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α-Lactalbumin, Amazing Calcium-Binding Protein. Biomolecules 2020; 10:biom10091210. [PMID: 32825311 PMCID: PMC7565966 DOI: 10.3390/biom10091210] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 08/14/2020] [Accepted: 08/17/2020] [Indexed: 02/06/2023] Open
Abstract
α-Lactalbumin (α-LA) is a small (Mr 14,200), acidic (pI 4–5), Ca2+-binding protein. α-LA is a regulatory component of lactose synthase enzyme system functioning in the lactating mammary gland. The protein possesses a single strong Ca2+-binding site, which can also bind Mg2+, Mn2+, Na+, K+, and some other metal cations. It contains several distinct Zn2+-binding sites. Physical properties of α-LA strongly depend on the occupation of its metal binding sites by metal ions. In the absence of bound metal ions, α-LA is in the molten globule-like state. The binding of metal ions, and especially of Ca2+, increases stability of α-LA against the action of heat, various denaturing agents and proteases, while the binding of Zn2+ to the Ca2+-loaded protein decreases its stability and causes its aggregation. At pH 2, the protein is in the classical molten globule state. α-LA can associate with membranes at neutral or slightly acidic pH at physiological temperatures. Depending on external conditions, α-LA can form amyloid fibrils, amorphous aggregates, nanoparticles, and nanotubes. Some of these aggregated states of α-LA can be used in practical applications such as drug delivery to tissues and organs. α-LA and some of its fragments possess bactericidal and antiviral activities. Complexes of partially unfolded α-LA with oleic acid are cytotoxic to various tumor and bacterial cells. α-LA in the cytotoxic complexes plays a role of a delivery carrier of cytotoxic fatty acid molecules into tumor and bacterial cells across the cell membrane. Perhaps in the future the complexes of α-LA with oleic acid will be used for development of new anti-cancer drugs.
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Pedersen JN, Frislev HKS, Pedersen JS, Otzen D. Structures and mechanisms of formation of liprotides. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2020; 1868:140505. [PMID: 32721568 DOI: 10.1016/j.bbapap.2020.140505] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 07/16/2020] [Indexed: 12/11/2022]
Abstract
Many proteins form complexes called liprotides with oleic acid and other cis-fatty acids under conditions where the protein is partially unfolded. The complexes vary in structure depending on the ratio of protein and lipid, but the most common structural organization is the core-shell structure, in which a layer of dynamic, partially unfolded and extended proteins surrounds a micelle-like fatty acid core. This structure, first reported for α-lactalbumin together with OA, resembles complexes formed between proteins and anionic surfactants like SDS. Liprotides first rose to fame through their anti-carcinogenic properties which still remains promising for topical applications though not yet implemented in the clinic. In addition, liprotides show potential in drug delivery thanks to the ability of the micelle core to solubilize and stabilize hydrophobic compounds, though applications are challenged by their sensitivity to acidic pH and dynamic exchange of lipids which makes them easy prey for serum "hoovers" such as albumin. However, liprotides are also of fundamental interest as a generic "protein complex structure", demonstrating the many and varied structural consequences of protein-lipid interactions. Here we provide an overview of the different types of liprotide complexes, ranging from quasi-native complexes via core-shell structures to multi-layer structures, and discuss the many conditions under which they form. Given the many variable types of complexes that can form, rigorous biophysical analysis (stoichiometry, shape and structure of the complexes) remains crucial for a complete understanding of the mechanisms of action of this fascinating group of protein-lipid complexes both in vitro and in vivo.
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Affiliation(s)
- Jannik Nedergaard Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Henriette Kristina Søster Frislev
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Novo Nordisk, Hallas Alle 1, DK-4400 Kalundborg, Denmark
| | - Jan Skov Pedersen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Department of Chemistry, Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark
| | - Daniel Otzen
- Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Gustav Wieds Vej 14, 8000 Aarhus C, Denmark; Department of Molecular Biology and Genetics, Aarhus University, Gustav Wieds Vej 10C, 8000 Aarhus C, Denmark.
