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The self-association properties of partially dephosphorylated bovine beta-casein. Food Hydrocoll 2023. [DOI: 10.1016/j.foodhyd.2022.108019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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2
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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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3
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Li W, Whitcomb KL, Warncke K. Confinement dependence of protein-associated solvent dynamics around different classes of proteins, from the EPR spin probe perspective. Phys Chem Chem Phys 2022; 24:23919-23928. [PMID: 36165617 PMCID: PMC10371532 DOI: 10.1039/d2cp03047k] [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] [Indexed: 12/29/2022]
Abstract
Protein function is modulated by coupled solvent fluctuations, subject to the degree of confinement from the surroundings. To identify universal features of the external confinement effect, the temperature dependence of the dynamics of protein-associated solvent over 200-265 K for proteins representative of different classes and sizes is characterized by using the rotational correlation time (detection bandwidth, 10-10-10-7 s) of the electron paramagnetic resonance (EPR, X-band) spin probe, TEMPOL, which is restricted to regions vicinal to protein in frozen aqueous solution. Weak (protein surrounded by aqueous-dimethylsulfoxide cryosolvent mesodomain) and strong (no added crysolvent) conditions of ice boundary confinement are imposed. The panel of soluble proteins represents large and small oligomeric (ethanolamine ammonia-lyase, 488 kDa; streptavidin, 52.8 kDa) and monomeric (myoglobin, 16.7 kDa) globular proteins, an intrinsically disordered protein (IDP, β-casein, 24.0 kDa), an unstructured peptide (protamine, 4.38 kDa) and a small peptide with partial backbone order (amyloid-β residues 1-16, 1.96 kDa). Expanded and condensate structures of β-casein and protamine are resolved by the spin probe under weak and strong confinement, respectively. At each confinement condition, the soluble globular proteins display common T-dependences of rotational correlation times and normalized weights, for two mobility components, protein-associated domain, PAD, and surrounding mesodomain. Strong confinement induces a detectable PAD component and emulation of globular protein T-dependence by the amyloid-β peptide. Confinement uniformly impacts soluble globular protein PAD dynamics, and is therefore a generic control parameter for modulation of soluble globular protein function.
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Affiliation(s)
- Wei Li
- Department of Physics, Emory University, Atlanta, Georgia, 30322.
| | | | - Kurt Warncke
- Department of Physics, Emory University, Atlanta, Georgia, 30322.
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4
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Christiansen MV, Dave A, Skibsted LH, Ahrné L. Functional properties of skim milk concentrates produced by reverse osmosis filtration and reconstituted commercial powders. Int Dairy J 2022. [DOI: 10.1016/j.idairyj.2021.105225] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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5
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Wijaya W, Khan S, Madsen M, Møller MS, Maria Rovers TA, Jæger TC, Ipsen R, Westh P, Svensson B. Tunable mixed micellization of β-casein in the presence of κ-casein. Food Hydrocoll 2021. [DOI: 10.1016/j.foodhyd.2020.106459] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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6
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Ma W, Tribet C, Guyot S, Zanchi D. Tannin-controlled micelles and fibrils of κ-casein. J Chem Phys 2020; 151:245103. [PMID: 31893889 DOI: 10.1063/1.5128057] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Effects of green tea tannin epigallocatechin-gallate (EGCG) on thermal-stress-induced amyloid fibril formation of reduced carboxymethylated bovine milk protein κ-casein were studied by dynamical light scattering and small angle X-ray scattering (SAXS). Two populations of aggregates, micelles, and fibrils dominated the time evolution of light scattering intensity and of effective hydrodynamic diameter. SAXS experiments allowed us to resolve micelles and fibrils so that the time dependence of the scattering profile revealed the structural evolution of the two populations. The low-Q scattering intensity prior to an expected increase in time due to fibril growth shows an intriguing rapid decrease, which is interpreted as the release of monomers from micelles. This phenomenon, observed both in the absence and in the presence of EGCG, indicates that under thermal stress free conditions, native monomers are converted to amyloid-prone monomers that do not form micelles. The consumption of free native monomers results in a release of native monomers from micelles because only native proteins participate in micelle-monomer (quasi)equilibrium. This release is reversible, indicating also that native-to-amyloid-prone monomer conversion is reversible as well. We show that EGCG does not bind to protein in fibrils, neither does it affect/prevent the proamyloid conversion of monomers. EGCG hinders the addition of monomers to growing fibrils. These facts allowed us to propose the kinetics model for EGCG-controlled amyloid aggregation of micellar proteins. Therein, we introduced the growth-rate inhibition function, which quantitatively accounts for the effect of EGCG on the fibril growth at any degree of thermal stress.
