101
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Serum trace elements in dysphagic gastrostomy candidates before endoscopic gastrostomy for long term enteral feeding. Clin Nutr 2016; 35:718-23. [DOI: 10.1016/j.clnu.2015.05.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2015] [Revised: 05/04/2015] [Accepted: 05/14/2015] [Indexed: 11/20/2022]
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102
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Abstract
The authors were asked by the Editors of ACS Chemical Biology to write an article titled "Why Nature Chose Selenium" for the occasion of the upcoming bicentennial of the discovery of selenium by the Swedish chemist Jöns Jacob Berzelius in 1817 and styled after the famous work of Frank Westheimer on the biological chemistry of phosphate [Westheimer, F. H. (1987) Why Nature Chose Phosphates, Science 235, 1173-1178]. This work gives a history of the important discoveries of the biological processes that selenium participates in, and a point-by-point comparison of the chemistry of selenium with the atom it replaces in biology, sulfur. This analysis shows that redox chemistry is the largest chemical difference between the two chalcogens. This difference is very large for both one-electron and two-electron redox reactions. Much of this difference is due to the inability of selenium to form π bonds of all types. The outer valence electrons of selenium are also more loosely held than those of sulfur. As a result, selenium is a better nucleophile and will react with reactive oxygen species faster than sulfur, but the resulting lack of π-bond character in the Se-O bond means that the Se-oxide can be much more readily reduced in comparison to S-oxides. The combination of these properties means that replacement of sulfur with selenium in nature results in a selenium-containing biomolecule that resists permanent oxidation. Multiple examples of this gain of function behavior from the literature are discussed.
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Affiliation(s)
- Hans J. Reich
- University of Wisconsin—Madison, Department of Chemistry, 1101 University Avenue, Madison, Wisconsin 53706, United States
| | - Robert J. Hondal
- University of Vermont, Department of Biochemistry, 89 Beaumont Ave, Given Laboratory, Room B413, Burlington, Vermont 05405, United States
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103
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Yurkerwich K, Quinlivan PJ, Rong Y, Parkin G. Phenylselenolate Mercury Alkyl Compounds, PhSeHgMe and PhSeHgEt: Molecular Structures, Protolytic Hg-C Bond Cleavage and Phenylselenolate Exchange. Polyhedron 2016; 103:307-314. [PMID: 26644634 PMCID: PMC4669890 DOI: 10.1016/j.poly.2015.06.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The phenylselenolate mercury alkyl compounds, PhSeHgMe and PhSeHgEt, have been structurally characterized by X-ray diffraction, thereby demonstrating that both compounds are monomeric with approximately linear coordination geometries; the mercury centers do, nevertheless, exhibit secondary Hg•••Se intermolecular interactions that serve to increase the coordination number in the solid state. The ethyl derivative, PhSeHgEt, undergoes facile protolytic cleavage of the Hg-C bond to release ethane at room temperature, whereas PhSeHgMe exhibits little reactivity under similar conditions. Interestingly, the cleavage of the Hg-C bond of PhSeHgEt is also more facile than that of the thiolate analogue, PhSHgEt, which demonstrates that coordination by selenium promotes protolytic cleavage of the mercury-carbon bond. The phenylselenolate compounds PhSeHgR (R = Me, Et) also undergo degenerate exchange reactions with, for example, PhSHgR and RHgCl. In each case, the alkyl groups preserve coupling to the 199Hg nuclei, thereby indicating that the exchange process involves metathesis of the Hg-SePh/Hg-X groups rather than metathesis of the Hg-R/Hg-R groups.
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Affiliation(s)
- Kevin Yurkerwich
- Department of Chemistry, Columbia University, New York New York 10027,
USA
| | | | - Yi Rong
- Department of Chemistry, Columbia University, New York New York 10027,
USA
| | - Gerard Parkin
- Department of Chemistry, Columbia University, New York New York 10027,
USA
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104
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Affeldt RF, Santos FP, da Silva RS, Rodrigues OED, Wessjohann LA, Lüdtke DS. Stereoselective glycoconjugation of steroids with selenocarbohydrates. RSC Adv 2016. [DOI: 10.1039/c6ra21485a] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
A methodology that brings together sugar and steroid scaffolds linked by a selenium atom is discussed in this work.
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Affiliation(s)
- Ricardo F. Affeldt
- Institute of Chemistry
- Universidade Federal do Rio Grande do Sul
- Porto Alegre
- Brazil
- Leibniz Institute of Plant Biochemistry
| | - Francisco P. Santos
- Institute of Chemistry
- Universidade Federal do Rio Grande do Sul
- Porto Alegre
- Brazil
| | | | | | | | - Diogo S. Lüdtke
- Institute of Chemistry
- Universidade Federal do Rio Grande do Sul
- Porto Alegre
- Brazil
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105
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Lennicke C, Rahn J, Heimer N, Lichtenfels R, Wessjohann LA, Seliger B. Redox proteomics: Methods for the identification and enrichment of redox-modified proteins and their applications. Proteomics 2015; 16:197-213. [PMID: 26508685 DOI: 10.1002/pmic.201500268] [Citation(s) in RCA: 56] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 09/14/2015] [Accepted: 10/15/2015] [Indexed: 01/24/2023]
Abstract
PTMs are defined as covalent additions to functional groups of amino acid residues in proteins like phosphorylation, glycosylation, S-nitrosylation, acetylation, methylation, lipidation, SUMOylation as well as oxidation. Oxidation of proteins has been characterized as a double-edged sword. While oxidative modifications, in particular of cysteine residues, are widely involved in the regulation of cellular homeostasis, oxidative stress resulting in the oxidation of biomolecules along with the disruption of their biological functions can be associated with the development of diseases, such as cancer, diabetes, and neurodegenerative diseases, respectively. This is also the case for advanced glycation end products, which result from chemical reactions of keto compounds such as oxidized sugars with proteins. The role of oxidative modifications under physiological and pathophysiological conditions remains largely unknown. Recently, novel technologies have been established that allow the enrichment, identification, and characterization of specific oxidative PTMs (oxPTMs). This is essential to develop strategies to prevent and treat diseases that are associated with oxidative stress. Therefore this review will focus on (i) the methods and technologies, which are currently applied for the detection, identification, and quantification of oxPTMs including the design of high throughput approaches and (ii) the analyses of oxPTMs related to physiological and pathological conditions.
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Affiliation(s)
- Claudia Lennicke
- Institute of Medical Immunology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Jette Rahn
- Institute of Medical Immunology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Nadine Heimer
- Institute of Medical Immunology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | - Rudolf Lichtenfels
- Institute of Medical Immunology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
| | | | - Barbara Seliger
- Institute of Medical Immunology, Martin Luther University Halle-Wittenberg, Halle/Saale, Germany
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106
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Surajbali P, Ramanah DK, Rhyman L, Alswaidan IA, Fun HK, Somanah R, Ramasami P. Density Functional Theory Study of Cyanoetheneselenol: A Molecule of Astrobiological Interest. ORIGINS LIFE EVOL B 2015; 45:455-68. [PMID: 26088762 DOI: 10.1007/s11084-015-9436-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2014] [Accepted: 03/18/2015] [Indexed: 11/28/2022]
Abstract
The interstellar medium has a rich chemistry which involves a wide variety of molecules. Of particular interest are molecules that have a link to prebiotic chemistry which hold the key to understanding of our origins. On the basis of suggestions that selenium may have been involved in the origin and evolution of life, we have studied the selenium analogue of cyanoethenethiol, namely the novel cyanoetheneselenol. Cyanoetheneselenol exhibits conformational and geometrical isomerism. This theoretical work deals with the study of four forms of cyanoetheneselenol in terms of their structural, spectroscopic and thermodynamic parameters. All computations were performed using density functional theory method with the B3LYP functional and the Pople basis set, 6-311 + G(d,p), for all atoms. The relative stability of the four isomers of cyanoetheneselenol was obtained and interpreted. The infrared spectra were generated and assignment of the normal modes of vibration was performed. Probable regions of detection, proposed on the basis of parameters obtained from this study for the four isomers, include comets, the molecular cloud: Sagittarius B2(N), and planetary atmospheres. The molecular and spectroscopic parameters should be useful for future identification of the astrobiological molecule cyanoetheneselenol and the development of the Square Kilometre Array. Graphical Abstract E and Z isomers of cyanoetheneselenol.
