1
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Melnikova D, Ranjan VV, Nesmelov YE, Skirda VD, Nesmelova IV. Translational Diffusion and Self-Association of an Intrinsically Disordered Protein κ-Casein Using NMR with Ultra-High Pulsed-Field Gradient and Time-Resolved FRET. J Phys Chem B 2024; 128:7781-7791. [PMID: 39106061 PMCID: PMC11331516 DOI: 10.1021/acs.jpcb.4c03625] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2024] [Revised: 07/09/2024] [Accepted: 07/17/2024] [Indexed: 08/07/2024]
Abstract
Much attention has been given to studying the translational diffusion of globular proteins, whereas the translational diffusion of intrinsically disordered proteins (IDPs) is less studied. In this study, we investigate the translational diffusion and how it is affected by the self-association of an IDP, κ-casein, using pulsed-field gradient nuclear magnetic resonance and time-resolved Förster resonance energy transfer. Using the analysis of the shape of diffusion attenuation and the concentration dependence of κ-casein diffusion coefficients and intermolecular interactions, we demonstrate that κ-casein exhibits continuous self-association. When the volume fraction of κ-casein is below 0.08, we observe that κ-casein self-association results in a macroscopic phase separation upon storage at 4 °C. At κ-casein volume fractions above 0.08, self-association leads to the formation of labile gel-like networks without subsequent macroscopic phase separation. Unlike α-casein, which shows a strong concentration dependence and extensive gel-like network formation, only one-third of κ-casein molecules participate in the gel network at a time, resulting in a more dynamic and less extensive structure. These findings highlight the unique association properties of κ-casein, contributing to a better understanding of its behavior under various conditions and its potential role in casein micelle formation.
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Affiliation(s)
- Daria
L. Melnikova
- Department
of Physics of Molecular Systems, Kazan Federal
University, Kazan 420011, Russia
| | - Venkatesh V. Ranjan
- Department
of Chemistry, University of North Carolina, Charlotte, North Carolina 28223, United States
- Department
of Physics and Optical Sciences, University
of North Carolina, Charlotte, North Carolina 28223, United States
| | - Yuri E. Nesmelov
- Department
of Physics and Optical Sciences, University
of North Carolina, Charlotte, North Carolina 28223, United States
| | - Vladimir D. Skirda
- Department
of Physics of Molecular Systems, Kazan Federal
University, Kazan 420011, Russia
| | - Irina V. Nesmelova
- Department
of Physics and Optical Sciences, University
of North Carolina, Charlotte, North Carolina 28223, United States
- School
of Data Science, University of North Carolina, Charlotte, North Carolina 28223, United States
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2
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Wijegunawardhana D, Wijesekara I, Liyanage R, Truong T, Silva M, Chandrapala J. Process-Induced Molecular-Level Protein-Carbohydrate-Polyphenol Interactions in Milk-Tea Blends: A Review. Foods 2024; 13:2489. [PMID: 39200417 PMCID: PMC11353574 DOI: 10.3390/foods13162489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2024] [Revised: 07/31/2024] [Accepted: 08/01/2024] [Indexed: 09/02/2024] Open
Abstract
The rapid increase in the production of powdered milk-tea blends is driven by a growing awareness of the presence of highly nutritious bioactive compounds and consumer demand for convenient beverages. However, the lack of literature on the impact of heat-induced component interactions during processing hinders the production of high-quality milk-tea powders. The production process of milk-tea powder blends includes the key steps of pasteurization, evaporation, and spray drying. Controlling heat-induced interactions, such as protein-protein, protein-carbohydrate, protein-polyphenol, carbohydrate-polyphenol, and carbohydrate-polyphenol, during pasteurization, concentration, and evaporation is essential for producing a high-quality milk-tea powder with favorable physical, structural, rheological, sensory, and nutritional qualities. Adjusting production parameters, such as the type and the composition of ingredients, processing methods, and processing conditions, is a great way to modify these interactions between components in the formulation, and thereby, provide improved properties and storage stability for the final product. Therefore, this review comprehensively discusses how molecular-level interactions among proteins, carbohydrates, and polyphenols are affected by various unit operations during the production of milk-tea powders.
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Affiliation(s)
- Dilema Wijegunawardhana
- School of Science, STEM College, RMIT University, Bundoora, VIC 3083, Australia; (D.W.); (T.T.); (M.S.)
- Department of Biosystems Technology, Faculty of Technology, University of Sri Jayewardenepura, Dampe-Pitipana Road, Homagama 10200, Sri Lanka;
| | - Isuru Wijesekara
- Department of Food Science and Technology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Gangodawila, Nugegoda 10250, Sri Lanka;
| | - Rumesh Liyanage
- Department of Biosystems Technology, Faculty of Technology, University of Sri Jayewardenepura, Dampe-Pitipana Road, Homagama 10200, Sri Lanka;
| | - Tuyen Truong
- School of Science, STEM College, RMIT University, Bundoora, VIC 3083, Australia; (D.W.); (T.T.); (M.S.)
- School of Science, Engineering & Technology, RMIT University, Ho Chi Minh City 700000, Vietnam
| | - Mayumi Silva
- School of Science, STEM College, RMIT University, Bundoora, VIC 3083, Australia; (D.W.); (T.T.); (M.S.)
| | - Jayani Chandrapala
- School of Science, STEM College, RMIT University, Bundoora, VIC 3083, Australia; (D.W.); (T.T.); (M.S.)
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3
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Holt C, Carver JA. Invited review: Modeling milk stability. J Dairy Sci 2024; 107:5259-5279. [PMID: 38522835 DOI: 10.3168/jds.2024-24779] [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: 02/12/2024] [Accepted: 02/15/2024] [Indexed: 03/26/2024]
Abstract
Novel insights into the stability of milk and milk products during storage and processing result from describing caseins near neutral pH as hydrophilic, intrinsically disordered, proteins. Casein solubility is strongly influenced by pH and multivalent ion binding. Solubility is high at a neutral pH or above, but decreases as the casein net charge approaches zero, allowing a condensed casein phase or gel to form, then increases at lower pH. Of particular importance for casein micelle stability near neutral pH is the proportion of free caseins in the micelle (i.e., caseins not bound directly to nanoclusters of calcium phosphate). Free caseins are more soluble and better able to act as molecular chaperones (to prevent casein and whey protein aggregation) than bound caseins. Some free caseins are highly phosphorylated and can also act as mineral chaperones to inhibit the growth of calcium phosphate phases and prevent mineralized deposits from forming on membranes or heat exchangers. Thus, casein micelle stability is reduced when free caseins bind to amyloid fibrils, destabilized whey proteins or calcium phosphate. The multivalent-binding model of the casein micelle quantitatively describes these and other factors affecting the stability of milk and milk protein products during manufacture and storage.
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Affiliation(s)
- C Holt
- School of Biomolecular Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
| | - J A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
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4
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Sun Y, Ding Y, Liu B, Guo J, Su Y, Yang X, Man C, Zhang Y, Jiang Y. Recent advances in the bovine β-casein gene mutants on functional characteristics and nutritional health of dairy products: Status, challenges, and prospects. Food Chem 2024; 443:138510. [PMID: 38281416 DOI: 10.1016/j.foodchem.2024.138510] [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: 10/16/2023] [Revised: 01/04/2024] [Accepted: 01/17/2024] [Indexed: 01/30/2024]
Abstract
β-casein is the second most abundant form of casein in milk. Changes in amino acid sequence at specific positions in the primary structure of β-casein in milk will produce gene mutations that affect the physicochemical properties of dairy products and the hydrolysis site of digestive enzymes. The screening method of β-casein allele frequency detection in dairy products also has attracted the extensive attention of scientists and farmers. The A1 and A2 β-casein is the two usual mutation types, distinguished by histidine and proline at position 67 in the peptide chain. This paper summarizes the effects of A1 and A2 β-casein on the physicochemical properties of dairy products and evaluates the effects on human health, and the genotyping methods were also concluded. Impressively, this review presents possible future opportunities and challenges for the promising field of A2 β-casein, providing a valuable reference for the development of the functional dairy market.
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Affiliation(s)
- Yilin Sun
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yixin Ding
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Biqi Liu
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Jinfeng Guo
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yue Su
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Xinyan Yang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Chaoxin Man
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China
| | - Yu Zhang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China.
| | - Yujun Jiang
- Key Laboratory of Dairy Science, Ministry of Education, Department of Food Science, Northeast Agricultural University, Harbin 150030, China; Food Laboratory of Zhongyuan, Luohe, Henan 462300, China.
