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Mateo-Roque P, Morales-Camacho JI, Jara-Romero GJ, Rosas-Cárdenas FDF, Huerta-González L, Luna-Suárez S. Supercritical CO 2 Treatment to Modify Techno-Functional Properties of Proteins Extracted from Tomato Seeds. Foods 2024; 13:1045. [PMID: 38611350 PMCID: PMC11011313 DOI: 10.3390/foods13071045] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2024] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/14/2024] Open
Abstract
Tomato seeds are a rich source of protein that can be utilized for various industrial food purposes. This study delves into the effects of using supercritical CO2 (scCO2) on the structure and techno-functional properties of proteins extracted from defatted tomato seeds. The defatted meal was obtained using hexane (TSMH) and scCO2 (TSMC), and proteins were extracted using water (PEWH and PEWC) and saline solution (PESH and PESC). The results showed that scCO2 treatment significantly improved the techno-functional properties of protein extracts, such as oil-holding capacity and foaming capacity (especially for PEWC). Moreover, emulsifying capacity and stability were enhanced for PEWC and PESC, ranging between 4.8 and 46.7% and 11.3 and 96.3%, respectively. This was made possible by the changes in helix structure content induced by scCO2 treatment, which increased for PEWC (5.2%) and decreased for PESC (8.0%). Additionally, 2D electrophoresis revealed that scCO2 hydrolyzed alkaline proteins in the extracts. These findings demonstrate the potential of scCO2 treatment in producing modified proteins for food applications.
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Affiliation(s)
- Paola Mateo-Roque
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Tepetitla 90700, Tlaxcala, Mexico; (P.M.-R.); (G.J.J.-R.); (F.d.F.R.-C.); (L.H.-G.)
| | - Jocksan I. Morales-Camacho
- Departamento de Ingeniería Química, Alimentos y Ambiental, Universidad de las Américas Puebla, San Andrés Cholula 72810, Puebla, Mexico;
| | - Guadalupe Janet Jara-Romero
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Tepetitla 90700, Tlaxcala, Mexico; (P.M.-R.); (G.J.J.-R.); (F.d.F.R.-C.); (L.H.-G.)
| | - Flor de Fátima Rosas-Cárdenas
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Tepetitla 90700, Tlaxcala, Mexico; (P.M.-R.); (G.J.J.-R.); (F.d.F.R.-C.); (L.H.-G.)
| | - Luis Huerta-González
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Tepetitla 90700, Tlaxcala, Mexico; (P.M.-R.); (G.J.J.-R.); (F.d.F.R.-C.); (L.H.-G.)
| | - Silvia Luna-Suárez
- Centro de Investigación en Biotecnología Aplicada, Instituto Politécnico Nacional, Tepetitla 90700, Tlaxcala, Mexico; (P.M.-R.); (G.J.J.-R.); (F.d.F.R.-C.); (L.H.-G.)
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2
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Saenger T, Schulte MF, Vordenbäumen S, Hermann FC, Bertelsbeck J, Meier K, Bleck E, Schneider M, Jose J. Structural Analysis of Breast-Milk α S1-Casein: An α-Helical Conformation Is Required for TLR4-Stimulation. Int J Mol Sci 2024; 25:1743. [PMID: 38339021 PMCID: PMC10855866 DOI: 10.3390/ijms25031743] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2023] [Revised: 01/19/2024] [Accepted: 01/21/2024] [Indexed: 02/12/2024] Open
Abstract
Breast-milk αS1-casein is a Toll-like receptor 4 (TLR4) agonist, whereas phosphorylated αS1-casein does not bind TLR4. The objective of this study was to analyse the structural requirements for these effects. In silico analysis of αS1-casein indicated high α-helical content with coiled-coil characteristics. This was confirmed by CD-spectroscopy, showing the α-helical conformation to be stable between pH 2 and 7.4. After in vitro phosphorylation, the α-helical content was significantly reduced, similar to what it was after incubation at 80 °C. This conformation showed no in vitro induction of IL-8 secretion via TLR4. A synthetic peptide corresponding to V77-E92 of αS1-casein induced an IL-8 secretion of 0.95 ng/mL via TLR4. Our results indicate that αS1-casein appears in two distinct conformations, an α-helical TLR4-agonistic and a less α-helical TLR4 non-agonistic conformation induced by phosphorylation. This is to indicate that the immunomodulatory role of αS1-casein, as described before, could be regulated by conformational changes induced by phosphorylation.
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Affiliation(s)
- Thorsten Saenger
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, PharmaCampus, Correnstr. 48, 48149 Münster, Germany; (T.S.); (M.F.S.)
| | - Marten F. Schulte
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, PharmaCampus, Correnstr. 48, 48149 Münster, Germany; (T.S.); (M.F.S.)
| | - Stefan Vordenbäumen
- Department of Rheumatology and Hiller Research Unit Rheumatology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Fabian C. Hermann
- Institute for Pharmaceutical Biology and Phytochemie, University of Münster, PharmaCampus, Correnstr. 48, 48149 Münster, Germany
| | - Juliana Bertelsbeck
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, PharmaCampus, Correnstr. 48, 48149 Münster, Germany; (T.S.); (M.F.S.)
| | - Kathrin Meier
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, PharmaCampus, Correnstr. 48, 48149 Münster, Germany; (T.S.); (M.F.S.)
| | - Ellen Bleck
- Department of Rheumatology and Hiller Research Unit Rheumatology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Matthias Schneider
- Department of Rheumatology and Hiller Research Unit Rheumatology, Medical Faculty, Heinrich-Heine-University Düsseldorf, Moorenstr. 5, 40225 Düsseldorf, Germany
| | - Joachim Jose
- Institute for Pharmaceutical and Medicinal Chemistry, University of Münster, PharmaCampus, Correnstr. 48, 48149 Münster, Germany; (T.S.); (M.F.S.)
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3
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Analysis of the Factors Affecting Static In Vitro Pepsinolysis of Food Proteins. Molecules 2022; 27:molecules27041260. [PMID: 35209049 PMCID: PMC8878058 DOI: 10.3390/molecules27041260] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Revised: 02/08/2022] [Accepted: 02/10/2022] [Indexed: 02/04/2023] Open
Abstract
In this meta-analysis, we collected 58 publications spanning the last seven decades that reported static in vitro protein gastric digestion results. A number of descriptors of the pepsinolysis process were extracted, including protein type; pepsin activity and concentration; protein concentration; pH; additives; protein form (e.g., ‘native’, ‘emulsion’, ‘gel’, etc.); molecular weight of the protein; treatment; temperature; and half-times (HT) of protein digestion. After careful analysis and the application of statistical techniques and regression models, several general conclusions could be extracted from the data. The protein form to digest the fastest was ‘emulsion’. The rate of pepsinolysis in the emulsion was largely independent of the protein type, whereas the gastric digestion of the native protein in the solution was strongly dependent on the protein type. The pepsinolysis was shown to be strongly dependent on the structural components of the proteins digested—specifically, β-sheet-inhibited and amino acid, leucine, methionine, and proline-promoted digestion. Interestingly, we found that additives included in the digestion mix to alter protein hydrolysis had, in general, a negligible effect in comparison to the clear importance of the protein form or additional treatment. Overall, the findings allowed for the targeted creation of foods for fast or slow protein digestion, depending on the nutritional needs.