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El-Fakharany EM, Redwan EM. Protein-lipid complexes: molecular structure, current scenarios and mechanisms of cytotoxicity. RSC Adv 2019; 9:36890-36906. [PMID: 35539089 PMCID: PMC9075609 DOI: 10.1039/c9ra07127j] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 10/21/2019] [Indexed: 02/04/2023] Open
Abstract
Some natural proteins can be complexed with oleic acid (OA) to form an active protein-lipid formulation that can induce tumor-selective apoptosis. The first explored protein was human milk α-lactalbumin (α-LA), called HAMLET when composed with OA in antitumor form. Several groups have prepared active protein-lipid complexes using a variety of approaches, all of which depend on target protein destabilization or direct OA-protein incubation to alter pH to acid or alkaline condition. In addition to performing vital roles in inflammatory processes and immune responses, fatty acids can disturb different metabolic pathways and cellular signals. Therefore, the tumoricidal action of these complexes is related to OA rather than the protein that keeps OA in solution and acts as a vehicle for transferring OA molecules to tumor cells. However, other studies have suggested that the antitumor efficacy of these complexes was exerted by both protein and OA together. The potential is not limited to the anti-tumor activity of protein-lipid complexes but extends to other functions such as bactericidal activity. The protein shell enhances the solubility and stability of the bound fatty acid. These protein-lipid complexes are promising candidates for fighting various cancer types and managing bacterial and viral infections.
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Affiliation(s)
- Esmail M El-Fakharany
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications (SRTA-City) New Borg EL-Arab 21934 Alexandria Egypt
| | - Elrashdy M Redwan
- Protein Research Department, Genetic Engineering and Biotechnology Research Institute, City for Scientific Research and Technology Applications (SRTA-City) New Borg EL-Arab 21934 Alexandria Egypt
- Department of Biological Sciences, Faculty of Sciences, King Abdulaziz University P. O. Box 80203 Jeddah Saudi Arabia
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Rath EM, Cheng YY, Pinese M, Sarun KH, Hudson AL, Weir C, Wang YD, Håkansson AP, Howell VM, Liu GJ, Reid G, Knott RB, Duff AP, Church WB. BAMLET kills chemotherapy-resistant mesothelioma cells, holding oleic acid in an activated cytotoxic state. PLoS One 2018; 13:e0203003. [PMID: 30157247 PMCID: PMC6114908 DOI: 10.1371/journal.pone.0203003] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2018] [Accepted: 08/13/2018] [Indexed: 12/29/2022] Open
Abstract
Malignant pleural mesothelioma is an aggressive cancer with poor prognosis. Here we have investigated in vitro efficacy of BAMLET and BLAGLET complexes (anti-cancer complexes consisting of oleic acid and bovine α-lactalbumin or β-lactoglobulin respectively) in killing mesothelioma cells, determined BAMLET and BLAGLET structures, and investigated possible biological mechanisms. We performed cell viability assays on 16 mesothelioma cell lines. BAMLET and BLAGLET having increasing oleic acid content inhibited human and rat mesothelioma cell line proliferation at decreasing doses. Most of the non-cancer primary human fibroblasts were more resistant to BAMLET than were human mesothelioma cells. BAMLET showed similar cytotoxicity to cisplatin-resistant, pemetrexed-resistant, vinorelbine-resistant, and parental rat mesothelioma cells, indicating the BAMLET anti-cancer mechanism may be different to drugs currently used to treat mesothelioma. Cisplatin, pemetrexed, gemcitabine, vinorelbine, and BAMLET, did not demonstrate a therapeutic window for mesothelioma compared with immortalised non-cancer mesothelial cells. We demonstrated by quantitative PCR that ATP synthase is downregulated in mesothelioma cells in response to regular dosing with BAMLET. We sought structural insight for BAMLET and BLAGLET activity by performing small angle X-ray scattering, circular dichroism, and scanning electron microscopy. Our results indicate the structural mechanism by which BAMLET and BLAGLET achieve increased cytotoxicity by holding increasing amounts of oleic acid in an active cytotoxic state encapsulated in increasingly unfolded protein. Our structural studies revealed similarity in the molecular structure of the protein components of these two complexes and in their encapsulation of the fatty acid, and differences in the microscopic structure and structural stability. BAMLET forms rounded aggregates and BLAGLET forms long fibre-like aggregates whose aggregation is more stable than that of BAMLET due to intermolecular disulphide bonds. The results reported here indicate that BAMLET and BLAGLET may be effective second-line treatment options for mesothelioma.