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Affiliation(s)
- P Surajbali
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit, 80837, Mauritius
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107
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Cebula M, Schmidt EE, Arnér ESJ. TrxR1 as a potent regulator of the Nrf2-Keap1 response system. Antioxid Redox Signal 2015; 23:823-53. [PMID: 26058897 PMCID: PMC4589110 DOI: 10.1089/ars.2015.6378] [Citation(s) in RCA: 175] [Impact Index Per Article: 19.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
SIGNIFICANCE All cells must maintain a balance between oxidants and reductants, while allowing for fluctuations in redox states triggered by signaling, altered metabolic flow, or extracellular stimuli. Furthermore, they must be able to rapidly sense and react to various challenges that would disrupt the redox homeostasis. RECENT ADVANCES Many studies have identified Keap1 as a key sensor for oxidative or electrophilic stress, with modification of Keap1 by oxidation or electrophiles triggering Nrf2-mediated transcriptional induction of enzymes supporting reductive and detoxification pathways. However, additional mechanisms for Nrf2 regulation are likely to exist upstream of, or in parallel with, Keap1. CRITICAL ISSUES Here, we propose that the mammalian selenoprotein thioredoxin reductase 1 (TrxR1) is a potent regulator of Nrf2. A high chemical reactivity of TrxR1 and its vital role for the thioredoxin (Trx) system distinguishes TrxR1 as a prime target for electrophilic challenges. Chemical modification of the selenocysteine (Sec) in TrxR1 by electrophiles leads to rapid inhibition of thioredoxin disulfide reductase activity, often combined with induction of NADPH oxidase activity of the derivatized enzyme, thereby affecting many downstream redox pathways. The notion of TrxR1 as a regulator of Nrf2 is supported by many publications on effects in human cells of selenium deficiency, oxidative stress or electrophile exposure, as well as the phenotypes of genetic mouse models. FUTURE DIRECTIONS Investigation of the role of TrxR1 as a regulator of Nrf2 activation will facilitate further studies of redox control in diverse cells and tissues of mammals, and possibly also in animals of other classes.
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Affiliation(s)
- Marcus Cebula
- 1 Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Stockholm, Sweden
| | - Edward E Schmidt
- 2 Microbiology and Immunology, Montana State University , Bozeman, Montana
| | - Elias S J Arnér
- 1 Division of Biochemistry, Department of Medical Biochemistry and Biophysics, Karolinska Institutet , Stockholm, Sweden
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108
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ω-Amidase: an underappreciated, but important enzyme in l-glutamine and l-asparagine metabolism; relevance to sulfur and nitrogen metabolism, tumor biology and hyperammonemic diseases. Amino Acids 2015; 48:1-20. [DOI: 10.1007/s00726-015-2061-7] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Accepted: 07/24/2015] [Indexed: 12/29/2022]
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109
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Quantification of volatile-alkylated selenium and sulfur in complex aqueous media using solid-phase microextraction. J Chromatogr A 2015; 1407:11-20. [PMID: 26150251 DOI: 10.1016/j.chroma.2015.06.054] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Revised: 06/16/2015] [Accepted: 06/19/2015] [Indexed: 01/20/2023]
Abstract
Biologically produced volatile-alkylated Se and S compounds play an important role in the global biogeochemical Se and S cycles, are important constituents of odorous industrial emissions, and contribute to (off-)flavors in food and beverages. This study presents a fully automated direct-immersion solid-phase microextraction (DI-SPME) method coupled with capillary gas chromatography-mass spectrometry (GC/MS) for the simultaneous quantification of 10 volatile-alkylated Se and S compounds in complex aqueous media. Instrumental parameters of the SPME procedure were optimized to yield extraction efficiencies of up to 96% from complex aqueous matrices. The effects of sample matrix composition and analyte transformation during sample storage were critically assessed. With the use of internal standards and procedural calibrations, the DI-SPME-GC/MS method allows for trace-level quantification of volatile Se and S compounds in the ng/L range (e.g. down to 30 ng/L dimethyl sulfide and 75 ng/L dimethyl selenide). The applicability and robustness of the presented method demonstrate that the method may be used to quantify volatile Se and S compounds in complex aqueous samples, such as industrial effluents or food and beverage samples.
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110
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Rafique J, Saba S, Canto RFS, Frizon TEA, Hassan W, Waczuk EP, Jan M, Back DF, Da Rocha JBT, Braga AL. Synthesis and biological evaluation of 2-picolylamide-based diselenides with non-bonded interactions. Molecules 2015; 20:10095-109. [PMID: 26039333 PMCID: PMC6272563 DOI: 10.3390/molecules200610095] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2015] [Revised: 05/23/2015] [Accepted: 05/27/2015] [Indexed: 12/28/2022] Open
Abstract
In this paper, we report the synthesis and biological evaluation of picolylamide-based diselenides with the aim of developing a new series of diselenides with O···Se non-bonded interactions. The synthesis of diselenides was performed by a simple and efficient synthetic route. All the products were obtained in good yields and their structures were determined by 1H-NMR, 13C-NMR and HRMS. All these new compounds showed promising activities when tested in different antioxidant assays. These amides exhibited strong thiol peroxidase-like (TPx) activity. In fact one of the compounds showed 4.66 times higher potential than the classical standard i.e., diphenyl diselenide. The same compound significantly inhibited iron (Fe)-induced thiobarbituric acid reactive species (TBARS) production in rat's brain homogenate. In addition, the X-ray structure of the most active compound showed non-bonded interaction between the selenium and the oxygen atom that are in close proximity and may be responsible for the increased antioxidant activity. The present study provides evidence about the possible biochemical influence of nonbonding interactions on organochalcogens potency.
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Affiliation(s)
- Jamal Rafique
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, Florianopolis 88040-900, SC, Brazil.
| | - Sumbal Saba
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, Florianopolis 88040-900, SC, Brazil.
| | - Rômulo Faria Santos Canto
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, Florianopolis 88040-900, SC, Brazil.
| | - Tiago Elias Allievi Frizon
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, Florianopolis 88040-900, SC, Brazil.
| | - Waseem Hassan
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, UFSM, Santa Maria 97105-900, RS, Brazil.
- Institute of Chemical Sciences, University of Peshawar, Peshawar 25120, KPK, Pakistan.
| | - Emily Pansera Waczuk
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, UFSM, Santa Maria 97105-900, RS, Brazil.
| | - Maryam Jan
- Institute of Chemical Sciences, University of Peshawar, Peshawar 25120, KPK, Pakistan.
| | - Davi Fernando Back
- Departamento de Química, Laboratório de Materiais Inorgânicos, Universidade Federal de Santa Maria, UFSM, Santa Maria 97115-900, RS, Brazil.
| | - João Batista Teixeira Da Rocha
- Departamento de Bioquímica e Biologia Molecular, Universidade Federal de Santa Maria, UFSM, Santa Maria 97105-900, RS, Brazil.
| | - Antonio Luiz Braga
- Departamento de Química, Universidade Federal de Santa Catarina, UFSC, Florianopolis 88040-900, SC, Brazil.
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111
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Koniev O, Wagner A. Developments and recent advancements in the field of endogenous amino acid selective bond forming reactions for bioconjugation. Chem Soc Rev 2015; 44:5495-551. [PMID: 26000775 DOI: 10.1039/c5cs00048c] [Citation(s) in RCA: 391] [Impact Index Per Article: 43.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Bioconjugation methodologies have proven to play a central enabling role in the recent development of biotherapeutics and chemical biology approaches. Recent endeavours in these fields shed light on unprecedented chemical challenges to attain bioselectivity, biocompatibility, and biostability required by modern applications. In this review the current developments in various techniques of selective bond forming reactions of proteins and peptides were highlighted. The utility of each endogenous amino acid-selective conjugation methodology in the fields of biology and protein science has been surveyed with emphasis on the most relevant among reported transformations; selectivity and practical use have been discussed.
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Affiliation(s)
- Oleksandr Koniev
- Laboratory of Functional Chemo-Systems (UMR 7199), Labex Medalis, University of Strasbourg, 74 Route du Rhin, 67401 Illkirch-Graffenstaden, France.
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112
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Esteva-Font C, Phuan PW, Lee S, Su T, Anderson MO, Verkman AS. Structure-activity analysis of thiourea analogs as inhibitors of UT-A and UT-B urea transporters. BIOCHIMICA ET BIOPHYSICA ACTA 2015; 1848:1075-80. [PMID: 25613743 PMCID: PMC4364388 DOI: 10.1016/j.bbamem.2015.01.004] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2014] [Revised: 12/10/2014] [Accepted: 01/09/2015] [Indexed: 10/24/2022]
Abstract
Small-molecule inhibitors of urea transporter (UT) proteins in kidney have potential application as novel salt-sparing diuretics. The urea analog dimethylthiourea (DMTU) was recently found to inhibit the UT isoforms UT-A1 (expressed in kidney tubule epithelium) and UT-B (expressed in kidney vasa recta endothelium) with IC50 of 2-3 mM, and was shown to have diuretic action when administered to rats. Here, we measured UT-A1 and UT-B inhibition activity of 36 thiourea analogs, with the goal of identifying more potent and isoform-selective inhibitors, and establishing structure-activity relationships. The analog set systematically explored modifications of substituents on the thiourea including alkyl, heterocycles and phenyl rings, with different steric and electronic features. The analogs had a wide range of inhibition activities and selectivities. The most potent inhibitor, 3-nitrophenyl-thiourea, had an IC50 of ~0.2 mM for inhibition of both UT-A1 and UT-B. Some analogs such as 4-nitrophenyl-thiourea were relatively UT-A1 selective (IC50 1.3 vs. 10 mM), and others such as thioisonicotinamide were UT-B selective (IC50>15 vs. 2.8 mM).