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5
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Runthala A, Mbye M, Ayyash M, Xu Y, Kamal-Eldin A. Caseins: Versatility of Their Micellar Organization in Relation to the Functional and Nutritional Properties of Milk. Molecules 2023; 28:molecules28052023. [PMID: 36903269 PMCID: PMC10004547 DOI: 10.3390/molecules28052023] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2022] [Revised: 02/10/2023] [Accepted: 02/11/2023] [Indexed: 02/24/2023] Open
Abstract
The milk of mammals is a complex fluid mixture of various proteins, minerals, lipids, and other micronutrients that play a critical role in providing nutrition and immunity to newborns. Casein proteins together with calcium phosphate form large colloidal particles, called casein micelles. Caseins and their micelles have received great scientific interest, but their versatility and role in the functional and nutritional properties of milk from different animal species are not fully understood. Caseins belong to a class of proteins that exhibit open and flexible conformations. Here, we discuss the key features that maintain the structures of the protein sequences in four selected animal species: cow, camel, human, and African elephant. The primary sequences of these proteins and their posttranslational modifications (phosphorylation and glycosylation) that determine their secondary structures have distinctively evolved in these different animal species, leading to differences in their structural, functional, and nutritional properties. The variability in the structures of milk caseins influence the properties of their dairy products, such as cheese and yogurt, as well as their digestibility and allergic properties. Such differences are beneficial to the development of different functionally improved casein molecules with variable biological and industrial utilities.
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Affiliation(s)
- Ashish Runthala
- Department of Biotechnology, Koneru Lakshmaiah Education Foundation, Vijayawada 522302, India
- Correspondence: (A.R.); (A.K.-E.); Tel.: +971-5-0138-9248 (A.K.-E.)
| | - Mustapha Mbye
- Department of Food Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Mutamed Ayyash
- Department of Food Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
| | - Yajun Xu
- Department of Nutrition and Food Hygiene, School of Public Health, Peking University, Beijing 100871, China
| | - Afaf Kamal-Eldin
- Department of Food Science, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- Zayed Bin Sultan Center for Health Sciences, United Arab Emirates University, Al Ain P.O. Box 15551, United Arab Emirates
- Correspondence: (A.R.); (A.K.-E.); Tel.: +971-5-0138-9248 (A.K.-E.)
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6
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Moreira TCP, Cunha RLD. Ultrasonic process affecting interactions between sodium caseinate and whey proteins. Food Res Int 2023; 164:112356. [PMID: 36737944 DOI: 10.1016/j.foodres.2022.112356] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2022] [Revised: 12/19/2022] [Accepted: 12/23/2022] [Indexed: 12/26/2022]
Abstract
Ultrasound has been widely explored for several applications, such as emulsification or structural modification of food materials such as proteins. In this work, the effect of ultrasound on the control of whey proteins (WPI) aggregation was evaluated in the presence of sodium caseinate (NaCas). Solutions of NaCas, WPI and both (1:1) were treated with ultrasound under different power and time conditions and were initially evaluated in terms of particle size distribution, charge density, pH and polyacrylamide gel electrophoresis. Three pairs of conditions were adopted to provide the same energy density - A1 (450 W / 300 s, 6750 MJ/m3), A2 (150 W / 900 s, 6750 MJ/m3), A3 (600 W / 300 s, 900 MJ/m3), A4 (202.5 W / 900 s, 9112.5 MJ/m3), A5 (742.5 W / 300 s, 11137.5 MJ/m3) and A6 (247.5 W / 900 s, 11137.5 MJ/m3). Best conditions of transmitted energy - A1, A3 and A5 - were studied for surface hydrophobicity, circular dichroism and infrared spectroscopy. The decrease of surface hydrophobicity of NaCas:WPI mixtures pointed to a protective effect of NaCas against WPI denaturation, confirmed by the presence of more ordered structures by FTIR analysis that were not observed in the absence of NaCas. Finally, the effect of these structural changes on the gelation capacity of the ultrasound-treated proteins was assessed. Ultrasound was able to reduce the stress at rupture from 1988.59 Pa (control) to 1655.31 Pa (A3) and 1871.24 Pa (A5), and more markedly increase the Young modulus from 113.69 kPa (control) to 243.30 kPa (A3) and 392.44 kPa (A5). This study identified that higher power values with shorter times were able to provide greater protein changes that affected gelation properties, showing that the modulation of ultrasound conditions can produce ingredients with different techno-functional properties.
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Affiliation(s)
- Thais Caldas Paiva Moreira
- Department of Food Engineering and Technology (DETA), School of Food Engineering, University of Campinas (UNICAMP), Rua Monteiro Lobato, 80, Campinas-SP, CEP 13083-862, Brazil.
| | - Rosiane Lopes da Cunha
- Department of Food Engineering and Technology (DETA), School of Food Engineering, University of Campinas (UNICAMP), Rua Monteiro Lobato, 80, Campinas-SP, CEP 13083-862, Brazil
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7
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Bahraminejad E, Paliwal D, Sunde M, Holt C, Carver JA, Thorn DC. Amyloid fibril formation by α S1- and β-casein implies that fibril formation is a general property of casein proteins. BIOCHIMICA ET BIOPHYSICA ACTA. PROTEINS AND PROTEOMICS 2022; 1870:140854. [PMID: 36087849 DOI: 10.1016/j.bbapap.2022.140854] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2022] [Revised: 08/31/2022] [Accepted: 09/02/2022] [Indexed: 06/15/2023]
Abstract
Caseins are a diverse family of intrinsically disordered proteins present in the milks of all mammals. A property common to two cow paralogues, αS2- and κ-casein, is their propensity in vitro to form amyloid fibrils, the highly ordered protein aggregates associated with many age-related, including neurological, diseases. In this study, we explored whether amyloid fibril-forming propensity is a general feature of casein proteins by examining the other cow caseins (αS1 and β) as well as β-caseins from camel and goat. Small-angle X-ray scattering measurements indicated that cow αS1- and β-casein formed large spherical aggregates at neutral pH and 20°C. Upon incubation at 65°C, αS1- and β-casein underwent conversion to amyloid fibrils over the course of ten days, as shown by thioflavin T binding, transmission electron microscopy, and X-ray fibre diffraction. At the lower temperature of 37°C where fibril formation was more limited, camel β-casein exhibited a greater fibril-forming propensity than its cow or goat orthologues. Limited proteolysis of cow and camel β-casein fibrils and analysis by mass spectrometry indicated a common amyloidogenic sequence in the proline, glutamine-rich, C-terminal region of β-casein. These findings highlight the persistence of amyloidogenic sequences within caseins, which likely contribute to their functional, heterotypic self-assembly; in all mammalian milks, at least two caseins coalesce to form casein micelles, implying that caseins diversified partly to avoid dysfunctional amyloid fibril formation.
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Affiliation(s)
- Elmira Bahraminejad
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Devashi Paliwal
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Margaret Sunde
- School of Medical Sciences, Faculty of Medicine and Health, and Sydney Nano, The University of Sydney, Sydney, NSW 2006, Australia
| | - Carl Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - David C Thorn
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia.
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8
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Daniloski D, McCarthy NA, Huppertz T, Vasiljevic T. What is the impact of amino acid mutations in the primary structure of caseins on the composition and functionality of milk and dairy products? Curr Res Food Sci 2022; 5:1701-1712. [PMID: 36212081 PMCID: PMC9535159 DOI: 10.1016/j.crfs.2022.09.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Revised: 09/25/2022] [Accepted: 09/28/2022] [Indexed: 11/19/2022] Open
Abstract
The impact of amino acid mutations within the peptide structure of bovine milk protein is important to understand as it can effect processability and subsequently effect its physiological properties. Genetic polymorphisms of bovine caseins can influence the chemical, structural, and technological properties, including casein micelle morphology, calcium distribution, network creation upon gelation, and surface activity. The A1 and A2 genetic variants of β-casein have recently acquired growing attention from both academia and industry, prompting new developments in the area. The difference between these two genetic variants is the inclusion of either proline in β-casein A2 or histidine in β-casein A1 at position 67 in the peptide chain. The aim of this review was to examine the extent to which milk and ingredient functionality is influenced by β-casein phenotype. One of the main findings of this review was although β-casein A1 was found to be the dominant variant in milks with superior acid gelation and rennet coagulation properties, milks comprised of β-casein A2 possessed greater emulsion and foam formation capabilities. The difference in the casein micelle assembly, hydrophobicity, and chaperone activity of caseins may explain the contrast in the functionality of milks containing β-casein from either A1 or A2 families. This review provides new insights into the subtle variations in the physicochemical properties of bovine milks, which could potentially support dairy producers in the development of new dairy products with different functional properties. Impact of β- and other caseins on the casein micelle structure and functionality. Proline and histidine in β-caseins play a key role in casein micelle conformation. Chaperone activity of β-casein A2 towards heat-induced aggregation of whey protein. Gels prepared of milks with β-casein A1 possess a denser and firmer structure. Ordered structure of β-casein A2 led to improved emulsion and foam formation.
