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Biskup K, Blanchard V, Castillo-Binder P, Alexander H, Engeland K, Schug S. N- and O-glycosylation patterns and functional testing of CGB7 versus CGB3/5/8 variants of the human chorionic gonadotropin (hCG) beta subunit. Glycoconj J 2020; 37:599-610. [PMID: 32767150 PMCID: PMC7501100 DOI: 10.1007/s10719-020-09936-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 06/26/2020] [Accepted: 07/23/2020] [Indexed: 12/28/2022]
Abstract
The classical function of human chorionic gonadotropin (hCG) is its role in supporting pregnancy. hCG is a dimer consisting of two highly glycosylated subunits, alpha (CGA) and beta (CGB). The beta-hCG protein is encoded by CGB3, CGB5, CGB7 and CGB8 genes. CGB3, 5 and 8 code for an identical protein, CGB3/5/8, whereas CGB7 differs in three amino acids from CGB3/5/8. We had observed earlier that CGB7 and CGB3/5/8 display very distinct tissue expression patterns and that the tumor suppressor and transcription factor p53 can activate expression of CGB7 but not of CGB3/5/8 genes. Here, we investigate the glycan structures and possible functional differences of the two CGB variants. To this end, we established a system to produce and isolate recombinant CGA, CGB7 and CGB3/5/8 proteins. We found that N- and O-glycosylation patterns of CGB7 and CGB3/5/8 are quite similar. Functional assays were performed by testing activation of the ERK1/2 pathway and demonstrated that CGB7 and CGB5/5/8 appear to be functionally redundant isoforms, although a slight difference in the kinetics of ERK1/2 pathway activation was observed. This is the first time that biological activity of CGB7 is shown. In summary, the results lead to the hypothesis that CGB7 and CGB3/5/8 do not hold significant functional differences but that timing and cell type of their expression is the key for understanding their divergent evolution.
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Affiliation(s)
- Karina Biskup
- Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Véronique Blanchard
- Charité Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Institute of Laboratory Medicine, Clinical Chemistry and Pathobiochemistry, Augustenburger Platz 1, 13353, Berlin, Germany
| | - Paola Castillo-Binder
- Division of Molecular Oncology and Division of Human Reproduction and Endocrinology, Department of Obstetrics and Gynecology, Medical School, University of Leipzig, Semmelweisstr. 14, 04103, Leipzig, Germany
| | - Henry Alexander
- Division of Molecular Oncology and Division of Human Reproduction and Endocrinology, Department of Obstetrics and Gynecology, Medical School, University of Leipzig, Semmelweisstr. 14, 04103, Leipzig, Germany
| | - Kurt Engeland
- Division of Molecular Oncology and Division of Human Reproduction and Endocrinology, Department of Obstetrics and Gynecology, Medical School, University of Leipzig, Semmelweisstr. 14, 04103, Leipzig, Germany.
| | - Sindy Schug
- Division of Molecular Oncology and Division of Human Reproduction and Endocrinology, Department of Obstetrics and Gynecology, Medical School, University of Leipzig, Semmelweisstr. 14, 04103, Leipzig, Germany
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Wang C, Qiang S, Jin W, Song X, Zhang Y, Huang L, Wang Z. Reductive chemical release of N-glycans as 1-amino-alditols and subsequent 9-fluorenylmethyloxycarbonyl labeling for MS and LC/MS analysis. J Proteomics 2018; 187:47-58. [DOI: 10.1016/j.jprot.2018.06.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2018] [Revised: 06/03/2018] [Accepted: 06/04/2018] [Indexed: 11/30/2022]
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3
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Karav S, Cohen JL, Barile D, de Moura Bell JMLN. Recent advances in immobilization strategies for glycosidases. Biotechnol Prog 2016; 33:104-112. [PMID: 27718339 DOI: 10.1002/btpr.2385] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2016] [Revised: 08/31/2016] [Indexed: 11/11/2022]
Abstract
Glycans play important biological roles in cell-to-cell interactions, protection against pathogens, as well as in proper protein folding and stability, and are thus interesting targets for scientists. Although their mechanisms of action have been widely investigated and hypothesized, their biological functions are not well understood due to the lack of deglycosylation methods for large-scale isolation of these compounds. Isolation of glycans in their native state is crucial for the investigation of their biological functions. However, current enzymatic and chemical deglycosylation techniques require harsh pretreatment and reaction conditions (high temperature and use of detergents) that hinder the isolation of native glycan structures. Indeed, the recent isolation of new endoglycosidases that are able to cleave a wider variety of linkages and efficiently hydrolyze native proteins has opened up the opportunity to elucidate the biological roles of a higher variety of glycans in their native state. As an example, our research group recently isolated a novel Endo-β-N-acetylglucosaminidase from Bifidobacterium longum subsp. infantis ATCC 15697 (EndoBI-1) that cleaves N-N'-diacetyl chitobiose moieties found in the N-linked glycan (N-glycan) core of high mannose, hybrid, and complex N-glycans. This enzyme is also active on native proteins, which enables native glycan isolation, a key advantage when evaluating their biological activities. Efficient, stable, and economically viable enzymatic release of N-glycans requires the selection of appropriate immobilization strategies. In this review, we discuss the state-of-the-art of various immobilization techniques (physical adsorption, covalent binding, aggregation, and entrapment) for glycosidases, as well as their potential substrates and matrices. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 33:104-112, 2017.
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Affiliation(s)
- Sercan Karav
- Department of Molecular Biology and Genetics, Canakkale 18 Mart University, Canakkale, Turkey
| | - Joshua L Cohen
- Department of Food Science and Technology, University of California, One Shields Avenue, Davis, CA, 95616
| | - Daniela Barile
- Department of Food Science and Technology, University of California, One Shields Avenue, Davis, CA, 95616.,Foods for Health Institute, University of California, One Shields Avenue, Davis, CA, 95616
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Nonreductive chemical release of intact N-glycans for subsequent labeling and analysis by mass spectrometry. Anal Biochem 2014; 462:1-9. [PMID: 24912132 DOI: 10.1016/j.ab.2014.05.029] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2014] [Revised: 05/19/2014] [Accepted: 05/29/2014] [Indexed: 11/23/2022]
Abstract
A novel strategy is proposed, using cost-saving chemical reactions to generate intact free reducing N-glycans and their fluorescent derivatives from glycoproteins for subsequent analysis. N-Glycans without core α-1,3-linked fucose are released in reducing form by selective hydrolysis of the N-type carbohydrate-peptide bond of glycoproteins under a set of optimized mild alkaline conditions and are comparable to those released by commonly used peptide-N-glycosidase (PNGase) F in terms of yield without any detectable side reaction (peeling or deacetylation). The obtained reducing glycans can be routinely derivatized with 2-aminobenzoic acid (2-AA), 1-phenyl-3-methyl-5-pyrazolone (PMP), and potentially some other fluorescent reagents for comprehensive analysis. Alternatively, the core α-1,3-fucosylated N-glycans are released in mild alkaline medium and derivatized with PMP in situ, and their yields are comparable to those obtained using commonly used PNGase A without conspicuous peeling reaction or any detectable deacetylation. Using this new technique, the N-glycans of a series of purified glycoproteins and complex biological samples were successfully released and analyzed by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry (MS/MS), demonstrating its general applicability to glycomic studies.
