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Michaels TM, Essop MF, Joseph DE. Potential Effects of Hyperglycemia on SARS-CoV-2 Entry Mechanisms in Pancreatic Beta Cells. Viruses 2024; 16:1243. [PMID: 39205219 PMCID: PMC11358987 DOI: 10.3390/v16081243] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2024] [Revised: 07/29/2024] [Accepted: 07/30/2024] [Indexed: 09/04/2024] Open
Abstract
The COVID-19 pandemic has revealed a bidirectional relationship between SARS-CoV-2 infection and diabetes mellitus. Existing evidence strongly suggests hyperglycemia as an independent risk factor for severe COVID-19, resulting in increased morbidity and mortality. Conversely, recent studies have reported new-onset diabetes following SARS-CoV-2 infection, hinting at a potential direct viral attack on pancreatic beta cells. In this review, we explore how hyperglycemia, a hallmark of diabetes, might influence SARS-CoV-2 entry and accessory proteins in pancreatic β-cells. We examine how the virus may enter and manipulate such cells, focusing on the role of the spike protein and its interaction with host receptors. Additionally, we analyze potential effects on endosomal processing and accessory proteins involved in viral infection. Our analysis suggests a complex interplay between hyperglycemia and SARS-CoV-2 in pancreatic β-cells. Understanding these mechanisms may help unlock urgent therapeutic strategies to mitigate the detrimental effects of COVID-19 in diabetic patients and unveil if the virus itself can trigger diabetes onset.
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Affiliation(s)
- Tara M. Michaels
- Centre for Cardio-Metabolic Research in Africa, Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch 7600, South Africa;
| | - M. Faadiel Essop
- Centre for Cardio-Metabolic Research in Africa, Division of Medical Physiology, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town 7505, South Africa;
| | - Danzil E. Joseph
- Centre for Cardio-Metabolic Research in Africa, Department of Physiological Sciences, Faculty of Science, Stellenbosch University, Stellenbosch 7600, South Africa;
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2
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Liu HZ, Song XQ, Zhang H. Sugar-coated bullets: Unveiling the enigmatic mystery 'sweet arsenal' in osteoarthritis. Heliyon 2024; 10:e27624. [PMID: 38496870 PMCID: PMC10944269 DOI: 10.1016/j.heliyon.2024.e27624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2023] [Revised: 03/01/2024] [Accepted: 03/04/2024] [Indexed: 03/19/2024] Open
Abstract
Glycosylation is a crucial post-translational modification process where sugar molecules (glycans) are covalently linked to proteins, lipids, or other biomolecules. In this highly regulated and complex process, a series of enzymes are involved in adding, modifying, or removing sugar residues. This process plays a pivotal role in various biological functions, influencing the structure, stability, and functionality of the modified molecules. Glycosylation is essential in numerous biological processes, including cell adhesion, signal transduction, immune response, and biomolecular recognition. Dysregulation of glycosylation is associated with various diseases. Glycation, a post-translational modification characterized by the non-enzymatic attachment of sugar molecules to proteins, has also emerged as a crucial factor in various diseases. This review comprehensively explores the multifaceted role of glycation in disease pathogenesis, with a specific focus on its implications in osteoarthritis (OA). Glycosylation and glycation alterations wield a profound influence on OA pathogenesis, intertwining with disease onset and progression. Diverse studies underscore the multifaceted role of aberrant glycosylation in OA, particularly emphasizing its intricate relationship with joint tissue degradation and inflammatory cascades. Distinct glycosylation patterns, including N-glycans and O-glycans, showcase correlations with inflammatory cytokines, matrix metalloproteinases, and cellular senescence pathways, amplifying the degenerative processes within cartilage. Furthermore, the impact of advanced glycation end-products (AGEs) formation in OA pathophysiology unveils critical insights into glycosylation-driven chondrocyte behavior and extracellular matrix remodeling. These findings illuminate potential therapeutic targets and diagnostic markers, signaling a promising avenue for targeted interventions in OA management. In this comprehensive review, we aim to thoroughly examine the significant impact of glycosylation or AGEs in OA and explore its varied effects on other related conditions, such as liver-related diseases, immune system disorders, and cancers, among others. By emphasizing glycosylation's role beyond OA and its implications in other diseases, we uncover insights that extend beyond the immediate focus on OA, potentially revealing novel perspectives for diagnosing and treating OA.
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Affiliation(s)
- Hong-zhi Liu
- Department of Orthopaedics, Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
| | - Xin-qiu Song
- The Third Affiliated Hospital of Sun Yat-sen University, Guangzhou, 510630, China
| | - Hongmei Zhang
- Department of Orthopaedics, Wangjing Hospital, China Academy of Chinese Medical Sciences, Beijing, China
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3
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Karhadkar TR, Chen W, Pilling D, Gomer RH. Inhibitors of the Sialidase NEU3 as Potential Therapeutics for Fibrosis. Int J Mol Sci 2022; 24:239. [PMID: 36613682 PMCID: PMC9820515 DOI: 10.3390/ijms24010239] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2022] [Revised: 12/09/2022] [Accepted: 12/13/2022] [Indexed: 12/24/2022] Open
Abstract
Fibrosing diseases are a major medical problem, and are associated with more deaths per year than cancer in the US. Sialidases are enzymes that remove the sugar sialic acid from glycoconjugates. In this review, we describe efforts to inhibit fibrosis by inhibiting sialidases, and describe the following rationale for considering sialidases to be a potential target to inhibit fibrosis. First, sialidases are upregulated in fibrotic lesions in humans and in a mouse model of pulmonary fibrosis. Second, the extracellular sialidase NEU3 appears to be both necessary and sufficient for pulmonary fibrosis in mice. Third, there exist at least three mechanistic ways in which NEU3 potentiates fibrosis, with two of them being positive feedback loops where a profibrotic cytokine upregulates NEU3, and the upregulated NEU3 then upregulates the profibrotic cytokine. Fourth, a variety of NEU3 inhibitors block pulmonary fibrosis in a mouse model. Finally, the high sialidase levels in a fibrotic lesion cause an easily observed desialylation of serum proteins, and in a mouse model, sialidase inhibitors that stop fibrosis reverse the serum protein desialylation. This then indicates that serum protein sialylation is a potential surrogate biomarker for the effect of sialidase inhibitors, which would facilitate clinical trials to test the exciting possibility that sialidase inhibitors could be used as therapeutics for fibrosis.
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Affiliation(s)
| | | | | | - Richard H. Gomer
- Department of Biology, Texas A&M University, College Station, TX 77843-3474, USA
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4
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Hu Q, Cao X, Li S, Liang Y, Luo Y, Feng W, Han D, Niu L. Electrochemically Controlled Atom Transfer Radical Polymerization for Electrochemical Aptasensing of Tumor Biomarkers. Anal Chem 2022; 94:13516-13521. [PMID: 36130914 DOI: 10.1021/acs.analchem.2c02797] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Tumor biomarkers are of great value in the liquid biopsy of malignant tumors. In this work, a simple and cost-friendly electrochemical aptasensor was presented for the highly sensitive and selective detection of glycoprotein tumor biomarkers. The DNA aptamer-modified electrode was used as the sensing interface to specifically capture the target glycoprotein tumor biomarkers, to which the alkyl halide initiators for atom transfer radical polymerization (ATRP) were then attached via the esterification crosslinking between the boronic acid group and the cis-dihydroxyl sites of the conjugated oligosaccharide chains on glycoprotein tumor biomarkers followed by the growth of long-chain polymers through electrochemically controlled ATRP (eATRP) to efficiently recruit the ferrocene detection tags. As there are tens to hundreds of cis-dihydroxyl sites on a glycoprotein tumor biomarker for attaching ATRP initiators while each long-chain polymer can recruit hundreds to thousands of ferrocene detection tags, a significantly high current signal can be generated even in the presence of ultralow-abundance targets. Hence, the eATRP-based electrochemical aptasensor is capable of sensitively and selectively detecting glycoprotein tumor biomarkers. Using alpha-fetoprotein as the model target, the limit of detection was demonstrated to be 0.32 pg/mL. Moreover, the aptasensor has been successfully applied to detect glycoprotein tumor biomarkers in human serum samples. In view of its high sensitivity and selectivity, simple operation, and cost-friendliness, the eATRP-based electrochemical aptasensor shows great promise in the glycoprotein-based liquid biopsy of malignant tumors, even at the early stage of development.