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Affiliation(s)
- Davor Daniloski
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities and College of Health and Biomedicine, Victoria University, Melbourne, VIC, 8001, Australia
- Food Chemistry and Technology Department, Teagasc Food Research Centre, Moorepark, Fermoy, P61 C996, Cork, Ireland
| | - Noel A. McCarthy
- Food Chemistry and Technology Department, Teagasc Food Research Centre, Moorepark, Fermoy, P61 C996, Cork, Ireland
| | - Thom Huppertz
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities and College of Health and Biomedicine, Victoria University, Melbourne, VIC, 8001, Australia
- FrieslandCampina, Amersfoort, the Netherlands
- Wageningen University & Research, Wageningen, the Netherlands
| | - Todor Vasiljevic
- Advanced Food Systems Research Unit, Institute for Sustainable Industries and Liveable Cities and College of Health and Biomedicine, Victoria University, Melbourne, VIC, 8001, Australia
- Corresponding author.
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9
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Horvath A, Fuxreiter M, Vendruscolo M, Holt C, Carver JA. Are casein micelles extracellular condensates formed by liquid-liquid phase separation? FEBS Lett 2022; 596:2072-2085. [PMID: 35815989 DOI: 10.1002/1873-3468.14449] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 06/27/2022] [Indexed: 11/05/2022]
Abstract
Casein micelles are extracellular polydisperse assemblies of unstructured casein proteins. Caseins are the major component of milk. Within casein micelles, casein molecules are stabilised by binding to calcium phosphate nanoclusters and, by acting as molecular chaperones, through multivalent interactions. In light of such interactions, we discuss whether casein micelles can be considered as extracellular condensates formed by liquid-liquid phase separation. We analyse the sequence, structure and interactions of caseins in comparison to proteins forming intracellular condensates. Furthermore, we review the similarities between caseins and small heat-shock proteins whose chaperone activity is linked to phase separation of proteins. By bringing these observations together, we describe a regulatory mechanism for protein condensates, as exemplified by casein micelles.
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Affiliation(s)
- Attila Horvath
- John Curtin School of Medical Research, The Australian National University, Acton, ACT, 2601, Australia
| | - Monika Fuxreiter
- Department of Biomedical Sciences, University of Padova, Via Ugo Bassi, 58/B 35131, Padova, Italy
| | - Michele Vendruscolo
- Centre for Misfolding Diseases, Yusuf Hamied Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, CB2 1EW, United Kingdom
| | - Carl Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, G12 8QQ, United Kingdom
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT, 2601, Australia
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10
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Parray ZA, Shahid M, Islam A. Insights into Fluctuations of Structure of Proteins: Significance of Intermediary States in Regulating Biological Functions. Polymers (Basel) 2022; 14:polym14081539. [PMID: 35458289 PMCID: PMC9025146 DOI: 10.3390/polym14081539] [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: 02/23/2022] [Revised: 03/30/2022] [Accepted: 04/05/2022] [Indexed: 02/01/2023] Open
Abstract
Proteins are indispensable to cellular communication and metabolism. The structure on which cells and tissues are developed is deciphered from proteins. To perform functions, proteins fold into a three-dimensional structural design, which is specific and fundamentally determined by their characteristic sequence of amino acids. Few of them have structural versatility, allowing them to adapt their shape to the task at hand. The intermediate states appear momentarily, while protein folds from denatured (D) ⇔ native (N), which plays significant roles in cellular functions. Prolific effort needs to be taken in characterizing these intermediate species if detected during the folding process. Protein folds into its native structure through definite pathways, which involve a limited number of transitory intermediates. Intermediates may be essential in protein folding pathways and assembly in some cases, as well as misfolding and aggregation folding pathways. These intermediate states help to understand the machinery of proper folding in proteins. In this review article, we highlight the various intermediate states observed and characterized so far under in vitro conditions. Moreover, the role and significance of intermediates in regulating the biological function of cells are discussed clearly.
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Affiliation(s)
- Zahoor Ahmad Parray
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India;
- Department of Chemistry, Indian Institute of Technology Delhi, IIT Campus, Hauz Khas, New Delhi 110016, India
| | - Mohammad Shahid
- Department of Basic Medical Sciences, College of Medicine, Prince Sattam bin Abdulaziz University, Al Kharj 11942, Saudi Arabia;
| | - Asimul Islam
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi 110025, India;
- Correspondence: ; Tel.: +91-93-1281-2007
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11
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Daniloski D, McCarthy NA, Markoska T, Auldist MJ, Vasiljevic T. Conformational and physicochemical characteristics of bovine skim milk obtained from cows with different genetic variants of β-casein. Food Hydrocoll 2022. [DOI: 10.1016/j.foodhyd.2021.107186] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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12
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Quantitative multivalent binding model of the structure, size distribution and composition of the casein micelles of cow milk. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2021.105292] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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13
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14
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Sun Y, Tai Z, Yan T, Dai Y, Hemar Y, Li N. Unveiling the structure of the primary caseinate particle using small-angle X-ray scattering and simulation methodologies. Food Res Int 2021; 149:110653. [PMID: 34600655 DOI: 10.1016/j.foodres.2021.110653] [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: 03/30/2021] [Revised: 08/11/2021] [Accepted: 08/17/2021] [Indexed: 11/27/2022]
Abstract
The low-resolution structure of casein (CN) clusters in sodium caseinate (NaCas) solution and its conformational dynamics were obtained by size-exclusion chromatography (SEC), analytical ultracentrifugation (AUC), small-angle X-ray scattering (SAXS), and molecular dynamics (MD) simulations. The results of sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and native PAGE revealed that the casein clusters consisted predominantly of α- and β-CN complexes, and a trace amount of κ-CN. The AUC analysis indicated that the casein clusters were composed of 34.6% of casein monomers, 19.2%, 20.4%, and 25.8% of complexes with molar weight (Mw) of ~50.3, ~70.6, and ~133 kDa, respectively. The volume fractions of components in casein clusters were quantified as 64.3% of αs1-β-αs2-CN, 22.3% of αs1-CN, 8.5% of αs2-CN, and 4.4% of αs1-αs2-CN, respectively. The ensemble optimization method (EOM) gave a fitting result where αs1-β-αs2-CN species coexisted in ~35.3% under compact conformation and ~64.7% in elongated conformation in solution. The three-dimensional structures of αs1-β-αs2-CN from EOM showed a good overlay on the casein clusters ab initio model obtained from DAMMIN and DAMMIX program. MD simulations revealed that αs1-β-αs2-CN underwent a conformational change from the elongated state into the compact state within the initial 200 ns of simulations. The addition of nonionic surfactants affected little the backbone-to-backbone interactions in the formation of the casein clusters. We propose that αs1-CN, β-CN, αs2-CN, and κ-CN associated in consecutive steps into casein clusters, and a trace of κ-CN may be located at the surface of the assemblies limiting the growth of casein aggregates.
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Affiliation(s)
- Yang Sun
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China.
| | - Zhonghong Tai
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China
| | - Tingting Yan
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China
| | - Yiqi Dai
- College of Vocational and Technical Education, Yunnan Normal University, Yieryi Avenue, No. 298, 650092 Kunming, Yunnan, People's Republic of China
| | - Yacine Hemar
- Catalyst Tec Limited., 16 Beatrice Tinsley Cresecnt, Rosedale 0632, Auckland, New Zealand; International Joint Research Laboratory for Functional Dairy Protein Ingredients, U.S.-China, People's Republic of China
| | - Na Li
- National Facility for Protein Science in Shanghai, Zhangjiang Lab, Shanghai Advanced Research Institute, CAS, No.333, Haike Road, Shanghai, Shanghai 201210, People's Republic of China.