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Krenkova J, Szekrenyes A, Keresztessy Z, Foret F, Guttman A. Oriented immobilization of peptide-N-glycosidase F on a monolithic support for glycosylation analysis. J Chromatogr A 2013; 1322:54-61. [DOI: 10.1016/j.chroma.2013.10.087] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/25/2013] [Accepted: 10/29/2013] [Indexed: 10/26/2022]
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Walczak MA, Hayashida J, Danishefsky SJ. Building biologics by chemical synthesis: practical preparation of di- and triantennary N-linked glycoconjugates. J Am Chem Soc 2013; 135:4700-3. [PMID: 23461434 PMCID: PMC3632434 DOI: 10.1021/ja401385v] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A unified strategy for the syntheses of bi- and triantennary fully sialylated N-glycans is described. The synthesis capitalizes on a global glycosylation strategy that delivers the desired undeca- and tetradecasaccharide in excellent yields. Finally, conjugation of the glycan to PSMA oligopeptide is described.
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Affiliation(s)
- Maciej A. Walczak
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065, United States
| | - Joji Hayashida
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065, United States
| | - Samuel J. Danishefsky
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065, United States
- Department of Chemistry, Columbia University, 3000 Broadway, New York, New York 10027, United States
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Nagorny P, Sane N, Fasching B, Aussedat B, Danishefsky SJ. Probing the frontiers of glycoprotein synthesis: the fully elaborated β-subunit of the human follicle-stimulating hormone. Angew Chem Int Ed Engl 2012; 51:975-9. [PMID: 22162182 PMCID: PMC3285374 DOI: 10.1002/anie.201107482] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2011] [Indexed: 01/22/2023]
Affiliation(s)
| | | | - Bernhard Fasching
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065, and Department of Chemistry, Columbia University, Havemeyer Hall, 3000 Broadway, New York, New York 10027(USA), Fax: (+1)212-772-8691
| | - Baptiste Aussedat
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065, and Department of Chemistry, Columbia University, Havemeyer Hall, 3000 Broadway, New York, New York 10027(USA), Fax: (+1)212-772-8691
| | - Samuel J. Danishefsky
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065, and Department of Chemistry, Columbia University, Havemeyer Hall, 3000 Broadway, New York, New York 10027(USA), Fax: (+1)212-772-8691
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8
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Nagorny P, Sane N, Fasching B, Aussedat B, Danishefsky SJ. Probing the Frontiers of Glycoprotein Synthesis: The Fully Elaborated β-Subunit of the Human Follicle-Stimulating Hormone. Angew Chem Int Ed Engl 2011. [DOI: 10.1002/ange.201107482] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
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9
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Damm JBL, Bergwerff AA, Hård K, Kamerling JP, Vliegenthart JFG. Sialic acid patterns in N-linked carbohydrate chains. Structural analysis of the N-acetyl-/N-glycolyl-neuraminic-acid-containing N-linked carbohydrate chains of bovine fibrinogen. ACTA ACUST UNITED AC 2010. [DOI: 10.1002/recl.19891081007] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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10
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Nagorny P, Fasching B, Li X, Chen G, Aussedat B, Danishefsky SJ. Toward fully synthetic homogeneous beta-human follicle-stimulating hormone (beta-hFSH) with a biantennary N-linked dodecasaccharide. synthesis of beta-hFSH with chitobiose units at the natural linkage sites. J Am Chem Soc 2009; 131:5792-9. [PMID: 19341309 PMCID: PMC2756579 DOI: 10.1021/ja809554x] [Citation(s) in RCA: 89] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
A highly convergent synthesis of the sialic acid-rich biantennary N-linked glycan found in human glycoprotein hormones and its use in the synthesis of a fragment derived from the beta-domain of human Follicle-Stimulating Hormone (hFSH) are described. The synthesis highlights the use of the Sinay radical glycosidation protocol for the simultaneous installation of both biantennary side-chains of the dodecasaccharide as well as the use of glycal chemistry to construct the tetrasaccharide core in an efficient manner. The synthetic glycan was used to prepare the glycosylated 20-27aa domain of the beta-subunit of hFSH under a Lansbury aspartylation protocol. The proposed strategy for incorporating the prepared N-linked dodecasaccharide-containing 20-27aa domain into beta-hFSH subunit was validated in the context of a model system, providing protected beta-hFSH subunit functionalized with chitobiose at positions 7 and 24.
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Affiliation(s)
- Pavel Nagorny
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065
| | - Bernhard Fasching
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065
| | - Xuechen Li
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065
| | - Gong Chen
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065
| | - Baptiste Aussedat
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065
| | - Samuel J. Danishefsky
- Laboratory for Bioorganic Chemistry, Sloan-Kettering Institute for Cancer Research, 1275 York Avenue, New York, New York 10065
- Department of Chemistry, Columbia University, Havemeyer Hall, 3000 Broadway, New York, New York 10027
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Blanchard V, Gadkari RA, Gerwig GJ, Leeflang BR, Dighe RR, Kamerling JP. Characterization of the N-linked oligosaccharides from human chorionic gonadotropin expressed in the methylotrophic yeast Pichia pastoris. Glycoconj J 2007; 24:33-47. [PMID: 17146714 DOI: 10.1007/s10719-006-9010-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Human chorionic gonadotropin (hCG) is a heterodimeric, placental glycoprotein hormone involved in the maintenance of the corpus luteum during the first trimester of pregnancy. Biologically active hCG has been successfully expressed in the yeast Pichia pastoris (phCG). In the context of structural studies and therapeutic applications of phCG, detailed information about its glycosylation pattern is a prerequisite. To this end N-glycans were released with peptide-N(4)-(N-acetyl-beta-glucosaminyl)asparagine amidase F and fractionated via anion-exchange chromatography (Resource Q) yielding both neutral (80%) and charged, phosphate-containing (20%) high-mannose-type structures. Subfractionations were carried out via normal phase (Lichrosorb-NH(2)) and high-pH anion-exchange (CarboPac PA-1) chromatography. Structural analyses of the released N-glycans were carried out by using HPLC profiling of fluorescent 2-aminobenzamide derivatives, MALDI-TOF mass spectrometry, and 500-MHz(1)H-NMR spectroscopy. Detailed neutral oligosaccharide structures, in the range of Man(8)GlcNAc(2) to Man(11)GlcNAc(2) including molecular isomers, could be established, and structures up to Man(15)GlcNAc(2) were indicated. Phosphate-containing oligosaccharides ranged from Man(9)PGlcNAc(2) to Man(13)PGlcNAc(2). Mannosyl O-glycans were not detected. Profiling studies carried out on different production batches showed that the oligosaccharide structures are similar, but their relative amounts varied with the culturing media.
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Affiliation(s)
- Véronique Blanchard
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, Padualaan 8, NL-3584 CH Utrecht, The Netherlands
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12
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Bernardes GJL, Gamblin DP, Davis BG. The Direct Formation of Glycosyl Thiols from Reducing Sugars Allows One-Pot Protein Glycoconjugation. Angew Chem Int Ed Engl 2006; 45:4007-11. [PMID: 16673441 DOI: 10.1002/anie.200600685] [Citation(s) in RCA: 106] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Gonçalo J L Bernardes
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, Mansfield Road, Oxford, OX1 3TA, UK.
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13
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Bernardes GJL, Gamblin DP, Davis BG. The Direct Formation of Glycosyl Thiols from Reducing Sugars Allows One-Pot Protein Glycoconjugation. Angew Chem Int Ed Engl 2006. [DOI: 10.1002/ange.200600685] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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14
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Sz�ll?si �, Kremmer T, Lud�nyi K, Imre T, Schlosser G, Boldizs�r M, Vincze B, V�key K. A Novel Method for the Separation and Purification of Human Serum Acid Alpha-1-Glycoprotein. Liquid Chromatographic and Mass Spectrometric Investigation of Tryptic Fragments. Chromatographia 2004. [DOI: 10.1365/s10337-004-0216-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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Abstract
Glycosylation of proteins represents one of the most important post-(co-)translational events in view of the ubiquity of the phenomenon. In most cases, the covalently linked glycans are involved in the functioning of these biomolecules in biological systems. Detailed information on the carbohydrate moieties including monosaccharide composition, anomeric configurations, type of glycosidic linkages and attachment sites at the protein is indispensable in describing the ultimate structure of a specific glycoprotein. This chapter presents a general strategy for the structural characterization of glycoproteins/glycopeptides focussed on the glycan part. Some of the techniques commonly used, like enzyme treatments, separation methods, chemical analyses, mass spectrometry and nuclear magnetic resonance spectroscopy are briefly reviewed.