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Affiliation(s)
- Wei Ma
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, F-75005 Paris, France
| | - Christophe Tribet
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, F-75005 Paris, France
| | - Sylvain Guyot
- INRA UR1268 BIA-Polyphenols, Reactivity, Processes, F-35653 Le Rheu, France
| | - Dražen Zanchi
- PASTEUR, Département de Chimie, École Normale Supérieure, PSL University, Sorbonne Université, CNRS, 24 rue Lhomond, F-75005 Paris, France
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7
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Application of preheating treatment in up- and down-regulating the glycation process of dietary proteins. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2019.105264] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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8
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Li M, Auty MA, Crowley SV, Kelly AL, O'Mahony JA, Brodkorb A. Self-association of bovine β-casein as influenced by calcium chloride, buffer type and temperature. Food Hydrocoll 2019. [DOI: 10.1016/j.foodhyd.2018.09.035] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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9
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Raak N, Schöne C, Rohm H, Jaros D. Acid-induced gelation of enzymatically cross-linked caseinate in different ionic milieus. Food Hydrocoll 2019. [DOI: 10.1016/j.foodhyd.2018.01.037] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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10
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Geicu OI, Stanca L, Dinischiotu A, Serban AI. Proteomic and immunochemical approaches to understanding the glycation behaviour of the casein and β-lactoglobulin fractions of flavoured drinks under UHT processing conditions. Sci Rep 2018; 8:12869. [PMID: 30150692 PMCID: PMC6110766 DOI: 10.1038/s41598-018-28943-4] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Accepted: 07/03/2018] [Indexed: 01/10/2023] Open
Abstract
Dairy technology used to produce sweetened milk products might introduce additional advanced glycation end products (AGEs) into the diet. These molecular messengers are linked to detrimental health effects. Using a model accurate to the thermal treatment, reducing sugars, main protein content, and prolonged storage of ultra-high-temperature-sterilized (UHT) milk, we studied the behaviour of milk proteins during glycation. Two-dimensional electrophoresis (2-DE) profiles and western blots of glycated total casein revealed the major contributions of αs2-casein and β-casein and the relatively minor contributions of κ-casein towards the formation of Nε-carboxymethyllysine (CML)-positive aggregates. Glycated κ-casein had the lowest furosine (FUR), 5-hydroxymethylfurfural (HMF) and AGEs content. Conversely, the α-casein fraction demonstrated a high susceptibility to glycation, having the highest FUR, HMF and AGE levels. The gel-filtration elution profiles and the corresponding fraction fluorescence revealed that glycated casein aggregates were highly fluorescent, while the β-lactoglobulin glycation profile was similar to that of bovine serum albumin, and fluorescence was detected mainly in tetramers. Although CML is not a cross-linking AGE, it was only detected in large molecular aggregates and not in glycated monomers. Our results also indicate that in casein, glycation-induced changes in the UHT conditions were less deleterious than the subsequent 90 day storage period.