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4
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Sim SYJ, SRV A, Chiang JH, Henry CJ. Plant Proteins for Future Foods: A Roadmap. Foods 2021; 10:1967. [PMID: 34441744 PMCID: PMC8391319 DOI: 10.3390/foods10081967] [Citation(s) in RCA: 62] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 08/16/2021] [Accepted: 08/19/2021] [Indexed: 12/19/2022] Open
Abstract
Protein calories consumed by people all over the world approximate 15-20% of their energy intake. This makes protein a major nutritional imperative. Today, we are facing an unprecedented challenge to produce and distribute adequate protein to feed over nine billion people by 2050, in an environmentally sustainable and affordable way. Plant-based proteins present a promising solution to our nutritional needs due to their long history of crop use and cultivation, lower cost of production, and easy access in many parts of the world. However, plant proteins have comparatively poor functionality, defined as poor solubility, foaming, emulsifying, and gelling properties, limiting their use in food products. Relative to animal proteins, including dairy products, plant protein technology is still in its infancy. To bridge this gap, advances in plant protein ingredient development and the knowledge to construct plant-based foods are sorely needed. This review focuses on some salient features in the science and technology of plant proteins, providing the current state of the art and highlighting new research directions. It focuses on how manipulating plant protein structures during protein extraction, fractionation, and modification can considerably enhance protein functionality. To create novel plant-based foods, important considerations such as protein-polysaccharide interactions, the inclusion of plant protein-generated flavors, and some novel techniques to structure plant proteins are discussed. Finally, the attention to nutrition as a compass to navigate the plant protein roadmap is also considered.
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Affiliation(s)
- Shaun Yong Jie Sim
- Clinical Nutrition Research Centre (CNRC), Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore 117599, Singapore; (A.S.); (J.H.C.); (C.J.H.)
| | - Akila SRV
- Clinical Nutrition Research Centre (CNRC), Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore 117599, Singapore; (A.S.); (J.H.C.); (C.J.H.)
| | - Jie Hong Chiang
- Clinical Nutrition Research Centre (CNRC), Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore 117599, Singapore; (A.S.); (J.H.C.); (C.J.H.)
| | - Christiani Jeyakumar Henry
- Clinical Nutrition Research Centre (CNRC), Singapore Institute of Food and Biotechnology Innovation (SIFBI), Agency for Science, Technology and Research (A*STAR), Singapore 117599, Singapore; (A.S.); (J.H.C.); (C.J.H.)
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117596, Singapore
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5
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McClements DJ, Grossmann L. The science of plant-based foods: Constructing next-generation meat, fish, milk, and egg analogs. Compr Rev Food Sci Food Saf 2021; 20:4049-4100. [PMID: 34056859 DOI: 10.1111/1541-4337.12771] [Citation(s) in RCA: 130] [Impact Index Per Article: 43.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 02/06/2023]
Abstract
Consumers are increasingly demanding foods that are more ethical, sustainable and nutritious to improve the health of themselves and the planet. The food industry is currently undergoing a revolution, as both small and large companies pivot toward the creation of a new generation of plant-based products to meet this consumer demand. In particular, there is an emphasis on the production of plant-based foods that mimic those that omnivores are familiar with, such as meat, fish, egg, milk, and their products. The main challenge in this area is to simulate the desirable appearance, texture, flavor, mouthfeel, and functionality of these products using ingredients that are isolated entirely from botanical sources, such as proteins, carbohydrates, and lipids. The molecular, chemical, and physical properties of plant-derived ingredients are usually very different from those of animal-derived ones. It is therefore critical to understand the fundamental properties of plant-derived ingredients and how they can be assembled into structures resembling those found in animal products. This review article provides an overview of the current status of the scientific understanding of plant-based foods and highlights areas where further research is required. In particular, it focuses on the chemical, physical, and functional properties of plant-derived ingredients; the processing operations that can be used to convert these ingredients into food products; and, the science behind the formulation of vegan meat, fish, eggs, and milk alternatives.
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Affiliation(s)
| | - Lutz Grossmann
- Department of Food Science, University of Massachusetts, Amherst, Massachusetts, USA
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6
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Palmer KS, Makarewicz CA, Tishkin AA, Tur SS, Chunag A, Diimajav E, Jamsranjav B, Buckley M. Comparing the Use of Magnetic Beads with Ultrafiltration for Ancient Dental Calculus Proteomics. J Proteome Res 2021; 20:1689-1704. [PMID: 33596076 DOI: 10.1021/acs.jproteome.0c00862] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Over the past two decades, proteomic analysis has greatly developed in application to the field of biomolecular archaeology, coinciding with advancements in LC-MS/MS instrumentation sensitivity and improvements in sample preparation methods. Recently, human dental calculus has received much attention for its well-preserved proteomes locked in mineralized dental plaque which stores information on human diets and the oral microbiome otherwise invisible to other biomolecular approaches. Maximizing proteome recovery in ancient dental calculus, available only in minute quantities and irreplaceable after destructive analysis, is of paramount importance. Here, we compare the more traditional ultrafiltration-based and acetone precipitation approaches with the newer paramagnetic bead approach in order to test the influence of demineralization acid on recovered proteome complexity obtained from specimens as well as the sequence coverages matched for significant proteins. We found that a protocol utilizing EDTA combined with paramagnetic beads increased proteome complexity, in some cases doubling the number of unique peptides and number of proteins matched, compared to protocols involving the use of HCl and either acetone precipitation or ultrafiltration. Although the increase in the number of proteins was almost exclusively of bacterial origin, a development that has implications for the study of diseases within these ancient populations, an increase in the peptide number for the dairy proteins β-lactoglobulin and casein was also observed reflecting an increase in sequence coverage for these dietary proteins of interest. We also consider structural explanations for the discrepancies observed between these two key dietary proteins preserved in archaeological dental calculus.
