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Reductive Stress of Sulfur-Containing Amino Acids within Proteins and Implication of Tandem Protein-Lipid Damage. Int J Mol Sci 2021; 22:ijms222312863. [PMID: 34884668 PMCID: PMC8657892 DOI: 10.3390/ijms222312863] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 11/25/2021] [Accepted: 11/26/2021] [Indexed: 12/23/2022] Open
Abstract
Reductive radical stress represents the other side of the redox spectrum, less studied but equally important compared to oxidative stress. The reactivity of hydrogen atoms (H•) and hydrated electrons (e-aq) connected with peptides/proteins is summarized, focusing on the chemical transformations of methionine (Met) and cystine (CysS-SCys) residues into α-aminobutyric acid and alanine, respectively. Chemical and mechanistic aspects of desulfurization processes with formation of diffusible sulfur-centered radicals, such as methanethiyl (CH3S•) and sulfhydryl (HS•) radicals, are discussed. These findings are further applied to biomimetic radical chemistry, modeling the occurrence of tandem protein-lipid damages in proteo-liposomes and demonstrating that generation of sulfur-centered radicals from a variety of proteins is coupled with the cis-trans isomerization of unsaturated lipids in membranes. Recent applications to pharmaceutical and pharmacological contexts are described, evidencing novel perspectives in the stability of formulations and mode of action of drugs, respectively.
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2
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Visual and ratiometric fluorescent determination of Al3+ by a red-emission carbon dot-quercetin system. Microchem J 2020. [DOI: 10.1016/j.microc.2020.104807] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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3
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Torreggiani A, Tinti A, Jurasekova Z, Capdevila M, Saracino M, Di Foggia M. Structural Lesions of Proteins Connected to Lipid Membrane Damages Caused by Radical Stress: Assessment by Biomimetic Systems and Raman Spectroscopy. Biomolecules 2019; 9:E794. [PMID: 31783702 PMCID: PMC6995617 DOI: 10.3390/biom9120794] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 11/25/2019] [Accepted: 11/27/2019] [Indexed: 12/16/2022] Open
Abstract
Model systems constituted by proteins and unsaturated lipid vesicles were used to gain more insight into the effects of the propagation of an initial radical damage on protein to the lipid compartment. The latter is based on liposome technology and allows measuring the trans unsaturated fatty acid content as a result of free radical stress on proteins. Two kinds of sulfur-containing proteins were chosen to connect their chemical reactivity with membrane lipid transformation, serum albumins and metallothioneins. Biomimetic systems based on radiation chemistry were used to mimic the protein exposure to different kinds of free radical stress and Raman spectroscopy to shed light on protein structural changes caused by the free radical attack. Among the amino acid residues, Cys is one of the most sensitive residues towards the attack of free radicals, thus suggesting that metal-Cys clusters are good interceptors of reactive species in metallothioneins, together with disulfides moieties in serum albumins. Met is another important site of the attack, in particular under reductive conditions. Tyr and Phe are sensitive to radical stress too, leading to electron transfer reactions or radical-induced modifications of their structures. Finally, modifications in protein folding take place depending on reactive species attacking the protein.
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Affiliation(s)
| | - Anna Tinti
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, via Belmeloro 8/2, 40126 Bologna, Italy; (A.T.); (M.D.F.)
| | - Zuzana Jurasekova
- Department of Biophysics, Faculty of Science, P.J. Safarik University, Jesenna 5, 04001 Kosice, Slovakia;
- Center for Interdisciplinary Biosciences, Technology and Innovation Park, P. J. Safarik University, Jesenna 5, 04001 Kosice, Slovakia
| | - Mercè Capdevila
- Departament de Quimica, Facultat de ciencies, Universitat Autònoma de Barcelona, 08193 Bellaterra, Catalonia, Spain;
| | - Michela Saracino
- Istituto I.S.O.F. (C.N.R.), via P. Gobetti 101, 40129 Bologna, Italy;
| | - Michele Di Foggia
- Dipartimento di Scienze Biomediche e Neuromotorie, Università di Bologna, via Belmeloro 8/2, 40126 Bologna, Italy; (A.T.); (M.D.F.)