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Grants
- TE_2012-3-0034, 15/26.04.2013 Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii (Executive Agency for Higher Education, Scientific Research, Development and Innovation Funding)
- TE_2012-3-0034, 15/26.04.2013 Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii (Executive Agency for Higher Education, Scientific Research, Development and Innovation Funding)
- TE_2012-3-0034, 15/26.04.2013 Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii (Executive Agency for Higher Education, Scientific Research, Development and Innovation Funding)
- TE_2012-3-0034, 15/26.04.2013 Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii (Executive Agency for Higher Education, Scientific Research, Development and Innovation Funding)
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Affiliation(s)
- Ovidiu I Geicu
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095, Bucharest, Romania
- Department of Preclinical Sciences, Faculty of Veterinary Medicine, University of Agronomic Sciences and Veterinary Medicine of Bucharest, 105 Splaiul Independentei, 050097, Bucharest, Romania
| | - Loredana Stanca
- Department of Preclinical Sciences, Faculty of Veterinary Medicine, University of Agronomic Sciences and Veterinary Medicine of Bucharest, 105 Splaiul Independentei, 050097, Bucharest, Romania
| | - Anca Dinischiotu
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095, Bucharest, Romania
| | - Andreea I Serban
- Department of Biochemistry and Molecular Biology, Faculty of Biology, University of Bucharest, 91-95 Splaiul Independentei, 050095, Bucharest, Romania.
- Department of Preclinical Sciences, Faculty of Veterinary Medicine, University of Agronomic Sciences and Veterinary Medicine of Bucharest, 105 Splaiul Independentei, 050097, Bucharest, Romania.
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11
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Lowe AD, Bawazeer S, Watson DG, McGill S, Burchmore RJS, Pomeroy PPP, Kennedy MW. Rapid changes in Atlantic grey seal milk from birth to weaning - immune factors and indicators of metabolic strain. Sci Rep 2017; 7:16093. [PMID: 29170469 PMCID: PMC5700954 DOI: 10.1038/s41598-017-16187-7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2017] [Accepted: 11/08/2017] [Indexed: 11/21/2022] Open
Abstract
True seals have the shortest lactation periods of any group of placental mammal. Most are capital breeders that undergo short, intense lactations, during which they fast while transferring substantial proportions of their body reserves to their pups, which they then abruptly wean. Milk was collected from Atlantic grey seals (Halichoerus grypus) periodically from birth until near weaning. Milk protein profiles matured within 24 hours or less, indicating the most rapid transition from colostrum to mature phase lactation yet observed. There was an unexpected persistence of immunoglobulin G almost until weaning, potentially indicating prolonged trans-intestinal transfer of IgG. Among components of innate immune protection were found fucosyllactose and siallylactose that are thought to impede colonisation by pathogens and encourage an appropriate milk-digestive and protective gut microbiome. These oligosaccharides decreased from early lactation to almost undetectable levels by weaning. Taurine levels were initially high, then fell, possibly indicative of taurine dependency in seals, and progressive depletion of maternal reserves. Metabolites that signal changes in the mother’s metabolism of fats, such as nicotinamide and derivatives, rose from virtual absence, and acetylcarnitines fell. It is therefore possible that indicators of maternal metabolic strain exist that signal the imminence of weaning.
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Affiliation(s)
- Amanda D Lowe
- Institute of Biodiversity, Animal Health & Comparative Medicine, and School of Life Sciences, Graham Kerr Building, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK
| | - Sami Bawazeer
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, Scotland, UK
| | - David G Watson
- Strathclyde Institute of Pharmacy and Biomedical Sciences, University of Strathclyde, 161 Cathedral Street, Glasgow, G4 0RE, Scotland, UK
| | - Suzanne McGill
- Institute of Infection, Immunity and Inflammation, and Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Campus, Glasgow, G12 1QH, Scotland, UK
| | - Richard J S Burchmore
- Institute of Infection, Immunity and Inflammation, and Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Campus, Glasgow, G12 1QH, Scotland, UK
| | - P P Paddy Pomeroy
- Sea Mammal Research Unit, Scottish Oceans Institute, University of St Andrews, St Andrews, Fife, United Kingdom
| | - Malcolm W Kennedy
- Institute of Biodiversity, Animal Health & Comparative Medicine, and School of Life Sciences, Graham Kerr Building, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, G12 8QQ, Scotland, UK.