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Affiliation(s)
- Karren S Palmer
- School of Natural Sciences, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
| | - Cheryl A Makarewicz
- Institute for Prehistoric and Protohistoric Archaeology, Kiel University, Johanna-Mestorf Strasse 2-6, D-24118 Kiel, Germany
| | - Alexey A Tishkin
- Department of Archeology, Ethnography, and Museology, Altai State University, Lenin Prospect 61, 656049 Barnaul, Russia
| | - Svetlana S Tur
- Department of Archeology, Ethnography, and Museology, Altai State University, Lenin Prospect 61, 656049 Barnaul, Russia
| | | | - Erdenebaatar Diimajav
- Department of Archaeology and History, Ulaanbataar State University, Luvsantseveen Street, 5th khoroo, 15th khorgoolol, Bayanzurk District 13343 Ulaanbaatar, Mongolia
| | - Bayarsaikhan Jamsranjav
- National Museum of Mongolia, Ulaanbaatar Mongolia, Juulchin Street-1, Ulaanbaatar 13343, Mongolia
| | - Michael Buckley
- School of Natural Sciences, Manchester Institute of Biotechnology, The University of Manchester, 131 Princess Street, Manchester M1 7DN, United Kingdom
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7
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Thorn DC, Bahraminejad E, Grosas AB, Koudelka T, Hoffmann P, Mata JP, Devlin GL, Sunde M, Ecroyd H, Holt C, Carver JA. Native disulphide-linked dimers facilitate amyloid fibril formation by bovine milk α S2-casein. Biophys Chem 2020; 270:106530. [PMID: 33545456 DOI: 10.1016/j.bpc.2020.106530] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 12/12/2020] [Accepted: 12/12/2020] [Indexed: 12/22/2022]
Abstract
Bovine milk αS2-casein, an intrinsically disordered protein, readily forms amyloid fibrils in vitro and is implicated in the formation of amyloid fibril deposits in mammary tissue. Its two cysteine residues participate in the formation of either intra- or intermolecular disulphide bonds, generating monomer and dimer species. X-ray solution scattering measurements indicated that both forms of the protein adopt large, spherical oligomers at 20 °C. Upon incubation at 37 °C, the disulphide-linked dimer showed a significantly greater propensity to form amyloid fibrils than its monomeric counterpart. Thioflavin T fluorescence, circular dichroism and infrared spectra were consistent with one or both of the dimer isomers (in a parallel or antiparallel arrangement) being predisposed toward an ordered, amyloid-like structure. Limited proteolysis experiments indicated that the region from Ala81 to Lys113 is incorporated into the fibril core, implying that this region, which is predicted by several algorithms to be amyloidogenic, initiates fibril formation of αS2-casein. The partial conservation of the cysteine motif and the frequent occurrence of disulphide-linked dimers in mammalian milks despite the associated risk of mammary amyloidosis, suggest that the dimeric conformation of αS2-casein is a functional, yet amyloidogenic, structure.
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Affiliation(s)
- David C Thorn
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia
| | - Elmira Bahraminejad
- 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
| | - Tomas Koudelka
- Institute of Experimental Medicine, University of Kiel, Kiel 24105, Germany
| | - Peter Hoffmann
- Future Industries Institute, University of South Australia, Mawson Lakes, SA 5095, Australia
| | - Jitendra P Mata
- Australian Centre for Neutron Scattering, Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - Glyn L Devlin
- Victorian Health and Human Services Building Authority, Melbourne, Victoria 3000, Australia
| | - Margaret Sunde
- Discipline of Pharmacology, School of Medical Sciences, Faculty of Medicine and Health and Sydney Nano, University of Sydney, Sydney, NSW 2006, Australia
| | - Heath Ecroyd
- Molecular Horizons and School of Chemistry and Molecular Bioscience, University of Wollongong and Illawarra Health and Medical Research Institute, Wollongong, NSW 2522, Australia
| | - Carl Holt
- Institute of Molecular, Cell & Systems Biology, University of Glasgow, Glasgow G12 8QQ, Scotland, United Kingdom
| | - John A Carver
- Research School of Chemistry, The Australian National University, Acton, ACT 2601, Australia.
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8
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Effects of material characteristics on the structural characteristics and flavor substances retention of meat analogs. Food Hydrocoll 2020. [DOI: 10.1016/j.foodhyd.2020.105752] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
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9
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Low pH-shifting treatment would improve functional properties of black turtle bean (Phaseolus vulgaris L.) protein isolate with immunoreactivity reduction. Food Chem 2020; 330:127217. [PMID: 32521404 DOI: 10.1016/j.foodchem.2020.127217] [Citation(s) in RCA: 31] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2020] [Revised: 05/27/2020] [Accepted: 05/31/2020] [Indexed: 01/10/2023]
Abstract
Low pH-shifting was firstly applied in the black turtle bean (Phaseolus vulgaris L.) protein isolate treatment by acidic (pH 1.0-3.0) buffer incubation for 8 h, then was adjusted to pH 7.2 and kept 3 h for protein stabilizing. Mild loss of secondary structure was confirmed in the protein isolate after low pH-shifting treatment by CD and FT-IR analyses. Intrinsic fluorescence, UV spectra, surface hydrophobicity, SH content and SDS-PAGE analyses indicated the protein conformation was unfolded with the exposure of much more buried hydrophobic residues, which would result in the enhancement of emulsifying properties, foaming properties and fat holding capacity, and lead to the reduction of solubility and water holding capacity. Furthermore, lower immunoreactivity was observed by the ELISA, and improved digestibility was found in in vitro digestion assay. Our results suggested the low pH-shifting treatments would broaden the application of bean protein isolate with better hydrophobic processing functions and safety.
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10
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Affiliation(s)
- Igor T Smykov
- Department of Physical Chemistry All‐Russian Scientific Research Institute of Butter‐ and Cheesemaking Krasnoarmeysky Boulevard 19 Uglich Yaroslavl Region 152613 Russia
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11
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Feyzi S, Varidi M, Housaindokht MR, Es'haghi Z. Binding of safranal to whey proteins in aqueous solution: Combination of headspace solid-phase microextraction/gas chromatography with multi spectroscopic techniques and docking studies. Food Chem 2019; 287:313-323. [DOI: 10.1016/j.foodchem.2019.02.065] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2018] [Revised: 02/12/2019] [Accepted: 02/14/2019] [Indexed: 01/17/2023]
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12
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Fontenele MA, Bastos MDS, dos Santos KM, Bemquerer MP, do Egito AS. Peptide profile of Coalho cheese: A contribution for Protected Designation of Origin (PDO). Food Chem 2017; 219:382-390. [DOI: 10.1016/j.foodchem.2016.09.171] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2016] [Revised: 09/22/2016] [Accepted: 09/27/2016] [Indexed: 02/07/2023]
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Chigira T, Nagatoishi S, Tsumoto K. Differential binding of prohibitin-2 to estrogen receptor α and to drug-resistant ERα mutants. Biochem Biophys Res Commun 2015; 463:726-31. [PMID: 26049107 DOI: 10.1016/j.bbrc.2015.06.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2015] [Accepted: 06/01/2015] [Indexed: 02/05/2023]
Abstract
Endocrine resistance is one of the most challenging problems in estrogen receptor alpha (ERα)-positive breast cancer. The transcriptional activity of ERα is controlled by several coregulators, including prohibitin-2 (PHB2). Because of its ability to repress the transcriptional activity of activated ERα, PHB2 is a promising antiproliferative agent. In this study, were analyzed the interaction of PHB2 with ERα and three mutants (Y537S, D538G, and E380Q) that are frequently associated with a lack of sensitivity to hormonal treatments, to help advance novel drug discovery. PHB2 bound to ERα wild-type (WT), Y537S, and D538G, but did not bind to E380Q. The binding thermodynamics of Y537S and D538G to PHB2 were favorably altered entropically compared with those of WT to PHB2. Our results show that PHB2 binds to the ligand binding domain of ERα with a conformational change in the helix 12 of ERα.