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Affiliation(s)
- G J Gerwig
- Bijvoet Center for Biomolecular Research, Department of Bio-Organic Chemistry, Utrecht University, Utrecht, The Netherlands
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16
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Bousfield GR, Baker VL, Gotschall RR, Butnev VY. Carbohydrate analysis of glycoprotein hormones. Methods 2000; 21:15-39. [PMID: 10764604 DOI: 10.1006/meth.2000.0972] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Complete carbohydrate composition analysis of glycoprotein hormones, their subunits, and oligosaccharides isolated from individual glycosylation sites can be accomplished using high-pH anion-exchange chromatography combined with pulsed amperometric detection. Neutral and amino sugars are analyzed from the same hydrolyzate by isocratic chromatography on a Dionex CarboPAC PA1 column in 16 mM NaOH. Sialic acid is quantified following mild hydrolysis conditions on the same column in 150 mM sodium acetate in 150 mM NaOH. Ion chromatography on a Dionex AS4A column in 1.8 mM Na(2)CO(3)/1.7 mM NaHCO(3); postcolumn, in-line anion micromembrane suppression; and conductivity detection can be used to quantify sulfate, a common component of pituitary glycoprotein hormone oligosaccharides. Mass spectrometric analysis before and after elimination of oligosaccharides from a single glycosylation site can provide an estimate of the average oligosaccharide mass, which facilitates interpretation of oligosaccharide composition data. Following release by peptide N-glycanase (PNGase) digestion and purification by ultrafiltration, oligosaccharides can be characterized by a high-resolution oligosaccharide mapping technique using the same equipment employed for composition analysis. Oligosaccharide mapping can be applied to the entire hormone, individual subunits, or individual glycosylation sites by varying PNGase digestion conditions or substrates. Oligosaccharide release by PNGase is readily monitored by SDS-PAGE. Site-specific deglycosylation can be confirmed by amino acid sequence analysis. For routine isolation of oligosaccharides, addition of 2-aminobenzamide at the reducing terminus facilitates detection; however, the oligosaccharide retention times are altered. Composition analysis is also affected as the 2-aminobenzamide-modified GlcNAc peak overlaps the fucose peak.
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Affiliation(s)
- G R Bousfield
- Department of Biological Sciences, Wichita State University, 1845 Fairmount, Wichita, Kansas 67260-0026, USA.
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18
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De Beer T, Van Zuylen CW, Leeflang BR, Hård K, Boelens R, Kaptein R, Kamerling JP, Vliegenthart JF. NMR studies of the free alpha subunit of human chorionic gonadotropin. Structural influences of N-glycosylation and the beta subunit on the conformation of the alpha subunit. EUROPEAN JOURNAL OF BIOCHEMISTRY 1996; 241:229-42. [PMID: 8898911 DOI: 10.1111/j.1432-1033.1996.0229t.x] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Human chorionic gonadotropin (hCG) is a heterodimeric glycoprotein hormone that is involved in the maintenance of the corpus luteum in early pregnancy. Glycosylation at Asn52 of its alpha subunit (alpha hCG) is essential for signal transduction, whereas the N-glycan at Asn78 stabilizes the structure of the protein. In this study, an almost complete 1H-NMR and a partial 13C-NMR spectral assignment for the amino acids and the N-glycans of alpha hCG and of an enzymatically deglycosylated form, which had a single GlcNAc residue at each of its two glycosylation sites, has been achieved. The secondary structure of alpha hCG is solution, which was determined based on NOE data, is partially similar to that of the alpha subunit in the crystal structure of hCG, but large structural differences are found for amino acid residues 33-58. In the crystal structure of hCG, residues 33-37 and 54-58 of the alpha subunit are part of an intersubunit seven-stranded beta-barrel and residues 41-47 constitute a 3(10)-helix. In contrast, in free alpha hCG in solution, amino acids 33-58 are part of a large disordered loop, indicating that in intact hCG interactions with the beta subunit of hCG stabilize the conformation of the alpha subunit. The NMR data of alpha hCG and its deglycosylated counterpart are very similar, indicating that removal of carbohydrate residues other than GlcNAc-1 does not notably affect the conformation of the protein part. However, numerous 1H-NOEs between the GlcNAc-1 residue at Asn78 and several amino acid residues show that this GlcNAc residue is tightly packed against the protein, being an integral part of the structure of the alpha subunit. 1H-NOEs across the glycosidic linkages of the glycan, resonance-line widths, and 1H and 13C chemical shifts of the other monosaccharides suggest that the remainder of the glycans at Asn78, and the glycans at Asn52 are largely extended in solution.
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Affiliation(s)
- T De Beer
- Department of Bio-Organic Chemistry, Bijvoet Center, Utrecht University, The Netherlands
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Gerwig GL, Calvete JJ, Töpfer-Petersen E, Vliegenthart JF. The structure of the O-linked carbohydrate chain of bovine seminal plasma protein PDC-109 revised by H-NMR spectroscopy A correction. FEBS Lett 1996; 387:99-100. [PMID: 8654577 DOI: 10.1016/0014-5793(96)00448-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Affiliation(s)
- G L Gerwig
- Bijvoet Center for Biomocular Research, Department of Bio-Organic Chemistry, Utrecht University, Utrecht, The Netherlands
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20
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Hokke CH, Bergwerff AA, Van Dedem GW, Kamerling JP, Vliegenthart JF. Structural analysis of the sialylated N- and O-linked carbohydrate chains of recombinant human erythropoietin expressed in Chinese hamster ovary cells. Sialylation patterns and branch location of dimeric N-acetyllactosamine units. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 228:981-1008. [PMID: 7737204 DOI: 10.1111/j.1432-1033.1995.tb20350.x] [Citation(s) in RCA: 121] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The N-linked carbohydrate chains of recombinant human erythropoietin expressed in CHO cells were quantitatively released with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F, separated from the remaining O-glycoprotein by gel-permeation chromatography, and subsequently fractionated via FPLC on Mono Q, HPLC on Lichrosorb-NH2 and high-pH anion-exchange chromatography on CarboPac PA1. The purified sialylated oligosaccharides were analyzed by one-dimensional and two-dimensional 500-MHz 1H-NMR spectroscopy. When necessary, oligosaccharides were treated with endo-beta-galactosidase (and N-acetyl-beta-glucosaminidase) followed by 1H-NMR analysis of the incubation products, to obtain additional structural information. Di-, tri-, tri'- and tetraantennary N-acetyllactosamine-type oligosaccharides occur which can be completely (major) or partially (minor) sialylated. Three different types of alpha 2-3-linked sialic acids are present, namely, N-acetylneuraminic acid (95%), N-glycolylneuraminic acid (2%) and N-acetyl-9-O-acetylneuraminic acid (3%). In the case of partial sialylation, a non-random distribution of the sialic acids over the branches is observed. One or two extra N-acetyllactosamine units, being exclusively located in the branches attached to the alpha 1-6-linked Man residue, can be present in completely or partially sialylated di-, tri'-, and tetraantennary oligosaccharides. Tetraantennary oligosaccharides with N-acetyllactosamine repeats could be digested quantitatively with endo-beta-galactosidase from Bacteroides fragilis, whereas under the same conditions tri' antennary oligosaccharides hardly reacted (< 15%). Using endo-beta-galactosidase from Escherichia freundii, these tri'antennary oligosaccharides could be digested more extensively (> 75%). The O-linked carbohydrate chains were released from the O-glycoprotein by alkaline borohydride treatment, and purified via FPLC on Mono Q and HPLC on Lichrosorb-NH2. Two O-glycans were found, namely, Neu5Ac alpha 2-3Gal beta 1-3GalNAc-ol and Neu5Ac alpha 2-3Gal beta 1-3(Neu5Ac alpha 2-6)GalNAc-ol.