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Affiliation(s)
- Qiong Hu
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Xiaojing Cao
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Shiqi Li
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Yiyi Liang
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Yilin Luo
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Wenxing Feng
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
| | - Dongxue Han
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China.,Guangdong Provincial Key Laboratory of Psychoactive Substances Monitoring and Safety, Anti-Drug Technology Center of Guangdong Province, Guangzhou 510230, P. R. China
| | - Li Niu
- Guangzhou Key Laboratory of Sensing Materials and Devices, Center for Advanced Analytical Science, School of Chemistry and Chemical Engineering, Guangzhou University, Guangzhou 510006, P. R. China
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5
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Samarathunga J, Wijesekara I, Jayasinghe M. Seaweed proteins as a novel protein alternative: Types, extractions, and functional food applications. FOOD REVIEWS INTERNATIONAL 2022. [DOI: 10.1080/87559129.2021.2023564] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Affiliation(s)
- Jayani Samarathunga
- Department of Food Science & Technology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Isuru Wijesekara
- Department of Food Science & Technology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
| | - Madhura Jayasinghe
- Department of Food Science & Technology, Faculty of Applied Sciences, University of Sri Jayewardenepura, Nugegoda, Sri Lanka
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6
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Gong Y, Qin S, Dai L, Tian Z. The glycosylation in SARS-CoV-2 and its receptor ACE2. Signal Transduct Target Ther 2021; 6:396. [PMID: 34782609 PMCID: PMC8591162 DOI: 10.1038/s41392-021-00809-8] [Citation(s) in RCA: 104] [Impact Index Per Article: 34.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2021] [Revised: 10/10/2021] [Accepted: 10/24/2021] [Indexed: 02/05/2023] Open
Abstract
Coronavirus disease 2019 (COVID-19), a highly infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has infected more than 235 million individuals and led to more than 4.8 million deaths worldwide as of October 5 2021. Cryo-electron microscopy and topology show that the SARS-CoV-2 genome encodes lots of highly glycosylated proteins, such as spike (S), envelope (E), membrane (M), and ORF3a proteins, which are responsible for host recognition, penetration, binding, recycling and pathogenesis. Here we reviewed the detections, substrates, biological functions of the glycosylation in SARS-CoV-2 proteins as well as the human receptor ACE2, and also summarized the approved and undergoing SARS-CoV-2 therapeutics associated with glycosylation. This review may not only broad the understanding of viral glycobiology, but also provide key clues for the development of new preventive and therapeutic methodologies against SARS-CoV-2 and its variants.
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Affiliation(s)
- Yanqiu Gong
- National Clinical Research Center for Geriatrics and Department of General Practice, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, 610041, Chengdu, China
| | - Suideng Qin
- School of Chemical Science & Engineering, Shanghai Key Laboratory of Chemical Assessment and Sustainability, Tongji University, 200092, Shanghai, China
| | - Lunzhi Dai
- National Clinical Research Center for Geriatrics and Department of General Practice, State Key Laboratory of Biotherapy, West China Hospital, Sichuan University, and Collaborative Innovation Center of Biotherapy, 610041, Chengdu, China.
| | - Zhixin Tian
- School of Chemical Science & Engineering, Shanghai Key Laboratory of Chemical Assessment and Sustainability, Tongji University, 200092, Shanghai, China.
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7
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Gruszewska E, Grytczuk A, Chrostek L. Glycosylation in viral hepatitis. Biochim Biophys Acta Gen Subj 2021; 1865:129997. [PMID: 34474116 DOI: 10.1016/j.bbagen.2021.129997] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Revised: 08/26/2021] [Accepted: 08/26/2021] [Indexed: 01/12/2023]
Abstract
BACKGROUND The interaction between hepatitis viruses and host cells is regulated by glycans exposed on the surfaces of human and viruses cells. As the biosynthesis and degradation of human glycoproteins take place at the highest level in the liver, the changes in glycosylation of serum proteins may potentially be useful in the diagnosis of liver pathology. On the other hand, specific alterations in viruses envelope glycans could cause large changes in the entry process of hepatitis viruses into a host cells. SCOPE OF REVIEW Unique alterations in glycosylation of specific proteins can be detected in HBV and HCV infected patients especially with confirmed fibrosis/cirrhosis. On the other hand, viral envelope proteins that bind to host cells are glycosylated. These glycosylated proteins play a key role in recognition, binding and penetration of the host cells. In this review we summarized the knowledge about significance of glycosylation for viral and host factors. MAJOR CONCLUSIONS Glycosylation changes in single serum glycoproteins are noticed in the sera of patients with viral hepatitis. However, a more specific biomarker for the diagnosis of chronic hepatitis than that of a single glycosylated molecule is systemic investigation of complete set of glycan structures (N-glycome). Glycans play important roles in the viral biology cycle especially as a connecting element with host receptors. GENERAL SIGNIFICANCE The interaction between virus glycoproteins and cellular receptors, which are also glycoproteins, determines the possibility of virus penetration into host cells. Therefore these glycans can be the targets for the developing of novel treatment strategies of viral hepatitis.
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Affiliation(s)
- Ewa Gruszewska
- Department of Biochemical Diagnostics, Medical University of Bialystok, Waszyngtona 15A, 15-269 Bialystok, Poland
| | - Agnieszka Grytczuk
- Department of Laboratory Diagnostics, University Clinical Hospital in Bialystok, Bialystok, Poland
| | - Lech Chrostek
- Department of Biochemical Diagnostics, Medical University of Bialystok, Waszyngtona 15A, 15-269 Bialystok, Poland.
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8
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Bordron A, Morel M, Bagacean C, Dueymes M, Pochard P, Harduin-Lepers A, Jamin C, Pers JO. Hyposialylation Must Be Considered to Develop Future Therapies in Autoimmune Diseases. Int J Mol Sci 2021; 22:ijms22073402. [PMID: 33810246 PMCID: PMC8036829 DOI: 10.3390/ijms22073402] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2021] [Revised: 03/16/2021] [Accepted: 03/22/2021] [Indexed: 12/14/2022] Open
Abstract
Autoimmune disease development depends on multiple factors, including genetic and environmental. Abnormalities such as sialylation levels and/or quality have been recently highlighted. The adjunction of sialic acid at the terminal end of glycoproteins and glycolipids is essential for distinguishing between self and non-self-antigens and the control of pro- or anti-inflammatory immune reactions. In autoimmunity, hyposialylation is responsible for chronic inflammation, the anarchic activation of the immune system and organ lesions. A detailed characterization of this mechanism is a key element for improving the understanding of these diseases and the development of innovative therapies. This review focuses on the impact of sialylation in autoimmunity in order to determine future treatments based on the regulation of hyposialylation.
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Affiliation(s)
- Anne Bordron
- Univ Brest, Inserm, LBAI, UMR1227 Brest, France; (M.M.); (C.B.); (M.D.); (C.J.); (J.-O.P.)
- Correspondence:
| | - Marie Morel
- Univ Brest, Inserm, LBAI, UMR1227 Brest, France; (M.M.); (C.B.); (M.D.); (C.J.); (J.-O.P.)
| | - Cristina Bagacean
- Univ Brest, Inserm, LBAI, UMR1227 Brest, France; (M.M.); (C.B.); (M.D.); (C.J.); (J.-O.P.)
- CHU de Brest, Laboratory of Immunolgy, 29200 Brest, France;
| | - Maryvonne Dueymes
- Univ Brest, Inserm, LBAI, UMR1227 Brest, France; (M.M.); (C.B.); (M.D.); (C.J.); (J.-O.P.)
- CHU de Brest, Laboratory of Immunolgy, 29200 Brest, France;
| | - Pierre Pochard
- CHU de Brest, Laboratory of Immunolgy, 29200 Brest, France;
| | - Anne Harduin-Lepers
- Univ. Lille, CNRS UMR 8576—UGSF—Unité de Glycobiologie Structurale et Fonctionnelle, 59000 Lille, France;
| | - Christophe Jamin
- Univ Brest, Inserm, LBAI, UMR1227 Brest, France; (M.M.); (C.B.); (M.D.); (C.J.); (J.-O.P.)