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Affiliation(s)
- Takeru Chigira
- Department of Chemistry and Biotechnology, School of Engineering, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan.
| | - Satoru Nagatoishi
- Department of Bioengineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan.
| | - Kouhei Tsumoto
- Department of Chemistry and Biotechnology, School of Engineering, University of Tokyo, 4-6-1 Shirokanedai, Minato-ku, Tokyo 108-8639, Japan; Department of Bioengineering, School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8654, Japan.
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14
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15
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Lisanti MT, Gambuti A, Genovese A, Piombino P, Moio L. Earthy off-flavour in wine: Evaluation of remedial treatments for geosmin contamination. Food Chem 2014; 154:171-8. [DOI: 10.1016/j.foodchem.2013.12.100] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2013] [Revised: 12/11/2013] [Accepted: 12/29/2013] [Indexed: 11/26/2022]
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16
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Ingber DE, Wang N, Stamenović D. Tensegrity, cellular biophysics, and the mechanics of living systems. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:046603. [PMID: 24695087 PMCID: PMC4112545 DOI: 10.1088/0034-4885/77/4/046603] [Citation(s) in RCA: 227] [Impact Index Per Article: 22.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
The recent convergence between physics and biology has led many physicists to enter the fields of cell and developmental biology. One of the most exciting areas of interest has been the emerging field of mechanobiology that centers on how cells control their mechanical properties, and how physical forces regulate cellular biochemical responses, a process that is known as mechanotransduction. In this article, we review the central role that tensegrity (tensional integrity) architecture, which depends on tensile prestress for its mechanical stability, plays in biology. We describe how tensional prestress is a critical governor of cell mechanics and function, and how use of tensegrity by cells contributes to mechanotransduction. Theoretical tensegrity models are also described that predict both quantitative and qualitative behaviors of living cells, and these theoretical descriptions are placed in context of other physical models of the cell. In addition, we describe how tensegrity is used at multiple size scales in the hierarchy of life—from individual molecules to whole living organisms—to both stabilize three-dimensional form and to channel forces from the macroscale to the nanoscale, thereby facilitating mechanochemical conversion at the molecular level.
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Affiliation(s)
- Donald E. Ingber
- Wyss Institute for Biologically Inspired Engineering at Harvard University, Harvard Medical School, Harvard School of Engineering and Applied Sciences, and Boston Children’s Hospital, 3 Blackfan Circle, CLSB5, Boston, MA 02115
| | - Ning Wang
- Department of Mechanical Science and Engineering, University of Illinois at Urbana-Champaign, 1206 W. Green St, Urbana, IL 61801
| | - Dimitrije Stamenović
- Department of Biomedical Engineering, and Division of Material Science and Engineering, College of Engineering, Boston University, 44 Cummington Mall, Boston, MA 02215
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17
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Distinct quaternary structures of the AAA+ Lon protease control substrate degradation. Proc Natl Acad Sci U S A 2013; 110:E2002-8. [PMID: 23674680 DOI: 10.1073/pnas.1307066110] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
Lon is an ATPase associated with cellular activities (AAA+) protease that controls cell division in response to stress and also degrades misfolded and damaged proteins. Subunits of Lon are known to assemble into ring-shaped homohexamers that enclose an internal degradation chamber. Here, we demonstrate that hexamers of Escherichia coli Lon also interact to form a dodecamer at physiological protein concentrations. Electron microscopy of this dodecamer reveals a prolate structure with the protease chambers at the distal ends and a matrix of N domains forming an equatorial hexamer-hexamer interface, with portals of ∼45 Å providing access to the enzyme lumen. Compared with hexamers, Lon dodecamers are much less active in degrading large substrates but equally active in degrading small substrates. Our results support a unique gating mechanism that allows the repertoire of Lon substrates to be tuned by its assembly state.
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Bachar M, Mandelbaum A, Portnaya I, Perlstein H, Even-Chen S, Barenholz Y, Danino D. Development and characterization of a novel drug nanocarrier for oral delivery, based on self-assembled β-casein micelles. J Control Release 2012; 160:164-71. [DOI: 10.1016/j.jconrel.2012.01.004] [Citation(s) in RCA: 98] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2011] [Revised: 01/05/2012] [Accepted: 01/06/2012] [Indexed: 12/14/2022]
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Onwulata CI, Tunick MH, Qi PX. Extrusion texturized dairy proteins: processing and application. ADVANCES IN FOOD AND NUTRITION RESEARCH 2011; 62:173-200. [PMID: 21504824 DOI: 10.1016/b978-0-12-385989-1.00005-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
The primary proteins in milk, casein and the whey proteins α-lactalbumin and β-lactoglobulin, have a number of health benefits and desirable functional properties. In a twin-screw extruder, mechanical shear forces, heat, and pressure cause considerable changes in the molecular structures of the dairy proteins, a process known as texturization. These changes further impart unique functional properties to dairy proteins, resulting in new protein-based food ingredients. The new functional behavior depends on the extent of texturization and the degree of structural change imparted and is controlled by adjusting parameters such as extrusion temperature and moisture level. Such texturized proteins can be used to produce puffed high-protein snacks. Softer gels and expanded structures can be made using supercritical fluid extrusion and cold extrusion, techniques that avoid elevated temperatures, minimizing possible damage to the nutritive components and functionality of the texturized dairy proteins. The uses of the texturized dairy ingredient in food products with improved functionality and enhanced nutritive profiles are presented.
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Affiliation(s)
- Charles I Onwulata
- Center of Excellence in Extrusion and Polymer Rheology, Eastern Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Wyndmoor, Pennsylvania, USA.