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Affiliation(s)
- C H Hokke
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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21
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Bergwerff AA, Van Oostrum J, Kamerling JP, Vliegenthart JF. The major N-linked carbohydrate chains from human urokinase. The occurrence of 4-O-sulfated, (alpha 2-6)-sialylated or (alpha 1-3)-fucosylated N-acetylgalactosamine(beta 1-4)-N-acetylglucosamine elements. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 228:1009-19. [PMID: 7737145 DOI: 10.1111/j.1432-1033.1995.tb20351.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
The primary structure of the major N-linked carbohydrate chains attached to Asn302 of urinary-type plasminogen activator (urokinase) have been determined. Urokinase was completely deglycosylated with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F from Flavobacterium meningosepticum. Released oligosaccharides were separated from the remaining protein using gel-permeation chromatography on Bio-Gel P-100, and then on Bio-Gel P-6. Fractionation of the oligosaccharides was achieved by a combination of FPLC anion-exchange chromatography on Mono Q HR 5/5 and amine-adsorption HPLC on LiChrospher 100-NH2. Analysis by 1H-NMR spectroscopy demonstrated that the collection of N-glycans comprises di-, tri-, and tri'-antennary structures. The glycans contain predominantly GalNAc beta 1-4GlcNAc beta instead of Gal beta 1-4GlcNAc beta elements. The GalNAc residue is mainly sulfated at O4, or to a lesser extent it bears N-acetylneuraminic acid at O6; alternatively the GlcNAc residue can be fucosylated at O3. The major component, which accounts for more than 30 mol/100 mol of the total oligosaccharide pool, consists of an (alpha 1-6)-fucosylated diantennary N-linked carbohydrate chain with (SO4-)-4GalNAc beta 1-4GlcNAc beta 1-2 antennae.
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Affiliation(s)
- A A Bergwerff
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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22
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Hokke CH, Bergwerff AA, Dedem GWK, Kamerling JP, Vliegenthart JFG. Structural Analysis of the Sialylated N- and O-Linked Carbohydrate Chains of Recombinant Human Erythropoietin Expressed in Chinese Hamster Ovary Cells. Sialylation Patterns and Branch Location of Dimeric N-acetyllactosamine Units. ACTA ACUST UNITED AC 1995. [DOI: 10.1111/j.1432-1033.1995.0981m.x] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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23
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Nemansky M, de Leeuw R, Wijnands RA, van den Eijnden DH. Enzymic remodelling of the N- and O-linked carbohydrate chains of human chorionic gonadotropin. Effects on biological activity and receptor binding. EUROPEAN JOURNAL OF BIOCHEMISTRY 1995; 227:880-8. [PMID: 7867650 DOI: 10.1111/j.1432-1033.1995.tb20214.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The effects of altered terminal sequences in human chorionic gonadotropin (hCG) N- and O-linked glycans on receptor binding and signal transduction were analyzed using forms of hCG with remodelled carbohydrate chains. hCG derivatives were obtained by enzymic removal of the alpha 3-linked sialic acid residues followed by alpha 6-sialylation, alpha 3-galactosylation or alpha 3-fucosylation of uncovered Gal beta 1-->4GlcNAc (LacNAc) termini, or alpha 3-sialylation of Gal beta 1-->3GalNAc sequences. Also a form that carried GalNAc beta 1-->4-GlcNAc units, which are typical for pituitary hormone oligosaccharides, was derived by enzymic desialylation and degalactosylation followed by beta 4-N-acetylgalactosaminylation. The potency to stimulate testosterone production and the binding to the lutotropin/choriogonadotropin receptor of the preparations were compared with those of native and desialylated hCG (as-hCG). The decrease in bioactivity caused by desialylation of hCG was only restored upon alpha 6-sialylation of the Gal beta 1-->4GlcNAc beta 1-->-2Man alpha 1-->3Man branch of the N-linked glycans. This was without a major effect on receptor binding. Further alpha 6-sialylation, occurring at the Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->6Man branch, resulted in a bioactivity below a level found with as-hCG, concomitant with a decreased receptor binding affinity. Similarly alpha 3-galactosylation of the Gal beta 1-->4GlcNAc beta 1-->2-Man alpha 1-->6Man branch yielded a hCG derivative that showed decreased bioactivity and receptor binding. alpha 3-Fucosylation of native as well as as-hCG also led to a decreased activity. Re-alpha 3-sialylation of the O-linked chains on as-hCG had little effect on the bioactivity and receptor binding. Hormone preparations with GalNAc beta 1-->4GlcNAc termini showed lower bioactivity and receptor affinity than as-hCG. It is concluded that the Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->3Man- rather than the Gal beta 1-->4GlcNAc beta 1-->2-Man alpha 1-->6Man branch of the N-linked glycans on hCG plays an essential role in signal transduction, whereas the latter branch can potentially interfere with receptor binding. Furthermore attachment of sialic acid, but not of other sugars, to the first branch fulfils the requirement for the full expression of bioactivity, while sialylation of the O-linked chains is of minor importance.
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Affiliation(s)
- M Nemansky
- Department of Medical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands
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24
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Niemelä R, Natunen J, Brotherus E, Saarikangas A, Renkonen O. alpha 1,3-Fucosylation of branched blood group I-type oligo-(N-acetyllactosamino)glycans by human milk transferases is restricted to distal N-acetyllactosamine units: the resulting isomers are separated by WGA-agarose chromatography. Glycoconj J 1995; 12:36-44. [PMID: 7795411 DOI: 10.1007/bf00731866] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A partially purified preparation of alpha 1,3-fucosyltransferase(s) from human milk was used to [14C]fucosylate oligosaccharides containing Gal beta 1-4GlcNAc units. Substitution of N-acetyllactosamine at position 3' with a beta-linked N-acetyl-glucosamine enhanced the reactivity of the acceptor, whereas similar substitution at position 6' was inhibitory. Thus, the trisaccharide GlcNAc beta 1-6Gal beta 1-4GlcNAc (5), the branched tetrasaccharide GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc (11) and the triply branched decasaccharide GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc beta 1-3[GlcNAc beta 1-3(GlcNAc beta 1-6)Gal beta 1-4GlcNAc beta 1-6]Gal beta 1-4GlcNAc (26) gave remarkably poor yields of alpha 1,3-fucosylated products in comparison to GlcNAc beta 1-3Gal beta 1-4GlcNAc (3). beta 1,4-Galactosyl derivatives of 5 and 11, however, gave good yields of alpha 1,3-fucosylated products, but the fucosylation was restricted to the distal N-acetyllactosamine units of Gal beta 1-4GlcNAc beta 1-6Gal beta 1-4GlcNAc (16), Gal beta 1-4GlcNAc beta 1-3(Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (18) and also in Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (22). Immobilized wheat germ agglutinin (WGA), possessing high affinity for 16 [1], revealed no affinity for the fucosylated derivative Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6Gal beta 1-4GlcNAc (17). The isomeric heptasaccharides Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (19) and Gal beta 1-4GlcNAc beta 1-3[Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6]Gal beta 1-4GlcNAc (20) were readily separated from each other on WGA agarose, and so were the isomeric nonasaccharides Gal alpha 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-3(Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-6)Gal beta 1-4GlcNAc (23) and Gal alpha 1-3Gal beta 1-4GlcNAc beta 1-3[Gal alpha 1-3Gal beta 1-4(Fuc alpha 1-3)GlcNAc beta 1-6]Gal beta 1-4GlcNAc (24).