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Affiliation(s)
- Cristina Esteva-Font
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Puay-Wah Phuan
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Sujin Lee
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Tao Su
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA
| | - Marc O Anderson
- Department of Chemistry and Biochemistry, San Francisco State University, San Francisco, CA 94132-4136, USA
| | - A S Verkman
- Departments of Medicine and Physiology, University of California, San Francisco, CA 94143-0521, USA.
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113
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Chen M, Heimer P, Imhof D. Synthetic strategies for polypeptides and proteins by chemical ligation. Amino Acids 2015; 47:1283-99. [DOI: 10.1007/s00726-015-1982-5] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Accepted: 04/02/2015] [Indexed: 11/30/2022]
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114
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Palmer J, Parkin G. Protolytic cleavage of Hg-C bonds induced by 1-methyl-1,3-dihydro-2H-benzimidazole-2-selone: synthesis and structural characterization of mercury complexes. J Am Chem Soc 2015; 137:4503-16. [PMID: 25822075 PMCID: PMC4415037 DOI: 10.1021/jacs.5b00840] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2015] [Indexed: 12/22/2022]
Abstract
Multinuclear ((1)H, (77)Se, and (199)Hg) NMR spectroscopy demonstrates that 1-methyl-1,3-dihydro-2H-benzimidazole-2-selone, H(sebenzim(Me)), a structural analogue of the selenoamino acid, selenoneine, binds rapidly and reversibly to the mercury centers of HgX2 (X = Cl, Br, I), while X-ray diffraction studies provide evidence for the existence of adducts of composition [H(sebenzim(Me))]xHgX2 (X = Cl, x = 2, 3, 4; X = I, x = 2) in the solid state. H(sebenzim(Me)) also reacts with methylmercury halides, but the reaction is accompanied by elimination of methane resulting from protolytic cleavage of the Hg-C bond, an observation that is of relevance to the report that selenoneine demethylates CysHgMe, thereby providing a mechanism for mercury detoxification. Interestingly, the structures of [H(sebenzim(Me))]xHgX2 exhibit a variety of different hydrogen bonding patterns resulting from the ability of the N-H groups to form hydrogen bonds with chlorine, iodine, and selenium.
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Affiliation(s)
- Joshua
H. Palmer
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
| | - Gerard Parkin
- Department
of Chemistry, Columbia University, New York, New York 10027, United States
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115
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Schmohl L, Wagner FR, Schümann M, Krause E, Schwarzer D. Semisynthesis and initial characterization of sortase A mutants containing selenocysteine and homocysteine. Bioorg Med Chem 2015; 23:2883-9. [PMID: 25900629 DOI: 10.1016/j.bmc.2015.03.057] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2015] [Revised: 03/19/2015] [Accepted: 03/21/2015] [Indexed: 12/14/2022]
Abstract
The bacterial transpeptidase sortase A is a well-established tool in protein chemistry and catalyzes the chemoselective ligation of peptides and proteins. During catalysis sortase A cleaves the conserved Leu-Pro-X-Thr-Gly sorting motif at the Thr residue under concomitant thioester formation at active site Cys184. We have used expressed protein ligation (EPL) to generate sortase mutants with Cys184 replaced by selenocysteine (Sec) and homocysteine (Hcy). Sec-sortase showed a moderate 2-3-fold reduction in catalytic activity in contrast to Hcy-sortase which is a poor catalyst with less than 1% of wild-type activity. The sensitivity of the active site nucleophiles towards an alkylation reagent correlated with the pKa values of the mutated residues. Furthermore, the pH-profile of Sec-sortase was shifted to more acidic conditions when compared to the wild-type enzyme. These observations provide information on sortase catalysis and the semisynthetic enzymes might represent useful tools for further biochemical investigations and engineering approaches of sortases A.
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Affiliation(s)
- Lena Schmohl
- Interfaculty Institute of Biochemistry, University of Tuebingen, Hoppe-Seyler-Str. 4, D-72076 Tuebingen, Germany
| | - Felix Roman Wagner
- Interfaculty Institute of Biochemistry, University of Tuebingen, Hoppe-Seyler-Str. 4, D-72076 Tuebingen, Germany
| | - Michael Schümann
- Laboratory of Mass Spectrometry, Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, D-13125 Berlin, Germany
| | - Eberhard Krause
- Laboratory of Mass Spectrometry, Leibniz-Institut für Molekulare Pharmakologie, Robert-Rössle-Strasse 10, D-13125 Berlin, Germany
| | - Dirk Schwarzer
- Interfaculty Institute of Biochemistry, University of Tuebingen, Hoppe-Seyler-Str. 4, D-72076 Tuebingen, Germany.
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116
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Hanold LE, Watkins CP, Ton NT, Liaw P, Beedle AM, Kennedy EJ. Design of a selenylsulfide-bridged EGFR dimerization arm mimic. Bioorg Med Chem 2015; 23:2761-6. [PMID: 25840798 DOI: 10.1016/j.bmc.2015.03.040] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2015] [Revised: 03/11/2015] [Accepted: 03/13/2015] [Indexed: 01/25/2023]
Abstract
The epidermal growth factor receptor (EGFR) dimerization arm is a key feature that stabilizes dimerization of the extracellular receptor, thereby mediating activation of the tyrosine kinase domain. Peptides mimicking this β-loop feature can disrupt dimer formation and kinase activation, yet these peptides lack structural constraints or contain redox sensitive disulfide bonds which may limit their stability in physiological environments. Selenylsulfide bonds are a promising alternative to disulfide bonds as they maintain much of the same structural and chemical behavior, yet they are inherently less prone to reduction. Herein, we describe the synthesis, stability and activity of selenylsulfide-bridged dimerization arm mimics. The synthesis was accomplished using an Fmoc-based strategy along with C-terminal labeling for improved overall yield. This selenylsulfide-bridged peptide displayed both proteolytic stability and structural stability even under reducing conditions, demonstrating the potential application of the selenylsulfide bond to generate redox stable β-loop peptides for disruption of protein-protein interactions.
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Affiliation(s)
- Laura E Hanold
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, 240 W. Green St., Athens, GA 30602, USA
| | - Christopher P Watkins
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, 240 W. Green St., Athens, GA 30602, USA
| | - Norman T Ton
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, 240 W. Green St., Athens, GA 30602, USA
| | - Peter Liaw
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, 240 W. Green St., Athens, GA 30602, USA
| | - Aaron M Beedle
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, 240 W. Green St., Athens, GA 30602, USA
| | - Eileen J Kennedy
- Department of Pharmaceutical and Biomedical Sciences, University of Georgia College of Pharmacy, 240 W. Green St., Athens, GA 30602, USA.
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117
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Chen W, Jiang Z, Lin N, Zheng Z, Chen Z, Zhang X, Guan X. Evaluation of N-acetyl-S-(p-chlorophenylcarbamoyl)cysteine as an irreversible inhibitor of mammalian thioredoxin reductase1. J Enzyme Inhib Med Chem 2015; 31:229-35. [PMID: 25778746 DOI: 10.3109/14756366.2015.1016512] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
CONTEXT Thioredoxin reductase (TrxR) is up-regulated in a number of human malignant cells and becomes a promising target for anticancer drug development. OBJECTIVE To evaluate N-acetyl-S-(p-chlorophenylcarbamoyl)cysteine (NACC), a potent anticancer agent against melanoma, as an inhibitor of mammalian TrxR1. MATERIAL AND METHODS The mechanism of inhibition against TrxR1 was investigated using substrate protection, dialysis and liquid chromatography-tandem mass spectrometry. RESULTS NACC inhibits TrxR1 in a time and concentration dependent manner. The K(I) and k(inact) of NACC against TrxR1 were determined to be 80 μM and 0.178 min(-1), respectively. The inhibition occurred only in the presence of NADPH and persisted after extensive dialysis. The tandem mass spectrometric analysis demonstrated that the selenocysteine rather than cysteine residue at the active site was p-chlorophenyl carbamoylated by NACC. Inhibition of intracellular TrxR by NACC in cultured melanoma cells was observed. DISCUSSION AND CONCLUSION NACC which irreversibly inhibits TrxR1 by forming a covalent bond with selenocysteine can be an effective tool in the study of TrxR1.