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Tian KZ, Cao CC, Nie XM, Wang W, Han CQ. Sensitive and label-free detection of protein secondary structure by amide III spectral signals using surface-enhanced Raman spectroscopy. CHINESE J CHEM PHYS 2019. [DOI: 10.1063/1674-0068/cjcp1811267] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Affiliation(s)
- Kang-zhen Tian
- Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Chang-chun Cao
- The 95979 Army of Chinese People’s Liberation Army, Taian 271200, China
| | - Xin-ming Nie
- Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Wen Wang
- Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Cai-qin Han
- Jiangsu Key Laboratory of Advanced Laser Materials and Devices, School of Physics and Electronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
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Wu Y, Wang X, Wang Z, Yan F, Zu F, Zhang H. A novel method for measuring cake porosity by ions detection technique in a conventional coagulation-ultrafiltration process. Sep Purif Technol 2019. [DOI: 10.1016/j.seppur.2019.03.061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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6
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Mohammad MA, Grimsey IM, Forbes RT, Blagbrough IS, Conway BR. Effect of mechanical denaturation on surface free energy of protein powders. Colloids Surf B Biointerfaces 2016; 146:700-6. [DOI: 10.1016/j.colsurfb.2016.07.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2016] [Revised: 06/09/2016] [Accepted: 07/04/2016] [Indexed: 12/12/2022]
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7
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Hung WL, Sun Hwang L, Shahidi F, Pan MH, Wang Y, Ho CT. Endogenous formation of trans fatty acids: Health implications and potential dietary intervention. J Funct Foods 2016. [DOI: 10.1016/j.jff.2016.05.006] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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8
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Mohammad MA, Grimsey IM, Forbes RT. Equation to Line the Borders of the Folding-Unfolding Transition Diagram of Lysozyme. J Phys Chem B 2016; 120:6911-6. [PMID: 27341101 DOI: 10.1021/acs.jpcb.6b01317] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
It is important for the formulators of biopharmaceuticals to predict the folding-unfolding transition of proteins. This enables them to process proteins under predetermined conditions, without denaturation. Depending on the apparent denaturation temperature (Tm) of lysozyme, we have derived an equation describing its folding-unfolding transition diagram. According to the water content and temperature, this diagram was divided into three different areas, namely, the area of the water-folded lysozyme phase, the area of the water-folded lysozyme phase and the bulk water phase, and the area of the denatured lysozyme phase. The water content controlled the appearance and intensity of the Raman band at ∼1787 cm(-1) when lysozyme powders were thermally denatured at temperatures higher than Tm.
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Affiliation(s)
- Mohammad Amin Mohammad
- Drug Delivery Group, School of Pharmacy, University of Bradford , Bradford, West Yorkshire BD7 1DP, U.K.,Department of Pharmaceutics, Faculty of Pharmacy, University of Damascus , Damascus, Syria
| | - Ian M Grimsey
- Drug Delivery Group, School of Pharmacy, University of Bradford , Bradford, West Yorkshire BD7 1DP, U.K
| | - Robert T Forbes
- Drug Delivery Group, School of Pharmacy, University of Bradford , Bradford, West Yorkshire BD7 1DP, U.K.,School of Pharmacy and Biological Sciences, University of Central Lancashire , Preston, Lancashire PR12HE, U.K
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9
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Mohammad MA, Grimsey IM, Forbes RT. Mapping the solid-state properties of crystalline lysozyme during pharmaceutical unit-operations. J Pharm Biomed Anal 2015; 114:176-83. [DOI: 10.1016/j.jpba.2015.05.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2015] [Revised: 05/11/2015] [Accepted: 05/13/2015] [Indexed: 11/28/2022]