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Affiliation(s)
- Emma M. Rath
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
| | - Yuen Yee Cheng
- Asbestos Diseases Research Institute (ADRI), Concord, NSW, Australia
- University of Sydney, Sydney, NSW, Australia
| | - Mark Pinese
- Kinghorn Cancer Centre and Garvan Institute of Medical Research, Sydney, NSW, Australia
| | - Kadir H. Sarun
- Asbestos Diseases Research Institute (ADRI), Concord, NSW, Australia
| | - Amanda L. Hudson
- Bill Walsh Translational Cancer Research Laboratory, Kolling Institute, University of Sydney, Sydney, NSW, Australia
| | - Christopher Weir
- Northern Blood Research Centre, Kolling Institute, University of Sydney, Sydney, NSW, Australia
| | - Yiwei D. Wang
- Burns Research, ANZAC Research Institute, Concord Hospital, University of Sydney, Concord, NSW, Australia
| | | | - Viive M. Howell
- Bill Walsh Translational Cancer Research Laboratory, Kolling Institute, University of Sydney, Sydney, NSW, Australia
| | - Guo Jun Liu
- Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Rd, Lucas Heights, NSW, Australia
- Brain and Mind Centre and Faculty of Health Sciences, University of Sydney, Sydney, NSW, Australia
| | - Glen Reid
- Asbestos Diseases Research Institute (ADRI), Concord, NSW, Australia
- University of Sydney, Sydney, NSW, Australia
| | - Robert B. Knott
- Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Rd, Lucas Heights, NSW, Australia
| | - Anthony P. Duff
- Australian Nuclear Science and Technology Organisation (ANSTO), New Illawarra Rd, Lucas Heights, NSW, Australia
| | - W. Bret Church
- Faculty of Pharmacy, University of Sydney, Sydney, NSW, Australia
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Park Y, Kim Y, Park Y, Jin S, Hwang H, Jung YM. Formation mechanism of α-lactalabumin/oleic acid complex characterized by 2D correlation analysis. SPECTROCHIMICA ACTA. PART A, MOLECULAR AND BIOMOLECULAR SPECTROSCOPY 2017; 185:93-97. [PMID: 28549296 DOI: 10.1016/j.saa.2017.05.028] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2017] [Accepted: 05/14/2017] [Indexed: 06/07/2023]
Abstract
Partially unfolded α-lactalbumin (ALA) forms a complex with oleic acid (OA) that exhibits cytotoxic activity. In this study, for the first time, the pH-induced formation mechanism for ALA/OA complexes with two different molar ratios was investigated at the molecular level. For a deeper understanding of the formation mechanism of the two different ALA/OA complexes with decreasing pH, principal component analysis (PCA) and two-dimensional (2D) correlation spectroscopy were used to examine the pH-dependent IR spectra of ALA/OA complexes. By tracking the secondary structural variations in the ALA/OA complexes with decreasing pH, we successfully elucidated the formation mechanism of the ALA/OA complexes at the molecular level. The results showed that the secondary structures of theses complexes exhibited the greatest change between pH4 and pH3.5 and that the components that mainly contributed to the pH-induced transition from the N-state to the A-state were dissimilar in the two different ALA/OA complexes.
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Affiliation(s)
- Yeonju Park
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Yeseul Kim
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Yujeong Park
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Sila Jin
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Hoon Hwang
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea
| | - Young Mee Jung
- Department of Chemistry, Institute for Molecular Science and Fusion Technology, Kangwon National University, Chuncheon 24341, Republic of Korea.