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Affiliation(s)
- R Niemelä
- Institute of Biotechnology, University of Helsinki, Finland
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25
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Dennis RP. A review of the biological significance of carbohydrates on glycoproteins and methods for their analysis. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1995; 376:1-11. [PMID: 8597235 DOI: 10.1007/978-1-4615-1885-3_1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- R P Dennis
- Oxford GlycoSystems, Abingdon, United Kingdom
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26
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de Beer T, van Zuylen CW, Hård K, Boelens R, Kaptein R, Kamerling JP, Vliegenthart JF. Rapid and simple approach for the NMR resonance assignment of the carbohydrate chains of an intact glycoprotein. Application of gradient-enhanced natural abundance 1H-13C HSQC and HSQC-TOCSY to the alpha-subunit of human chorionic gonadotropin. FEBS Lett 1994; 348:1-6. [PMID: 8026573 DOI: 10.1016/0014-5793(94)00547-8] [Citation(s) in RCA: 56] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
The structure assessment of an intact glycoprotein in solution requires an extensive assignment of the carbohydrate NMR resonances. However, assignment of homonuclear spectra is very complicated because of the severe overlap of protein and carbohydrate signals. Application of pulsed field gradients allowed high quality natural abundance 1H-13C HSQC and HSQC-TOCSY spectra to be recorded of the alpha-subunit of human chorionic gonadotropin. Most carbohydrate 1H-13C correlations appear in a distinct region between the aromatic region and the protein C alpha-H alpha region. The enormous reduction in overlap led to fast and unambiguous assignment of the anomeric 1H-13C correlations. Subsequently, correlations of the monosaccharide skeleton atoms were readily assigned in the HSQC-TOCSY spectrum.
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Affiliation(s)
- T de Beer
- Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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27
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Hokke CH, Damm JB, Penninkhof B, Aitken RJ, Kamerling JP, Vliegenthart JF. Structure of the O-linked carbohydrate chains of porcine zona pellucida glycoproteins. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 221:491-512. [PMID: 8168537 DOI: 10.1111/j.1432-1033.1994.tb18762.x] [Citation(s) in RCA: 72] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The N-linked carbohydrate chains of porcine zona pellucida glycoproteins were released by digestion with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F and subsequently separated from the O-glycoprotein by gel-permeation chromatography on Bio-Gel P-100. The O-linked carbohydrate chains were released from the O-glycoprotein by alkaline borohydride treatment. Fractionation of the extremely heterogeneous mixture of O-linked oligosaccharide alditols was achieved by a combination of chromatographic techniques comprising gel-permeation chromatography on Bio-Gel P-4 and P-6, anion-exchange FPLC on Mono Q, and high-pH anion-exchange chromatography on CarboPac PA-1. The primary structures of 32 O-glycans were determined by one- and two-dimensional 1H-NMR spectroscopy. The major part of the analyzed compounds contain a combination of the structural elements Gal beta 1-4GlcNAc beta 1-3Gal beta 1-3GalNAc-ol, Gal beta 1-4(6SO4-)GlcNAc, and alpha 2-3-linked Neu5Gc or Neu5Ac. This series of compounds has the following structure, where n = 0 to > 6: [Neu5Gc/Ac alpha2-3]0-1[Gal beta 1-4(6SO4-)GlcNAc beta 1-3]nGal beta 1-4GlcNAc beta 1-3Gal Beta 1-3GalNAc-ol. In addition, smaller compounds were identified in which the Gal beta 1-3GalNAc-ol core is substituted by Neu5Gc/Ac alpha 2-6-linked to GalNAc-ol and/or Neu5Gc/Ac alpha 2-3-linked to Gal. Furthermore, oligosaccharides were obtained in which the distribution of 6-O-sulfated GlcNAc residues differs from that in the above-mentioned general structure, and a small portion of the oligosaccharides has the GlcNAc beta 1-3GalNAc-ol core structure. Analysis of the endo-beta-galactosidase digests of pools of N- and O-glycans indicated that the two types of oligosaccharides contain qualitatively similar poly(N-acetyllactosamine) chains. In the case of the N-linked carbohydrate chains, multiple branching of the core structures occurs, resulting in an even larger heterogeneity than observed for the O-linked carbohydrate chains.
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Affiliation(s)
- C H Hokke
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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28
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Cooper CA, Packer NH, Redmond JW. The elimination of O-linked glycans from glycoproteins under non-reducing conditions. Glycoconj J 1994; 11:163-7. [PMID: 7804006 DOI: 10.1007/bf00731156] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
A simple procedure is described for the elimination of O-linked glycans from bovine submaxillary mucin under non-reducing conditions, using triethylamine in aqueous hydrazine. The glycans were isolated as the hydrazones, which were converted to the reducing glycans by exchange with acetone in neutral aqueous solution. The glycan alditols obtained after reduction corresponded to those obtained by the reductive beta-elimination of O-glycans.
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Affiliation(s)
- C A Cooper
- School of Chemistry, Macquarie University, North Ryde, NSW, Australia
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29
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Hokke CH, Roosenboom MJ, Thomas-Oates JE, Kamerling JP, Vliegenthart JF. Structure determination of the disialylated poly-(N-acetyllactosamine)-containing O-linked carbohydrate chains of equine chorionic gonadotropin. Glycoconj J 1994; 11:35-41. [PMID: 8193552 DOI: 10.1007/bf00732430] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The disialylated poly-(N-acetyllactosamine)-containing O-linked oligosaccharide alditols, released by alkaline borohydride treatment of the enzymically N-deglycosylated beta-subunit of equine chorionic gonadotropin, were purified by fast protein liquid chromatography (FPLC) on Mono Q and analysed by fast ion bombardment mass spectrometry (FAB-MS) and 1H-NMR spectroscopy. The identified oligosaccharide alditols have the following structure: [Formula: see text]
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Affiliation(s)
- C H Hokke
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht, The Netherlands
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30
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D'Andrea G, D'Alessandro AM, Salucci ML, Oratore A. Primary structure of the major glycan from human seminal transferrin. JOURNAL OF PROTEIN CHEMISTRY 1994; 13:31-6. [PMID: 8011069 DOI: 10.1007/bf01891990] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Human seminal transferrin (HSmT) is an iron-containing glycoprotein whose structural properties have not been adequately investigated. The carbohydrate content of the purified glycoprotein amount to 6.1%, and monosaccharide analysis revealed the major oligosaccharide moiety to be of the N-glycoside type. The carbohydrate chains were released from the iron-free form by digestion with peptide N-glycosidase F (PNGase F) in the presence of detergents such as SDS and beta-octylglucoside. After ethanol precipitation and fractionation on Bio-Gel P-6 and Bio-Gel P-2, the oligosaccharide was further purified on Mono-Q and desalted on Bio-Gel P-2. By 600-MHz 1H-NMR spectroscopy, the primary structure of the major N-linked oligosaccharide component was established to be: [formula: see text]
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Affiliation(s)
- G D'Andrea
- Department of Sciences and Biomedical Technologies and Biometrics, University of L'Aquila, Italy
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31
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Hokke CH, Damm JB, Kamerling JP, Vliegenthart JF. Structure of three acidic O-linked carbohydrate chains of porcine zona pellucida glycoproteins. FEBS Lett 1993; 329:29-34. [PMID: 8354402 DOI: 10.1016/0014-5793(93)80186-x] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
Structural analysis by 1D and 2D 1H NMR spectroscopy of three acidic O-linked oligosaccharide alditols, released from porcine zona pellucida glycoproteins by alkaline borohydride treatment, afforded the following structures: Gal beta 1-4(6SO4)GlcNAc beta 1-3Gal beta 1-4GlcNAc beta 1-3Gal beta 1-3GalNAc- ol Neu5Gc alpha 2-3Gal beta 1-4(6SO4-)GlcNAc beta 1-3Gal beta 1- 4GlcNAc beta 1-3Gal beta 1-3GalNAc-ol Neu5Ac alpha 2-3Gal beta 1-4(6SO4-)GlcNAc beta 1-3Gal beta 1-4GlcNAc beta 1- 3Gal beta 1-3GalNAc-ol These oligosaccharides are the smallest compounds that contain the structural elements which are present in the acidic, high-molecular mass O-linked carbohydrate chains of porcine zona pellucida glycoproteins.