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10
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Harder SJ, Matthews Q, Isabelle M, Brolo AG, Lum JJ, Jirasek A. A Raman spectroscopic study of cell response to clinical doses of ionizing radiation. APPLIED SPECTROSCOPY 2015; 69:193-204. [PMID: 25588147 DOI: 10.1366/14-07561] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
The drive toward personalized radiation therapy (RT) has created significant interest in determining patient-specific tumor and normal tissue responses to radiation. Raman spectroscopy (RS) is a non-invasive and label-free technique that can detect radiation response through assessment of radiation-induced biochemical changes in tumor cells. In the current study, single-cell RS identified specific radiation-induced responses in four human epithelial tumor cell lines: lung (H460), breast (MCF-7, MDA-MB-231), and prostate (LNCaP), following exposure to clinical doses of radiation (2-10 Gy). At low radiation doses (2 Gy), H460 and MCF-7 cell lines showed an increase in glycogen-related spectral features, and the LNCaP cell line showed a membrane phospholipid-related radiation response. In these cell lines, only spectral information from populations receiving 10 Gy or less was required to identify radiation-related features using principal component analysis (PCA). In contrast, the MDA-MB-231 cell line showed a significant increase in protein relative to nucleic acid and lipid spectral features at doses of 6 Gy or higher, and high-dose information (30, 50 Gy) was required for PCA to identify this biological response. The biochemical nature of the radiation-related changes occurring in cells exposed to clinical doses was found to segregate by status of p53 and radiation sensitivity. Furthermore, the utility of RS to identify a biological response in human tumor cells exposed to therapeutic doses of radiation was found to be governed by the extent of the biochemical changes induced by a radiation response and is therefore cell line specific. The results of this study demonstrate the utility and effectiveness of single-cell RS to identify and measure biological responses in tumor cells exposed to standard radiotherapy doses.
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Affiliation(s)
- Samantha J Harder
- University of Victoria, Department of Physics and Astronomy, PO Box 1700 STN CSC, Victoria, British Columbia V8W 2Y2, Canada
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11
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Navarra G, Tinti A, Di Foggia M, Leone M, Militello V, Torreggiani A. Metal ions modulate thermal aggregation of beta-lactoglobulin: A joint chemical and physical characterization. J Inorg Biochem 2014; 137:64-73. [DOI: 10.1016/j.jinorgbio.2014.04.003] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2014] [Revised: 04/02/2014] [Accepted: 04/02/2014] [Indexed: 10/25/2022]
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12
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Chatgilialoglu C, Ferreri C, Melchiorre M, Sansone A, Torreggiani A. Lipid geometrical isomerism: from chemistry to biology and diagnostics. Chem Rev 2013; 114:255-84. [PMID: 24050531 DOI: 10.1021/cr4002287] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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13
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Kocherbitov V, Latynis J, Misiu̅nas A, Barauskas J, Niaura G. Hydration of Lysozyme Studied by Raman Spectroscopy. J Phys Chem B 2013; 117:4981-92. [DOI: 10.1021/jp4017954] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vitaly Kocherbitov
- Biomedical Science, Faculty
of Health and Society, Malmö University, SE-20506 Malmö, Sweden
| | - Jekaterina Latynis
- Institute of Biochemistry, Vilnius University, Mokslininkų 12, LT-08662
Vilnius, Lithuania
| | - Audrius Misiu̅nas
- Institute of Biochemistry, Vilnius University, Mokslininkų 12, LT-08662
Vilnius, Lithuania
- Institute