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15
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Holt C. A quantitative calcium phosphate nanocluster model of the casein micelle: the average size, size distribution and surface properties. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2021; 50:847-866. [PMID: 33866398 DOI: 10.1007/s00249-021-01533-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2020] [Revised: 01/22/2021] [Accepted: 03/28/2021] [Indexed: 10/21/2022]
Abstract
Caseins (αS1, αS2, β and κ) are the main protein fraction of bovine milk. Together with nanoclusters of amorphous calcium phosphate (CaP) and divalent cations, they combine to form a polydisperse distribution of particles called casein micelles. A casein micelle model is proposed which is consistent with the way in which intrinsically disordered proteins interact through predominantly polar, short, linear, motifs. Using the model, an expression is derived for the size distribution of casein micelles formed when caseins bind to the CaP nanoclusters and the complexes further associate with each other and the remaining mixture of free caseins. The result is a refined coat-core model in which the core is formed mainly by the nanocluster complexes and the coat is formed exclusively by the free caseins. Example calculations of the size distribution and surface composition of an average bovine milk are compared with experiment. The average size, size distribution and surface composition of the micelles is shown to depend on the affinity of the nanocluster complexes for each other in competition with their affinity for free caseins, and on the concentrations of free caseins, calcium ions and other salts in the continuous phase.
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Affiliation(s)
- Carl Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow, G12 8QQ, UK.
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16
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Trimethylamine N-oxide alters structure-function integrity of β-casein: Structural disorder co-regulates the aggregation propensity and chaperone activity. Int J Biol Macromol 2021; 182:921-930. [PMID: 33872615 DOI: 10.1016/j.ijbiomac.2021.04.060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 03/31/2021] [Accepted: 04/09/2021] [Indexed: 11/23/2022]
Abstract
Intrinsically disordered proteins (IDPs), involved in the regulation and function of various cellular processes like transcription, translation, cell cycle etc., exist as ensembles of rapidly interconverting structures with functional plasticity. Among numerous cellular regulatory mechanisms involved in structural and functional regulation of IDPs, osmolytes are emerging as promising regulatory agents due to their ability to affect the structure-function integrity of IDPs. The present study investigated the effect of methylamine osmolytes on β-casein, an IDP essential for maintaining the overall stability of casein complex in milk. It was observed that trimethylamine N-oxide induces a compact structural state in β-casein with slightly decreased chaperone activity and insignificant aggregation propensity. However, the other two osmolytes from this group, i.e., sarcosine and betaine, had no significant effect on the overall structure and chaperone activity of the IDP. The present study hints towards the possible evolutionary selection of higher structural disorder in β-casein, compared to α-casein, for stability of the casein complex and prevention of amyloidosis in the mammary gland.
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The molecular chaperone β-casein prevents amorphous and fibrillar aggregation of α-lactalbumin by stabilisation of dynamic disorder. Biochem J 2020; 477:629-643. [PMID: 31939601 PMCID: PMC7015860 DOI: 10.1042/bcj20190638] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Revised: 01/10/2020] [Accepted: 01/15/2020] [Indexed: 02/07/2023]
Abstract
Deficits in protein homeostasis (proteostasis) are typified by the partial unfolding or misfolding of native proteins leading to amorphous or fibrillar aggregation, events that have been closely associated with diseases including Alzheimer's and Parkinson's diseases. Molecular chaperones are intimately involved in maintaining proteostasis, and their mechanisms of action are in part dependent on the morphology of aggregation-prone proteins. This study utilised native ion mobility–mass spectrometry to provide molecular insights into the conformational properties and dynamics of a model protein, α-lactalbumin (α-LA), which aggregates in an amorphous or amyloid fibrillar manner controlled by appropriate selection of experimental conditions. The molecular chaperone β-casein (β-CN) is effective at inhibiting amorphous and fibrillar aggregation of α-LA at sub-stoichiometric ratios, with greater efficiency against fibril formation. Analytical size-exclusion chromatography demonstrates the interaction between β-CN and amorphously aggregating α-LA is stable, forming a soluble high molecular weight complex, whilst with fibril-forming α-LA the interaction is transient. Moreover, ion mobility–mass spectrometry (IM-MS) coupled with collision-induced unfolding (CIU) revealed that α-LA monomers undergo distinct conformational transitions during the initial stages of amorphous (order to disorder) and fibrillar (disorder to order) aggregation. The structural heterogeneity of monomeric α-LA during fibrillation is reduced in the presence of β-CN along with an enhancement in stability, which provides a potential means for preventing fibril formation. Together, this study demonstrates how IM-MS and CIU can investigate the unfolding of proteins as well as examine transient and dynamic protein–chaperone interactions, and thereby provides detailed insight into the mechanism of chaperone action and proteostasis mechanisms.
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18
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Cao F, Xia Y, Chen D, Xu N, Hemar Y, Li N, Sun Y. Insights on the structure of caseinate particles based on surfactants-induced dissociation. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.105766] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
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19
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Mantziari A, Tölkkö S, Ouwehand AC, Löyttyniemi E, Isolauri E, Salminen S, Rautava S. The Effect of Donor Human Milk Fortification on The Adhesion of Probiotics In Vitro. Nutrients 2020; 12:nu12010182. [PMID: 31936487 PMCID: PMC7019708 DOI: 10.3390/nu12010182] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2019] [Revised: 01/01/2020] [Accepted: 01/04/2020] [Indexed: 12/22/2022] Open
Abstract
Preterm delivery complications are the primary cause of death among children under the age of five. Preventive strategies include the use of pasteurized donor human milk (DHM), its fortification with human milk fortifiers (protein supplements), and supplementation with probiotics. Our aim was to examine the impact of DHM and fortified DHM (FDHM) on the mucus adhesion properties of two widely used probiotics. The study covered two forms of human milk fortifier, liquid and powdered, with or without probiotics and storage at 4 °C for 24 h. To test the adhesion properties of the probiotic strains, DHM+probiotics and FDHM+probiotics were prepared and added to immobilized mucus isolated from the stool of healthy Finnish infants. The probiotic adhesion was then measured by liquid scintillation. Our results suggest that addition of liquid or powdered human milk fortifier in donor human milk had no impact on probiotic adhesion. In addition, given the increased adhesion of probiotics suspended in buffer, other matrices should be further studied. These factors need to be considered when designing future intervention strategies using probiotics in preterm infants.
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Affiliation(s)
- Anastasia Mantziari
- Functional Foods Forum, Faculty of Medicine, University of Turku, Itäinen Pitkäkatu 4A, 20520 Turku, Finland; (S.T.); (S.S.)
- Correspondence: ; Tel.: +35-829-450-3820
| | - Satu Tölkkö
- Functional Foods Forum, Faculty of Medicine, University of Turku, Itäinen Pitkäkatu 4A, 20520 Turku, Finland; (S.T.); (S.S.)
| | - Artur C. Ouwehand
- DuPont Nutrition and Biosciences, Sokeritehtaantie 20, 02460 Kantvik, Finland;
| | - Eliisa Löyttyniemi
- Unit of Biostatistics, Department of Clinical Medicine University of Turku, Kiinamyllynkatu 10, 20520 Turku, Finland;
| | - Erika Isolauri
- Department of Pediatrics, University of Turku and Turku University Hospital, Kiinamyllynkatu 4-8, 20520 Turku, Finland; (E.I.); (S.R.)
| | - Seppo Salminen
- Functional Foods Forum, Faculty of Medicine, University of Turku, Itäinen Pitkäkatu 4A, 20520 Turku, Finland; (S.T.); (S.S.)
| | - Samuli Rautava
- Department of Pediatrics, University of Turku and Turku University Hospital, Kiinamyllynkatu 4-8, 20520 Turku, Finland; (E.I.); (S.R.)
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20
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Manguy J, Shields DC. Implications of kappa-casein evolutionary diversity for the self-assembly and aggregation of casein micelles. ROYAL SOCIETY OPEN SCIENCE 2019; 6:190939. [PMID: 31824707 PMCID: PMC6837221 DOI: 10.1098/rsos.190939] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2019] [Accepted: 09/24/2019] [Indexed: 06/10/2023]
Abstract
Milk alpha-, beta- and kappa-casein proteins assemble into casein micelles in breast epithelial cells. The glycomacropeptide (GMP) tails of kappa-casein that extend from the surface of the micelle are key to assembly and aggregation. Aggregation is triggered by stomach pepsin cleavage of GMP from para-kappa-casein (PKC). While one casein micelle model emphasizes the importance of hydrophobic interactions, another focuses on polar residues. We performed an evolutionary analysis of kappa-casein primary sequence and predicted features that potentially impact on protein interactions. We noted more rapid change in the earlier period (166 to 60 Ma). Pepsin and plasmin cleavage sites were avoided in the GMP, which may partly explain its amino acid composition. Short tandem repeats have led to modest expansions of PKC, and to large GMP expansions, suggesting the GMP is less length constrained. Amino acid compositional constraints were assessed across species. Polarity and hydrophobicity properties were insufficient to explain differences between PKC and GMP. Among polar residues, threonine dominates the GMP, compared to serine, probably reflecting its preference for O-glycosylation over phosphorylation. Glutamine, enriched in the bovine PQ-rich region, is not positionally conserved in other species. Among hydrophobic residues, isoleucine is clearly preferred over leucine in the GMP, and patches of hydrophobicity are not markedly positionally conserved. PKC tyrosine and charged residues showed stronger conservation of position, suggesting a role for pi-interactions, seen in other structurally dynamic protein membraneless assemblies. Independent acquisitions of cysteines are consistent with a trend of increasing stabilization of multimers by covalent disulphide bonds, over evolutionary time. In conclusion, kappa-casein compositional and positional constraints appear to be influenced by modification preferences, protease evasion and protein-protein interactions.