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12
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Gao Z, Huang Y, Zhao J, Yao X, Zhang K, Fang Y, Nishinari K, Phillips GO, Yang H. Edible Pickering emulsion stabilized by protein fibrils: Part 2. Effect of dipalmitoyl phosphatidylcholine (DPPC). Food Hydrocoll 2017. [DOI: 10.1016/j.foodhyd.2017.03.028] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
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13
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Castillo DS, Cassola A. Novel sensitive monoclonal antibody based competitive enzyme-linked immunosorbent assay for the detection of raw and processed bovine beta-casein. PLoS One 2017; 12:e0182447. [PMID: 28759641 PMCID: PMC5536360 DOI: 10.1371/journal.pone.0182447] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Accepted: 07/18/2017] [Indexed: 11/18/2022] Open
Abstract
Cow milk protein allergy (CMPA) is the most common childhood food allergy, which can sometimes persist or can newly develop in adulthood with severe symptoms. CMPA's treatment is complete dietary avoidance of milk proteins. To achieve this task, patients have to be aware of milk proteins found as "hidden allergens" in food commodities. In regard to milk proteins, it has been reported that allergenicity of caseins remains unaffected upon heat treatment. For these reasons, we aimed to obtain monoclonal antibodies (mAbs) against native and denatured β-casein, one of the most abundant and antigenic caseins, in order to develop an indirect competitive ELISA (icELISA) to detect and quantify traces of this milk allergen in raw and processed foodstuffs. We developed two specific hybridoma clones, 1H3 and 6A12, which recognized β-casein in its denatured and native conformations by indirect ELISA (iELISA). Cross-reaction analysis by Western blot and iELISA indicated that these mAbs specifically recognized β-casein from bovine and goat milk extracts, while they did not cross-react with proteins present in other food matrixes. These highly specific mAbs enabled the development of sensitive, reliable and reproducible icELISAs to detect and quantify this milk protein allergen in food commodities. The extraction of β-casein from foodstuff was efficiently carried out at 60°C for 15 minutes, using an extraction buffer containing 1% SDS. The present study establishes a valid 1H3 based-icELISA, which allows the detection and quantification -0.29 ppm and 0.80 ppm, respectively- of small amounts of β-casein in raw and processed foods. Furthermore, we were able to detect milk contamination in incurred food samples with the same sensitivity as a commercial sandwich ELISA thus showing that this icELISA constitutes a reliable analytical method for control strategies in food industry and allergy prevention.
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Affiliation(s)
- Daniela S. Castillo
- Instituto de Investigaciones Biotecnológicas—Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM)—Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Buenos Aires, Argentina
| | - Alejandro Cassola
- Instituto de Investigaciones Biotecnológicas—Instituto Tecnológico de Chascomús (IIB-INTECH), Universidad Nacional de San Martín (UNSAM)—Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), San Martín, Buenos Aires, Argentina
- * E-mail:
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14
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15
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Ingham B, Smialowska A, Erlangga GD, Matia-Merino L, Kirby NM, Wang C, Haverkamp RG, Carr AJ. Revisiting the interpretation of casein micelle SAXS data. SOFT MATTER 2016; 12:6937-53. [PMID: 27491477 DOI: 10.1039/c6sm01091a] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/02/2023]
Abstract
An in-depth, critical review of model-dependent fitting of small-angle X-ray scattering (SAXS) data of bovine skim milk has led us to develop a new mathematical model for interpreting these data. Calcium-edge resonant soft X-ray scattering data provides unequivocal evidence as to the shape and location of the scattering due to colloidal calcium phosphate, which is manifested as a correlation peak centred at q = 0.035 Å(-1). In SAXS data this feature is seldom seen, although most literature studies attribute another feature centred at q = 0.08-0.1 Å(-1) to CCP. This work shows that the major SAXS features are due to protein arrangements: the casein micelle itself; internal regions approximately 20 nm in size, separated by water channels; and protein structures which are inhomogeneous on a 1-3 nm length scale. The assignment of these features is consistent with their behaviour under various conditions, including hydration time after reconstitution, addition of EDTA (a Ca-chelating agent), addition of urea, and reduction of pH.