of Chemistry, Center
for Physical Sciences and Technology, Goštauto 9, LT-01108
Vilnius, Lithuania
| | - Justas Barauskas
- Biomedical Science, Faculty
of Health and Society, Malmö University, SE-20506 Malmö, Sweden
- Institute of Biochemistry, Vilnius University, Mokslininkų 12, LT-08662
Vilnius, Lithuania
| | - Gediminas Niaura
- Institute of Biochemistry, Vilnius University, Mokslininkų 12, LT-08662
Vilnius, Lithuania
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Non-enzymatic modifications in metallothioneins connected to lipid membrane damages: structural and biomimetic studies under reductive radical stress. J Proteomics 2013; 92:204-15. [PMID: 23542714 DOI: 10.1016/j.jprot.2013.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2013] [Revised: 02/08/2013] [Accepted: 02/10/2013] [Indexed: 11/20/2022]
Abstract
UNLABELLED Metallothioneins (MTs) are small cysteine-rich proteins with the ability to coordinate heavy metal atoms through metal-thiolate bonds, which are widely distributed among the animal and plant kingdoms. Multifunctional roles for MTs have been proposed, including their ability to scavenger various radicals and reactive oxygen species. In the present article we summarize available information of four MT polypeptides from different organisms, forming metal complexes with Zn(II), Cd(II) or Cu (I) ions. Non-enzymatic modifications of MTs under ionizing radiations and their consequences on the lipidic membrane compartment were studied by Raman spectroscopy and a biomimetic model, respectively. The latter is based on liposome technology and allows to measure the trans unsaturated fatty acid content as a result of reductive radical stress on MTs. BIOLOGICAL SIGNIFICANCE The effect of radical stress on the cell metabolism and functions is a very active field of research connecting various disciplines in life sciences. In this contest tandem radical damage has been the subject of recent investigations that pointed out its harmfulness in the general scenario of establishing the consequences of radical stress. By using biomimetic models of tandem damage we have for the first time tested the capability of metallothioneins (MTs), small metalloproteins rich of Cys residues, to damage another cell compartment like lipid membranes when they are undergone to reductive radical stress. The connection of MT reactivity with membrane lipid transformation can give a contribution to the puzzling context of radical stress occurring to biomolecules and the role as biological signaling. To this purpose, MT polypeptides from different organisms, exhibiting different sequence peculiarities, have been analyzed here. The spectroscopic analysis of these systems has allowed to identify modifications affecting metal-thiolate clusters, cystines, and Met residues, acting as efficient interceptors of reducing radical species. The chemical mechanism involving sulfur-containing moieties under reductive conditions discloses new scenarios that bring to the loss of sulfur-centered radicals by desulfurization reactions that change the natural sequences of MTs. Ala is a genetically coded amino acid, therefore the mutation of Cys to Ala occurring to a sequence by the radical process so far discussed, corresponds to a post-translational modification. Research on such mutation connected also to a free radical stress will be important to contribute for a complete picture of the degeneration associated to diseases and aging. Analogously, the Met to Aba mutation occurring after reductive stress transforms a natural amino acid into a natural, non-genetically-coded congener. Aba corresponds to a homologation of the alkyl chains normally present in genetically codified amino acids, such as methyl (in Ala) and isopropyl (in Leu), with an ethyl unit. Based on alkyl substitution, this modification can therefore be studied in order to understand its general consequences on the structure-activity relationships in proteins and, in particular, on molecular interactions. This article is part of a Special issue entitled: Posttranslational Protein modifications in biology and Medicine.