- CHU de Brest, Laboratory of Immunolgy, 29200 Brest, France;
| | - Jacques-Olivier Pers
- Univ Brest, Inserm, LBAI, UMR1227 Brest, France; (M.M.); (C.B.); (M.D.); (C.J.); (J.-O.P.)
- CHU de Brest, Laboratory of Immunolgy, 29200 Brest, France;
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9
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Pathak P, Baird MA, Shvartsburg AA. High-Resolution Ion Mobility Separations of Isomeric Glycoforms with Variations on the Peptide and Glycan Levels. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2020; 31:1603-1609. [PMID: 32501708 DOI: 10.1021/jasms.0c00183] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Glycosylation is a ubiquitous post-translational modification (PTM) that strongly affects the protein folding and function. Glycosylation patterns are impacted by many diseases, making promising biomarkers. Glycans are also the most complex PTMs, exhibiting isomers (linkage, anomers, and those with isomeric moieties). Permuted with localization variants that occur for all PTMs, these produce numerous isomeric glycoforms. Characterizing them by mass spectrometry and ion mobility spectrometry (IMS) has been a challenge. High-definition differential IMS (FAIMS) had robustly disentangled isomeric peptides involving other PTMs but was not evaluated for glycopeptides that featured multilevel isomerism. Here, we apply it to representative mucin glycopeptides with O-linked glycans: three GalNAc localization variants, a pair with α/β GalNAc anomers, and another with GalNAc/GlcNAc isomers. The first two classes were separated baseline with the resolution exceeding previous benchmarks by 10-fold, and the last pair was partly resolved. The recently demonstrated straightforward coupling to ultrahigh-resolution MS and electron-transfer dissociation makes high-definition FAIMS an attractive tool for glycoproteomics.
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Affiliation(s)
- Pratima Pathak
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
| | - Matthew A Baird
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
| | - Alexandre A Shvartsburg
- Department of Chemistry, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260, United States
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10
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Loschwitz J, Olubiyi OO, Hub JS, Strodel B, Poojari CS. Computer simulations of protein-membrane systems. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2020; 170:273-403. [PMID: 32145948 PMCID: PMC7109768 DOI: 10.1016/bs.pmbts.2020.01.001] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The interactions between proteins and membranes play critical roles in signal transduction, cell motility, and transport, and they are involved in many types of diseases. Molecular dynamics (MD) simulations have greatly contributed to our understanding of protein-membrane interactions, promoted by a dramatic development of MD-related software, increasingly accurate force fields, and available computer power. In this chapter, we present available methods for studying protein-membrane systems with MD simulations, including an overview about the various all-atom and coarse-grained force fields for lipids, and useful software for membrane simulation setup and analysis. A large set of case studies is discussed.
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Affiliation(s)
- Jennifer Loschwitz
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany; Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
| | - Olujide O Olubiyi
- Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany; Department of Pharmaceutical Chemistry, Faculty of Pharmacy, Obafemi Awolowo University, Ile-Ife, Nigeria
| | - Jochen S Hub
- Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany
| | - Birgit Strodel
- Institute of Theoretical and Computational Chemistry, Heinrich Heine University Düsseldorf, Düsseldorf, Germany; Institute of Biological Information Processing (IBI-7: Structural Biochemistry), Forschungszentrum Jülich, Jülich, Germany
| | - Chetan S Poojari
- Theoretical Physics and Center for Biophysics, Saarland University, Saarbrücken, Germany.
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11
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Ramírez AS, Kowal J, Locher KP. Cryo–electron microscopy structures of human oligosaccharyltransferase complexes OST-A and OST-B. Science 2019; 366:1372-1375. [DOI: 10.1126/science.aaz3505] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2019] [Accepted: 11/13/2019] [Indexed: 12/22/2022]
Abstract
Oligosaccharyltransferase (OST) catalyzes the transfer of a high-mannose glycan onto secretory proteins in the endoplasmic reticulum. Mammals express two distinct OST complexes that act in a cotranslational (OST-A) or posttranslocational (OST-B) manner. Here, we present high-resolution cryo–electron microscopy structures of human OST-A and OST-B. Although they have similar overall architectures, structural differences in the catalytic subunits STT3A and STT3B facilitate contacts to distinct OST subunits, DC2 in OST-A and MAGT1 in OST-B. In OST-A, interactions with TMEM258 and STT3A allow ribophorin-I to form a four-helix bundle that can bind to a translating ribosome, whereas the equivalent region is disordered in OST-B. We observed an acceptor peptide and dolichylphosphate bound to STT3B, but only dolichylphosphate in STT3A, suggesting distinct affinities of the two OST complexes for protein substrates.
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Affiliation(s)
- Ana S. Ramírez
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Julia Kowal
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Kaspar P. Locher
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
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12
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Jonnada M, El Rassi Z. Poly (N-acryloxysuccinimide-co-ethylene glycol dimethacrylate) precursor monolith and its post polymerization modification with alkyl ligands, trypsin and lectins for reversed-phase chromatography, miniaturized enzyme reactors and lectin affinity chromato. Electrophoresis 2017; 38:2870-2879. [DOI: 10.1002/elps.201700221] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2017] [Revised: 07/03/2017] [Accepted: 08/01/2017] [Indexed: 11/09/2022]
Affiliation(s)
- Murthy Jonnada
- Department of chemistry; Oklahoma State University; Stillwater OK USA
| | - Ziad El Rassi
- Department of chemistry; Oklahoma State University; Stillwater OK USA
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13
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Elharar Y, Podilapu AR, Guan Z, Kulkarni SS, Eichler J. Assembling Glycan-Charged Dolichol Phosphates: Chemoenzymatic Synthesis of a Haloferax volcanii N-Glycosylation Pathway Intermediate. Bioconjug Chem 2017; 28:2461-2470. [PMID: 28809486 DOI: 10.1021/acs.bioconjchem.7b00436] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
N-glycosylation, the covalent attachment of glycans to select protein target Asn residues, is a post-translational modification performed by all three domains of life. In the halophilic archaea Haloferax volcanii, in which understanding of this universal protein-processing event is relatively well-advanced, genes encoding the components of the archaeal glycosylation (Agl) pathway responsible for the assembly and attachment of an N-linked pentasaccharide have been identified. As elsewhere, the N-linked glycan is assembled on phosphodolichol carriers before transfer to target Asn residues. However, as little is presently known of the Hfx. volcanii Agl pathway at the protein level, the seemingly unique ability of Archaea to use dolichol phosphate (DolP) as the glycan lipid carrier, rather than dolichol pyrophosphate used by eukaryotes, remains poorly understood. With this in mind, a chemoenzymatic approach was taken to biochemically study AglG, one of the five glycosyltransferases of the pathway. Accordingly, a novel regio- and stereoselective reduction of naturally isolated polyprenol gave facile access to S-dolichol via asymmetric transfer hydrogenation under very mild conditions. This compound was used to generate glucose-charged DolP, a precursor of the N-linked pentasaccharide, as well as DolP-glucose-glucuronic acid and DolP-glucuronic acid. AglG, purified from Hfx. volcanii membranes in hypersaline conditions, like those encountered in situ, was subsequently combined with uridine diphosphate (UDP)-glucuronic acid and DolP-glucose to yield DolP-glucose-glucuronic acid. The in vitro system for the study of AglG activity developed here represents the first such tool for studying halophilic glycosyltransferases and will allow for a detailed understanding of archaeal N-glycosylation.
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Affiliation(s)
- Yifat Elharar
- Department of Life Sciences, Ben Gurion University of the Negev , Beersheva 8410501, Israel
| | - Ananda Rao Podilapu
- Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India
| | - Ziqiang Guan
- Department of Biochemistry, Duke University Medical Center , Durham, North Carolina 27710, United States
| | - Suvarn S Kulkarni
- Department of Chemistry, Indian Institute of Technology Bombay , Powai, Mumbai 400076, India
| | - Jerry Eichler
- Department of Life Sciences, Ben Gurion University of the Negev , Beersheva 8410501, Israel
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Audagnotto M, Dal Peraro M. Protein post-translational modifications: In silico prediction tools and molecular modeling. Comput Struct Biotechnol J 2017; 15:307-319. [PMID: 28458782 PMCID: PMC5397102 DOI: 10.1016/j.csbj.2017.03.004] [Citation(s) in RCA: 109] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 03/17/2017] [Accepted: 03/21/2017] [Indexed: 02/09/2023] Open
Abstract
Post-translational modifications (PTMs) occur in almost all proteins and play an important role in numerous biological processes by significantly affecting proteins' structure and dynamics. Several computational approaches have been developed to study PTMs (e.g., phosphorylation, sumoylation or palmitoylation) showing the importance of these techniques in predicting modified sites that can be further investigated with experimental approaches. In this review, we summarize some of the available online platforms and their contribution in the study of PTMs. Moreover, we discuss the emerging capabilities of molecular modeling and simulation that are able to complement these bioinformatics methods, providing deeper molecular insights into the biological function of post-translational modified proteins.