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Abstract
The maintenance of the levels and correct folding state of proteins (proteostasis) is a fundamental prerequisite for life. Life has evolved complex mechanisms to maintain proteostasis and many of these that operate inside cells are now well understood. The same cannot yet be said of corresponding processes in extracellular fluids of the human body, where inappropriate protein aggregation is known to underpin many serious diseases such as Alzheimer's disease, type II diabetes and prion diseases. Recent research has uncovered a growing family of abundant extracellular chaperones in body fluids which appear to selectively bind to exposed regions of hydrophobicity on misfolded proteins to inhibit their toxicity and prevent them from aggregating to form insoluble deposits. These extracellular chaperones are also implicated in clearing the soluble, stabilized misfolded proteins from body fluids via receptor-mediated endocytosis for subsequent lysosomal degradation. Recent work also raises the possibility that extracellular chaperones may play roles in modulating the immune response. Future work will better define the in vivo functions of extracellular chaperones in proteostasis and immunology and pave the way for the development of new treatments for serious diseases.
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Dabbs RA, Wyatt AR, Yerbury JJ, Ecroyd H, Wilson MR. Extracellular Chaperones. Top Curr Chem (Cham) 2010. [PMID: 21516385 DOI: 10.1007/128_2010_85] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
The maintenance of the levels and correct folding state of proteins (proteostasis) is a fundamental prerequisite for life. Life has evolved complex mechanisms to maintain proteostasis and many of these that operate inside cells are now well understood. The same cannot yet be said of corresponding processes in extracellular fluids of the human body, where inappropriate protein aggregation is known to underpin many serious diseases such as Alzheimer's disease, type II diabetes and prion diseases. Recent research has uncovered a growing family of abundant extracellular chaperones in body fluids which appear to selectively bind to exposed regions of hydrophobicity on misfolded proteins to inhibit their toxicity and prevent them from aggregating to form insoluble deposits. These extracellular chaperones are also implicated in clearing the soluble, stabilized misfolded proteins from body fluids via receptor-mediated endocytosis for subsequent lysosomal degradation. Recent work also raises the possibility that extracellular chaperones may play roles in modulating the immune response. Future work will better define the in vivo functions of extracellular chaperones in proteostasis and immunology and pave the way for the development of new treatments for serious diseases.
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Mora-Gutierrez A, Attaie R, Farrell HM. Lipid oxidation in algae oil-in-water emulsions stabilized by bovine and caprine caseins. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2010; 58:5131-5139. [PMID: 20232823 DOI: 10.1021/jf904343f] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
Caseins (alpha(s1)-, alpha(s2)-, and beta-casein) are phosphoproteins that are capable of binding transition metals and scavenging free radicals; this property makes them good candidates to be used as natural antioxidants in oil-in-water emulsions. Caprine casein exhibits variability in alpha(s1)-casein content generated by genetic polymorphism. This variability in composition could lead to altered antioxidant properties. Thus, the ability of two caprine caseins differing in alpha(s1)-casein content to inhibit lipid oxidation in algae oil-in-water emulsions at 5% oil was investigated and compared to bovine caseinate. All caseins inhibited the formation of lipid oxidation at pH 7.0 as determined by lipid hydroperoxides and thiobarbituric acid reactive substances (TBARS). However, caprine caseins were in general more effective inhibitors of lipid oxidation than the bovine caseins, which may be attributed to their altered casein amino acid content and/or metal binding capabilities. The combination of the carotenoids with bovine and caprine caseins was highly effective at repressing oxidation leading to the speculation that the caseins may inhibit the loss of the carotenoids and/or react with and enhance the carotenoid activity; again some differences between bovine and caprine caseins were observed with caprine caseins being slightly more effective in the presence of carotenoids.
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Affiliation(s)
- Adela Mora-Gutierrez
- Cooperative Agricultural Research Center, Prairie View A&M University, Prairie View, Texas 77446, USA.
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Hidalgo ME, Pires MS, Risso PH. A study on bovine kappa-casein aggregation after the enzymatic action of chymosin. Colloids Surf B Biointerfaces 2010; 76:556-63. [DOI: 10.1016/j.colsurfb.2009.12.018] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2009] [Revised: 12/07/2009] [Accepted: 12/20/2009] [Indexed: 11/16/2022]
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24
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Otzen DE, Sehgal P, Westh P. α-Lactalbumin is unfolded by all classes of surfactants but by different mechanisms. J Colloid Interface Sci 2009; 329:273-83. [DOI: 10.1016/j.jcis.2008.10.021] [Citation(s) in RCA: 94] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2008] [Revised: 10/08/2008] [Accepted: 10/09/2008] [Indexed: 11/30/2022]
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25
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Chakraborty A, Basak S. Interaction with Al and Zn induces structure formation and aggregation in natively unfolded caseins. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY B-BIOLOGY 2008; 93:36-43. [DOI: 10.1016/j.jphotobiol.2008.06.011] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2008] [Revised: 06/09/2008] [Accepted: 06/28/2008] [Indexed: 11/16/2022]
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26
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Alvarez EM, Risso PH, Canales MAM, Pires MS, Gatti CA. Hydrodynamic properties–structure relationship for sodium caseinates in presence of calcium. Colloids Surf A Physicochem Eng Asp 2008. [DOI: 10.1016/j.colsurfa.2008.06.003] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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27
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28
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Gaspar AM, Appavou MS, Busch S, Unruh T, Doster W. Dynamics of well-folded and natively disordered proteins in solution: a time-of-flight neutron scattering study. EUROPEAN BIOPHYSICS JOURNAL: EBJ 2008; 37:573-82. [PMID: 18228014 DOI: 10.1007/s00249-008-0266-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/13/2007] [Revised: 12/19/2007] [Accepted: 01/08/2008] [Indexed: 11/28/2022]
Abstract
Casein proteins belong to the class of natively disordered proteins. The existence of disordered biologically active proteins questions the assumption that a well-folded structure is required for function. A hypothesis generally put forward is that the unstructured nature of these proteins results from the functional need of a higher flexibility. This interplay between structure and dynamics was investigated in a series of time-of-flight neutron scattering experiments, performed on casein proteins, as well as on three well-folded proteins with distinct secondary structures, namely, myoglobin (alpha), lysozyme (alpha/beta) and concanavalin A (beta). To illustrate the subtraction of the solvent contribution from the scattering spectra, we used the dynamic susceptibility spectra emphasizing the high frequency part of the spectrum, where the solvent dominates. The quality of the procedure is checked by comparing the corrected spectra to those of the dry and hydrated protein with negligible solvent contamination. Results of spectra analysis reveal differences in motional amplitudes of well-folded proteins, where beta-sheet structures appear to be more rigid than a cluster of alpha-helices. The disordered caseins display the largest conformational displacements. Moreover their global diffusion rates deviate from the expected dependence, suggesting further large-scale conformational motions.