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Affiliation(s)
- Jean Manguy
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
- Food for Health Ireland, University College Dublin, Belfield, Dublin 4, Ireland
| | - Denis C. Shields
- UCD Conway Institute, University College Dublin, Belfield, Dublin 4, Ireland
- School of Medicine, University College Dublin, Belfield, Dublin 4, Ireland
- Food for Health Ireland, University College Dublin, Belfield, Dublin 4, Ireland
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21
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Thekkilaveedu S, Krishnaswami V, Mohanan DP, Alagarsamy S, Natesan S, Kandasamy R. Lactic acid‐mediated isolation of alpha‐, beta‐ and kappa‐casein fractions by isoelectric precipitation coupled with cold extraction from defatted cow milk. INT J DAIRY TECHNOL 2019. [DOI: 10.1111/1471-0307.12646] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Saranya Thekkilaveedu
- Department of Pharmaceutical Technology, University College of Engineering National Facility for Bioactive Peptides from Milk (NFBP), Centre for Excellence in Nanobio Translational Research (CENTRE), Anna University, BIT Campus Tiruchirappalli Tamil Nadu India
| | - Venkateshwaran Krishnaswami
- Department of Pharmaceutical Technology, University College of Engineering National Facility for Bioactive Peptides from Milk (NFBP), Centre for Excellence in Nanobio Translational Research (CENTRE), Anna University, BIT Campus Tiruchirappalli Tamil Nadu India
| | - Dhilin Pathayappurakkal Mohanan
- Department of Pharmaceutical Technology, University College of Engineering National Facility for Bioactive Peptides from Milk (NFBP), Centre for Excellence in Nanobio Translational Research (CENTRE), Anna University, BIT Campus Tiruchirappalli Tamil Nadu India
| | - Shanmugarathinam Alagarsamy
- Department of Pharmaceutical Technology, University College of Engineering National Facility for Bioactive Peptides from Milk (NFBP), Centre for Excellence in Nanobio Translational Research (CENTRE), Anna University, BIT Campus Tiruchirappalli Tamil Nadu India
| | - Subramanian Natesan
- Department of Pharmaceutical Technology, University College of Engineering National Facility for Bioactive Peptides from Milk (NFBP), Centre for Excellence in Nanobio Translational Research (CENTRE), Anna University, BIT Campus Tiruchirappalli Tamil Nadu India
| | - Ruckmani Kandasamy
- Department of Pharmaceutical Technology, University College of Engineering National Facility for Bioactive Peptides from Milk (NFBP), Centre for Excellence in Nanobio Translational Research (CENTRE), Anna University, BIT Campus Tiruchirappalli Tamil Nadu India
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22
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Wu Z, Yin H, Liu W, Huang D, Hu N, Yang C, Zhao X. Xanthan gum assisted foam fractionation for the recovery of casein from the dairy wastewater. Prep Biochem Biotechnol 2019; 50:37-46. [PMID: 31453755 DOI: 10.1080/10826068.2019.1658119] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Casein was the major protein in the milk of mammals and it was massively lost in the discharged wastewater during dairy product manufacture. This work was aimed at recovering casein from the dairy wastewater by using foam fractionation. In order to improve the foam stability, xanthan gum was used as the foam stabilizer based on the association between protein and polysaccharide. The results of the scanning electron microscope (SEM) and fluorescence emission spectrum suggested that casein could be associated with xanthan gum primarily through electrostatic attraction, which was significantly affected by pH. Moreover, the introduction of xanthan gum had a marked impact on the surface tension, foam ability, foam stability, turbidity, zeta potential and average particle size of casein dispersion. Foam fractionation was performed under the suitable operation condition of pH 6.0, loading liquid volume 400 mL, amount ratio of casein and xanthan gum 1:2, volumetric airflow rate 100 mL/min and pore diameter of gas distributor 0.180 mm. The enrichment ratio and the recovery percentage of casein reached as high as 16.81 and 86.51%, respectively. This work is expected to provide a cost-effective method to recover the trace desired material through improving foam stability based on intermolecular forces.Research highlightsFoam fractionation has been proposed to recover casein from dairy wastewater.Xanthan gum has been used to improve the foam stability of casein.The main interaction between casein and xanthan gum was an electrostatic attraction.Xanthan gum contributed to weakening the flowability of interstitial liquid.
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Affiliation(s)
- Zhaoliang Wu
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - Hao Yin
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - Wei Liu
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - Di Huang
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - Nan Hu
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - Chunyan Yang
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
| | - Xiaomei Zhao
- School of Chemical Engineering and Technology, Hebei University of Technology, Tianjin, China
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23
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Chinak OA, Shernyukov AV, Ovcherenko SS, Sviridov EA, Golyshev VM, Fomin AS, Pyshnaya IA, Kuligina EV, Richter VA, Bagryanskaya EG. Structural and Aggregation Features of a Human κ-Casein Fragment with Antitumor and Cell-Penetrating Properties. Molecules 2019; 24:E2919. [PMID: 31408975 PMCID: PMC6721048 DOI: 10.3390/molecules24162919] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/06/2019] [Accepted: 08/09/2019] [Indexed: 11/23/2022] Open
Abstract
Intrinsically disordered proteins play a central role in dynamic regulatory and assembly processes in the cell. Recently, a human κ-casein proteolytic fragment called lactaptin (8.6 kDa) was found to induce apoptosis of human breast adenocarcinoma MCF-7 and MDA-MB-231 cells with no cytotoxic activity toward normal cells. Earlier, we had designed some recombinant analogs of lactaptin and compared their biological activity. Among these analogs, RL2 has the highest antitumor activity, but the amino acid residues and secondary structures that are responsible for RL2's activity remain unclear. To elucidate the structure-activity relations of RL2, we studied the structural and aggregation features of this fairly large intrinsically disordered fragment of human milk κ-casein by a combination of physicochemical methods: NMR, paramagnetic relaxation enhancement (PRE), Electron Paramagnetic Resonance (EPR), circular dichroism, dynamic light scattering, atomic force microscopy, and a cytotoxic activity assay. It was found that in solution, RL2 exists as stand-alone monomeric particles and large aggregates. Whereas the disulfide-bonded homodimer turned out to be more prone to assembly into large aggregates, the monomer predominantly forms single particles. NMR relaxation analysis of spin-labeled RL2 showed that the RL2 N-terminal region, which is essential not only for multimerization of the peptide but also for its proapoptotic action on cancer cells, is more ordered than its C-terminal counterpart and contains a site with a propensity for α-helical secondary structure.
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Affiliation(s)
- Olga A Chinak
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia
| | - Andrey V Shernyukov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova Str., Novosibirsk 630090, Russia
| | - Sergey S Ovcherenko
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova Str., Novosibirsk 630090, Russia
| | - Evgeniy A Sviridov
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova Str., Novosibirsk 630090, Russia
| | - Victor M Golyshev
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia
| | - Alexander S Fomin
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia
| | - Inna A Pyshnaya
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia
| | - Elena V Kuligina
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia
| | - Vladimir A Richter
- Institute of Chemical Biology and Fundamental Medicine SB RAS, Novosibirsk 630090, Russia
| | - Elena G Bagryanskaya
- N.N. Vorozhtsov Novosibirsk Institute of Organic Chemistry SB RAS, Novosibirsk 630090, Russia.
- Department of Natural Sciences, Novosibirsk State University, 1 Pirogova Str., Novosibirsk 630090, Russia.
