of Food Science, Faculty of Science, University of Copenhagen, Rolighedsvej 26, 1958 Frederiksberg C, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3, 2200 Copenhagen N, Denmark
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13
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Streicher C, Nguyen NH, Anema SG. Modifying whey protein concentrate/isolate by heating in the presence of cysteine. Int Dairy J 2020. [DOI: 10.1016/j.idairyj.2020.104675] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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Kinetics of heat-induced denaturation of proteins in model infant milk formulas as a function of whey protein composition. Food Chem 2020; 302:125296. [DOI: 10.1016/j.foodchem.2019.125296] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2019] [Revised: 07/25/2019] [Accepted: 07/29/2019] [Indexed: 02/07/2023]
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15
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Giblin L, Yalçın AS, Biçim G, Krämer AC, Chen Z, Callanan MJ, Arranz E, Davies MJ. Whey proteins: targets of oxidation, or mediators of redox protection. Free Radic Res 2019; 53:1136-1152. [PMID: 31510814 DOI: 10.1080/10715762.2019.1632445] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bovine whey proteins are highly valued dairy ingredients. This is primarily due to their amino acid content, digestibility, bioactivities and their processing characteristics. One of the reported bioactivities of whey proteins is antioxidant activity. Numerous dietary intervention trials with humans and animals indicate that consumption of whey products can modulate redox biomarkers to reduce oxidative stress. This bioactivity has in part been assigned to whey peptides using a range of biochemical or cellular assays in vitro. Superimposing whey peptide sequences from gastrointestinal samples, with whey peptides proven to be antioxidant in vitro, allows us to propose peptides from whey likely to exhibit antioxidant activity in the diet. However, whey proteins themselves are targets of oxidation during processing particularly when exposed to high thermal loads and/or extensive processing (e.g. infant formula manufacture). Oxidative damage of whey proteins can be selective with regard to the residues that are modified and are associated with the degree of protein unfolding, with α-Lactalbumin more susceptible than β-Lactoglobulin. Such oxidative damage may have adverse effects on human health. This review summarises how whey proteins can modulate cellular redox pathways and conversely how whey proteins can be oxidised during processing. Given the extensive processing steps that whey proteins are often subjected to, we conclude that oxidation during processing is likely to compromise the positive health attributes associated with whey proteins.
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Affiliation(s)
- Linda Giblin
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | - A Süha Yalçın
- Department of Biochemistry, School of Medicine, Marmara University, İstanbul, Turkey
| | - Gökhan Biçim
- Department of Biochemistry, School of Medicine, Marmara University, İstanbul, Turkey
| | - Anna C Krämer
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Zhifei Chen
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Michael J Callanan
- Department of Biological Sciences, Cork Institute of Technology, Cork, Ireland
| | - Elena Arranz
- Teagasc Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
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16
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Krämer AC, Davies MJ. Effect of Methylglyoxal-Induced Glycation on the Composition and Structure of β-Lactoglobulin and α-Lactalbumin. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2019; 67:699-710. [PMID: 30577692 DOI: 10.1021/acs.jafc.8b05809] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
Glycation, and particularly reactions between aldehydes and nucleophiles (thiols, amines), can initiate changes in the structure, solubility, composition, hydrophobicity, conformation, function, and susceptibility to proteolysis of proteins. This can have adverse consequences for mammals, plants, foodstuffs, and pharmaceuticals. Low-molecular-mass dialdehydes such as methylglyoxal (MGO) are much more reactive than parent glucose and therefore potentially highly damaging. These are present at significant levels in some foods. This study investigated whether and how MGO exposure, with or without concurrent heat exposure, affected the major whey proteins β-lactoglobulin and α-lactalbumin. MGO diminished the formation of heat-induced, reducible, intermolecular disulfide cross-links for both proteins, with this being associated, at least in part, with alternative thiol consuming reactions of MGO. At long incubation times, nonreducible protein cross-links were formed in a dose-dependent manner, with LC-MS/MS and UPLC analysis showing the presence of methylglyoxal-lysine dimers (MOLD). UPLC analysis revealed MGO-dependent consumption of specific amino acids in the order Cys > Arg > Lys > Trp for both proteins, with α-lactalbumin affected to a greater extent than β-lactoglobulin. SDS-PAGE revealed altered protein mobility consistent with modification of charged residues. MGO exposure also resulted in increased binding of the hydrophobic dye, 8-anilino-1-naphthalene sulfonic acid, consistent with limited protein unfolding. Overall, these data are consistent with rapid reaction of MGO residues at Cys residues (when available) and surface accessible Arg and Lys residues, with formation of adducts and cross-linked materials. These alternative reactions of dialdehydes diminish direct heat-induced (disulfide) cross-link formation and result in limited protein unfolding.