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Affiliation(s)
- Wei Chen
- a Zhejiang Cancer Research Institute, Zhejiang Cancer Hospital, Zhejiang Cancer Center , Hangzhou , Zhejiang Province , China .,b Zhejiang Key Laboratory of Diagnosis and Treatment Technology on Thoracic Oncology (Lung and Esophagus) , Zhejiang Cancer Hospital , Hangzhou , Zhejiang , China
| | - Zhiming Jiang
- a Zhejiang Cancer Research Institute, Zhejiang Cancer Hospital, Zhejiang Cancer Center , Hangzhou , Zhejiang Province , China .,b Zhejiang Key Laboratory of Diagnosis and Treatment Technology on Thoracic Oncology (Lung and Esophagus) , Zhejiang Cancer Hospital , Hangzhou , Zhejiang , China
| | - Nengming Lin
- c Institute for Individualized Medicine, Hangzhou First People's Hospital , Hangzhou , Zhejiang , China
| | - Zhiguo Zheng
- a Zhejiang Cancer Research Institute, Zhejiang Cancer Hospital, Zhejiang Cancer Center , Hangzhou , Zhejiang Province , China .,b Zhejiang Key Laboratory of Diagnosis and Treatment Technology on Thoracic Oncology (Lung and Esophagus) , Zhejiang Cancer Hospital , Hangzhou , Zhejiang , China
| | - Zhongjian Chen
- a Zhejiang Cancer Research Institute, Zhejiang Cancer Hospital, Zhejiang Cancer Center , Hangzhou , Zhejiang Province , China
| | - Xiaoying Zhang
- d ACEA Bio Co., Ltd. , Hangzhou , Zhejiang Province , China , and
| | - Xiangming Guan
- e Department of Pharmaceutical Sciences , South Dakota State University , Brookings , SD , USA
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118
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Poole LB. The basics of thiols and cysteines in redox biology and chemistry. Free Radic Biol Med 2015; 80:148-57. [PMID: 25433365 PMCID: PMC4355186 DOI: 10.1016/j.freeradbiomed.2014.11.013] [Citation(s) in RCA: 597] [Impact Index Per Article: 66.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 10/20/2014] [Accepted: 11/17/2014] [Indexed: 02/06/2023]
Abstract
Cysteine is one of the least abundant amino acids, yet it is frequently found as a highly conserved residue within functional (regulatory, catalytic, or binding) sites in proteins. It is the unique chemistry of the thiol or thiolate group of cysteine that imparts to functional sites their specialized properties (e.g., nucleophilicity, high-affinity metal binding, and/or ability to form disulfide bonds). Highlighted in this review are some of the basic biophysical and biochemical properties of cysteine groups and the equations that apply to them, particularly with respect to pKa and redox potential. Also summarized are the types of low-molecular-weight thiols present in high concentrations in most cells, as well as the ways in which modifications of cysteinyl residues can impart or regulate molecular functions important to cellular processes, including signal transduction.
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Affiliation(s)
- Leslie B Poole
- Department of Biochemistry, Wake Forest School of Medicine, Winston-Salem, NC 27157, USA.
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119
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Struppe J, Zhang Y, Rozovsky S. (77)Se chemical shift tensor of L-selenocystine: experimental NMR measurements and quantum chemical investigations of structural effects. J Phys Chem B 2015; 119:3643-50. [PMID: 25654666 DOI: 10.1021/jp510857s] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The genetically encoded amino acid selenocysteine and its dimeric form, selenocystine, are both utilized by nature. They are found in active sites of selenoproteins, enzymes that facilitate a diverse range of reactions, including the detoxification of reactive oxygen species and regulation of redox pathways. Due to selenocysteine and selenocystine's specialized biological roles, it is of interest to examine their (77)Se NMR properties and how those can in turn be employed to study biological systems. We report the solid-state (77)Se NMR measurements of the L-selenocystine chemical shift tensor, which provides the first experimental chemical shift tensor information on selenocysteine-containing systems. Quantum chemical calculations of L-selenocystine models were performed to help understand various structural effects on (77)Se L-selenocystine's chemical shift tensor. The effects of protonation state, protein environment, and substituent of selenium-bonded carbon on the isotropic chemical shift were found to be in a range of ca. 10-20 ppm. However, the conformational effect was found to be much larger, spanning ca. 600 ppm for the C-Se-Se-C dihedral angle range of -180° to +180°. Our calculations show that around the minimum energy structure with a C-Se-Se-C dihedral angle of ca. -90°, the energy costs to alter the dihedral angle in the range from -120° to -60° are within only 2.5 kcal/mol. This makes it possible to realize these conformations in a protein or crystal environment. (77)Se NMR was found to be a sensitive probe to such changes and has an isotropic chemical shift range of 272 ± 30 ppm for this energetically favorable conformation range. The energy-minimized structures exhibited calculated isotropic shifts that lay within 3-9% of those reported in previous solution NMR studies. The experimental solid-state NMR isotropic chemical shift is near the lower bound of this calculated range for these readily accessible conformations. These results suggest that the dihedral information may be deduced for a protein with appropriate structural models. These first-time experimental and theoretical results will facilitate future NMR studies of selenium-containing compounds and proteins.
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Affiliation(s)
- Jochem Struppe
- Bruker BioSpin Corporation, 15 Fortune Drive, Manning Park, Billerica, Massachusetts 01821, United States
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120
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Tsubomoto Y, Hayashi S, Nakanishi W. Dynamic and static behavior of the E–E′ bonds (E, E′ = S and Se) in cystine and derivatives, elucidated by AIM dual functional analysis. RSC Adv 2015. [DOI: 10.1039/c4ra13276a] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
AIM-DFA (AIM dual functional analysis) is applied to the E–E′ bonds (E, E′ = S and Se) in R-cystine (1), its derivatives and MeEE′Me. The nature of E–E′ is elucidated by (θp, κp: dynamic behavior) and (R, θ: static behavior), through AIM-DFA.
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Affiliation(s)
- Yutaka Tsubomoto
- Department of Material Science and Chemistry
- Faculty of Systems Engineering
- Wakayama University
- Wakayama 640-8510
- Japan
| | - Satoko Hayashi
- Department of Material Science and Chemistry
- Faculty of Systems Engineering
- Wakayama University
- Wakayama 640-8510
- Japan
| | - Waro Nakanishi
- Department of Material Science and Chemistry
- Faculty of Systems Engineering
- Wakayama University
- Wakayama 640-8510
- Japan
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121
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Hyrup Møller L, Bahnsen JS, Nielsen HM, Østergaard J, Stürup S, Gammelgaard B. Selenium as an alternative peptide label - comparison to fluorophore-labelled penetratin. Eur J Pharm Sci 2014; 67:76-84. [PMID: 25447743 DOI: 10.1016/j.ejps.2014.11.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2014] [Accepted: 11/05/2014] [Indexed: 12/22/2022]
Abstract
In the present study, the impact on peptide properties of labelling peptides with the fluorophore TAMRA or the selenium (Se) containing amino acid SeMet was evaluated. Three differently labelled variants of the cell-penetrating peptide (CPP) penetratin (Pen) were synthesized, PenM(Se), TAMRA-PenM(Se) and TAMRA-Pen. The labelled peptides were characterized in terms of hydrodynamic radius, secondary structure during peptide-membrane interaction, effect on membrane leakage induction, uptake efficiency in HeLa cells. Furthermore, stability of peptides and identities of degradation products in cell media and cell lysate were evaluated. TAMRA-labelling increased the hydrodynamic radius of Pen and PenM(Se) significantly. Labelling with Se caused no or minimal changes in size, secondary structure and membrane leakage induction in concentration levels relevant for cellular uptake studies. Similar degradation patterns of all labelled peptides were observed in HBSS media; degradation was mainly due to oxidation. Cellular uptake was significantly higher for the TAMRA labelled peptides as compared to Se-labelled Pen. Extensive degradation was observed in media during cellular uptake studies, however, in all cell lysates, primarily the intact peptide (PenM(Se), TAMRA-PenM(Se) or TAMRA-Pen) was observed. Selenium labelling caused minimal alteration of the physicochemical properties of the peptide and allowed for absolute quantitative determination of cellular uptake by inductively coupled plasma mass spectrometry. Selenium is thus proposed as a promising alternative label for quantification of peptides in general, altering the properties of the peptide to a minor extent as compared to commonly used peptide labels.