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24
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Sequence characteristics responsible for protein‐protein interactions in the intrinsically disordered regions of caseins, amelogenins, and small heat‐shock proteins. Biopolymers 2019; 110:e23319. [DOI: 10.1002/bip.23319] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2019] [Revised: 06/11/2019] [Accepted: 06/19/2019] [Indexed: 01/01/2023]
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25
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Lambrecht MA, Jansens KJ, Rombouts I, Brijs K, Rousseau F, Schymkowitz J, Delcour JA. Conditions Governing Food Protein Amyloid Fibril Formation. Part II: Milk and Legume Proteins. Compr Rev Food Sci Food Saf 2019; 18:1277-1291. [DOI: 10.1111/1541-4337.12465] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2019] [Revised: 04/26/2019] [Accepted: 05/16/2019] [Indexed: 02/06/2023]
Affiliation(s)
- Marlies A. Lambrecht
- Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe)KU Leuven Kasteelpark Arenberg 20 B‐3001 Leuven Belgium
| | - Koen J.A. Jansens
- Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe)KU Leuven Kasteelpark Arenberg 20 B‐3001 Leuven Belgium
| | - Ine Rombouts
- Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe)KU Leuven Kasteelpark Arenberg 20 B‐3001 Leuven Belgium
| | - Kristof Brijs
- Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe)KU Leuven Kasteelpark Arenberg 20 B‐3001 Leuven Belgium
| | - Frederic Rousseau
- Switch LaboratoryVIB B‐3000 Leuven Belgium
- Dept. of Cellular and Molecular MedicineKU Leuven B‐3000 Leuven Belgium
| | - Joost Schymkowitz
- Switch LaboratoryVIB B‐3000 Leuven Belgium
- Dept. of Cellular and Molecular MedicineKU Leuven B‐3000 Leuven Belgium
| | - Jan A. Delcour
- Laboratory of Food Chemistry and Biochemistry and Leuven Food Science and Nutrition Research Centre (LFoRCe)KU Leuven Kasteelpark Arenberg 20 B‐3001 Leuven Belgium
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26
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Dynamical Oligomerisation of Histidine Rich Intrinsically Disordered ProteinS Is Regulated through Zinc-Histidine Interactions. Biomolecules 2019; 9:biom9050168. [PMID: 31052346 PMCID: PMC6571702 DOI: 10.3390/biom9050168] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 04/26/2019] [Accepted: 04/26/2019] [Indexed: 12/19/2022] Open
Abstract
Intrinsically disordered proteins (IDPs) can form functional oligomers and in some cases, insoluble disease related aggregates. It is therefore vital to understand processes and mechanisms that control pathway distribution. Divalent cations including Zn2+ can initiate IDP oligomerisation through the interaction with histidine residues but the mechanisms of doing so are far from understood. Here we apply a multi-disciplinary approach using small angle X-ray scattering, nuclear magnetic resonance spectroscopy, calorimetry and computations to show that that saliva protein Histatin 5 forms highly dynamic oligomers in the presence of Zn2+. The process is critically dependent upon interaction between Zn2+ ions and distinct histidine rich binding motifs which allows for thermodynamic switching between states. We propose a molecular mechanism of oligomerisation, which may be generally applicable to other histidine rich IDPs. Finally, as Histatin 5 is an important saliva component, we suggest that Zn2+ induced oligomerisation may be crucial for maintaining saliva homeostasis.
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27
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Melnikova DL, Skirda VD, Nesmelova IV. Effect of Reducing Agent TCEP on Translational Diffusion and Supramolecular Assembly in Aqueous Solutions of α-Casein. J Phys Chem B 2019; 123:2305-2315. [PMID: 30789730 DOI: 10.1021/acs.jpcb.8b12511] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The translational diffusion coefficient is highly sensitive to the size change of diffusing species and is ideally suited for the study of molecular association. Here, we used translational diffusion measurements by a pulsed-field gradient nuclear magnetic resonance (PFG NMR) technique to investigate the role of disulfide bonds in the formation of a supramolecular gel-like structure in the concentrated solution of α-casein. To reduce disulfide bonds, we added a commonly used reducing reagent tris(2-carboxyethyl)phosphine (TCEP) to α-casein solution. We found that the disruption of a disulfide bond Cys36-Cys40 in αs2-casein does not alter the translational diffusion or secondary structure of α-casein in dilute, 1 and 3% (wt %) solution. On the contrary, in concentrated, 15% (wt %) α-casein solution, in addition to the disruption of disulfide bonds, TCEP induced significant changes in gel properties. New long-lived intermolecular interactions formed, leading to the irreversible gel formation. While a few side reactions of TCEP (as well as other reducing agents, e.g., dithiothreitol) have been reported, this area is still understudied. Here, we provide new data on the side reaction of the reducing agent TCEP in concentrated protein solution, suggesting that at high protein concentrations TCEP should be used with caution.
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Affiliation(s)
- Daria L Melnikova
- Department of Physics , Kazan Federal University , Kazan 420011 , Russia
| | - Vladimir D Skirda
- Department of Physics , Kazan Federal University , Kazan 420011 , Russia
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28
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Carver JA, Holt C. Functional and dysfunctional folding, association and aggregation of caseins. PROTEIN MISFOLDING 2019; 118:163-216. [DOI: 10.1016/bs.apcsb.2019.09.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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29
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Lam E, McKinnon I, Marchesseau S, Otter D, Zhou P, Hemar Y. The effect of transglutaminase on reconstituted skim milks at alkaline pH. Food Hydrocoll 2018. [DOI: 10.1016/j.foodhyd.2018.06.047] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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A quantitative model of the bovine casein micelle: ion equilibria and calcium phosphate sequestration by individual caseins in bovine milk. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2018; 48:45-59. [PMID: 30128695 DOI: 10.1007/s00249-018-1330-2] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/08/2018] [Revised: 08/02/2018] [Accepted: 08/13/2018] [Indexed: 10/28/2022]
Abstract
The white appearance of skim milk is due to strong light scattering by colloidal particles called casein micelles. Bovine casein micelles comprise expressed proteins from four casein genes together with significant fractions of the total calcium, inorganic phosphate, magnesium and citrate ions in the milk. Thus, the milk salts are partitioned between the casein micelles, where they are mostly in the form of nanoclusters of an amorphous calcium phosphate sequestered by caseins through their phosphorylated residues, with the remainder in the continuous phase. Previously, a salt partition calculation was made assuming that the nanoclusters are sequestered only by short, highly phosphorylated casein sequences, sometimes called phosphate centres. Three of the four caseins have a proportion of their phosphorylated residues in either one or two phosphate centres and these were proposed to react with the nanoclusters equally and independently. An improved model of the partition of caseins and salts in milk is described in which all the phosphorylated residues in competent caseins act together to bind to and sequester the nanoclusters. The new model has been applied to results from a recent study of variation in salt and casein composition in the milk of individual cows. Compared to the previous model, it provides better agreement with experiment of the partition of caseins between free and bound states and equally good results for the partition of milk salts. In addition, new calculations are presented for the charge on individual caseins in their bound and free states.
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Li H, Yang C, Chen C, Ren F, Li Y, Mu Z, Wang P. The Use of Trisodium Citrate to Improve the Textural Properties of Acid-Induced, Transglutaminase-Treated Micellar Casein Gels. Molecules 2018; 23:molecules23071632. [PMID: 29973558 PMCID: PMC6100453 DOI: 10.3390/molecules23071632] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2018] [Revised: 06/30/2018] [Accepted: 07/01/2018] [Indexed: 12/03/2022] Open
Abstract
In this study, the effect of trisodium citrate on the textural properties and microstructure of acid-induced, transglutaminase-treated micellar casein gels was investigated. Various concentrations of trisodium citrate (0 mmol/L, 10 mmol/L, 20 mmol/L, and 30 mmol/L) were added to micellar casein dispersions. After being treated with microbial transglutaminase (mTGase), all dispersions were acidified with 1.3% (w/v) gluconodelta-lactone (GDL) to pH 4.4–4.6. As the concentration of trisodium citrate increased from 0 mmol/L to 30 mmol/L, the firmness and water-holding capacity increased significantly. The final storage modulus (G′) of casein gels was positively related to the concentration of trisodium citrate prior to mTGase treatment of micellar casein dispersions. Cryo-scanning electron microscopy images indicated that more interconnected networks and smaller pores were present in the gels with higher concentrations of trisodium citrate. Overall, when micellar casein dispersions are treated with trisodium citrate prior to mTGase crosslinking, the resulted acid-induced gels are firmer and the syneresis is reduced.
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Affiliation(s)
- Hongliang Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Chang Yang
- Inner Mongolia Mengniu Dairy (Group) CO., Ltd., Hohhot 750306, China.
| | - Chong Chen
- Key Laboratory of Functional Dairy, Co-Constructed by Ministry of Education and Beijing Government, Beijing 100083, China.
| | - Fazheng Ren
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Yuan Li
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
| | - Zhishen Mu
- Inner Mongolia Mengniu Dairy (Group) CO., Ltd., Hohhot 750306, China.
| | - Pengjie Wang
- Beijing Advanced Innovation Center for Food Nutrition and Human Health, College of Food Science & Nutritional Engineering, China Agricultural University, Beijing 100083, China.