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Affiliation(s)
- Anna C Krämer
- Department of Biomedical Sciences, Panum Institute , University of Copenhagen , Copenhagen 2200 , Denmark
| | - Michael J Davies
- Department of Biomedical Sciences, Panum Institute , University of Copenhagen , Copenhagen 2200 , Denmark
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17
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The effect of thiol reagents on the denaturation of the whey protein in milk and whey protein concentrate solutions. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2018.06.012] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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18
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Nielsen LR, Nielsen SB, Zhao Z, Olsen K, Nielsen JH, Lund MN. Control of α-Lactalbumin Aggregation by Modulation of Temperature and Concentration of Calcium and Cysteine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2018; 66:7110-7120. [PMID: 29916707 DOI: 10.1021/acs.jafc.8b01172] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
The effect of free cysteine (in different concentrations) on the thermal aggregation of calcium-saturated (Ca-sat) and -depleted (Ca-dep) α-lactalbumin (α-LA) was investigated at 25, 50, and 70 °C. The temperatures chosen were below the denaturation temperature ( Td) of Ca-dep and Ca-sat α-LA (25 °C), above the Td of Ca-dep α-LA and below that of Ca-sat α-LA (50 °C), and above the Td of Ca-sat α-LA (70 °C). Size-exclusion chromatography coupled to multiangle light scattering showed that no aggregation or only minor aggregation was obtained at the investigated temperatures for both Ca-dep and Ca-sat α-LA even at extended holding times. Aggregates of Ca-sat α-LA were larger than those developed for Ca-dep α-LA. The addition of cysteine, a low-molecular-mass free thiol, resulted in increased aggregation of both Ca-sat and Ca-dep α-LA. Comparisons of SDS-PAGE run under reducing and nonreducing conditions showed that the formed cross-links were primarily disulfide bonds, but Western blots also showed small contributions from dityrosine cross-link formation. The aggregation kinetics related to monomer loss during heat treatment were determined by RP-UPLC and showed that the addition of cysteine increased the rate of aggregation. The activation energies for Ca-dep α-LA with 0.35 and 0.7 mM cysteine were found to be 59 ± 1 and 46 ± 4 kJ/mol, respectively, which showed that less energy was needed for the enhanced thermal aggregation of α-LA when the cysteine concentration was increased. This study showed that it was possible to control the aggregation size of α-LA by manipulating the incubation temperature and the cysteine concentration.
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Affiliation(s)
- Line R Nielsen
- Innovation R&D, Discover Department , Arla Foods Ingredients Group P/S , Sønderupvej 26 , Videbaek 6920 , Denmark
- Department of Food Science, Faculty of Science , University of Copenhagen , Rolighedsvej 26 , Frederiksberg 1958 , Denmark
| | - Søren B Nielsen
- Innovation R&D, Discover Department , Arla Foods Ingredients Group P/S , Sønderupvej 26 , Videbaek 6920 , Denmark
| | - Zichen Zhao
- Department of Food Science, Faculty of Science , University of Copenhagen , Rolighedsvej 26 , Frederiksberg 1958 , Denmark
| | - Karsten Olsen
- Department of Food Science, Faculty of Science , University of Copenhagen , Rolighedsvej 26 , Frederiksberg 1958 , Denmark
| | - Jacob H Nielsen
- Innovation R&D, Discover Department , Arla Foods Ingredients Group P/S , Sønderupvej 26 , Videbaek 6920 , Denmark
| | - Marianne N Lund
- Department of Food Science, Faculty of Science , University of Copenhagen , Rolighedsvej 26 , Frederiksberg 1958 , Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences , University of Copenhagen , Blegdamsvej 3 , Copenhagen 2200 , Denmark
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