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Affiliation(s)
| | | | | | | | - Stefan Stürup
- Department of Pharmacy, University of Copenhagen, Denmark
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122
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Barik A, Singh BG, Sharma A, Jain VK, Priyadarsini KI. Pulse Radiolysis Studies of 3,5-Dimethyl Pyrazole Derivatives of Selenoethers. J Phys Chem A 2014; 118:10179-87. [DOI: 10.1021/jp507369q] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Atanu Barik
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Beena G. Singh
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Asmita Sharma
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - Vimal K. Jain
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
| | - K. Indira Priyadarsini
- Radiation & Photochemistry Division and ‡Chemistry Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085, India
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123
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Pinto JT, Krasnikov BF, Alcutt S, Jones ME, Dorai T, Villar MT, Artigues A, Li J, Cooper AJL. Kynurenine aminotransferase III and glutamine transaminase L are identical enzymes that have cysteine S-conjugate β-lyase activity and can transaminate L-selenomethionine. J Biol Chem 2014; 289:30950-61. [PMID: 25231977 DOI: 10.1074/jbc.m114.591461] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Three of the four kynurenine aminotransferases (KAT I, II, and IV) that synthesize kynurenic acid, a neuromodulator, are identical to glutamine transaminase K (GTK), α-aminoadipate aminotransferase, and mitochondrial aspartate aminotransferase, respectively. GTK/KAT I and aspartate aminotransferase/KAT IV possess cysteine S-conjugate β-lyase activity. The gene for the former enzyme, GTK/KAT I, is listed in mammalian genome data banks as CCBL1 (cysteine conjugate beta-lyase 1). Also listed, despite the fact that no β-lyase activity has been assigned to the encoded protein in the genome data bank, is a CCBL2 (synonym KAT III). We show that human KAT III/CCBL2 possesses cysteine S-conjugate β-lyase activity, as does mouse KAT II. Thus, depending on the nature of the substrate, all four KATs possess cysteine S-conjugate β-lyase activity. These present studies show that KAT III and glutamine transaminase L are identical enzymes. This report also shows that KAT I, II, and III differ in their ability to transaminate methyl-L-selenocysteine (MSC) and L-selenomethionine (SM) to β-methylselenopyruvate (MSP) and α-ketomethylselenobutyrate, respectively. Previous studies have identified these seleno-α-keto acids as potent histone deacetylase inhibitors. Methylselenol (CH3SeH), also purported to have chemopreventive properties, is the γ-elimination product of SM and the β-elimination product of MSC catalyzed by cystathionine γ-lyase (γ-cystathionase). KAT I, II, and III, in part, can catalyze β-elimination reactions with MSC generating CH3SeH. Thus, the anticancer efficacy of MSC and SM will depend, in part, on the endogenous expression of various KAT enzymes and cystathionine γ-lyase present in target tissue coupled with the ability of cells to synthesize in situ either CH3SeH and/or seleno-keto acid metabolites.
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Affiliation(s)
- John T Pinto
- From the Departments of Biochemistry and Molecular Biology and
| | | | - Steven Alcutt
- From the Departments of Biochemistry and Molecular Biology and
| | - Melanie E Jones
- From the Departments of Biochemistry and Molecular Biology and
| | - Thambi Dorai
- Urology, New York Medical College, Valhalla, New York 10595
| | - Maria T Villar
- the Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, and
| | - Antonio Artigues
- the Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, and
| | - Jianyong Li
- the Department of Biochemistry, Virginia Tech, Blacksburg, Virginia 24061
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Abstract
Selenoproteins use the rare amino acid selenocysteine (Sec) to act as the first line of defense against oxidants, which are linked to aging, cancer, and neurodegenerative diseases. Many selenoproteins are oxidoreductases in which the reactive Sec is connected to a neighboring Cys and able to form a ring. These Sec-containing redox motifs govern much of the reactivity of selenoproteins. To study their fundamental properties, we have used (77)Se NMR spectroscopy in concert with theoretical calculations to determine the conformational preferences and mobility of representative motifs. This use of (77)Se as a probe enables the direct recording of the properties of Sec as its environment is systematically changed. We find that all motifs have several ring conformations in their oxidized state. These ring structures are most likely stabilized by weak, nonbonding interactions between the selenium and the amide carbon. To examine how the presence of selenium and ring geometric strain governs the motifs' reactivity, we measured the redox potentials of Sec-containing motifs and their corresponding Cys-only variants. The comparisons reveal that for C-terminal motifs the redox potentials increased between 20-25 mV when the selenenylsulfide bond was changed to a disulfide bond. Changes of similar magnitude arose when we varied ring size or the motifs' flanking residues. This suggests that the presence of Sec is not tied to unusually low redox potentials. The unique roles of selenoproteins in human health and their chemical reactivities may therefore not necessarily be explained by lower redox potentials, as has often been claimed.
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125
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Lothrop AP, Snider GW, Ruggles EL, Patel AS, Lees WJ, Hondal RJ. Selenium as an electron acceptor during the catalytic mechanism of thioredoxin reductase. Biochemistry 2014; 53:654-63. [PMID: 24422500 PMCID: PMC3957198 DOI: 10.1021/bi400658g] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
![]()
Mammalian thioredoxin reductase (TR)
is a pyridine nucleotide disulfide
oxidoreductase that uses the rare amino acid selenocysteine (Sec)
in place of the more commonly used amino acid cysteine (Cys) in the
redox-active tetrapeptide Gly-Cys-Sec-Gly motif to catalyze thiol/disulfide
exchange reactions. Sec can accelerate the rate of these exchange
reactions (i) by being a better nucleophile than Cys, (ii) by being
a better electrophile than Cys, (iii) by being a better leaving group
than Cys, or (iv) by using a combination of all three of these factors,
being more chemically reactive than Cys. The role of the selenolate
as a nucleophile in the reaction mechanism was recently demonstrated
by creating a mutant of human thioredoxin reductase-1 in which the
Cys497-Sec498 dyad of the C-terminal redox center
was mutated to either a Ser497-Cys498 dyad or
a Cys497-Ser498 dyad. Both mutant enzymes were
incubated with human thioredoxin (Trx) to determine which mutant formed
a mixed disulfide bond complex. Only the mutant containing the Ser497-Cys498 dyad formed a complex, and this structure
has been determined by X-ray crystallography [Fritz-Wolf, K., Kehr,
S., Stumpf, M., Rahlfs, S., and Becker, K. (2011) Crystal structure
of the human thioredoxin reductase-thioredoxin complex. Nat.
Commun. 2, 383]. This experimental observation most likely
means that the selenolate is the nucleophile initially attacking the
disulfide bond of Trx because a complex resulted only when Cys was
present in the second position of the dyad. As a nucleophile, the
selenolate of Sec helps to accelerate the rate of this exchange reaction
relative to Cys in the Sec → Cys mutant enzyme. Another thiol/disulfide
exchange reaction that occurs in the enzymatic cycle of the enzyme
is the transfer of electrons from the thiolate of the interchange
Cys residue of the N-terminal redox center to the eight-membered selenosulfide
ring of the C-terminal redox center. The selenium atom of the selenosulfide
could accelerate this exchange reaction by being a good leaving group
(attack at the sulfur atom) or by being a good electrophile (attack
at the selenium atom). Here we provide strong evidence that the selenium
atom is attacked in this exchange step. This was shown by creating
a mutant enzyme containing a Gly-Gly-Seccoo- motif
that had 0.5% of the activity of the wild-type enzyme. This mutant
lacks the adjacent, resolving Cys residue, which acts by attacking
the mixed selenosulfide bond that occurs between the enzyme and substrate.
A similar result was obtained when Sec was replaced with homocysteine.
These results highlight the role of selenium as an electron acceptor
in the catalytic mechanism of thioredoxin reductase as well as its
established role as a donor of an electron to the substrate.
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Affiliation(s)
- Adam P Lothrop
- Department of Biochemistry, University of Vermont, College of Medicine , 89 Beaumont Avenue, Given Building Room B413, Burlington, Vermont 05405, United States
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Lothrop AP, Snider GW, Flemer S, Ruggles EL, Davidson RS, Lamb AL, Hondal RJ. Compensating for the absence of selenocysteine in high-molecular weight thioredoxin reductases: the electrophilic activation hypothesis. Biochemistry 2014; 53:664-74. [PMID: 24490974 PMCID: PMC3931472 DOI: 10.1021/bi4007258] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
![]()
Mammalian thioredoxin reductase (TR)
is a pyridine disulfide oxidoreductase
that uses the rare amino acid selenocysteine (Sec) in place of the
more commonly used amino acid cysteine (Cys). Selenium is a Janus-faced
element because it is both highly nucleophilic and highly electrophilic.
Cys orthologs of Sec-containing enzymes may compensate for the absence
of a Sec residue by making the active site Cys residue more (i) nucleophilic,
(ii) electrophilic, or (iii) reactive by increasing both S-nucleophilicity and S-electrophilicity. It has
already been shown that the Cys ortholog TR from Drosophila
melanogaster (DmTR) has increased S-nucleophilicity
[Gromer, S., Johansson, L., Bauer, H., Arscott, L. D., Rauch, S.,
Ballou, D. P., Williams, C. H., Jr., Schrimer, R. H., and Arnér,
E. S (2003) Active sites of thioredoxin reductases: Why selenoproteins? Proc. Natl. Acad. Sci. U.S.A. 100, 12618–12623].
Here we present evidence that DmTR also enhances the electrophilicity
of Cys490 through the use of an “electrophilic activation”
mechanism. This mechanism is proposed to work by polarizing the disulfide
bond that occurs between Cys489 and Cys490 in the C-terminal redox
center by the placement of a positive charge near Cys489. This polarization
renders the sulfur atom of Cys490 electron deficient and enhances
the rate of thiol/disulfide exchange that occurs between the N- and
C-terminal redox centers. Our hypothesis was developed by using a
strategy of homocysteine (hCys) for Cys substitution in the Cys-Cys
redox dyad of DmTR to differentiate the function of each Cys residue.