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Woods KN, Pfeffer J. Using THz Spectroscopy, Evolutionary Network Analysis Methods, and MD Simulation to Map the Evolution of Allosteric Communication Pathways in c-Type Lysozymes. Mol Biol Evol 2016; 33:40-61. [PMID: 26337549 PMCID: PMC4693973 DOI: 10.1093/molbev/msv178] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
It is now widely accepted that protein function is intimately tied with the navigation of energy landscapes. In this framework, a protein sequence is not described by a distinct structure but rather by an ensemble of conformations. And it is through this ensemble that evolution is able to modify a protein's function by altering its landscape. Hence, the evolution of protein functions involves selective pressures that adjust the sampling of the conformational states. In this work, we focus on elucidating the evolutionary pathway that shaped the function of individual proteins that make-up the mammalian c-type lysozyme subfamily. Using both experimental and computational methods, we map out specific intermolecular interactions that direct the sampling of conformational states and accordingly, also underlie shifts in the landscape that are directly connected with the formation of novel protein functions. By contrasting three representative proteins in the family we identify molecular mechanisms that are associated with the selectivity of enhanced antimicrobial properties and consequently, divergent protein function. Namely, we link the extent of localized fluctuations involving the loop separating helices A and B with shifts in the equilibrium of the ensemble of conformational states that mediate interdomain coupling and concurrently moderate substrate binding affinity. This work reveals unique insights into the molecular level mechanisms that promote the progression of interactions that connect the immune response to infection with the nutritional properties of lactation, while also providing a deeper understanding about how evolving energy landscapes may define present-day protein function.
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Mahanta S, Paul S. Bovine α-lactalbumin functionalized graphene oxide nano-sheet exhibits enhanced biocompatibility: A rational strategy for graphene-based targeted cancer therapy. Colloids Surf B Biointerfaces 2015. [PMID: 26196090 DOI: 10.1016/j.colsurfb.2015.06.061] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Graphene oxide nanosheet (GOns) with sharp edges was synthesized using controlled pyrolysis of citric acid. Scanning electron, as well as atomic force microscopy of the sample confirmed the formation of multilayered GOns with an average sheet length of 150 nm. X-ray diffraction pattern and Raman spectra also confirmed the formation of GOns. Furthermore, GOns was successfully functionalized (FGOns) by cross-linking with a small protein bovine α-lactalbumin (BLA). The crosslinking of protein with GOns in FGOns was confirmed by infrared spectroscopy, and the conformational change of BLA was observed by fluorescence, as well as circular dichroism spectroscopy. When applied to human erythrocytes, GOns demonstrated profound hemolysis; however, such hemolytic effect was drastically reduced by FGOns. To evaluate the potential biomedical application of FGOns, the cytotoxicity of the sample was also assessed. The administration of both GOns and FGOns in breast cancer cells MCF-7 and MDAMB-231 demonstrated more than 88% cell death within 24 h and such cytotoxicity against cancer cells was caused due to the generation of reactive oxygen species (ROS), as revealed from the N-acetyl-L-cysteine (NAC, a ROS-inhibitor)-based assay. FGOns demonstrated excellent biocompatibility against normal cells such as HaCaT and 3T3 compared to GOns that demonstrated dose-dependent toxicity. Moreover, FGOns demonstrated more efficient cellular uptake than GOns by cancer cells. Therefore, our present study demonstrated that the functionalization of GOns using small protein could improve its biocompatibility multifold and such strategy might represent wide opportunity to use GO like nanomaterial safely in various biomedical applications.
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Affiliation(s)
- Sailendra Mahanta
- Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela 769008, Odisha, India
| | - Subhankar Paul
- Structural Biology and Nanomedicine Laboratory, Department of Biotechnology and Medical Engineering, National Institute of Technology, Rourkela 769008, Odisha, India.