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Affiliation(s)
- Martina Audagnotto
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
| | - Matteo Dal Peraro
- Institute of Bioengineering, School of Life Sciences, École Polytechnique Fédérale de Lausanne (EPFL), Lausanne, Switzerland
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15
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Tabasum S, Noreen A, Kanwal A, Zuber M, Anjum MN, Zia KM. Glycoproteins functionalized natural and synthetic polymers for prospective biomedical applications: A review. Int J Biol Macromol 2017; 98:748-776. [PMID: 28111295 DOI: 10.1016/j.ijbiomac.2017.01.078] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2016] [Revised: 01/05/2017] [Accepted: 01/16/2017] [Indexed: 02/06/2023]
Abstract
Glycoproteins have multidimensional properties such as biodegradability, biocompatibility, non-toxicity, antimicrobial and adsorption properties; therefore, they have wide range of applications. They are blended with different polymers such as chitosan, carboxymethyl cellulose (CMC), polyvinyl pyrrolidone (PVP), polycaprolactone (PCL), heparin, polystyrene fluorescent nanoparticles (PS-NPs) and carboxyl pullulan (PC) to improve their properties like thermal stability, mechanical properties, resistance to pH, chemical stability and toughness. Considering the versatile charateristics of glycoprotein based polymers, this review sheds light on synthesis and characterization of blends and composites of glycoproteins, with natural and synthetic polymers and their potential applications in biomedical field such as drug delivery system, insulin delivery, antimicrobial wound dressing uses, targeting of cancer cells, development of anticancer vaccines, development of new biopolymers, glycoproteome research, food product and detection of dengue glycoproteins. All the technical scientific issues have been addressed; highlighting the recent advancement.
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Affiliation(s)
- Shazia Tabasum
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | - Aqdas Noreen
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | - Arooj Kanwal
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | - Mohammad Zuber
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan
| | | | - Khalid Mahmood Zia
- Institute of Chemistry, Government College University, Faisalabad 38030, Pakistan.
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Impact of glycosylation on stability, structure and unfolding of soybean agglutinin (SBA): an insight from thermal perturbation molecular dynamics simulations. Glycoconj J 2015; 32:371-84. [DOI: 10.1007/s10719-015-9601-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2015] [Revised: 05/18/2015] [Accepted: 05/26/2015] [Indexed: 11/26/2022]
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17
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Structural features of the Nogo receptor signaling complexes at the neuron/myelin interface. Neurosci Res 2014; 87:1-7. [PMID: 24956133 DOI: 10.1016/j.neures.2014.06.003] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 05/23/2014] [Accepted: 06/13/2014] [Indexed: 11/22/2022]
Abstract
Upon spinal cord injury, the central nervous system axons are unable to regenerate, partially due to the repulsive action of myelin inhibitors, such as the myelin-associated glycoprotein (MAG), Nogo-A and the oligodendrocyte myelin glycoprotein (OMgp). These inhibitors bind and signal through a single receptor/co-receptor complex that comprises of NgR1/LINGO-1 and either p75 or TROY, triggering intracellular downstream signaling that impedes the re-growth of axons. Structure-function analysis of myelin inhibitors and their neuronal receptors, particularly the NgRs, have provided novel information regarding the molecular details of the inhibitor/receptor/co-receptor interactions. Structural and biochemical studies have revealed the architecture of many of these proteins and identified the molecular regions important for assembly of the inhibitory signaling complexes. It was also recently shown that gangliosides, such as GT1b, mediate receptor/co-receptor binding. In this review, we highlight these studies and summarize our current understanding of the multi-protein cell-surface complexes mediating inhibitory signaling events at the neuron/myelin interface.
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McCarthy C, Saldova R, Wormald MR, Rudd PM, McElvaney NG, Reeves EP. The Role and Importance of Glycosylation of Acute Phase Proteins with Focus on Alpha-1 Antitrypsin in Acute and Chronic Inflammatory Conditions. J Proteome Res 2014; 13:3131-43. [DOI: 10.1021/pr500146y] [Citation(s) in RCA: 102] [Impact Index Per Article: 10.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- Cormac McCarthy
- Respiratory
Research Division, Royal College of Surgeons in Ireland, Beaumont
Hospital, Dublin 9, Ireland
| | - Radka Saldova
- NIBRT
GlycoScience Group, The National Institute for Bioprocessing Research
and Training, University College Dublin, Dublin 4, Ireland
| | - Mark R Wormald
- Department of Biochemistry, Oxford Glycobiology Institute, University of Oxford, Oxford OX1 3QU, U.K
| | - Pauline M. Rudd
- NIBRT
GlycoScience Group, The National Institute for Bioprocessing Research
and Training, University College Dublin, Dublin 4, Ireland
| | - Noel G. McElvaney
- Respiratory
Research Division, Royal College of Surgeons in Ireland, Beaumont
Hospital, Dublin 9, Ireland
| | - Emer P. Reeves
- Respiratory
Research Division, Royal College of Surgeons in Ireland, Beaumont
Hospital, Dublin 9, Ireland
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Jian W, Edom RW, Wang D, Weng N, Zhang SW. Relative quantitation of glycoisoforms of intact apolipoprotein C3 in human plasma by liquid chromatography-high-resolution mass spectrometry. Anal Chem 2013; 85:2867-74. [PMID: 23368640 DOI: 10.1021/ac3034757] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Glycosylation is one of the most important post-translational modifications to mammalian proteins. Distribution of different glycoisoforms of certain proteins may reflect disease conditions and, therefore, can potentially be utilized as biomarkers. Apolipoprotein C3 (ApoC3) is one of the many plasma glycoproteins extensively studied for association with disease states. ApoC3 exists in three main glycoisoforms, including ApoC3-1 and ApoC3-2, which contain an O-linked carbohydrate moiety consisting of three and four monosaccharide residues, respectively, and ApoC3-0 that lacks the entire glycosylation chain. Changes in the ratio of different glycoisoforms of ApoC3 have been observed in pathological conditions such as kidney disease, liver disease, and diabetes. They may provide important information for diagnosis, prognosis, and evaluation of therapeutic response for metabolic conditions. In this current work, a liquid chromatography (LC)-high-resolution (HR) time-of-flight (TOF) mass spectrometry (MS) method was developed for relative quantitation of different glycoisoforms of intact ApoC3 in human plasma. The samples were processed using a solid-phase extraction (SPE) method and then subjected to LC-full scan HRMS analysis. Isotope peaks for each targeted glycoisoform at two charge states were extracted using a window of 50 mDa and integrated into a chromatographic peak. The peak area ratios of ApoC3-1/ApoC3-0 and ApoC3-2/ApoC3-0 were calculated and evaluated for assay performance. The results indicated that the ratio can be determined with excellent reproducibility in multiple subjects. It has also been observed that the ratios remained constant in plasma exposed to room temperature, freeze-thaw cycles, and long-term frozen storage. The method was applied in preliminary biomarker research of diabetes by analyzing plasma samples collected from normal, prediabetic, and diabetic subjects. Significant differences were revealed in the ApoC3-1/ApoC3-0 ratio and in the ApoC3-2/ApoC3-0 ratio among the three groups. The workflow of intact protein analysis using full scan HRMS established in this current work can be potentially extended to relative quantitation of other glycosylated proteins. To our best knowledge, this is the first time that a systematic approach of relative quantitation of targeted intact protein glycoisoforms using LC-MS has been established and utilized in biomarker research.