The results show that hCys could substitute for Cys490 with little
loss of thioredoxin reductase activity, but that substitution of hCys
for Cys489 resulted in a 238-fold reduction in activity. We hypothesize
that replacement of Cys489 with hCys destroys an interaction between
the sulfur atom of Cys489 and His464 crucial for the proposed electrophilic
activation mechanism. This electrophilic activation serves as a compensatory
mechanism in the absence of the more electrophilic Sec residue. We
present an argument for the importance of S-electrophilicity
in Cys orthologs of selenoenzymes.
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Affiliation(s)
- Adam P Lothrop
- Department of Biochemistry, University of Vermont, College of Medicine , 89 Beaumont Avenue, Given Building Room B413, Burlington, Vermont 05405, United States
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127
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Møller LH, Gabel-Jensen C, Franzyk H, Bahnsen JS, Stürup S, Gammelgaard B. Quantification of pharmaceutical peptides using selenium as an elemental detection label. Metallomics 2014; 6:1639-47. [DOI: 10.1039/c4mt00085d] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Se-labelling of pharmaceutical biomolecules provides detailed quantitative and qualitative information on the fate of the biomolecule in cell uptake studies.
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Affiliation(s)
| | | | - Henrik Franzyk
- University of Copenhagen
- Department of Drug Design and Pharmacology
- Denmark
| | | | - Stefan Stürup
- University of Copenhagen
- Department of Pharmacy
- Denmark
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128
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Siscar R, Koenig S, Torreblanca A, Solé M. The role of metallothionein and selenium in metal detoxification in the liver of deep-sea fish from the NW Mediterranean Sea. THE SCIENCE OF THE TOTAL ENVIRONMENT 2014; 466-467:898-905. [PMID: 23973552 DOI: 10.1016/j.scitotenv.2013.07.081] [Citation(s) in RCA: 40] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/05/2013] [Revised: 07/22/2013] [Accepted: 07/23/2013] [Indexed: 06/02/2023]
Abstract
Seven deep-sea fish species were sampled in the Blanes Canyon area (NW Mediterranean) at a depth of 1200 m during winter. The concentrations of nine metals were determined in the liver of these species by ICP-MS. Furthermore, the metal detoxification potential was determined for each species by analysing the hepatic metallothionein (MT) content, relations between metals and the molar ratio between MT and/or selected metals. The potential effect of metal content on their physiology was assessed using general stress markers such as the enzyme activities of acetylcholinesterase (AChE) and lactate dehydrogenase (LDH) in muscle. Levels of metals in the seven Mediterranean deep-sea fish species studied were intermediate to equivalent species of fish either from Atlantic waters or hydrothermal vents. The metal detoxification potential varied among species depending on MT, selenium (Se) or zinc (Zn) as reliable mechanisms to handle potential metal toxicity. The role of Se was especially relevant when the liver content of mercury (Hg) was higher. AChE and LDH activities did seem to be affected by metal loads and thus the activities reported would correspond to baseline activities of the selected species.
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Affiliation(s)
- Rosario Siscar
- Department of Functional Biology, Faculty of Biological Sciences, University of Valencia, Dr. Moliner, 50, 46100 Burjassot, Valencia, Spain
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129
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130
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Reschke S, Niks D, Wilson H, Sigfridsson KGV, Haumann M, Rajagopalan KV, Hille R, Leimkühler S. Effect of Exchange of the Cysteine Molybdenum Ligand with Selenocysteine on the Structure and Function of the Active Site in Human Sulfite Oxidase. Biochemistry 2013; 52:8295-303. [DOI: 10.1021/bi4008512] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Stefan Reschke
- Department
of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
| | - Dimitri Niks
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
| | - Heather Wilson
- Department
of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
| | | | - Michael Haumann
- Institute
of Experimental Physics, Free University Berlin, 14195 Berlin, Germany
| | - K. V. Rajagopalan
- Department
of Biochemistry, Duke University Medical Center, Durham, North Carolina 27710, United States
| | - Russ Hille
- Department
of Biochemistry, University of California, Riverside, California 92521, United States
| | - Silke Leimkühler
- Department
of Molecular Enzymology, Institute of Biochemistry and Biology, University of Potsdam, 14476 Potsdam, Germany
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131
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Snider GW, Ruggles E, Khan N, Hondal RJ. Selenocysteine confers resistance to inactivation by oxidation in thioredoxin reductase: comparison of selenium and sulfur enzymes. Biochemistry 2013; 52:5472-81. [PMID: 23865454 DOI: 10.1021/bi400462j] [Citation(s) in RCA: 74] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Mammalian thioredoxin reductase (TR) is a selenocysteine (Sec)-containing homodimeric pyridine nucleotide oxidoreductase which catalyzes the reduction of oxidized thioredoxin. We have previously demonstrated the full-length mitochondrial mammalian TR (mTR3) enzyme to be resistant to inactivation from exposure to 50 mM H2O2. Because a Sec residue oxidizes more rapidly than a cysteine (Cys) residue, it has been previously thought that Sec-containing enzymes are "sensitive to oxidation" compared to Cys-orthologues. Here we show for the first time a direct comparison of the abilities of Sec-containing mTR3 and the Cys-orthologue from D. melanogaster (DmTR) to resist inactivation by oxidation from a variety of oxidants including H2O2, hydroxyl radical, peroxynitrite, hypochlorous acid, hypobromous acid, and hypothiocyanous acid. The results show that the Sec-containing TR is far superior to the Cys-orthologue TR in resisting inactivation by oxidation. To further test our hypothesis that the use of Sec confers strong resistance to inactivation by oxidation, we constructed a chimeric enzyme in which we replaced the active site Cys nucleophile of DmTR with a Sec residue using semisynthesis. The chimeric Sec-containing enzyme has similar ability to resist inactivation by oxidation as the wild type Sec-containing TR from mouse mitochondria. The use of Sec in the chimeric enzyme "rescued" the enzyme from oxidant-induced inactivation for all of the oxidants tested in this study, in direct contrast to previous understanding. We discuss two possibilities for this rescue effect from inactivation under identical conditions of oxidative stress: (i) Sec resists overoxidation and inactivation, whereas a Cys residue can be permanently overoxidized to the sulfinic acid form, and (ii) Sec protects the body of the enzyme from harmful oxidation by allowing the enzyme to metabolize (turnover) various oxidants much better than a Cys-containing TR.
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Affiliation(s)
- Gregg W Snider
- Department of Biochemistry, University of Vermont, 89 Beaumont Ave, Given Building Room B413, Burlington, VT 05405, USA
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132
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Galano E, Mangiapane E, Bianga J, Palmese A, Pessione E, Szpunar J, Lobinski R, Amoresano A. Privileged incorporation of selenium as selenocysteine in Lactobacillus reuteri proteins demonstrated by selenium-specific imaging and proteomics. Mol Cell Proteomics 2013; 12:2196-204. [PMID: 23660472 DOI: 10.1074/mcp.m113.027607] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An analytical approach was developed to study the incorporation of selenium (Se), an important trace element involved in the protection of cells from oxidative stress, into the well-known probiotic Lactobacillus reuteri Lb2 BM-DSM 16143. The analyses revealed that about half of the internalized Se was covalently incorporated into soluble proteins. Se-enriched proteins were detected in 2D gels by laser ablation inductively coupled plasma mass spectrometry imaging (LA-ICP MSI) and identified by capillary HPLC with the parallel ICP MS ((78)Se) and electrospray Orbitrap MS/MS detection. On the basis of the identification of 10 richest in selenium proteins, it was demonstrated that selenium was incorporated by the strain exclusively as selenocysteine. Also, the exact location of selenocysteine within the primary sequence was determined. This finding is in a striking contrast to another common nutraceutical, Se-enriched yeast, which incorporates Se principally as selenomethionine.
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Affiliation(s)
- Eugenio Galano
- Department of Chemical Sciences, University of Naples Federico II, Italy
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133
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Hondal RJ, Marino SM, Gladyshev VN. Selenocysteine in thiol/disulfide-like exchange reactions. Antioxid Redox Signal 2013; 18:1675-89. [PMID: 23121622 PMCID: PMC3613276 DOI: 10.1089/ars.2012.5013] [Citation(s) in RCA: 121] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
SIGNIFICANCE Among trace elements used as cofactors in enzymes, selenium is unique in that it is incorporated into proteins co-translationally in the form of an amino acid, selenocysteine (Sec). Sec differs from cysteine (Cys) by only one atom (selenium versus sulfur), yet this switch dramatically influences important aspects of enzyme reactivity. RECENT ADVANCES The main focus of this review is an updated and critical discussion on how Sec might be used to accelerate thiol/disulfide-like exchange reactions in natural selenoenzymes, compared with their Cys-containing homologs. CRITICAL ISSUES We discuss in detail three major aspects associated with thiol/disulfide exchange reactions: (i) nucleophilicity of the attacking thiolate (or selenolate); (ii) electrophilicity of the center sulfur (or selenium) atom; and (iii) stability of the leaving group (sulfur or selenium). In all these cases, we analyze the benefits that selenium might provide in these types of reactions. FUTURE DIRECTIONS It is the biological thiol oxidoreductase-like function that benefits from the use of Sec, since Sec functions to chemically accelerate the rate of these reactions. We review various hypotheses that could help explain why Sec is used in enzymes, particularly with regard to competitive chemical advantages provided by the presence of the selenium atom in enzymes. Ultimately, these chemical advantages must be connected to biological functions of Sec.