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Affiliation(s)
- A M Gaspar
- E13, Physik Department, Technische Universität München, Lichtenberg str 1, 85747 Garching bei München, Germany.
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29
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Glomm WR, Halskau, Ø, Hanneseth AMD, Volden S. Adsorption Behavior of Acidic and Basic Proteins onto Citrate-Coated Au Surfaces Correlated to Their Native Fold, Stability, and pI. J Phys Chem B 2007; 111:14329-45. [DOI: 10.1021/jp074839d] [Citation(s) in RCA: 79] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Wijesinha-Bettoni R, Gao C, Jenkins JA, Mackie AR, Wilde PJ, Mills ENC, Smith LJ. Heat Treatment of Bovine α-Lactalbumin Results in Partially Folded, Disulfide Bond Shuffled States with Enhanced Surface Activity. Biochemistry 2007; 46:9774-84. [PMID: 17676769 DOI: 10.1021/bi700897n] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Prolonged heating of holo bovine alpha-lactalbumin (BLA) at 80 degrees C in pH 7 phosphate buffer in the absence of a thiol initiator improves the surface activity of the protein at the air:water interface, as determined by surface tension measurements. Samples after 30, 60, and 120 min of heating were analyzed on cooling to room temperature. Size-exclusion chromatography shows sample heterogeneity that increases with the length of heating. After 120 min of heating monomeric, dimeric, and oligomeric forms of BLA are present, with aggregates formed from disulfide bond linked hydrolyzed protein fragments. NMR characterization at pH 7 in the presence of Ca2+ of the monomer species isolated from the sample heated for 120 min showed that it consisted of a mixture of refolded native protein and partially folded protein and that the partially folded protein species had spectral characteristics similar to those of the pH 2 molten globule state of the protein. Circular dichroism spectroscopy showed that the non-native species had approximately 40% of the alpha-helical content of the native state, but lacked persistent tertiary interactions. Proteomic analysis using thermolysin digestion of three predominant non-native monomeric forms isolated by high-pressure liquid chromatography indicated the presence of disulfide shuffled isomers, containing the non-native 61-73 disulfide bond. These partially folded, disulfide shuffled species are largely responsible for the pronounced improvement in surface activity of the protein on heating.
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32
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Effect of size, proteic composition, and heat treatment on the colloidal stability of proteolyzed bovine casein micelles. Colloid Polym Sci 2007. [DOI: 10.1007/s00396-006-1629-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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33
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Saguer E, Fort N, Parés D, Toldrà M, Carretero C. Improvement of gelling properties of porcine blood plasma using microbial transglutaminase. Food Chem 2007. [DOI: 10.1016/j.foodchem.2005.11.050] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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34
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Matthews BD, Thodeti CK, Ingber DE. Activation of Mechanosensitive Ion Channels by Forces Transmitted Through Integrins and the Cytoskeleton. MECHANOSENSITIVE ION CHANNELS, PART A 2007. [DOI: 10.1016/s1063-5823(06)58003-2] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
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35
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Tunick MH, Onwulata CI. Rheological Properties of Extruded Milk Powders. INTERNATIONAL JOURNAL OF FOOD PROPERTIES 2006. [DOI: 10.1080/10942910600669899] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
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36
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Lorenzen PC, Schrader K. A comparative study of the gelation properties of whey protein concentrate and whey protein isolate. ACTA ACUST UNITED AC 2006. [DOI: 10.1051/lait:2006008] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
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37
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Casein micelle structure: What can be learned from milk synthesis and structural biology? Curr Opin Colloid Interface Sci 2006. [DOI: 10.1016/j.cocis.2005.11.005] [Citation(s) in RCA: 178] [Impact Index Per Article: 9.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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38
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Abstract
Analysis of cellular mechanotransduction, the mechanism by which cells convert mechanical signals into biochemical responses, has focused on identification of critical mechanosensitive molecules and cellular components. Stretch-activated ion channels, caveolae, integrins, cadherins, growth factor receptors, myosin motors, cytoskeletal filaments, nuclei, extracellular matrix, and numerous other structures and signaling molecules have all been shown to contribute to the mechanotransduction response. However, little is known about how these different molecules function within the structural context of living cells, tissues, and organs to produce the orchestrated cellular behaviors required for mechanosensation, embryogenesis, and physiological control. Recent work from a wide range of fields reveals that organ, tissue, and cell anatomy are as important for mechanotransduction as individual mechanosensitive proteins and that our bodies use structural hierarchies (systems within systems) composed of interconnected networks that span from the macroscale to the nanoscale in order to focus stresses on specific mechanotransducer molecules. The presence of isometric tension (prestress) at all levels of these multiscale networks ensures that various molecular scale mechanochemical transduction mechanisms proceed simultaneously and produce a concerted response. Future research in this area will therefore require analysis, understanding, and modeling of tensionally integrated (tensegrity) systems of mechanochemical control.
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Affiliation(s)
- Donald E Ingber
- Vascular Biology Program, Karp Family Research Laboratories 11.127, Department of Pathology, Harvard Medical School and Children's Hospital, 300 Longwood Ave., Boston, Massachusetts 02115, USA.
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39
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Guichard E. Flavour retention and release from protein solutions. Biotechnol Adv 2006; 24:226-9. [PMID: 16377118 DOI: 10.1016/j.biotechadv.2005.11.003] [Citation(s) in RCA: 76] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2005] [Accepted: 11/22/2005] [Indexed: 10/25/2022]
Abstract
This paper briefly presents the main results obtained up to now on protein-flavour binding and release in relation with flavour perception. Among the food proteins, beta-lactoglobulin is the most extensively studied for its binding properties, which involve both hydrophobic and hydrogen binding. Recent developments using molecular modelling and Quantitative Structure-Activity Relationship confirmed the existence of two different binding sites for flavour compounds on beta-lactoglobulin. During the aroma release process in the mouth, not only free aroma compounds are released but also those reversibly bound by the protein, pointing out the fact that flavour perception is only affected if strong binding occurs.
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Affiliation(s)
- Elisabeth Guichard
- UMR-INRA-ENESAD-FLAVIC, FLAveur, Vision et Comportement du consommateur, INRA, 17 Rue Sully, 21065 Dijon Cedex, France.