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Affiliation(s)
- Wenying Jian
- Janssen Research and Development, Johnson & Johnson, 1000 Route 202 South, Raritan, New Jersey 08869, United States
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Mining the virgin land of neurotoxicology: a novel paradigm of neurotoxic peptides action on glycosylated voltage-gated sodium channels. J Toxicol 2012; 2012:843787. [PMID: 22829817 PMCID: PMC3399347 DOI: 10.1155/2012/843787] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2012] [Revised: 04/17/2012] [Accepted: 05/24/2012] [Indexed: 12/30/2022] Open
Abstract
Voltage-gated sodium channels (VGSCs) are important membrane protein carrying on the molecular basis for action potentials (AP) in neuronal firings. Even though the structure-function studies were the most pursued spots, the posttranslation modification processes, such as glycosylation, phosphorylation, and alternative splicing associating with channel functions captured less eyesights. The accumulative research suggested an interaction between the sialic acids chains and ion-permeable pores, giving rise to subtle but significant impacts on channel gating. Sodium channel-specific neurotoxic toxins, a family of long-chain polypeptides originated from venomous animals, are found to potentially share the binding sites adjacent to glycosylated region on VGSCs. Thus, an interaction between toxin and glycosylated VGSC might hopefully join the campaign to approach the role of glycosylation in modulating VGSCs-involved neuronal network activity. This paper will cover the state-of-the-art advances of researches on glycosylation-mediated VGSCs function and the possible underlying mechanisms of interactions between toxin and glycosylated VGSCs, which may therefore, fulfill the knowledge in identifying the pharmacological targets and therapeutic values of VGSCs.
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Tep S, Hincapie M, Hancock WS. The characterization and quantitation of glycomic changes in CHO cells during a bioreactor campaign. Biotechnol Bioeng 2012; 109:3007-17. [DOI: 10.1002/bit.24590] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2012] [Revised: 06/05/2012] [Accepted: 06/20/2012] [Indexed: 12/13/2022]
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22
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A general approach for the purification and quantitative glycomic analysis of human plasma. Anal Bioanal Chem 2012; 402:2687-700. [DOI: 10.1007/s00216-012-5712-5] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2011] [Revised: 12/28/2011] [Accepted: 01/04/2012] [Indexed: 11/26/2022]
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23
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Tep S, Hincapie M, Hancock WS. A MALDI-TOF MS method for the simultaneous and quantitative analysis of neutral and sialylated glycans of CHO-expressed glycoproteins. Carbohydr Res 2012; 347:121-9. [DOI: 10.1016/j.carres.2011.10.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2011] [Revised: 10/04/2011] [Accepted: 10/06/2011] [Indexed: 01/05/2023]
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24
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Saha N, Kolev MV, Semavina M, Himanen J, Nikolov DB. Ganglioside mediate the interaction between Nogo receptor 1 and LINGO-1. Biochem Biophys Res Commun 2011; 413:92-7. [DOI: 10.1016/j.bbrc.2011.08.060] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2011] [Accepted: 08/15/2011] [Indexed: 12/11/2022]
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25
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Calo D, Kaminski L, Eichler J. Protein glycosylation in Archaea: Sweet and extreme. Glycobiology 2010; 20:1065-76. [DOI: 10.1093/glycob/cwq055] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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26
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Optimization of the enzymatic one pot reaction for the synthesis of uridine 5'-diphosphogalactose. Bioprocess Biosyst Eng 2010; 33:71-8. [PMID: 19714366 DOI: 10.1007/s00449-009-0365-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2009] [Accepted: 07/28/2009] [Indexed: 10/20/2022]
Abstract
Five recombinant Escherichia coli extracts harboring overexpressed galactokinase, galactose-1-phosphate uridyltransferase, UDP-glucose pyrophophorylase, UMP kinase, and acetate kinase (AK) were utilized for the production of UDP-galactose (UDP-Gal). We analyzed the parameters which limit the yield of UDP-Gal in the reaction, and the reaction was optimized by increasing the concentration of AK. AK was used for the ATP regeneration as well as the conversion of UDP to UTP. The activities of four overexpressed enzymes were identically fixed, and then we increased the activity of AK to 20 times higher than others. The extracts catalyzed the production of UDP-Gal from UMP (10 mM), galactose (12 mM), ATP (1 mM), and acetyl phosphate (40 mM). As the result of the reaction, the conversion yield of UDP-Gal reached to 95% from 10 mMUMP.
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27
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Hwang H, Zhang J, Chung KA, Leverenz JB, Zabetian CP, Peskind ER, Jankovic J, Su Z, Hancock AM, Pan C, Montine TJ, Pan S, Nutt J, Albin R, Gearing M, Beyer RP, Shi M, Zhang J. Glycoproteomics in neurodegenerative diseases. MASS SPECTROMETRY REVIEWS 2010; 29:79-125. [PMID: 19358229 PMCID: PMC2799547 DOI: 10.1002/mas.20221] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
Protein glycosylation regulates protein function and cellular distribution. Additionally, aberrant protein glycosylations have been recognized to play major roles in human disorders, including neurodegenerative diseases. Glycoproteomics, a branch of proteomics that catalogs and quantifies glycoproteins, provides a powerful means to systematically profile the glycopeptides or glycoproteins of a complex mixture that are highly enriched in body fluids, and therefore, carry great potential to be diagnostic and/or prognostic markers. Application of this mass spectrometry-based technology to the study of neurodegenerative disorders (e.g., Alzheimer's disease and Parkinson's disease) is relatively new, and is expected to provide insight into the biochemical pathogenesis of neurodegeneration, as well as biomarker discovery. In this review, we have summarized the current understanding of glycoproteins in biology and neurodegenerative disease, and have discussed existing proteomic technologies that are utilized to characterize glycoproteins. Some of the ongoing studies, where glycoproteins isolated from cerebrospinal fluid and human brain are being characterized in Parkinson's disease at different stages versus controls, are presented, along with future applications of targeted validation of brain specific glycoproteins in body fluids.
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Affiliation(s)
- Hyejin Hwang
- Department of Pathology, University of Washington, Seattle, Washington
| | - Jianpeng Zhang
- Department of Pathology, University of Washington, Seattle, Washington
| | - Kathryn A. Chung
- Department of Neurology, Oregon Health and Science University, Portland, Oregon
| | - James B. Leverenz
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington
| | - Cyrus P. Zabetian
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington
| | - Elaine R. Peskind
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington
- Department of Neurology, University of Washington School of Medicine, Seattle, Washington
| | - Joseph Jankovic
- Department of Neurology, Baylor College of Medicine, Houston, Texas
| | - Zhen Su
- Department of Pathology, University of Washington, Seattle, Washington
| | - Aneeka M. Hancock
- Department of Pathology, University of Washington, Seattle, Washington
| | - Catherine Pan
- Department of Pathology, University of Washington, Seattle, Washington
| | - Thomas J. Montine
- Department of Pathology, University of Washington, Seattle, Washington
| | - Sheng Pan
- Department of Pathology, University of Washington, Seattle, Washington
| | - John Nutt
- Department of Neurology, Oregon Health and Science University, Portland, Oregon
| | - Roger Albin
- Ann Arbor VAMC GRECC and Department of Neurology, University of Michigan, Ann Arbor, Michigan
| | - Marla Gearing
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, Georgia
| | - Richard P. Beyer
- Department of Environmental & Occupational Health Sciences, University of Washington School of Medicine, Seattle, Washington
| | - Min Shi
- Department of Pathology, University of Washington, Seattle, Washington
| | - Jing Zhang
- Department of Pathology, University of Washington, Seattle, Washington
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Makovitzky J, Richter S. The relevance of the aldehyde bisulfite toluidine blue reaction and its variants in the submicroscopic carbohydrate research. Acta Histochem 2009; 111:273-91. [PMID: 19157525 PMCID: PMC7172417 DOI: 10.1016/j.acthis.2008.11.027] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Carbohydrates are chemical compounds that contain only oxygen, hydrogen and carbon. They are classified by their number of sugar units: monosaccharides (such as glucose and fructose), and disaccharides (such as sucrose and lactose) are simple carbohydrates; oligosaccharides and polysaccharides (such as starch, glycogen and cellulose) are complex carbohydrates. Carbohydrates play a crucial role in diverse biological systems [Hricovín M. Structural aspects of carbohydrates and the relation with their biological properties. Curr Med Chem 2004;11:2565-83]. According to Roseman [Sugars of the cell membrane. In: Weissmann G, Clairborn E, editors. Cell membranes. Biochemistry, Cell Biology, Pathology. New York: H. P. Publ. Co; 1975. p. 55-64], two classes of glycoproteins are described. Free glycoproteins are localised in the surface coat of the membranes and form a thick mobile layer, without any association to the membrane itself. Functionally, however, they are located in a close association with the membrane (e.g. in the duodenal mucosa). The other group consists of the membrane glycoproteins, which are integral to the membranes and are located in the outer layer. The oligosaccharide chains are bound to the N-terminal part of proteins, and are situated in the hydrophilic zone. Glycoproteins have diverse functions. They are important in specific receptor functions, in immunological cell destruction and play a significant role in reactions with lectins, antibodies, as well as in cell association and mutual recognition of the cells. This paper focuses on aspects of a summary of polarisation optical investigations and biological functions of the following three groups of carbohydrates: oligosaccharides, glycoproteins and glycosaminoglycans.