- Beijing Laboratory of Food Quality and Safety, Beijing Higher Institution Engineering Research Center of Animal Product, Beijing 100083, China.
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Carver JA, Ecroyd H, Truscott RJW, Thorn DC, Holt C. Proteostasis and the Regulation of Intra- and Extracellular Protein Aggregation by ATP-Independent Molecular Chaperones: Lens α-Crystallins and Milk Caseins. Acc Chem Res 2018; 51:745-752. [PMID: 29442498 DOI: 10.1021/acs.accounts.7b00250] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Molecular chaperone proteins perform a diversity of roles inside and outside the cell. One of the most important is the stabilization of misfolding proteins to prevent their aggregation, a process that is potentially detrimental to cell viability. Diseases such as Alzheimer's, Parkinson's, and cataract are characterized by the accumulation of protein aggregates. In vivo, many proteins are metastable and therefore under mild destabilizing conditions have an inherent tendency to misfold, aggregate, and hence lose functionality. As a result, protein levels are tightly regulated inside and outside the cell. Protein homeostasis, or proteostasis, describes the network of biological pathways that ensures the proteome remains folded and functional. Proteostasis is a major factor in maintaining cell, tissue, and organismal viability. We have extensively investigated the structure and function of intra- and extracellular molecular chaperones that operate in an ATP-independent manner to stabilize proteins and prevent their misfolding and subsequent aggregation into amorphous particles or highly ordered amyloid fibrils. These types of chaperones are therefore crucial in maintaining proteostasis under normal and stress (e.g., elevated temperature) conditions. Despite their lack of sequence similarity, they exhibit many common features, i.e., extensive structural disorder, dynamism, malleability, heterogeneity, oligomerization, and similar mechanisms of chaperone action. In this Account, we concentrate on the chaperone roles of α-crystallins and caseins, the predominant proteins in the eye lens and milk, respectively. Intracellularly, the principal ATP-independent chaperones are the small heat-shock proteins (sHsps). In vivo, sHsps are the first line of defense in preventing intracellular protein aggregation. The lens proteins αA- and αB-crystallin are sHsps. They play a crucial role in maintaining solubility of the crystallins (including themselves) with age and hence in lens proteostasis and, ultimately, lens transparency. As there is little metabolic activity and no protein turnover in the lens, crystallins are very long lived proteins. Lens proteostasis is therefore very different to that in normal, metabolically active cells. Crystallins undergo extensive post-translational modification (PTM), including deamidation, racemization, phosphorylation, and truncation, which can alter their stability. Despite this, the lens remains transparent for tens of years, implying that lens proteostasis is intimately integrated with crystallin PTMs. Many PTMs do not significantly alter crystallin stability, solubility, and functionality, which thereby facilitates lens transparency. In the long term, however, extensive accumulation of crystallin PTMs leads to large-scale crystallin aggregation, lens opacification, and cataract formation. Extracellularly, various ATP-independent molecular chaperones exist that exhibit sHsp-like structural and functional features. For example, caseins, the major milk proteins, exhibit chaperone ability by inhibiting the amorphous and amyloid fibrillar aggregation of a diversity of destabilized proteins. Caseins maintain proteostasis within milk by preventing deleterious casein amyloid fibril formation via incorporation of thousands of individual caseins into an amorphous structure known as the casein micelle. Hundreds of nanoclusters of calcium phosphate are sequestered within each casein micelle through interactions with short, highly phosphorylated casein sequences. This results in a stable biofluid that contains a high concentration of potentially amyloidogenic caseins and concentrations of calcium and phosphate that can be far in excess of the solubility of calcium phosphate. Casein micelle formation therefore performs vital roles in neonatal nutrition and calcium homeostasis in the mammary gland.
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Affiliation(s)
- John A. Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Heath Ecroyd
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | - Roger J. W. Truscott
- Illawarra Health and Medical Research Institute and School of Biological Sciences, University of Wollongong, Wollongong, NSW 2522, Australia
| | - David C. Thorn
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Carl Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, United Kingdom
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Ryder K, Ali MA, Billakanti J, Carne A. Fundamental characterisation of caseins harvested by dissolved air flotation from dairy wastewater and comparison with skim milk powder. Int Dairy J 2018. [DOI: 10.1016/j.idairyj.2017.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
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Chanat E, Dessauge F. Technical note: Quantification of caseins from a crude extract of mammary epithelial cells. J Dairy Sci 2018; 101:3583-3587. [PMID: 29428746 DOI: 10.3168/jds.2017-14049] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 12/17/2017] [Indexed: 11/19/2022]
Abstract
En masse secretion of milk proteins, notably the caseins in the form of casein micelles, is a unique feature of the milk-secreting mammary epithelial cell. Caseins are therefore specific markers of these cells and constitute an ideal tool to monitor their differentiation, as well as functional status, during the development of the gland. To use them as such, a reliable method for quantitative analysis of the caseins from mammary cells or tissue is needed. Here we show that the caseins are heat-stable, a feature that leads to their complete extraction from a complex cellular extract by boiling. This allows for high enrichment and direct analysis of the caseins, even when they are poorly expressed in the starting material.
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Affiliation(s)
- Eric Chanat
- INRA, UMR1348 PEGASE, F-35590 Saint-Gilles, France; Agrocampus Ouest, UMR1348 PEGASE, F-35000 Rennes, France.
| | - Frédéric Dessauge
- INRA, UMR1348 PEGASE, F-35590 Saint-Gilles, France; Agrocampus Ouest, UMR1348 PEGASE, F-35000 Rennes, France
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Size Separation Techniques for the Characterisation of Cross-Linked Casein: A Review of Methods and Their Applications. SEPARATIONS 2018. [DOI: 10.3390/separations5010014] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
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Lam E, Holt C, Edwards P, McKinnon I, Otter D, Li N, Hemar Y. The effect of transglutaminase treatment on the physico-chemical properties of skim milk with added ethylenediaminetetraacetic acid. Food Hydrocoll 2017. [DOI: 10.1016/j.foodhyd.2017.02.002] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Carver JA, Thorn DC, Ecroyd H, Holt C. Letter to the Editor: A response to Horne and Lucey (2017). J Dairy Sci 2017. [PMID: 28624068 DOI: 10.3168/jds.2017-13053] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Affiliation(s)
- John A Carver
- Research School of Chemistry, College of Physical and Mathematical Sciences, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - David C Thorn
- Research School of Chemistry, College of Physical and Mathematical Sciences, The Australian National University, Acton, Australian Capital Territory 2601, Australia
| | - Heath Ecroyd
- School of Biological Sciences and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, New South Wales 2522, Australia
| | - Carl Holt
- Institute of Molecular, Cellular and Systems Biology, University of Glasgow, Glasgow, G12 8QQ, United Kingdom.
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Carver JA, Grosas AB, Ecroyd H, Quinlan RA. The functional roles of the unstructured N- and C-terminal regions in αB-crystallin and other mammalian small heat-shock proteins. Cell Stress Chaperones 2017; 22:627-638. [PMID: 28391594 PMCID: PMC5465038 DOI: 10.1007/s12192-017-0789-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2017] [Revised: 03/06/2017] [Accepted: 03/16/2017] [Indexed: 01/18/2023] Open
Abstract
Small heat-shock proteins (sHsps), such as αB-crystallin, are one of the major classes of molecular chaperone proteins. In vivo, under conditions of cellular stress, sHsps are the principal defence proteins that prevent large-scale protein aggregation. Progress in determining the structure of sHsps has been significant recently, particularly in relation to the conserved, central and β-sheet structured α-crystallin domain (ACD). However, an understanding of the structure and functional roles of the N- and C-terminal flanking regions has proved elusive mainly because of their unstructured and dynamic nature. In this paper, we propose functional roles for both flanking regions, based around three properties: (i) they act in a localised crowding manner to regulate interactions with target proteins during chaperone action, (ii) they protect the ACD from deleterious amyloid fibril formation and (iii) the flexibility of these regions, particularly at the extreme C-terminus in mammalian sHsps, provides solubility for sHsps under chaperone and non-chaperone conditions. In the eye lens, these properties are highly relevant as the crystallin proteins, in particular the two sHsps αA- and αB-crystallin, are present at very high concentrations.