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Affiliation(s)
- C H Hokke
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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32
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Nemansky M, van den Eijnden DH. Enzymatic characterization of CMP-NeuAc:Gal beta 1-4GlcNAc-R alpha(2-3)-sialyltransferase from human placenta. Glycoconj J 1993; 10:99-108. [PMID: 8395270 DOI: 10.1007/bf00731193] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
In this report we present the enzymatic characterization of CMP-NeuAc:Gal beta 1-4GlcNAc-R alpha(2-3)-sialyltransferase from human placenta using placenta membranes as an enzyme preparation. This sialyltransferase is highly sensitive to detergents and prefers type 2 chain (Gal beta 1-4GlcNAc) over type 1 chain (Gal beta 1-3GlcNAc) acceptors. Oligosaccharides and glycopeptides were better acceptor substrates than glycoproteins. Of the branched oligosaccharides, those with a bisected N-acetylglucosamine (GlcNAc) structure appeared to be poorer substrates, while triantennary structures containing a Gal beta 1-4GlcNAc beta 1-4Man alpha 1-3Man branch were preferred. Product characterization, using 400 MHz 1H-NMR spectroscopy, confirmed that sialic acid was introduced into the Gal beta 1-4GlcNAc-R units of the acceptor substrates in an alpha (2-3) linkage, and revealed that this sialyltransferase does not prefer either of the two branches of a complex type di-antennary glycopeptide acceptor for sialic acid attachment. These properties distinguish this enzyme from all other sialyltransferases characterized to date.
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Affiliation(s)
- M Nemansky
- Department of Medical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands
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33
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Patel T, Bruce J, Merry A, Bigge C, Wormald M, Jaques A, Parekh R. Use of hydrazine to release in intact and unreduced form both N- and O-linked oligosaccharides from glycoproteins. Biochemistry 1993; 32:679-93. [PMID: 8422375 DOI: 10.1021/bi00053a037] [Citation(s) in RCA: 268] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The use of hydrazine to release unreduced N- and O-linked oligosaccharides from glycoproteins has been investigated using several "standard" glycoproteins of previously defined glycosylation. It is shown that hydrazinolysis can be used to release intact N- and O-linked oligosaccharides in an unreduced form. The release of O-linked oligosaccharides occurs with a lower temperature dependence than the release of N-linked oligosaccharides, and the kinetic parameters governing release of oligosaccharides from these standard glycoproteins have been determined. These parameters allow a definition of reaction conditions under which anhydrous hydrazinolysis can be used to selectively release O-linked oligosaccharides (60 degrees C, 5 h) or release both N- and O-linked oligosaccharides (95 degrees C, 4 h) in high yield (> 85%) from all glycoproteins investigated (n = 11). Under these reaction conditions, the recovered N- and O-linked oligosaccharides are structurally intact (as judged by 600-MHz 1H-NMR, laser-desorption mass spectrometry, HPAEC-PAD, gel filtration, and glycosidase digestion), with the possible exception of certain N- and O-acyl substituents of sialic acid. This use of mild hydrazinolysis therefore allows both the simultaneous and sequential chemical release from glycoproteins of O- and N-linked oligosaccharides in their intact unreduced form.
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Affiliation(s)
- T Patel
- Oxford GlycoSystems Limited, Unit 4, Abingdon, Oxon, England
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34
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Nemansky M, Schiphorst WE, Koeleman CA, Van den Eijnden DH. Human liver and human placenta both contain CMP-NeuAc:Gal beta 1-->4GlcNAc-R alpha 2-->3- as well as alpha 2-->6-sialyltransferase activity. FEBS Lett 1992; 312:31-6. [PMID: 1426235 DOI: 10.1016/0014-5793(92)81404-a] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A high pH anion exchange chromatographic (HPAEC) system for the separation of isomeric sialo-oligosaccharide products was developed. Employing this system, using Gal beta 1-->4GlcNAc beta 1-->2Man alpha 1-->6Man beta 1-->4GlcNAc as a substrate, a Gal beta 1-->4GlcNAc-R alpha 2-->3-sialyltransferase activity was detected for the first time in human liver. This activity is expressed together with the prevalent alpha 2-->6-sialyltransferase. Furthermore, in addition to the major alpha 2-->3-sialyltransferase, a low but distinct activity of alpha 2-->6-sialyltransferase was detected in human placenta. This activity could not be found by methods based on methylation analysis or high resolution NMR spectroscopy. It is concluded that HPAEC, in combination with the use of the pentasaccharide as an acceptor substrate, is suited for the specific detection of minor, Gal beta 1-->4GlcNAc-specific sialyltransferase activities.
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Affiliation(s)
- M Nemansky
- Department of Medical Chemistry, Vrije Universiteit, Amsterdam, The Netherlands
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35
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Watson E, Bhide A, Kenney WC, Lin FK. High-performance anion-exchange chromatography of asparagine-linked oligosaccharides. Anal Biochem 1992; 205:90-5. [PMID: 1280004 DOI: 10.1016/0003-2697(92)90583-s] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Oligosaccharides released enzymatically by N-glycanase from fetuin, alpha-acid glycoprotein, human chorionic gonadotropin, platelet-derived growth factor, and kallikrein were chromatographed on a polymeric pellicular anion-exchange column at pH values of 5 and 13. Separations occurred into groups of peaks containing the same number of sialic acids with an additional separation dependent upon the nature of the antennary structure present. High pH conditions were required for the optimum separation of fetuin oligosaccharides, while low pH conditions significantly improved resolution of oligosaccharides obtained from the other glycoproteins. The analytical separation of oligosaccharides under conditions of low pH has important implications in the development of chromatographic mapping and identification techniques for N-linked oligosaccharides present on recombinant proteins.