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Nemashkalova EL, Kazakov AS, Khasanova LM, Permyakov EA, Permyakov SE. Structural characterization of more potent alternatives to HAMLET, a tumoricidal complex of α-lactalbumin and oleic acid. Biochemistry 2013; 52:6286-99. [PMID: 23947814 DOI: 10.1021/bi400643s] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
HAMLET is a complex of human α-lactalbumin (hLA) with oleic acid (OA) that kills various tumor cells and strains of Streptococcus pneumoniae. More potent protein-OA complexes were previously reported for bovine α-lactalbumin (bLA) and β-lactoglobulin (bLG), and pike parvalbumin (pPA), and here we explore their structural features. The concentration dependencies of the tryptophan fluorescence of hLA, bLA, and bLG complexes with OA reveal their disintegration at protein concentrations below the micromolar level. Chemical cross-linking experiments provide evidence that association with OA shifts the distribution of oligomeric forms of hLA, bLA, bLG, and pPA toward higher-order oligomers. This effect is confirmed for bLA and bLG using the dynamic light scattering method, while pPA is shown to associate with OA vesicles. Like hLA binding, OA binding increases the affinity of bLG for small unilamellar dipalmitoylphosphatidylcholine vesicles, while pPA efficiently binds to the vesicles irrespective of OA binding. The association of OA with bLG and pPA increases their α-helix and cross-β-sheet content and resistance to enzymatic proteolysis, which is indicative of OA-induced protein structuring. The lack of excess heat sorption during melting of bLG and pPA in complex with OA and the presence of a cooperative thermal transition at the level of their secondary structure suggest that the OA-bound forms of bLG and pPA lack a fixed tertiary structure but exhibit a continuous thermal transition. Overall, despite marked differences, the HAMLET-like complexes that were studied exhibit a common feature: a tendency toward protein oligomerization. Because OA-induced oligomerization has been reported for other proteins, this phenomenon is inherent to many proteins.
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Affiliation(s)
- Ekaterina L Nemashkalova
- Institute for Biological Instrumentation of the Russian Academy of Sciences , Pushchino, Moscow region 142290, Russia
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The biological activities of protein/oleic acid complexes reside in the fatty acid. BIOCHIMICA ET BIOPHYSICA ACTA-PROTEINS AND PROTEOMICS 2013; 1834:1125-43. [DOI: 10.1016/j.bbapap.2013.02.041] [Citation(s) in RCA: 70] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Revised: 02/18/2013] [Accepted: 02/20/2013] [Indexed: 12/12/2022]
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Zhang YB, Gong JL, Xing TY, Zheng SP, Ding W. Autophagy protein p62/SQSTM1 is involved in HAMLET-induced cell death by modulating apotosis in U87MG cells. Cell Death Dis 2013; 4:e550. [PMID: 23519119 PMCID: PMC3615731 DOI: 10.1038/cddis.2013.77] [Citation(s) in RCA: 84] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
HAMLET is a complex of oleic acids and decalcified α-lactalbumin that was discovered to selectively kill tumor cells both in vitro and in vivo. Autophagy is an important cellular process involved in drug-induced cell death of glioma cells. We treated U87MG human glioma cells with HAMLET and found that the cell viability was significantly decreased and accompanied with the activation of autophagy. Interestingly, we observed an increase in p62/SQSTM1, an important substrate of autophagosome enzymes, at the protein level upon HAMLET treatment for short periods. To better understand the functionality of autophagy and p62/SQSTM1 in HAMLET-induced cell death, we modulated the level of autophagy or p62/SQSTM1 with biochemical or genetic methods. The results showed that inhibition of autophagy aggravated HAMLET-induced cell death, whereas activation of authophagy attenuated this process. Meanwhile, we found that overexpression of wild-type p62/SQSTM1 was able to activate caspase-8, and then promote HAMLET-induced apoptosis, whereas knockdown of p62/SQSTM1 manifested the opposite effect. We further demonstrated that the function of p62/SQSTM1 following HAMLET treatment required its C-terminus UBA domain. Our results indicated that in addition to being a marker of autophagy activation in HAMLET-treated glioma cells, p62/SQSTM1 could also function as an important mediator for the activation of caspase-8-dependent cell death.