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Affiliation(s)
- John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT, 2601, Australia.
| | - Aidan B Grosas
- Research School of Chemistry, The Australian National University, Acton, ACT, 2601, Australia
| | - Heath Ecroyd
- School of Biological Sciences and the Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong, NSW, 2522, Australia
| | - Roy A Quinlan
- Department of Biosciences, Durham University, Durham, DH1 3LE, UK
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Secondary structure and colloidal stability of beta-casein in microheterogeneous water-ethanol solutions. Food Hydrocoll 2017. [DOI: 10.1016/j.foodhyd.2016.09.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Liu J, Dehle FC, Liu Y, Bahraminejad E, Ecroyd H, Thorn DC, Carver JA. The Effect of Milk Constituents and Crowding Agents on Amyloid Fibril Formation by κ-Casein. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2016; 64:1335-1343. [PMID: 26807595 DOI: 10.1021/acs.jafc.5b04977] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
When not incorporated into the casein micelle, κ-casein, a major milk protein, rapidly forms amyloid fibrils at physiological pH and temperature. In this study, the effects of milk components (calcium, lactose, lipids, and heparan sulfate) and crowding agents on reduced and carboxymethylated (RCM) κ-casein fibril formation was investigated using far-UV circular dichroism spectroscopy, thioflavin T binding assays, and transmission electron microscopy. Longer-chain phosphatidylcholine lipids, which form the lining of milk ducts and milk fat globules, enhanced RCM κ-casein fibril formation irrespective of whether the lipids were in a monomeric or micellar state, whereas shorter-chain phospholipids and triglycerides had little effect. Heparan sulfate, a component of the milk fat globule membrane and catalyst of amyloid deposition in extracellular tissue, had little effect on the kinetics of RCM κ-casein fibril formation. Major nutritional components such as calcium and lactose also had no significant effect. Macromolecular crowding enhances protein-protein interactions, but in contrast to other fibril-forming species, the extent of RCM κ-casein fibril formation was reduced by the presence of a variety of crowding agents. These data are consistent with a mechanism of κ-casein fibril formation in which the rate-determining step is dissociation from the oligomer to give the highly amyloidogenic monomer. We conclude that the interaction of κ-casein with membrane-associated phospholipids along its secretory pathway may contribute to the development of amyloid deposits in mammary tissue. However, the formation of spherical oligomers such as casein micelles is favored over amyloid fibrils in the crowded environment of milk, within which the occurrence of amyloid fibrils is low.
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Affiliation(s)
- Jihua Liu
- Pharmacy College, Jilin University , Changchun, Jilin Province 130021, China
- Department of Chemistry, School of Physical Sciences, The University of Adelaide , Adelaide, South Australia 5005, Australia
| | - Francis C Dehle
- Department of Chemistry, School of Physical Sciences, The University of Adelaide , Adelaide, South Australia 5005, Australia
| | - Yanqin Liu
- Department of Chemistry, School of Physical Sciences, The University of Adelaide , Adelaide, South Australia 5005, Australia
| | - Elmira Bahraminejad
- Research School of Chemistry, The Australian National University , Acton, Australian Capital Territory 2601, Australia
| | - Heath Ecroyd
- School of Biological Sciences and Illawarra Health & Medical Research Institute, University of Wollongong , Wollongong, New South Wales 2522, Australia
| | - David C Thorn
- Research School of Chemistry, The Australian National University , Acton, Australian Capital Territory 2601, Australia
| | - John A Carver
- Research School of Chemistry, The Australian National University , Acton, Australian Capital Territory 2601, Australia
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Portnaya I, Avni S, Kesselman E, Boyarski Y, Sukenik S, Harries D, Dan N, Cogan U, Danino D. Competing processes of micellization and fibrillization in native and reduced casein proteins. Phys Chem Chem Phys 2016; 18:22516-25. [DOI: 10.1039/c6cp04582k] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Competition between micellization and fibrillization in milk caseins, intrinsically disordered proteins (IDPs).
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Affiliation(s)
- Irina Portnaya
- Department of Biotechnology and Food Engineering
- Technion – Israel Institute of Technology
- Haifa 3200003
- Israel
| | - Sharon Avni
- Department of Biotechnology and Food Engineering
- Technion – Israel Institute of Technology
- Haifa 3200003
- Israel
| | - Ellina Kesselman
- Department of Biotechnology and Food Engineering
- Technion – Israel Institute of Technology
- Haifa 3200003
- Israel
| | - Yoav Boyarski
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
| | - Shahar Sukenik
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
| | - Daniel Harries
- Institute of Chemistry and the Fritz Haber Research Center
- The Hebrew University
- Jerusalem 91904
- Israel
| | - Nily Dan
- Department of Chemical and Biological Engineering
- Drexel University
- Philadelphia
- USA
| | - Uri Cogan
- Department of Biotechnology and Food Engineering
- Technion – Israel Institute of Technology
- Haifa 3200003
- Israel
| | - Dganit Danino
- Department of Biotechnology and Food Engineering
- Technion – Israel Institute of Technology
- Haifa 3200003
- Israel
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Lenton S, Seydel T, Nylander T, Holt C, Härtlein M, Teixeira S, Zaccai G. Dynamic footprint of sequestration in the molecular fluctuations of osteopontin. J R Soc Interface 2015; 12:0506. [PMID: 26354827 PMCID: PMC4614460 DOI: 10.1098/rsif.2015.0506] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2015] [Accepted: 08/19/2015] [Indexed: 11/12/2022] Open
Abstract
The sequestration of calcium phosphate by unfolded proteins is fundamental to the stabilization of biofluids supersaturated with respect to hydroxyapatite, such as milk, blood or urine. The unfolded state of osteopontin (OPN) is thought to be a prerequisite for this activity, which leads to the formation of core-shell calcium phosphate nanoclusters. We report on the structures and dynamics of a native OPN peptide from bovine milk, studied by neutron spectroscopy and small-angle X-ray and neutron scattering. The effects of sequestration are quantified on the nanosecond- ångström resolution by elastic incoherent neutron scattering. The molecular fluctuations of the free phosphopeptide are in agreement with a highly flexible protein. An increased resilience to diffusive motions of OPN is corroborated by molecular fluctuations similar to those observed for globular proteins, yet retaining conformational flexibilities. The results bring insight into the modulation of the activity of OPN and phosphopeptides with a role in the control of biomineralization. The quantification of such effects provides an important handle for the future design of new peptides based on the dynamics-activity relationship.
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Affiliation(s)
- S Lenton
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France Environment, Physical Sciences and Applied Mathematics Research Institute, Keele University, Staffordshire ST5 5BG, UK
| | - T Seydel
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France
| | - T Nylander
- Division of Physical Chemistry, Lund University, PO Box 124, 221 00 Lund, Sweden
| | - C Holt
- Institute of Molecular, Cell and Systems Biology, University of Glasgow, Glasgow G12 8QQ, UK
| | - M Härtlein
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France
| | - S Teixeira
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France Environment, Physical Sciences and Applied Mathematics Research Institute, Keele University, Staffordshire ST5 5BG, UK
| | - G Zaccai
- Institut Laue-Langevin, 71 Avenue des Martyrs, 38042 Grenoble cedex 9, France C.N.R.S., Institut de Biologie Structurale, F-38044 Grenoble, France
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Redwan EM, Almehdar HA, EL-Fakharany EM, Baig AWK, Uversky VN. Potential antiviral activities of camel, bovine, and human lactoperoxidases against hepatitis C virus genotype 4. RSC Adv 2015; 5:60441-60452. [DOI: 10.1039/c5ra11768b] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2023] Open
Abstract
Lactoperoxidases (LPOs) were assayed against hepatitis C virus (HCV) using PCR. Direct interaction of HCV with LPO neutralized the viral particles and prevented entry into cells. LPOs inhibited virus amplification in infected HepG2 cells with a relative activity of 100%.
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Affiliation(s)
- Elrashdy M. Redwan
- Department of Biological Science
- Faculty of Science
- King Abdulaziz University
- Jeddah 21589
- Saudi Arabia
| | - Hussein A. Almehdar
- Department of Biological Science
- Faculty of Science
- King Abdulaziz University
- Jeddah 21589
- Saudi Arabia
| | - Esmail M. EL-Fakharany
- Protective and Therapeutic Proteins Laboratory
- Protein Research Department
- Genetic Engineering and Biotechnology Research Institute GEBRI
- City for Scientific Research and Technology Applications
- Alexandria
| | - Abdul-Wahab K. Baig
- Department of Biological Science
- Faculty of Science
- King Abdulaziz University
- Jeddah 21589
- Saudi Arabia
| | - Vladimir N. Uversky
- Department of Biological Science
- Faculty of Science
- King Abdulaziz University
- Jeddah 21589
- Saudi Arabia
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