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40
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Halskau O, Underhaug J, Frøystein NA, Martínez A. Conformational flexibility of alpha-lactalbumin related to its membrane binding capacity. J Mol Biol 2005; 349:1072-86. [PMID: 15913646 DOI: 10.1016/j.jmb.2005.04.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2005] [Revised: 04/04/2005] [Accepted: 04/12/2005] [Indexed: 10/25/2022]
Abstract
Different folding states of the small, globular milk protein bovine alpha-lactalbumin (BLA) induced by the anionic surfactant sodium dodecylsulphate (SDS) have been examined by fluorescence spectroscopy, CD and NMR. The solution structure of the protein in the absence of SDS was also determined, indicating fluidity even under native conditions. BLA is partly denatured to a molten globule (MG)-like state by micromolar concentrations of SDS, and the transitions from native to MG-like state are dependent on pH, the protein being more sensitive to the surfactant at pH 6.5. As indicated by measurements of the intrinsic emission fluorescence, the tertiary structure disappears at lower concentrations of SDS than most of the secondary structure, as estimated from CD data. The MG-like state induced by low concentrations of SDS is not observable by NMR, and is probably fluctuating and/or aggregating. At higher concentrations of SDS above the critic concentration of micelles, an NMR-observable state reappears. This micelle-associated conformer was partially assigned, and found to bear strong resemblance to the acid-tri-fluoroethanol state, retaining weakened versions of the A and C helix of native BLA. We discuss the results in terms of the inherent flexibility of the protein, and its ability to form multiple folding states and to bind to membranes. Also, we propose that proteins with stable MG-like conformers can have these states stabilized by low levels of compounds with surfactant properties in vivo.
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Affiliation(s)
- Oyvind Halskau
- Department of Biomedicine, University of Bergen, Jonas Lies vei 91, 5009 Bergen, Norway
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41
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Livney YD, Schwan AL, Dalgleish DG. A Study of β-Casein Tertiary Structure by Intramolecular Crosslinking and Mass Spectrometry. J Dairy Sci 2004; 87:3638-47. [PMID: 15483147 DOI: 10.3168/jds.s0022-0302(04)73502-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The objective of this study was to obtain experimental evidence to extend the discussion on the 3-D structure of beta-casein (beta-CN). The approach involved the preparation of homobifunctional crosslinkers, bis(sulfosuccinimidyl) derivatives of dicarboxylic acids of several lengths, which specifically react with primary amines of lysinyl residues or the N-terminal in the protein. The intramolecular crosslinks formed were determined by enzymatic digestion and by matrix-assisted laser desorption and ionization time-of-flight mass spectrometry combined with comparison against the theoretical digestion patterns. This procedure allowed the measurement of distances between the crosslinked residues. Ten different masses arising from 8 different specific intramolecular crosslinks were identified. Of these, 5 crosslinks were in good agreement with a published model (Kumosinski et al., 1993). Two other crosslinks each connected 2 residues that are much closer together, according to the model, than the maximum length of the crosslink. However, one of the crosslinks apparently connected 2 residues that are predicted by the model to be 16.7 A farther apart than the crosslink's stretched length. This disparity might be explained by structural flexibility. The structure expressed by the model is probably one of several energetically favorable conformations of the beta-CN molecule, whose structure is best described as rheomorphic rather than either a fixed structure or a random coil.
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Affiliation(s)
- Y D Livney
- Department of Food Science, University of Guelph, ON, Canada N1G 2W1
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42
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Farrell HM, Jimenez-Flores R, Bleck GT, Brown EM, Butler JE, Creamer LK, Hicks CL, Hollar CM, Ng-Kwai-Hang KF, Swaisgood HE. Nomenclature of the Proteins of Cows’ Milk—Sixth Revision. J Dairy Sci 2004; 87:1641-74. [PMID: 15453478 DOI: 10.3168/jds.s0022-0302(04)73319-6] [Citation(s) in RCA: 730] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
This report of the American Dairy Science Association Committee on the Nomenclature, Classification, and Methodology of Milk Proteins reviews changes in the nomenclature of milk proteins necessitated by recent advances of our knowledge of milk proteins. Identification of major caseins and whey proteins continues to be based upon their primary structures. Nomenclature of the immunoglobulins consistent with new international standards has been developed, and all bovine immunoglobulins have been characterized at the molecular level. Other significant findings related to nomenclature and protein methodology are elucidation of several new genetic variants of the major milk proteins, establishment by sequencing techniques and sequence alignment of the bovine caseins and whey proteins as the reference point for the nomenclature of all homologous milk proteins, completion of crystallographic studies for major whey proteins, and advances in the study of lactoferrin, allowing it to be added to the list of fully characterized milk proteins.
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Affiliation(s)
- H M Farrell
- US Department of Agriculture, Eastern Regional Research Center, Wyndmoor, PA 19038, USA.
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43
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Sutovsky H, Gazit E. The von Hippel-Lindau tumor suppressor protein is a molten globule under native conditions: implications for its physiological activities. J Biol Chem 2004; 279:17190-6. [PMID: 14963040 DOI: 10.1074/jbc.m311225200] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023] Open
Abstract
The von-Hippel Lindau tumor suppressor protein (pVHL) is conserved throughout evolution, as its homologues are found in organisms ranging from mammals to the Drosophila melanogaster and Anopheles gambiae insects and the Caenorhabditis elegans nematode. Although the physiological role of pVHL is not fully understood, it has been shown to interact with a large number of unrelated proteins and was suggested to play a role in protein degradation as an E3 ubiquitin ligase component in the ubiquitin pathway. To gain insight into the molecular basis of pVHL activity, we analyzed its folding and stability in solution under physiologically relevant conditions. Dynamic light-scattering and gel filtration chromatography of the purified pVHL clearly indicated that the Stokes radius of the protein is larger than what would be expected from its crystal structure. However, under these conditions, the protein shows a clear secondary structure as determined by far-UV circular dichroism. Yet, the near-UV CD experiments show an absence of a tertiary structure. Upon the addition of urea, even at very low concentrations, the protein unfolds in a non-reversible manner, leading to the formation of amorphous aggregates. Furthermore, a large increase in fluorescence (>50-fold) is observed upon the addition of pVHL into a solution containing 8-anilino-1-naphthalene sulfonic acid. We therefore conclude that, under native conditions, the non-bound pVHL has a molten globule configuration with marginal stability. Although molten globular structures can be induced in many proteins under extreme conditions, this is one of the few reported cases of such a structure under the physiological conditions of pH, ionic strength, and temperature. The significance of the pVHL structural properties is being discussed in the context of its physiological activities.