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Affiliation(s)
- Josef Makovitzky
- Department of Neuropathology, University Heidelberg, Im Neuenheimer Feld 220, D-69120 Heidelberg, Germany.
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29
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Yuan Chuan L. Tracing the development of Structural Elucidation of N-glycans. TRENDS GLYCOSCI GLYC 2009. [DOI: 10.4052/tigg.21.53] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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30
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Eggs. Food Chem 2008. [DOI: 10.1007/978-3-540-69934-7_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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31
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Pham VT, Ewing E, Kaplan H, Choma C, Hefford MA. Glycation improves the thermostability of trypsin and chymotrypsin. Biotechnol Bioeng 2008; 101:452-9. [DOI: 10.1002/bit.21919] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Mitra N, Sinha S, Ramya TNC, Surolia A. N-linked oligosaccharides as outfitters for glycoprotein folding, form and function. Trends Biochem Sci 2006; 31:156-63. [PMID: 16473013 DOI: 10.1016/j.tibs.2006.01.003] [Citation(s) in RCA: 233] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2005] [Revised: 01/06/2006] [Accepted: 01/30/2006] [Indexed: 01/27/2023]
Abstract
Glycosylation, particularly N-linked glycosylation, profoundly affects protein folding, oligomerization and stability. The increased efficiency of folding of glycosylated proteins could be due to the chaperone-like activity of glycans, which is observed even when the glycan is not attached to the protein. Covalently linked glycans could also facilitate oligomerization by mediating inter-subunit interactions in the protein or stabilizing the oligomer in other ways. Glycosylation also affects the rate of fibril formation in prion proteins: N-glycans reduce the rate of fibril formation, and O-glycans affect the rate either way depending on factors such as position and orientation. It has yet to be determined whether there is any correlation among the sites of glycosylation and the ensuing effect in multiply glycosylated proteins. It is also not apparent whether there is a common pattern in the conservation of glycans in a related family of glycoproteins, but it is evident that glycosylation is a multifaceted post-translational modification. Indeed, glycosylation serves to "outfit" proteins for fold-function balance.
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Affiliation(s)
- Nivedita Mitra
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore 560 012, India
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Nikandrov NN, Deshimaru M, Tani A, Chijiwa T, Shibata H, Chang CC, Fukumaki Y, Ito T, Ohno M. Purification, primary structures and evolution of coagulant proteases from Deinagkistrodon actus venom. Toxicon 2005; 46:907-17. [PMID: 16257431 DOI: 10.1016/j.toxicon.2005.08.016] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2005] [Revised: 08/25/2005] [Accepted: 08/25/2005] [Indexed: 11/25/2022]
Abstract
Deinagkistrodon (formerly Agkistrodon) actus (Taiwan) snake venom was found to contain at least seven closely related coagulant proteases. One of them, named actibin, was purified to homogeneity by means of four chromatographic steps. Actibin acted on fibrinogen to form fibrin clots with extremely high specific activity of 1,630 NIH units/mg and preferentially released fibrinopeptide A. Actibin was an acidic glycoprotein (pI 3.4) with molecular weight of 41,000, which was reduced to 28,800 after deglycosylation with N-glycanase. The k(cat)/K(m) values of actibin for hydrolysis of tosyl-l-arginine methyl ester and benzoyl-l-arginine p-nitroanilide were one-third to a half those for thrombin, reflecting a high potency of actibin in fibrinogen clotting. The amidase activities of actibin and its family proteases were inhibited by 3,4-dichloroisocoumarin, a serine protease inhibitor, indicating that actibin and its family proteases are serine proteases. Four cDNAs, named DaP1 and DaP7-DaP9, encoding D. actus coagulant proteases were cloned. All cDNAs contain an open reading frame of 780 bp coding for 260 amino acid residues, including a signal peptide of 24 amino acid residues. Their amino acid sequences predicted are highly homologous to one another with one to five amino acid substitutions. When four D. actus protease cDNAs were compared with the cDNAs coding for Trimeresurus flavoviridis and T. gramineus venom serine proteases, accelerated evolution was clearly observed. Similarity of the nucleotide sequences of four D. actus protease cDNAs with no synonymous and one to five nonsynonymous substitutions seems not to be in direct conformity with accelerated evolution. This possibly suggests that they have evolved to a similar direction to enhance their clotting activity rather than to produce other physiological activities.
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Affiliation(s)
- Nikolai N Nikandrov
- Laboratory of Chemistry and Technology of Animal Products, Division of Biological Resources and Environmental Science, Graduate School of Kyushu University, Fukuoka 812-8581, Japan
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BENDIAK B, COOK GMW. Kinetic Parameters of a β-d-Galactoside α2→6 Sialyltransferase from Embryonic Chicken Liver. ACTA ACUST UNITED AC 2005. [DOI: 10.1111/j.1432-1033.1982.tb06972.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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36
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Voisin S, Houliston RS, Kelly J, Brisson JR, Watson D, Bardy SL, Jarrell KF, Logan SM. Identification and characterization of the unique N-linked glycan common to the flagellins and S-layer glycoprotein of Methanococcus voltae. J Biol Chem 2005; 280:16586-93. [PMID: 15723834 DOI: 10.1074/jbc.m500329200] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The flagellum of Methanococcus voltae is composed of four structural flagellin proteins FlaA, FlaB1, FlaB2, and FlaB3. These proteins possess a total of 15 potential N-linked sequons (NX(S/T)) and show a mass shift on an SDS-polyacrylamide gel indicating significant post-translational modification. We describe here the structural characterization of the flagellin glycan from M. voltae using mass spectrometry to examine the proteolytic digests of the flagellin proteins in combination with NMR analysis of the purified glycan using a sensitive, cryogenically cooled probe. Nano-liquid chromatography-tandem mass spectrometry analysis of the proteolytic digests of the flagellin proteins revealed that they are post-translationally modified with a novel N-linked trisaccharide of mass 779 Da that is composed of three sugar residues with masses of 318, 258, and 203 Da, respectively. In every instance the glycan is attached to the peptide through the asparagine residue of a typical N-linked sequon. The glycan modification has been observed on 14 of the 15 sequon sites present on the four flagellin structural proteins. The novel glycan structure elucidated by NMR analysis was shown to be a trisaccharide composed of beta-ManpNAcA6Thr-(1-4)-beta-Glc-pNAc3NAcA-(1-3)-beta-GlcpNAc linked to Asn. In addition, the same trisaccharide was identified on a tryptic peptide of the S-layer protein from this organism implicating a common N-linked glycosylation pathway.
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Affiliation(s)
- Sebastien Voisin
- Institute for Biological Sciences, National Research Council, Ottawa, Ontario K1A OR6, Canada
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Chan AKC, Berry LR, Paredes N, Parmar N. Isoform composition of antithrombin in a covalent antithrombin-heparin complex. Biochem Biophys Res Commun 2003; 309:986-91. [PMID: 13679071 DOI: 10.1016/j.bbrc.2003.08.109] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Antithrombin (AT) circulates in two isoforms, alpha- (90-95%) and beta-AT (5-10%). AT inhibits clotting factors such as thrombin and factor Xa, a reaction catalyzed by heparin. Heparin has been used in many clinical situations but suffers from limitations such as a short intravenous half-life, bleeding risk, and the inability to inhibit thrombin bound to fibrin clots. In order to overcome some of heparin's limitations, we prepared a covalent AT-heparin complex (ATH) that has increased intravenous half-life, reduced bleeding risk, and can directly inhibit clot-bound thrombin. However, structural analysis is required to further develop this promising antithrombotic agent. It was found that the proportion of isoforms in ATH (55% alpha-AT, and 45% beta-AT) was significantly different than that in the commercial AT starting material (80% alpha-AT and 20% beta-AT). Further analysis of the rate of heparin-catalyzed inhibition of thrombin by AT isoforms prepared from ATH revealed that the beta-variant reacted approximately 2-fold faster.