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Affiliation(s)
- Robert J Hondal
- Given Laboratory, Department of Biochemistry, University of Vermont, Burlington, VT 05405, USA.
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134
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Zaharia V, Ignat A, Ngameni B, Kuete V, Moungang ML, Fokunang CN, Vasilescu M, Palibroda N, Cristea C, Silaghi-Dumitrescu L, Ngadjui BT. Heterocycles 23: Synthesis, characterization and anticancer activity of new hydrazinoselenazole derivatives. Med Chem Res 2013. [DOI: 10.1007/s00044-013-0558-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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135
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Palmer JH, Parkin G. 2-Seleno-1-alkylbenzimidazoles and their Diselenides: Synthesis and Structural Characterization of a 2-Seleno-1-methylbenzimidazole Complex of Mercury. Polyhedron 2013; 52:658-668. [PMID: 23543946 PMCID: PMC3610765 DOI: 10.1016/j.poly.2012.07.090] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
2-Seleno-1-methylbenzimidazole, H(sebenzimMe), can be synthesized from 1-methylbenzimidazole by sequential treatment with (i) BunLi, (ii) elemental selenium and (iii) HCl(aq). This method is also applicable to the synthesis of 2-seleno-1-t-butylbenzimidazole, H(sebenzimBut ). Single crystal X-ray diffraction and NMR spectroscopic data demonstrate that H(sebenzimMe) and H(sebenzimBut ) exist as the selone rather than the selenol tautomers, which is in accord with the results of density functional theory (B3LYP) calculations. The data also indicate that the selone is best represented as a C+-Se- zwitterion rather than as a C=Se doubly bonded species. Aerobic oxidation of H(sebenzimMe) and H(sebenzimBut ) in the presence of Et3N yields the diselenides, (sebenzimMe)2 and (sebenzimBut )2. In addition, H(sebenzimMe) reacts with HgCl2 to give [H(sebenzimMe)]2HgCl2, the first structurally characterized example of a 2-seleno-1-alkylimidazole mercury complex.
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Affiliation(s)
- Joshua H. Palmer
- Department of Chemistry, Columbia University, New York, New York 10027, USA
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136
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Draft genome sequence of Turicella otitidis ATCC 51513, isolated from middle ear fluid from a child with otitis media. J Bacteriol 2013; 194:5968-9. [PMID: 23045487 DOI: 10.1128/jb.01412-12] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Turicella otitidis is an unusual corynebacterium with a controversial role in otitis media in children. Metabolic capabilities deduced from the draft genome indicate its adaptation to habitats on the human skin and in the intestine. The lack of candidate virulence factors implies that T. otitidis has a low pathogenic potential.
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137
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Kawasoko CY, Foletto P, Rodrigues OED, Dornelles L, Schwab RS, Braga AL. Straightforward synthesis of non-natural l-chalcogen and l-diselenide N-Boc-protected-γ-amino acid derivatives. Org Biomol Chem 2013; 11:5173-83. [DOI: 10.1039/c3ob40879e] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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138
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Schaefer SA, Dong M, Rubenstein RP, Wilkie WA, Bahnson BJ, Thorpe C, Rozovsky S. (77)Se enrichment of proteins expands the biological NMR toolbox. J Mol Biol 2012; 425:222-31. [PMID: 23159557 DOI: 10.1016/j.jmb.2012.11.011] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Revised: 11/06/2012] [Accepted: 11/07/2012] [Indexed: 10/27/2022]
Abstract
Sulfur, a key contributor to biological reactivity, is not amendable to investigations by biological NMR spectroscopy. To utilize selenium as a surrogate, we have developed a generally applicable (77)Se isotopic enrichment method for heterologous proteins expressed in Escherichia coli. We demonstrate (77)Se NMR spectroscopy of multiple selenocysteine and selenomethionine residues in the sulfhydryl oxidase augmenter of liver regeneration (ALR). The resonances of the active-site residues were assigned by comparing the NMR spectra of ALR bound to oxidized and reduced flavin adenine dinucleotide. An additional resonance appears only in the presence of the reducing agent and disappears readily upon exposure to air and subsequent reoxidation of the flavin. Hence, (77)Se NMR spectroscopy can be used to report the local electronic environment of reactive and structural sulfur sites, as well as changes taking place in those locations during catalysis.
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Affiliation(s)
- Stephanie A Schaefer
- 136 Brown Laboratory, Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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139
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Zaluzhna O, Li Y, Allison TC, Tong YJ. Inverse-Micelle-Encapsulated Water-Enabled Bond Breaking of Dialkyl Diselenide/Disulfide: A Critical Step for Synthesizing High-Quality Gold Nanoparticles. J Am Chem Soc 2012; 134:17991-6. [DOI: 10.1021/ja3068758] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Oksana Zaluzhna
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington,
D.C. 20057, United States
| | - Ying Li
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington,
D.C. 20057, United States
| | - Thomas C. Allison
- National Institute of Standards and Technology, 100 Bureau Drive, Gaithersburg,
Maryland 20899-8320, United States
| | - YuYe J. Tong
- Department of Chemistry, Georgetown University, 37th and O Streets NW, Washington,
D.C. 20057, United States
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140
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Zuazo A, Plano D, Ansó E, Lizarraga E, Font M, Martínez Irujo JJ. Cytotoxic and proapototic activities of imidoselenocarbamate derivatives are dependent on the release of methylselenol. Chem Res Toxicol 2012; 25:2479-89. [PMID: 23043559 DOI: 10.1021/tx300306t] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
In the search for new molecules with potential antiangiogenic activity, we found that several imidoselenocarbamate derivatives effectively suppressed the expression of vascular endothelial growth factor (VEGF) induced by hypoxia in NCI-H157 tumor cells. Mechanistic studies indicated that these compounds inhibited STAT3 phosphorylation triggered by hypoxia, suggesting that inhibition of STAT3 function may play a role in VEGF inhibition. Moreover, these molecules showed interesting proapoptotic and antiproliferative effects. Both the presence of selenium, but not sulfur, and the nature of the radical substituents were important for activity. Interestingly, under hypoxic conditions, several methyl imidoselenocarbamate derivatives released methylselenol, a highly reactive and cytotoxic gas, which was responsible for their biological activities. The kinetics of the release of methylselenol by these molecules was highly dependent on the nature of the substituent radicals and correlated with their early proapoptotic activity. Our results support the notion that pharmacological activities reported for methyl imidoselenocarbamate derivatives are dependent on the release of methylselenol. Given the well-known antitumor activities of this compound, imidoselenocarbamate derivatives represent a promising approach to develop new drugs that release methylselenol in a controlled way.
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Affiliation(s)
- Alicia Zuazo
- Department of Biochemistry and Molecular Biology, University of Navarra, Irunlarrea 1, E-31008 Pamplona, Spain
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141
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Liu J, Srinivasan P, Pham DN, Rozovsky S. Expression and purification of the membrane enzyme selenoprotein K. Protein Expr Purif 2012; 86:27-34. [PMID: 22963794 DOI: 10.1016/j.pep.2012.08.014] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2012] [Revised: 08/18/2012] [Accepted: 08/20/2012] [Indexed: 12/18/2022]
Abstract
Selenoprotein K (SelK) is a membrane protein residing in the endoplasmic reticulum. The function of SelK is mostly unknown; however, it has been shown to participate in anti-oxidant defense, calcium regulation and in the endoplasmic reticulum associated protein degradation (ERAD) pathway. In order to study the function of SelK and the role of selenocysteine in catalysis, we have tested heterologous expression of human SelK in E. coli. Consequently, we have developed an over-expression strategy that exploits the maltose binding protein as a fusion partner to stabilize and solubilize SelK. The fusion partner can be cleaved from SelK in the presence of a variety of detergents compatible with structural characterization and the protein purified to homogeneity. SelK acquires a helical secondary structure in detergent micelles, even though it was predicted to be an intrinsically disordered protein due to its high percentage of polar residues. The same strategy was successfully applied to preparation of SelK binding partner - selenoprotein S (SelS). Hence, this heterologous expression and purification strategy can be applied to other members of the membrane enzyme family to which SelK belongs.