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Affiliation(s)
- E Watson
- Amgen Inc., Amgen Center, Thousand Oaks, California 91320
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36
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Hård K, Damm JB, Spruijt MP, Bergwerff AA, Kamerling JP, Van Dedem GW, Vliegenthart JF. The carbohydrate chains of the beta subunit of human chorionic gonadotropin produced by the choriocarcinoma cell line BeWo. Novel O-linked and novel bisecting-GlcNAc-containing N-linked carbohydrates. EUROPEAN JOURNAL OF BIOCHEMISTRY 1992; 205:785-98. [PMID: 1374031 DOI: 10.1111/j.1432-1033.1992.tb16843.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The N-linked carbohydrate chains of the beta subunit of human chorionic gonadotropin (hCG-beta) isolated from the culture fluid of the choriocarcinoma cell line BeWo were released enzymatically by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. Subsequently, the O-linked oligosaccharides were split off from the N-deglycosylated protein by mild alkaline borohydride treatment. The carbohydrate chains were purified in their intact sialylated forms by FPLC anion-exchange chromatography on Mono Q, HPLC on Lichrosorb-NH2, and high-pH anion-exchange chromatography on CarboPac PA1. 1H-NMR spectroscopic analysis of the major fractions demonstrates the occurrence of the following sialylated diantennary and triantennary N-linked oligosaccharides. Residues not written in bold letters are variably present. [formula: see text] The incidence of triantennary carbohydrate chains is much higher than in normal urinary hCG-beta (26% vs 2%). The same holds for the alpha 1-6-fucosylation of the asparagine-bound GlcNAc (95% vs 42%). The presence of a bisecting GlcNAc and the occurrence of alpha 2-6-linked Neu5Ac in the most abundant N-glycans, are new features for hCG-beta. The major O-linked carbohydrate chains identified are the tetrasaccharide Neu5Ac alpha 2-3Gal beta 1-3(Neu5Ac alpha 2-6)GalNAc-ol and the hexasaccharide Neu5Ac alpha 2-3Gal beta 1-4GlcNAc beta 1-6(Neu5Ac alpha 2-3Gal beta 1-3)GalNAc-ol, both also found in normal urinary hCG. In addition, two novel O-glycans were characterized: [formula: see text]
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Affiliation(s)
- K Hård
- Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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37
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Demel RA, Van Doorn JM, Van der Horst DJ. Insect apolipophorin III: interaction of locust apolipophorin III with diacylglycerol. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1124:151-8. [PMID: 1543737 DOI: 10.1016/0005-2760(92)90091-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
In the formation of low-density lipophorin (LDLp) by the loading of diacylglycerol onto high-density lipophorin (HDLp) in insect hemolymph, apolipophorin III (apoLp-III) plays an essential role by binding to the increasing surface of the expanding lipoprotein particle. The present data on the surface properties of apoLp-III from Locusta migratoria demonstrate a preferential interaction with diacylglycerol. Injection of apoLp-III underneath a diacylglycerol monolayer results in a rapid interaction with the lipid; interaction with a phosphatidylcholine monolayer was considerably less. Locust apoLp-III binds with high affinity (Kd = 7.9.10(-9) M) to 1,2-diacylglycerol, which is consistent with its function in the LDLp particle; affinity for phosphatidylcholine is considerably lower. While the molecular area of locust apoLp-III in a monolayer is 2080 A2/molecule at the collapse pressure, in mixed monolayers of apoLp-III and lipid, the mean molecular area is decreased. Deglycosylation of the apoLp-III did not affect its interfacial stability. ApoLp-III from the moth Manduca sexta, which we included for comparison, demonstrated a similar reduction in molecular area resulting from interaction with lipid. These data do not support the hypothesis that interaction of apoLp-III with a lipid surface will lead to doubling of the molecular area of the protein (Kawooya, J.K., Meredith, S.C., Wells, M.A., Kézdy, F.J. and Law, J.H. (1986) J. Biol. Chem. 261, 13588-13591). The area of locust apoLp-III of 12.9 A2/amino acid residue at the collapse pressure is consistent with monolayers of alpha-helical proteins; circular dichroic spectra confirm a high alpha-helix content. The surface properties of apoLp-III reported here enable a high surface concentration of diacylglycerol in the LDLp particle, allowing the lipoprotein to act as an efficient reutilizable lipid shuttle.
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Affiliation(s)
- R A Demel
- Centre for Biomembranes, University of Utrecht, The Netherlands
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38
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High-Resolution 1H-Nuclear Magnetic Resonance Spectroscopy of Oligosaccharide-Alditols Released from Mucin-Type O-Glycoproteins. ACTA ACUST UNITED AC 1992. [DOI: 10.1007/978-1-4757-9474-8_1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
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39
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Hård K, Spronk BA, Hokke CH, Kamerling JP, Vliegenthart JF. The potency of amide protons for assignments of NMR spectra of carbohydrate chains of glycoproteins, recorded in 1H2O solutions. FEBS Lett 1991; 287:108-12. [PMID: 1879518 DOI: 10.1016/0014-5793(91)80027-z] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Three glycoprotein N-glycans, namely, a disialylated diantennary carbohydrate chain linked to Asn, a monosialylated, fucosylated diantennary glycopeptide with bisecting N-acetylglucosamine, and a tetrasialylated, fucosylated tetra-antennary oligosaccharide, have been investigated by two-dimensional NOE and HOHAHA spectroscopy in 1H2O as solvent. The amide protons of all N-acetylglucosamine and sialic acid residues could readily be assigned. The large chemical-shift dispersion of the amide resonances of the N-acetylglucosamine residues, allowed the unambiguous assignment of every N-acetyl methyl signal, via strong NOEs. Subspectra could be obtained of all N-acetylglucosamine residues in HOHAHA spectra. These results have as main implication that several biologically important large glycans will now [corrected] become amenable for conformational studies by multidimensional NMR in 1H2O solution.
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Affiliation(s)
- K Hård
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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40
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Hokke CH, Kamerling JP, van Dedem GW, Vliegenthart JF. Determination of the branch location of extra N-acetyllactosamine units in sialo N-linked tetraantennary oligosaccharides. FEBS Lett 1991; 286:18-24. [PMID: 1907570 DOI: 10.1016/0014-5793(91)80931-r] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
An approach is presented for the determination of the branch location of 1 or 2 extra N-acetyllactosamine units in sialo N-linked carbohydrate chains from glycoproteins. Tetraantennary oligosaccharides containing extra N-acetyllactosamine units were digested with endo-beta-galactosidase, followed by treatment with N-acetyl-beta-glucosaminidase, yielding products which could be analysed by 1H-NMR spectroscopy, thereby giving conclusive data about the location of the extra units in the intact structures.
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Affiliation(s)
- C H Hokke
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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41
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Structure determination by 1H NMR spectroscopy of (sulfated) sialylated N-linked carbohydrate chains released from porcine thyroglobulin by peptide-N4-(N-acetyl-β-glucosaminyl)asparagine amidase-F. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(20)64312-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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42
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Bovine glomerular basement membrane. Location and structure of the asparagine-linked oligosaccharide units and their potential role in the assembly of the 7 S collagen IV tetramer. J Biol Chem 1991. [DOI: 10.1016/s0021-9258(18)52290-0] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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43
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Weisshaar G, Hiyama J, Renwick AG, Nimtz M. NMR investigations of the N-linked oligosaccharides at individual glycosylation sites of human lutropin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1991; 195:257-68. [PMID: 1991473 DOI: 10.1111/j.1432-1033.1991.tb15702.x] [Citation(s) in RCA: 77] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Human lutropin or luteinizing hormone (hLH) is a heterodimeric glycoprotein, composed of two subunits. hLH alpha (N-glycosylated at Asn52 and Asn78) and hLH beta (N-glycosylated at Asn30). The sugar chains were liberated by hydrazinolysis from intact hLH beta and from glycopeptides obtained after tryptic digestion of hLH alpha, subsequently reduced and fractionated as alditols by anion-exchange and ion-suppression amine-adsorption HPLC and identified mainly by one-dimensional (1D) and two-dimensional (2D) 1H-NMR spectroscopy. The results indicate predominantly diantennary. N-acetyllactosamine-type structures at all three glycosylation sites. The oligosaccharides attached to Asn52 (hLH alpha) and Asn30 (hLH beta) show a remarkably similar pattern, with mainly chain-terminating 4-sulphated 2-deoxy-2-N-acetylamino-D-galactose (GalNAc) and a sulphated/sialylated structure as the major single component. However, virtually all N-glycans on the beta subunit bear a fucose residue alpha 1-6-linked to the proximal GlcNAc, whereas those at Asn52 (and Asn78) of the alpha subunit are predominantly non-fucosylated. The oligosaccharides at Asn78 (hLH alpha) are sialylated rather than sulphated and contain the unique sequence NeuAc alpha 2-6 GalNAc beta 1-4GlcNAc beta 1-2 Man alpha 1-3 as part of the majority of mono- and disialylated compounds. The major single constituent at Asn78 has the following structure: [formula, see text]
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Affiliation(s)
- G Weisshaar
- Department of Biochemistry, University of Auckland, New Zealand
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44
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Hokke CH, Bergwerff AA, van Dedem GW, van Oostrum J, Kamerling JP, Vliegenthart JF. Sialylated carbohydrate chains of recombinant human glycoproteins expressed in Chinese hamster ovary cells contain traces of N-glycolylneuraminic acid. FEBS Lett 1990; 275:9-14. [PMID: 2124546 DOI: 10.1016/0014-5793(90)81427-p] [Citation(s) in RCA: 90] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
HPLC analysis of sialic acids released from recombinant variants of human tissue plasminogen activator, human chimeric plasminogen activator, human erythropoietin, and human follitropin, expressed in Chinese hamster ovary cells, demonstrates for each glycoprotein the presence of N-acetylneuraminic acid and N-glycolylneuraminic acid in a ratio of 97:3. Structural analysis by 500 MHz1H-NMR spectroscopy, of the enzymatically released N-linked carbohydrate chains of chimeric plasminogen activator and of erythropoietin, showed that alpha 2-3 linked N-glycolylneuraminic acid can occur in different N-acetyllactosamine type antennary structures.