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Affiliation(s)
- Hadar Sutovsky
- Department of Molecular Microbiology and Biotechnology, George S. Wise Faculty of Life Sciences, Tel Aviv University, Tel Aviv 69978, Israel
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44
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Aouzelleg A, Bull LA. Differential scanning calorimetry study of pressure/temperature processed β-lactoglobulin: The effect of dextran sulphate. Food Res Int 2004. [DOI: 10.1016/j.foodres.2004.06.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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45
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Abstract
The role of the phosphoserine residues on the dynamical and structural properties of beta-casein was studied by molecular dynamics of the protein in water/lipid interfacial regions. The initial protein structure adopted in the modeling was that proposed for bovine beta-casein A2, where the five phosphoserine residues, originally present in its primary structure, were partially or totally substituted by serine residues. The simulations revealed a dependence of the interfacial behavior of beta-casein on the phosphorylation grade. When only partially dephosphorylated, the protein showed a similar behavior as that observed for the original beta-casein reported in previous work. During dynamics, the protein migrated from the aqueous environment towards the lipid medium, and remained attached to the interface separating both media. Quite different was the dynamics of the totally dephosphorylated beta-casein, that did not perceive the interface and immersed incessantly into lipid medium. The results suggest that the phosphoserine residues appear to be, in fact, intrinsically related to the mechanisms of beta-casein emulsion stabilization.
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Affiliation(s)
- M M Cassiano
- Departamento de Nutrição, Faculdade de Saúde Pública, Universidade de São Paulo Av. Dr. Arnaldo, 715, 01246-904, São Paulo, Brazil.
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46
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Agasøster AV, Halskau Ø, Fuglebakk E, Frøystein NA, Muga A, Holmsen H, Martínez A. The interaction of peripheral proteins and membranes studied with alpha-lactalbumin and phospholipid bilayers of various compositions. J Biol Chem 2003; 278:21790-7. [PMID: 12660251 DOI: 10.1074/jbc.m211466200] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
To characterize the interaction of peripheral proteins and membranes at the molecular level, we studied the reversible association of bovine alpha-lactalbumin (BLA) with lipid bilayers composed of different molecular forms of phosphatidylserine or equimolar mixtures of these phosphatidylserine forms and egg yolk phosphatidylcholine. At pH 4.5, almost all BLA (>90%) associates to negatively charged small unilamellar vesicles. The conformational changes that binding to these bilayers induced on the protein were characterized by circular dichroism and fluorescence spectroscopy. Because binding of BLA to negatively charged vesicles is reverted by adjusting the pH back to >6.0, we also investigated the conformation of the membrane-bound protein by NMR-monitored H-D exchange of the backbone amide protons. The conformation adopted by BLA bound to these bilayers resembles a molten globule-like state but the negative ellipticity at 222 nm and the apparent alpha-helix content of the bound protein senses the changes in the physical properties of the membrane. Binding to bilayers in the gel state appears to correlate with an increased amount of alpha-helical structure and with a lower extent of integration into the membrane, corresponding to the adsorbed protein, while the opposite is found for BLA bound to vesicles in the liquid-crystalline phase, corresponding to the embedded conformation. A common feature for the membrane-bound conformations of BLA is that the amphipathic helix C (residues 86 to 99) is an important determinant for the adsorption and further integration of the protein into the membrane.
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Affiliation(s)
- Armelle Varnier Agasøster
- Department of Biochemistry and Molecular Biology, University of Bergen, Jonas Liesvei 91, N-5009 Bergen, Norway
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Abstract
In 1993, a Commentary in this journal described how a simple mechanical model of cell structure based on tensegrity architecture can help to explain how cell shape, movement and cytoskeletal mechanics are controlled, as well as how cells sense and respond to mechanical forces (J. Cell Sci. 104, 613-627). The cellular tensegrity model can now be revisited and placed in context of new advances in our understanding of cell structure, biological networks and mechanoregulation that have been made over the past decade. Recent work provides strong evidence to support the use of tensegrity by cells, and mathematical formulations of the model predict many aspects of cell behavior. In addition, development of the tensegrity theory and its translation into mathematical terms are beginning to allow us to define the relationship between mechanics and biochemistry at the molecular level and to attack the larger problem of biological complexity. Part I of this two-part article covers the evidence for cellular tensegrity at the molecular level and describes how this building system may provide a structural basis for the hierarchical organization of living systems--from molecule to organism. Part II, which focuses on how these structural networks influence information processing networks, appears in the next issue.
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Affiliation(s)
- Donald E Ingber
- Department of Surgery, Children's Hospital and Harvard Medical School, Enders 1007, 300 Longwood Avenue, Boston, MA 02115, USA.
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Farrell HM, Cooke PH, Wickham ED, Piotrowski EG, Hoagland PD. Environmental influences on bovine kappa-casein: reduction and conversion to fibrillar (amyloid) structures. JOURNAL OF PROTEIN CHEMISTRY 2003; 22:259-73. [PMID: 12962326 DOI: 10.1023/a:1025020503769] [Citation(s) in RCA: 96] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The caseins of milk form a unique calcium-phosphate transport complex that provides these necessary nutrients to the neonate. The colloidal stability of these particles is primarily the result of kappa-casein. As purified from milk, this protein occurs as spherical particles with a weight average molecular weight of 1.18 million. The protein exhibits a unique disulfide bonding pattern, which (in the absence of reducing agents) ranges from monomer to octamers and above on SDS-PAGE. Severe heat treatment of the kappa-casein (90 degrees C) in the absence of SDS, before electrophoresis, caused an increase in the polymeric distribution: up to 40% randomly aggregated high-molecular weight polymers, presumably promoted by free sulfhydryl groups (J. Protein Chem. 17: 73-84, 1998). To ascertain the role of the sulfhydryl groups, the protein was reduced and carboxymethylated (RCM-K). Surprisingly, at only 37 degrees C, the RCM-kappa-casein exhibited an increase in weight average molecular weight and tendency to self-association when studied at 3000 rpm by analytical ultracentrifugation. Electron microscopy (EM) of the 37 degrees C RCM sample showed that, in addition to the spherical particles found in the native protein, there was a high proportion of fibrillar structures. The fibrillar structures were up to 600 nm in length. Circular dichroism (CD) spectroscopy was used to investigate the temperature-induced changes in the secondary structure of the native and RCM-kappa-caseins. These studies indicate that there was little change in the distribution of secondary structural elements during this transition, with extended strand and beta turns predominating. On the basis of three-dimensional molecular modeling predictions, there may exist a tyrosine-rich repeated sheet-turn-sheet motif in kappa-casein (residues 15-65), which may allow for the stacking of the molecules into fibrillar structures. Previous studies on amyloid proteins have suggested that such motifs promote fibril formation, and near-ultraviolet CD and thioflavin-T binding studies on RCM-kappa-casein support this concept. The results are discussed with respect to the role that such fibrils may play in the synthesis and secretion of casein micelles in lactating mammary gland.
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Affiliation(s)
- Harold M Farrell
- United States Department of Agriculture, ARS, Eastern Regional Research Center, Wyndmoor, Pennsylvania 19038, USA.
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