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Hiidenhovi J, Mäkinen J, Huopalahti R, Ryhänen EL. Comparison of different egg albumen fractions as sources of ovomucin. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2002; 50:2840-2845. [PMID: 11982409 DOI: 10.1021/jf011333y] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Ovomucin was fractionated from whole egg albumen, thick egg albumen, liquid egg albumen, and a liquid egg albumen filtration byproduct by using the isoelectric precipitation method. The amounts of ovomucin measured in the above-mentioned fractions were 280, 340, 500, and 520 mg per 100 g of albumen, respectively. There was great variation between the beta-ovomucin contents of the different albumen fractions. Whole egg albumen contained about 25 mg of beta-ovomucin in 100 g of albumen, whereas thick egg albumen, liquid egg albumen, and the filtration byproduct contained about 1.5, 3, and 5 times more beta-ovomucin, respectively, as compared to whole egg albumen. The results indicate that both the liquid egg albumen fraction and especially the filtration byproduct fraction appear to be potential sources of ovomucin when it is used as an ingredient for functional foods.
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Affiliation(s)
- Jaakko Hiidenhovi
- MTT Agrifood Research Finland, Food Research, FIN-31600 Jokioinen, Finland.
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40
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Spiro RG. Protein glycosylation: nature, distribution, enzymatic formation, and disease implications of glycopeptide bonds. Glycobiology 2002; 12:43R-56R. [PMID: 12042244 DOI: 10.1093/glycob/12.4.43r] [Citation(s) in RCA: 977] [Impact Index Per Article: 44.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Formation of the sugar-amino acid linkage is a crucial event in the biosynthesis of the carbohydrate units of glycoproteins. It sets into motion a complex series of posttranslational enzymatic steps that lead to the formation of a host of protein-bound oligosaccharides with diverse biological functions. These reactions occur throughout the entire phylogenetic spectrum, ranging from archaea and eubacteria to eukaryotes. It is the aim of this review to describe the glycopeptide linkages that have been found to date and specify their presence on well-characterized glycoproteins. A survey is also made of the enzymes involved in the formation of the various glycopeptide bonds as well as the site of their intracellular action and their affinity for particular peptide domains is evaluated. This examination indicates that 13 different monosaccharides and 8 amino acids are involved in glycoprotein linkages leading to a total of at least 41 bonds, if the anomeric configurations, the phosphoglycosyl linkages, as well as the GPI (glycophosphatidylinositol) phosphoethanolamine bridge are also considered. These bonds represent the products of N- and O-glycosylation, C-mannosylation, phosphoglycation, and glypiation. Currently at least 16 enzymes involved in their formation have been identified and in many cases cloned. Their intracellular site of action varies and includes the endoplasmic reticulum, Golgi apparatus, cytosol, and nucleus. With the exception of the Asn-linked carbohydrate and the GPI anchor, which are transferred to the polypeptide en bloc, the sugar-amino acid linkages are formed by the enzymatic transfer of an activated monosaccharide directly to the protein. This review also deals briefly with glycosidases, which are involved in physiologically important cleavages of glycopeptide bonds in higher organisms, and with a number of human disease states in which defects in enzymatic transfer of saccharides to protein have been implicated.
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Affiliation(s)
- Robert G Spiro
- Department of Biological Chemistry, Harvard Medical School and the Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA
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41
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Abstract
Statistical analysis was carried out to study the sequential aspects of amino acids around the O-glycosylated Ser/Thr. 992 sequences containing O-glycosylated Ser/Thr were selected from the O-GLYCBASE database of O-glycosylated proteins. The frequency of occurrence of amino acid residues around the glycosylated Ser/Thr revealed that there is an increased number of proline residues around the O-glycosylation sites in comparison with the nonglycosylated serine and threonine residues. The deviation parameter calculated as a measure of preferential and nonpreferential occurrence of amino acid residues around the glycosylation site shows that Pro has the maximum preference around the O-glycosylation site. Pro at +3 and/or -1 positions strongly favors glycosylation irrespective of single and multiple glycosylation sites. In addition, serine and threonine are preferred around the multiple glycosylation sites due to the effect of clusters of closely spaced glycosylated Ser/Thr. The preference of amino acids around the sites of mucin-type glycosylation is found likely to be similar to that of the O-glycosylation sites when taken together, but the acidic amino acids are more preferred around Ser/Thr in mucin-type glycosylation when compared totally. Aromatic amino acids hinder O-glycosylation in contrast to N-glycosylation. Cysteine and amino acids with bulky side chains inhibit O-glycosylation. The preference of certain potential sequence motifs of glycosylation has been discussed.
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Affiliation(s)
- T H Thanka Christlet
- Department of Physics, Manonmaniam Sundaranar University, Tirunelveli 627 012, Tamil Nadu, India
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Beppu M, Yokoyama N, Motohashi M, Kikugawa K. Enhanced adhesion of oxidized mouse polymorphonuclear leukocytes to macrophages by a cell-surface sugar-dependent mechanism. Biol Pharm Bull 2001; 24:19-26. [PMID: 11201240 DOI: 10.1248/bpb.24.19] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Mouse thioglycollate-induced peritoneal macrophages effectively, in the absence of serum, recognized mouse polymorphonuclear leukocytes (PMNs) mildly oxidized with diamide, superoxide (hypoxanthine/xanthine oxidase) or t-butyhydroperoxide, or modified with N-ethylmaleimide (NEM). The recognition reached a maximum when PMNs were treated wtih each of the reagents at relatively low concentrations, and the recognition was decreased on treatment with reagents at higher concentrations. Glutathione depletion in the diamide-oxidized PMNs may cause enhanced adhesion to macrophages. Sialylated sugar chains attached to a peptide chain in glycophorin A and sialylated poly-N-acetyllactosaminyl sugar chains in lactoferrin and band 3 glycoprotein effectively inhibited the increased adhesion of the diamide-oxidized PMNs. Enzymatic removal of sialyl residues and the degradation of poly-N-acetyllactosaminyl sugar chains by pretreatment of PMNs with neuraminidase or endo-beta-galactosidase, respectively, lost their increasing ability for macrophage adhesion after oxidation with diamide, superoxide or t-butylhydroperoxide. Clustered sialylated poly-N-acetyllactosaminyl sugar chains on the cell surface may be involved in the increased adhesion of the oxidized PMNs to macrophages.
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Affiliation(s)
- M Beppu
- School of Pharmacy, Tokyo University of Pharmacy and Life Science, Hachioji, Japan
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43
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Liberek B, Konitz A, Frankowski R, Smiatacz Z. The synthesis and structure of the derivatives of 2-deoxy-2-hydroxyimino-D-lyxo-hexopyranosyl-L-cysteine and -thiophenol. Carbohydr Res 2000; 326:151-8. [PMID: 10877098 DOI: 10.1016/s0008-6215(00)00035-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
3,4,6-Tri-O-acetyl-2-deoxy-2-hydroxyimino-beta and -alpha-D-lyxo-hexopyranosides of thiophenol (3, 4) and the methyl ester of N-benzoyl-L-cysteine have been synthesised by condensation of 3,4,6-tri-O-acetyl-2-deoxy-2-nitroso-alpha-D-galactopyranosyl chloride with thiophenol and the L-cysteine derivative, respectively. The conformation of the sugar residue and configuration of the anomeric centre as well as of the hydroxyimino group were established on the basis of the 1H NMR (DQF-COSY, ROESY, TOCSY) spectrometric techniques and polarimetric data. Additionally, the structure of S-[3,4,6-tri-O-acetyl-2-deoxy-2-(Z)-hydroxyimino-beta-D-lyxo -hexopyranosyl]-thiophenol (3) was supported by X-ray diffraction data.