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Affiliation(s)
- Y-B Zhang
- Department of Biochemistry and Molecular Biology, School of Basic Medical Sciences, Capital Medical University, Beijing, China
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Brinkmann CR, Thiel S, Otzen DE. Protein-fatty acid complexes: biochemistry, biophysics and function. FEBS J 2013; 280:1733-49. [DOI: 10.1111/febs.12204] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2012] [Revised: 11/29/2012] [Accepted: 02/12/2013] [Indexed: 02/01/2023]
Affiliation(s)
| | - Steffen Thiel
- Department of Biomedicine, Faculty of Health Sciences; Aarhus University; Denmark
| | - Daniel E. Otzen
- Interdisciplinary Nanoscience Centre (iNANO), Centre for Insoluble Protein Structures (inSPIN), Department of Molecular Biology and Genetics; Aarhus University; Denmark
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Roth-Walter F, Starkl P, Zuberbier T, Hummel K, Nöbauer K, Razzazi-Fazeli E, Brunner R, Pali-Schöll I, Kinkel J, Felix F, Jensen-Jarolim E, Kinaciyan T. Glutathione exposes sequential IgE-epitopes in ovomucoid relevant in persistent egg allergy. Mol Nutr Food Res 2013; 57:536-44. [PMID: 23349099 DOI: 10.1002/mnfr.201200612] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2012] [Revised: 10/30/2012] [Accepted: 11/13/2012] [Indexed: 11/06/2022]
Abstract
SCOPE Patients with persistent egg allergy have more immunoglobulin E (IgE) against sequential than conformational epitopes of ovomucoid (OVO). Here, we aimed to identify compounds capable to render sequential epitopes in egg. METHODS AND RESULTS Glutathione was used for in vitro reduction of OVO and circular dichroism analyses were performed. Glutathione reduced OVO in a concentration-dependent manner. Egg white was analyzed for reduced proteins with a thiol probe and by MALDI-TOF/TOF. In unprocessed total egg white, several reduced proteins were detected by the thiol probe, among them reduced ovalbumin could be confirmed with MS analyses. Egg-allergics or sensitized controls were tested serologically (n = 19) for IgE against native and reduced OVO and in skin prick tests (n = 9). More patients had IgE against reduced than native OVO in Western blots. In skin prick test, five out of seven persistent egg-allergics and none of the controls reacted with reduced OVO. CONCLUSION Reduced egg proteins are present in natural egg white. Glutathione, which is present in egg and furthermore is used as texture-improving additive in processed food, is capable of reducing OVO. Patients with persistent egg allergy reacted rather to reduce the native OVO. Hence, our data indicate that reduction is a novel natural and processing-associated principle, which contributes to the allergenicity of food.
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Affiliation(s)
- Franziska Roth-Walter
- Comparative Medicine, Messerli Research Institute, University of Veterinary Medicine Vienna, Vienna, Medical University of Vienna and University of Vienna, Austria
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Ramakrishnan B, Qasba PK. In vitro folding of β-1,4galactosyltransferase and polypeptide-α-N-acetylgalactosaminyltransferase from the inclusion bodies. Methods Mol Biol 2013; 1022:321-33. [PMID: 23765672 DOI: 10.1007/978-1-62703-465-4_24] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The aim of this article is to present a unique in vitro folding technique for glycosyltransferases to generate active proteins that can be used for X-ray crystallographic and bioconjugation protocols. Although a number of in vitro refolding methods are available, β1,4galactosyltransferases in large quantities can be made using the current protocol only. This technique is not only limited to glycosyltransferases alone but has been successfully used to refold single-chain antibodies and other molecules. Although this in vitro folding method is quite similar to other methods, it differs from them by the use of S-sulfonation of the inclusion bodies before setting up the in vitro refolding of the protein.
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Affiliation(s)
- Boopathy Ramakrishnan
- Structural Glycobiology Section and Basic Science Program, SAIC-Frederick, Inc., Center for Cancer Research Nanobiology Program, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, MD, USA
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14
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pH- and heat-induced structural changes of bovine α-lactalbumin in response to oleic acid binding. Eur Food Res Technol 2012. [DOI: 10.1007/s00217-012-1882-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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