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15
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Zhu M, Chen X, Wang Z, Chen Y, Ma D, Peng H, Zhang J. Structural and optical characteristics of silicon nanowires fabricated by wet chemical etching. Chem Phys Lett 2011. [DOI: 10.1016/j.cplett.2011.06.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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16
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Use of Raman spectroscopy for the identification of radical-mediated damages in human serum albumin. Anal Bioanal Chem 2011; 400:2921-31. [PMID: 21494773 DOI: 10.1007/s00216-011-4970-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Revised: 03/26/2011] [Accepted: 03/28/2011] [Indexed: 01/14/2023]
Abstract
Damages induced by free radicals on human serum albumin (HSA), the most prominent protein in plasma, were investigated by Raman spectroscopy. HSA underwent oxidative and reductive radical stress. Gamma-irradiation was used to simulate the endogenous formation of reactive radical species such as hydrogen atoms ((•)H), solvated electrons (e(aq)(-)) and hydroxyl radicals ((•)OH). Raman spectroscopy was shown to be a useful tool in identifying conformational changes of the protein structure and specific damages occurring at sensitive amino acid sites. In particular, the analysis of the S-S stretching region suggested the radical species caused modifications in the 17 disulphide bridges of HSA. The concomitant action of e(aq)(-) and (•)H atoms caused the formation of cyclic disulphide bridges, showing how cystine pairs act as efficient interceptors of reducing species, by direct scavenging and electron transfer reactions within the protein. This conclusion was further confirmed by the modifications visible in the Raman bands due to Phe and Tyr residues. As regards to protein folding, both oxidative and reductive radical stresses were able to cause a loss in α-helix content, although the latter remains the most abundant secondary structure component. β-turns motifs significantly increased as a consequence of the synergic action of e(aq)(-) and (•)H atoms, whereas a larger increase in the β-sheet content was found following the exposure to (•)OH and/or (•)H attack.
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17
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Salzano AM, Renzone G, Scaloni A, Torreggiani A, Ferreri C, Chatgilialoglu C. Human serum albumin modifications associated with reductive radical stress. ACTA ACUST UNITED AC 2011; 7:889-98. [DOI: 10.1039/c0mb00223b] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
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18
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Zhao W, Yang R. Experimental Study on Conformational Changes of Lysozyme in Solution Induced by Pulsed Electric Field and Thermal Stresses. J Phys Chem B 2009; 114:503-10. [DOI: 10.1021/jp9081189] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Wei Zhao
- State Key Laboratory of Food Science & Technology and School of Food Science and Technology, Jiangnan University, No. 1800 Lihu Road, Wuxi 214122, China
| | - Ruijin Yang
- State Key Laboratory of Food Science & Technology and School of Food Science and Technology, Jiangnan University, No. 1800 Lihu Road, Wuxi 214122, China
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Torreggiani A, Domènech J, Orihuela R, Ferreri C, Atrian S, Capdevila M, Chatgilialoglu C. Zinc and Cadmium Complexes of a Plant Metallothionein under Radical Stress: Desulfurisation Reactions Associated with the Formation oftrans-Lipids in Model Membranes. Chemistry 2009; 15:6015-24. [PMID: 19418517 DOI: 10.1002/chem.200802533] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Affiliation(s)
- Armida Torreggiani
- ISOF, Consiglio Nazionale delle Ricerche, Via P. Gobetti 101, 40129 Bologna, Italy.
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20
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The effect of pulsed electric fields on the inactivation and structure of lysozyme. Food Chem 2008; 110:334-43. [DOI: 10.1016/j.foodchem.2008.02.008] [Citation(s) in RCA: 64] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2007] [Revised: 12/27/2007] [Accepted: 02/04/2008] [Indexed: 11/22/2022]
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21
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Zhao W, Yang R. Comparative study of inactivation and conformational change of lysozyme induced by pulsed electric fields and heat. Eur Food Res Technol 2008. [DOI: 10.1007/s00217-008-0905-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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22
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Basar N, Uzun L, Güner A, Denizli A. Spectral characterization of lysozyme adsorption on dye-affinity beads. J Appl Polym Sci 2008. [DOI: 10.1002/app.27972] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Lin CC, Sawicki SM, Metters AT. Free-radical-mediated protein inactivation and recovery during protein photoencapsulation. Biomacromolecules 2007; 9:75-83. [PMID: 18088094 DOI: 10.1021/bm700782c] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Photoencapsulation of protein therapeutics is very attractive for preparing biomolecule-loaded hydrogels for a variety of biomedical applications. However, detrimental effects of highly active radical species generated during photoencapsulation must be carefully evaluated to maintain efficient hydrogel cross-linking while preserving the structure and bioactivity of encapsulated biomolecules. Here, we examine the free-radical-mediated inactivation and incomplete release of proteins from photocurable hydrogels utilizing lysozyme as a conservative model system. Various protein photoencapsulation conditions were tested to determine the factors affecting lysozyme structural integrity and bioactivity. It was found that a portion of the lysozyme becomes conjugated to polymer chains at high photoinitiator concentrations and long polymerization times. We also found that the more hydrophilic photoinitiator Irgacure-2959 (I-2959, 2-hydroxy-1-[4-(hydroxyethoxy)phenyl]-2-methyl-1-propanone) causes more damage to lysozyme compared to the hydrophobic photoinitiator Irgacure-651 (I-651, 2,2-dimethoxy-2-phenylacetophenone), even though I-2959 has been previously shown to be more cytocompatible. Furthermore, while nonacrylated PEG provides only limited protection from the denaturing free radicals that are present during hydrogel curing, acrylated PEG macromers effectively preserve lysozyme structural integrity and bioactivity in the presence of either photoinitiator. Overall, these findings indicate how photopolymerization conditions (e.g., photoinitiator type and concentration, UV exposure time, etc.) must be optimized to obtain a functional hydrogel device that can preserve protein bioactivity and provide maximal protein release.