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Affiliation(s)
- B Ingham
- Callaghan Innovation, P.O. Box 31310, Lower Hutt 5040, New Zealand.
| | - A Smialowska
- School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - G D Erlangga
- School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - L Matia-Merino
- School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - N M Kirby
- Australian Synchrotron, 800 Blackburn Road, Clayton, VIC 3168, Australia
| | - C Wang
- Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA
| | - R G Haverkamp
- School of Engineering and Advanced Technology, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
| | - A J Carr
- School of Food and Nutrition, Massey University, Private Bag 11222, Palmerston North 4442, New Zealand
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16
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Milk proteins interact with goat Binder of SPerm (BSP) proteins and decrease their binding to sperm. Cell Tissue Res 2016; 366:427-442. [PMID: 27432314 DOI: 10.1007/s00441-016-2438-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2015] [Accepted: 05/31/2016] [Indexed: 12/20/2022]
Abstract
Seminal plasma Binder of SPerm (BSP) proteins bind to sperm at ejaculation and promote capacitation. When in excess, however, BSP proteins damage the sperm membrane. It has been suggested that milk components of semen extenders associate with BSP proteins, potentially protecting sperm. Thus, this study was conducted to investigate if milk proteins interact with BSP proteins and reduce BSP binding to goat sperm. Using gel filtration chromatography, milk was incubated with goat seminal plasma proteins and loaded onto columns with and without calcium. Milk was also fractionated into parts containing mostly whey proteins or mostly caseins, incubated with seminal plasma proteins and subjected to gel filtration. Eluted fractions were evaluated by immunoblot using anti-goat BSP antibodies, confirming milk protein-BSP protein interactions. As determined by ELISA, milk proteins coated on polystyrene wells bound to increasing of goat BSP proteins. Far-western dot blots confirmed that BSP proteins bound to caseins and β-lactoglobulin in a concentration-dependent manner. Then, cauda epididymal sperm from five goats was incubated with seminal plasma; seminal plasma followed by milk; and milk followed by seminal plasma. Sperm membrane proteins were extracted and evaluated by immunoblotting. The pattern of BSP binding to sperm membrane proteins was reduced by 59.3 % when epididymal sperm were incubated with seminal plasma and then with skimmed milk (p < 0.05). When epididymal sperm were treated with milk followed by seminal plasma, coating of sperm with BSP proteins was not significantly reduced (57.6 %; p > 0.05). In conclusion, goat BSP proteins have an affinity for caseins and whey proteins. Milk reduces BSP binding to goat sperm, depending whether or not sperm had been previously exposed to seminal plasma. Such events may explain the protective effect of milk during goat sperm preservation.
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17
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Kuchlyan J, Roy A, Dutta R, Sen S, Sarkar N. Effect of the submicellar concentration of bile salts on structural alterations of β-casein micelles. RSC Adv 2016. [DOI: 10.1039/c6ra14804b] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
The role of bile salts, sodium deoxycholate (NaDC) and sodium cholate (NaCh), on the self-assembly behavior of β-casein micelles (β-CMs) was investigated using various fluorescence techniques.