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Affiliation(s)
- Jun Liu
- Department of Chemistry and Biochemistry, University of Delaware, Newark, DE 19716, USA
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142
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Font M, Zuazo A, Ansó E, Plano D, Sanmartín C, Palop JA, Martínez-Irujo JJ. Novel structural insights for imidoselenocarbamates with antitumoral activity related to their ability to generate methylselenol. Bioorg Med Chem 2012; 20:5110-6. [PMID: 22863528 DOI: 10.1016/j.bmc.2012.07.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/27/2012] [Accepted: 07/06/2012] [Indexed: 12/26/2022]
Abstract
In the search for molecules with potential antiangiogenic activity we found that several imidoselenocarbamate derivatives, which have pro-apoptotic and antiproliferative activities, under hypoxic conditions release methylselenol, a volatile and highly reactive gas that was considered to be responsible for the observed biological activity. The kinetic for the liberation of methylselenol is highly dependent on the nature of the overall structure and correlate with their proven pro-apoptotic activity in lung cancer cell line H157. The preliminary structure-activity relationships allow us to select as the basic structural element a scaffold constructed with an imidoselenocarbamate fragment decorated with a methyl residue on the Se central atom and two heteroaromatic lateral rings. These imidoselenocarbamate derivatives may be of interest both for their antitumoral activities and because they have a structure that can be considered as a template for the design of new derivatives with apoptotic activity. This activity is related to the controlled delivery of methylselenol and makes this an interesting approach to develop new antitumoral agents.
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Affiliation(s)
- María Font
- Sección de Modelización Molecular, Departamento de Química Orgánica y Farmacéutica, University of Navarra, Irunlarrea 1, E-31008 Pamplona, Spain.
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143
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Kitajima T, Jigami Y, Chiba Y. Cytotoxic mechanism of selenomethionine in yeast. J Biol Chem 2012; 287:10032-10038. [PMID: 22311978 DOI: 10.1074/jbc.m111.324244] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Although selenium is an essential element, its excessive uptake is detrimental to living organisms. The significance of selenium for living organisms has been exploited for various purposes. However, the molecular basis of selenium toxicity is not completely understood. Here, we applied a capillary electrophoresis time-of-flight mass spectrometry-based metabolomics approach to analysis of yeast cells treated with selenomethionine. The data indicated that intracellular thiol compounds are significantly decreased, and diselenide and selenosulfide compounds are increased in selenomethionine-treated cells. The growth defect induced by selenomethionine was recovered by extracellular addition of cysteine and by genetic modification of yeast cells that have an additional de novo synthetic pathway for cysteine. Because cysteine is an intermediate of thiol compounds, these results suggested that the loss of a reduced form of thiol compounds due to selenomethionine causes a growth defect of yeast cells.
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Affiliation(s)
- Toshihiko Kitajima
- Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Yoshifumi Jigami
- Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
| | - Yasunori Chiba
- Research Center for Medical Glycoscience, National Institute of Advanced Industrial Science and Technology, Central 6, 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan.
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144
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Natarajan S, Mathews R. (Z)-2-[(4-Methyl-phen-yl)sulfon-yl]-1,2-diphenyl-ethene-selenol. Acta Crystallogr Sect E Struct Rep Online 2012; 68:o442. [PMID: 22347053 PMCID: PMC3275197 DOI: 10.1107/s1600536812001638] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Accepted: 01/13/2012] [Indexed: 11/30/2022]
Abstract
In the title compound, C(21)H(18)O(2)SSe, the dihedral angle between the cis phenyl rings is 64.3 (1)° and those between the toluene and the phenyl rings are 21.1 (2) and 72.0 (1)°, respectively. An intra-molecular Se-H⋯O hydrogen bond occurs. In the crystal, mol-ecules are connected by C-H⋯O hydrogen bonds and weak C-H⋯π inter-actions help to consolidate the crystal packing.
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Affiliation(s)
- Sampath Natarajan
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143 701, Republic of Korea
| | - Rita Mathews
- Department of Advanced Technology Fusion, Konkuk University, 1 Hwayang-dong, Gwangjin-gu, Seoul 143 701, Republic of Korea
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145
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Abbas M, Wessjohann LA. Direct synthesis of sensitive selenocysteine peptides by the Ugi reaction. Org Biomol Chem 2012; 10:9330-3. [DOI: 10.1039/c2ob26552d] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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146
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Boutureira O, Bernardes GJL, Fernández-González M, Anthony DC, Davis BG. Selenenylsulfide-Linked Homogeneous Glycopeptides and Glycoproteins: Synthesis of Human “Hepatic Se Metabolite A”. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201106658] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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147
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Boutureira O, Bernardes GJL, Fernández-González M, Anthony DC, Davis BG. Selenenylsulfide-Linked Homogeneous Glycopeptides and Glycoproteins: Synthesis of Human “Hepatic Se Metabolite A”. Angew Chem Int Ed Engl 2011; 51:1432-6. [DOI: 10.1002/anie.201106658] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2011] [Indexed: 12/22/2022]
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148
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Ninomiya M, Garud DR, Koketsu M. Biologically significant selenium-containing heterocycles. Coord Chem Rev 2011. [DOI: 10.1016/j.ccr.2011.07.009] [Citation(s) in RCA: 85] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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149
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Marino SM, Gladyshev VN. Redox biology: computational approaches to the investigation of functional cysteine residues. Antioxid Redox Signal 2011; 15:135-46. [PMID: 20812876 PMCID: PMC3110093 DOI: 10.1089/ars.2010.3561] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2010] [Revised: 08/19/2010] [Accepted: 09/02/2010] [Indexed: 12/18/2022]
Abstract
Cysteine (Cys) residues serve many functions, such as catalysis, stabilization of protein structure through disulfides, metal binding, and regulation of protein function. Cys residues are also subject to numerous post-translational modifications. In recent years, various computational tools aiming at classifying and predicting different functional categories of Cys have been developed, particularly for structural and catalytic Cys. On the other hand, given complexity of the subject, bioinformatics approaches have been less successful for the investigation of regulatory Cys sites. In this review, we introduce different functional categories of Cys residues. For each category, an overview of state-of-the-art bioinformatics methods and tools is provided, along with examples of successful applications and potential limitations associated with each approach. Finally, we discuss Cys-based redox switches, which modify the view of distinct functional categories of Cys in proteins.
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Affiliation(s)
- Stefano M Marino
- Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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150
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Huang HH, Day L, Cass CL, Ballou DP, Williams CH, Williams DL. Investigations of the catalytic mechanism of thioredoxin glutathione reductase from Schistosoma mansoni. Biochemistry 2011; 50:5870-82. [PMID: 21630672 DOI: 10.1021/bi200107n] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
Thioredoxin glutathione reductase from Schistosoma mansoni (SmTGR) catalyzes the reduction of both thioredoxin and glutathione disulfides (GSSG), thus playing a crucial role in maintaining redox homeostasis in the parasite. In line with this role, previous studies have demonstrated that SmTGR is a promising drug target for schistosomiasis. To aid in the development of efficacious drugs that target SmTGR, it is essential to understand the catalytic mechanism of SmTGR. SmTGR is a dimeric flavoprotein in the glutathione reductase family and has a head-to-tail arrangement of its monomers; each subunit has the components of both a thioredoxin reductase (TrxR) domain and a glutaredoxin (Grx) domain. However, the active site of the TrxR domain is composed of residues from both subunits: FAD and a redox-active Cys-154/Cys-159 pair from one subunit and a redox-active Cys-596'/Sec-597' pair from the other; the active site of the Grx domain contains a redox-active Cys-28/Cys-31 pair. Via its Cys-28/Cys-31 dithiol and/or its Cys-596'/Sec-597' thiol-selenolate, SmTGR can catalyze the reduction of a variety of substrates by NADPH. It is presumed that SmTGR catalyzes deglutathionylation reactions via the Cys-28/Cys-31 dithiol. Our anaerobic titration data suggest that reducing equivalents from NADPH can indeed reach the Cys-28/Cys-31 disulfide in the Grx domain to facilitate reductions effected by this cysteine pair. To clarify the specific chemical roles of each redox-active residue with respect to its various reactivities, we generated variants of SmTGR. Cys-28 variants had no Grx deglutathionylation activity, whereas Cys-31 variants retained partial Grx deglutathionylation activity, indicating that the Cys-28 thiolate is the nucleophile initiating deglutathionylation. Lags in the steady-state kinetics, found when wild-type SmTGR was incubated at high concentrations of GSSG, were not present in Grx variants, indicating that this cysteine pair is in some way responsible for the lags. A Sec-597 variant was still able to reduce a variety of substrates, albeit slowly, showing that selenocysteine is important but is not the sole determinant for the broad substrate tolerance of the enzyme. Our data show that Cys-520 and Cys-574 are not likely to be involved in the catalytic mechanism.
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Affiliation(s)
- Hsin-Hung Huang
- Department of Microbiology and Immunology, Rush University Medical Center, Chicago, Illinois 60612, United States
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