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Affiliation(s)
- Chien-Chi Lin
- Department of Bioengineering, Clemson University, Clemson, South Carolina, USA
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Zhao W, Yang R, Lu R, Tang Y, Zhang W. Investigation of the mechanisms of pulsed electric fields on inactivation of enzyme: lysozyme. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2007; 55:9850-9858. [PMID: 17956144 DOI: 10.1021/jf072186s] [Citation(s) in RCA: 47] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
Lysozyme was selected as a model enzyme to investigate the effects of pulsed electric fields (PEF) on its activity and structure. The irreversible inactivation of lysozyme in sodium phosphate buffer (10 mM, pH 6.2) induced by PEF at 35 kV/cm followed a first-order model when the treatment time was longer than 300 micros. Unfolding of lysozyme structure was induced by PEF, accompanied by the cleavage of disulfide bonds and self-association aggregation when the applied PEF dosage was higher than a critical level. The inactivation of lysozyme by PEF was correlated to the loss of alpha-helix in secondary structure. The relative residual activity of PEF-treated lysozyme was in close agreement with the relative molar ellipticity at 208 nm. Both PEF- and heat-induced inactivations of lysozyme were correlated to the alteration of the secondary structure of lysozyme, but the effects of PEF and heat treatment on secondary structure were inconsistent.
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Affiliation(s)
- Wei Zhao
- State Key Laboratory of Food Science, Jiangnan University (Southern Yangtze University), Wuxi, China
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Ferreri C, Panagiotaki M, Chatgilialoglu C. Trans Fatty Acids in Membranes: The Free Radical Path. Mol Biotechnol 2007; 37:19-25. [PMID: 17914159 DOI: 10.1007/s12033-007-0054-9] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 11/24/2022]
Abstract
The double bond geometry of most of the naturally occurring unsaturated fatty acid residues is cis. Due to the relevance of fatty acids as structural components of cell membranes and as biologically active molecules, the change of the cis geometry means a change of the associated functions and activities. The finding that the cis to trans isomerization is effective in phospholipids by the intervention of radical species led to the discovery that there can indeed occur an endogenous formation of trans fatty acids, whose significance in biological systems started to be addressed with in vitro and in vivo studies. Studies of liposome models simulating the formation of isomerizing species and evaluating their ability to interact with the hydrophobic part of the membrane bilayer has contributed to the gain in knowledge of the fundamental features of the lipid isomerization in membranes. Further work is in progress for the identification of the real culprits of the in vivo lipid isomerization, and recent results are shown on oleic acid micelles, where *NO2 radicals are not able to induce double bond isomerization in comparison with amphiphilic thiol, such as 2-mercaptoethanol. H2S and sulfur-containing amino acid residues are two of the possible species involved in this process at a biological level. An update of the scenario of the geometrical isomerization in membranes by free radicals is provided, together with applications and perspectives in life sciences.
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