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Affiliation(s)
- Jagannath Kuchlyan
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Arpita Roy
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Rupam Dutta
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Swagata Sen
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
| | - Nilmoni Sarkar
- Department of Chemistry
- Indian Institute of Technology
- Kharagpur 721302
- India
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18
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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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19
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Raynes JK, Day L, Augustin MA, Carver JA. Structural differences between bovine A(1) and A(2) β-casein alter micelle self-assembly and influence molecular chaperone activity. J Dairy Sci 2015; 98:2172-82. [PMID: 25648798 DOI: 10.3168/jds.2014-8800] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2014] [Accepted: 12/22/2014] [Indexed: 11/19/2022]
Abstract
Within each milk protein there are many individual protein variants and marked alterations to milk functionality can occur depending on the genetic variants of each protein present. Bovine A(1) and A(2) β-casein (β-CN) are 2 variants that contribute to differences in the gelation performance of milk. The A(1) and A(2) β-CN variants differ by a single AA, the substitution of histidine for proline at position 67. β-Casein not only participates in formation of the casein micelle but also forms an oligomeric micelle itself and functions as a molecular chaperone to prevent the aggregation of a wide range of proteins, including the other caseins. Micelle assembly of A(1) and A(2) β-CN was investigated using dynamic light scattering and small-angle X-ray scattering, whereas protein functionality was assessed using fluorescence techniques and molecular chaperone assays. The A(2) β-CN variant formed smaller micelles than A(1) β-CN, with the monomer-micelle equilibrium of A(2) β-CN being shifted toward the monomer. This shift most likely arose from structural differences between the 2 β-CN variants associated with the adoption of greater polyproline-II helix in A(2) β-CN and most likely led to enhanced chaperone activity of A(2) β-CN compared with A(1) β-CN. The difference in micelle assembly, and hence chaperone activity, may provide explain differences in the functionality of homozygous A(1) and A(2) milk. The results of this study highlight that substitution of even a single AA can significantly alter the properties of an intrinsically unstructured protein such as β-CN and, in this case, may have an effect on the functionality of milk.
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Affiliation(s)
- J K Raynes
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Food and Nutrition, Werribee, Victoria 3030, Australia.
| | - L Day
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Food and Nutrition, Werribee, Victoria 3030, Australia
| | - M A Augustin
- Commonwealth Scientific and Industrial Research Organisation (CSIRO), Food and Nutrition, Werribee, Victoria 3030, Australia
| | - J A Carver
- Research School of Chemistry, College of Physical and Mathematical Sciences, The Australian National University, Canberra 0200, Australia
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Holm LS, Mcumber A, Rasmussen JE, Obiols‐Rabasa M, Thulstrup PW, Kasimova MR, Randolph TW, van de Weert M. The Effect of Protein PEGylation on Physical Stability in Liquid Formulation. J Pharm Sci 2014; 103:3043-54. [DOI: 10.1002/jps.24094] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2014] [Revised: 05/21/2014] [Accepted: 06/30/2014] [Indexed: 12/22/2022]
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Liu Y, Yang L, Mao H, Guo R. Comparative studies on the interaction of [C4mim]Br, and [C8mim]Br with β-casein micelles. Colloids Surf A Physicochem Eng Asp 2014. [DOI: 10.1016/j.colsurfa.2013.10.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Pinto MS, Léonil J, Henry G, Cauty C, Carvalho AF, Bouhallab S. Heating and glycation of β-lactoglobulin and β-casein: Aggregation and in vitro digestion. Food Res Int 2014. [DOI: 10.1016/j.foodres.2013.10.030] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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Effect of calcium ions on both the co-assembly of αs-casein with soy phosphatidylcholine and the novel functionality of their complex particles. Food Hydrocoll 2014. [DOI: 10.1016/j.foodhyd.2013.03.018] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Sun Y, Liang X, Zhao Y, Fan J. Aggregation-Induced Emission of 1,8-NaphthalimideCasein Micelle: Investigation by Synchronous Spectrographic Method. Chem Biodivers 2013; 10:1597-605. [DOI: 10.1002/cbdv.201200405] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2012] [Indexed: 01/03/2023]