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Affiliation(s)
- B Liberek
- Faculty of Chemistry, University of Gdańsk, Poland
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Abstract
Most proteins within living organisms contain glycans. Glycan structures can modulate the biological properties and functions of glycoproteins. The major glycans of glycoproteins can be classified into two groups, N-glycans and O-glycans, according to their glycan-peptide linkage regions. Developments in glycobiology have revealed a new type of glycosidic linkage to the peptide portion, the O-mannosyl linkage, in mammals, while so far it had been thought to be specific to yeast. This review will give an outline of the O-mannosyl glycans of mammalian glycoproteins. Since one of the most well known O-mannosyl-modified mammalian glycoproteins is dystroglycan, the functional aspects of the O-mannosyl glycan of dystroglycan will be described to help understand this new glycobiological field.
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Affiliation(s)
- T Endo
- Department of Glycobiology, Tokyo Metropolitan Institute of Gerontology, 35-2 Sakaecho, Itabashi-ku, Tokyo, Japan.
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Sievi E, Helin J, Heikinheimo R, Makarow M. Glycan engineering of proteins with whole living yeast cells expressing rat liver alpha2,3-sialytransferase in the porous cell wall. FEBS Lett 1998; 441:177-80. [PMID: 9883879 DOI: 10.1016/s0014-5793(98)01550-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The N-glycans of recombinant proteins produced via the secretory pathway of cultured mammalian cells are often undersialylated, and insect cells lack sialytransferases. Undersialylated glycoproteins are rapidly cleared from the circulation, compromising the effect of pharmaceuticals. We show that incubation with living Saccharomyces cerevisiae cells expressing the catalytic ectodomain of rat liver alpha2,3-sialyltransferase (ST3Ne) in the porous cell wall resulted in sialylation of glycoproteins. The Km values of the yeast enzyme for several substrates were similar to those of recombinant ST3Ne from insect cells and of authentic ST3N. The yeast strain provides an inexpensive self-perpetuating source of ST3N activity for glycan engineering of recombinant proteins.
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Affiliation(s)
- E Sievi
- Institute of Biotechnology, University of Helsinki, Finland
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Haddad A, André JC. Hyalocyte-like cells are more numerous in the posterior chamber than they are in the vitreous of the rabbit eye. Exp Eye Res 1998; 66:709-18. [PMID: 9657903 DOI: 10.1006/exer.1997.0476] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The distribution and concentration of free cells inside the eye chambers of rabbits were investigated using semi-quantitative analysis of histological paraffin sections. Studies using light (methacrylate sections) as well as transmission and scanning electron microscopy were undertaken for the morphological characterization of the free cells. Immunocytochemistry and autoradiography were employed in an attempt to find out their nature and their origin, respectively. It was observed that cells morphologically similar to the vitreous hyalocytes were more numerous inside the posterior chamber than were the hyalocytes in the cortical vitreous. Neither the hyalocytes nor the posterior-chamber cells reacted with an antibody to rabbit macrophages. The finding of labeled free cells after an intravitreal injection of 3H-thymidine indicates that these cells can renew themselves and that their number does not depend exclusively on monocytes migrating from the blood stream to the eye chambers, as is believed to occur. In conclusion, hyalocytes or hyalocyte-like cells are more concentrated in the posterior chamber than they are in the vitreous. Both the hyalocytes and the posterior-chamber cells could not be characterized as fully developed macrophages.
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Affiliation(s)
- A Haddad
- Departamento de Morfologia, Faculdade de Medicina de Ribeirão Preto-USP, Ribeirão Preto-S.P., 14049-900, Brazil
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Spiro RG, Bhoyroo VD. Characterization of a spleen sulphotransferase responsible for the 6-O-sulphation of the galactose residue in sialyl-N-acetyl-lactosamine sequences. Biochem J 1998; 331 ( Pt 1):265-71. [PMID: 9512489 PMCID: PMC1219348 DOI: 10.1042/bj3310265] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
An enzyme which catalyses the transfer of sulphate from 3'-phosphoadenosine 5'-phosphosulphate (PAPS) to C-6 of galactose in the NeuAcalpha2-3Galbeta1-4GlcNAc (3'SLN) sequence has been found in rat spleen microsomes and its specificity indicates that it is well suited to participate in the assembly of 3'-sialyl-6'-sulpho-LacNAc [NeuAcalpha2-3Gal(6-SO4)beta1-4GlcNAc] and 3'-sialyl-6'-sulpho-LewisX [NeuAcalpha2-3Gal(6-SO4)beta1-4(Fucalpha1-3)GlcNAc] saccharide groups which have been implicated as selectin ligands. This sulphotransferase has a strict requirement for oligosaccharide acceptors which are capped by an alpha2-3-linked sialic acid residue, although GlcNAc in 3'SLN can be substituted by Glc, and Galbeta1-4GlcNAc can be replaced by Galbeta1-3GlcNAc without loss of activity. The finding that 3'-sialyl LewisX was inert as an acceptor suggested that fucosylation, in contrast with sialylation, follows the addition of the sulphate group. Since fetuin glycopeptides containing the NeuAcalpha2-3Galbeta1-4GlcNAc sequence had a similar affinity for the enzyme as the unattached 3'SLN, it would appear that the acceptor determinants reside primarily in the peripheral trisaccharide constellation. The position of the sulphate on C-6 of galactose was elucidated by Smith periodate oxidation, hydrazine/nitrous acid/NaBH4 treatment and elder (Sambucus nigra) bark lectin chromatography of the desialylated [35S]sulphate-labelled products of the enzyme. Assays carried out with 3'SLN as acceptor indicated that the sulphotransferase had a pH optimum between 6.5 and 7.0 and a dependence on a bivalent cation best met by Mn2+ (12-25 mM); Triton X-100 (0.02 to 0.35%) brought about maximal stimulation. Tentative Km values determined for this enzyme were 4.7 microM for PAPS, and 0.72 mM and 1.16 mM for 3'SLN and fetuin glycopeptides respectively. A survey of several rat organs indicated that the PAPS:3'SLN-6-O-sulphotransferase is selectively distributed with maximal activity occurring in spleen which was substantially greater than thymus or lymph nodes. In contrast, other enzymes (i.e. PAPS:Gal-3-O-and GlcNAc-6-O-sulphotransferases) involved in the sulphation of sialyl-lactosamine and lactosamine sequences, which in the sulphated form are believed to also be selectin ligands, were more evenly distributed in lymphoid tissues. Relatively high activities for all three enzymes were found in brain.
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Affiliation(s)
- R G Spiro
- Department of Biological Chemistry and Medicine (Harvard Medical School) and Joslin Diabetes Center, One Joslin Place, Boston, MA 02215, USA
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Abstract
The efficiency and reliability of radioactive fucose as a specific label for newly synthesized glycoproteins were investigated. Young adult male rabbits were injected intravitreally with [3H]-fucose, [3H]-galactose. [3H]-mannose, N-acetyl-[3H]-glucosamine or N-acetyl-[3H]-mannosamine, and killed 40 h after injection. In another series of experiments rabbits were injected with either [3H]-fucose or several tritiated amino acids and the specific activity of the vitreous proteins was determined. Vitreous samples were also processed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and histological sections of retina, ciliary body and lens (the eye components around the vitreous body) were processed for radioautography. The specific activity (counts per minute per microgram of protein) of the glycoproteins labeled with [3H]-fucose was always much higher than that of the proteins labeled with any of the other monosaccharides or any of the amino acids. There was a good correlation between the specific activity of the proteins labeled by any of the above precursors and the density of the vitreous protein bands detected by fluorography. This was also true for the silver grain density on the radioautographs of the histological sections of retina, ciliary body and lens. The contribution of radioautography (after [3H]-fucose administration) to the elucidation of the biogenesis of lysosomal and membrane glycoproteins and to the determination of the intracellular process of protein secretion was reviewed. Radioactive fucose is the precursor of choice for studying glycoprotein secretion because it is specific, efficient and practical for this purpose.
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Affiliation(s)
- A Haddad
- Departamento de Morfologia, Faculdade de Medicina de Ribeirão Preto, Universidade de São Paulo, Brasil
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50
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Structural elucidation of the N-linked oligosaccharides of glycoproteins using high pH anion-exchange chromatography. ACTA ACUST UNITED AC 1997. [DOI: 10.1016/s1874-5261(97)80004-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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