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de Kruif CGK, Pedersen J, Huppertz T, Anema SG. Coacervates of lactotransferrin and β- or κ-casein: structure determined using SAXS. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2013; 29:10483-10490. [PMID: 23859400 DOI: 10.1021/la402236f] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
Lactotransferrin (LF) is a large globular protein in milk with immune-regulatory and bactericidal properties. At pH 6.5, LF (M = 78 kDa) carries a net (calculated) charge of +21. β-Casein (BCN) and κ-casein (KCN) are part of the casein micelle complex in milk. Both BCN and KCN are amphiphillic proteins with a molar mass of 24 and 19 kDa and carry net charges of -14 and -4, respectively. Both BCN and KCN form soap-like micelles, with 40 and 65 monomers, respectively. The net negative charges are located in the corona of the micelles. On mixing LF with the caseins, coacervates are formed. We analyzed the structure of these coarcervates using SAXS. It was found that LF binds to the corona of the micellar structures, at the charge neutrality point. BCN/LF and KCN/LF ratios at the charge neutrality point were found to be ~1.2 and ~5, respectively. We think that the findings are relevant for the protection mechanism of globular proteins in bodily fluids where unstructured proteins are abundant (saliva). The complexes will prevent docking of enzymes on specific charged groups on the globular protein.
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Affiliation(s)
- C G Kees de Kruif
- Van 't Hoff laboratory for Physical and Colloid Chemistry, Padualaan 8, Utrecht University, The Netherlands.
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Holt C, Carver JA, Ecroyd H, Thorn DC. Invited review: Caseins and the casein micelle: their biological functions, structures, and behavior in foods. J Dairy Sci 2013; 96:6127-46. [PMID: 23958008 DOI: 10.3168/jds.2013-6831] [Citation(s) in RCA: 282] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Accepted: 06/09/2013] [Indexed: 12/27/2022]
Abstract
A typical casein micelle contains thousands of casein molecules, most of which form thermodynamically stable complexes with nanoclusters of amorphous calcium phosphate. Like many other unfolded proteins, caseins have an actual or potential tendency to assemble into toxic amyloid fibrils, particularly at the high concentrations found in milk. Fibrils do not form in milk because an alternative aggregation pathway is followed that results in formation of the casein micelle. As a result of forming micelles, nutritious milk can be secreted and stored without causing either pathological calcification or amyloidosis of the mother's mammary tissue. The ability to sequester nanoclusters of amorphous calcium phosphate in a stable complex is not unique to caseins. It has been demonstrated using a number of noncasein secreted phosphoproteins and may be of general physiological importance in preventing calcification of other biofluids and soft tissues. Thus, competent noncasein phosphoproteins have similar patterns of phosphorylation and the same type of flexible, unfolded conformation as caseins. The ability to suppress amyloid fibril formation by forming an alternative amorphous aggregate is also not unique to caseins and underlies the action of molecular chaperones such as the small heat-shock proteins. The open structure of the protein matrix of casein micelles is fragile and easily perturbed by changes in its environment. Perturbations can cause the polypeptide chains to segregate into regions of greater and lesser density. As a result, the reliable determination of the native structure of casein micelles continues to be extremely challenging. The biological functions of caseins, such as their chaperone activity, are determined by their composition and flexible conformation and by how the casein polypeptide chains interact with each other. These same properties determine how caseins behave in the manufacture of many dairy products and how they can be used as functional ingredients in other foods.
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Affiliation(s)
- C Holt
- Institute of Molecular, Cell and Systems Biology, School of Life Sciences, University of Glasgow, Glasgow G12 8QQ, United Kingdom.
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Mehranfar F, Bordbar AK, Haertlé T, Moosavi-Movahedi AA, Farzi N. Micellar properties of β-casein–cationic surfactant solutions. MONATSHEFTE FUR CHEMIE 2013. [DOI: 10.1007/s00706-013-0951-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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