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Affiliation(s)
- C H Hokke
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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45
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Hård K, Mekking A, Damm JB, Kamerling JP, de Boer W, Wijnands RA, Vliegenthart JF. Isolation and structure determination of the intact sialylated N-linked carbohydrate chains of recombinant human follitropin expressed in Chinese hamster ovary cells. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 193:263-71. [PMID: 2121479 DOI: 10.1111/j.1432-1033.1990.tb19332.x] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
Biologically active recombinant human follitropin has been expressed in Chinese hamster ovary cells. The carbohydrate chains of the recombinant glycoprotein hormone were enzymatically released by peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F. The oligosaccharides were separated from the N-deglycosylated protein by gel-permeation chromatography on Bio-Gel P-100, and fractionated by a combination of FPLC on Mono Q and HPLC on Lichrosorb-NH2. The structures of the carbohydrate chains were determined by 500- or 600-MHz 1H-NMR spectroscopy. The following types of carbohydrates occur: monosialylated diantennary (10%), disialylated diantennary (43%), disialylated tri-antennary (5%), trisialylated tri-antennary (13%), trisialylated tri'-antennary (8%), and tetrasialylated tetraantennary (12%) N-acetyllactosamine type of carbohydrate chains, all bearing exclusively alpha 2-3-linked N-acetylneuraminic acid (Neu5Ac). Previously, for pituitary follitropin mono-, di-, tri-, tri'-, and tetra-antennary oligosaccharides containing alpha 2-3- as well as alpha 2-6-linked Neu5Ac residues were reported. The bisecting GlcNAc residues present in native follitropin were not detected in the recombinant glycoprotein. Of the oligosaccharides 29% have an alpha 1-6-linked Fuc residue at the asparagine-bound GlcNAc, whereas this amount is about 50% in pituitary follitropin. In some of the tri-, tri'- and tetra-antennary oligosaccharide fractions small amounts (less than 5%) of compounds were detected having one or more additional N-acetyllactosamine units.
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Affiliation(s)
- K Hård
- Bijvoet Center, Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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46
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Likhosherstov LM, Novikova OS, Derevitskaya VA, Kochetkov NK. A selective method for sequential splitting of O- and N-linked glycans from N,O-glycoproteins. Carbohydr Res 1990; 199:67-76. [PMID: 1696170 DOI: 10.1016/0008-6215(90)84093-a] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
O-Linked oligosaccharides from N,O-glycoproteins were selectively split off by treatment with alkaline sodium borohydride in the presence of cadmium salt. The side reaction of reductive cleavage of N-glycosylamide and peptide bonds, observed under standard conditions of splitting of O-linked chains (M NaBH4 and 50mM NaOH, 16 h, 50 degrees), was inhibited by addition of 50-10 mM cadium acetate and 5-10mM EDTA.Na4, as shown by treatment of model compounds and several glycoproteins (ovomucoid, group-specific glycoproteins H and B, fetuin, and asialofetuin). This treatment, in combination with the previously developed procedure for the release of the N-linked oligosaccharide chains by lithium borohydride, allows a sequential, selective cleavage of O-, and then N-linked oligosaccharides from N,O-glycoproteins by chemical methods.
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Affiliation(s)
- L M Likhosherstov
- N. D. Zelinsky Institute of Organic Chemistry, Academy of Sciences, U.S.S.R., Moscow
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47
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Damm JB, Hård K, Kamerling JP, van Dedem GW, Vliegenthart JF. Structure determination of the major N- and O-linked carbohydrate chains of the beta subunit from equine chorionic gonadotropin. EUROPEAN JOURNAL OF BIOCHEMISTRY 1990; 189:175-83. [PMID: 2331995 DOI: 10.1111/j.1432-1033.1990.tb15474.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The carbohydrate moieties of equine chorionic gonadotropin alpha and beta subunits were released from the protein backbones by successive treatments with peptide-N4-(N-acetyl-beta-glucosaminyl)asparagine amidase F and alkaline borohydride and then fractionated by FPLC and HPLC. The major N- and O-linked glycans of the beta subunit were characterized by 500-MHz 1H-NMR spectroscopy, showing a remarkable structural heterogeneity for the N-glycosidically linked chains, comprising mono-, di-, tri- and tri'-antennary N-acetyllactosamine type of glycans, being partly alpha 1-6 fucosylated at the Asn-bound GlcNAc residue and having alpha 2-6 and alpha 2-3 linked N-acetyl- and N-acetyl-4-O-acetylneuraminic acid residues as sialic acid constituents. Significant differences in this respect were detected for the partially characterized glycans of the alpha subunit. The major part of the O-linked carbohydrate chains, occurring solely in the beta subunit, is formed by tri-, tetra-, penta- and hexa-saccharides. There are indications for the presence of oligo(N-acetyllactosamine) units in both the N- and O-linked glycans of the beta subunit.
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Affiliation(s)
- J B Damm
- Department of Bio-Organic Chemistry, Utrecht University, The Netherlands
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48
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Katoh H, Ohgi K, Irie M, Endo T, Kobata A. The structure of the asparagine-linked sugar chains of bovine brain ribonuclease. Carbohydr Res 1990; 195:273-93. [PMID: 2331705 DOI: 10.1016/0008-6215(90)84171-p] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The asparagine-linked sugar chains of bovine brain ribonuclease were quantitatively released as oligosaccharides from the polypeptide backbone by hydrazinolysis. After N-acetylation, they were converted into radioactively-labeled oligosaccharides by NaB3H4 reduction. The radioactive oligosaccharide mixture was fractionated by ion-exchange chromatography, and the acidic oligosaccharides were converted into neutral oligosaccharides by sialidase digestion. The neutral oligosaccharides were then fractionated by Bio-Gel P-4 column chromatography. Structural studies of each oligosaccharide by sequential exoglycosidase digestion in combination with methylation analysis revealed that bovine brain ribonuclease showed extensive heterogeneity. It contains bi- and tri-antennary, complex-type oligosaccharides having alpha-D-Manp-(1----3)-[alpha-D-Manp-(1----6)]-beta-D-Manp -(1----4)-beta-D- GlcpNAc-(1----4)-[alpha-L-Fucp-(1----6)]-D-GlcNAc as their common core. Four different outside oligosaccharide chains, i.e., beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----, alpha-Neu5Ac-(2----6)-beta-D- Galp-(1----4)-beta-D-GlcpNAc-(1----, alpha-Neu5Ac-(2----3)-beta-D-Galp-(1----4)- beta-D-GlcpNAc-(1----, and alpha-D-Galp-(1----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc-(1----, were found. The preferential distribution of the alpha-D-Galp-(1----3)-beta-D-Galp-(1----4)-beta-D-GlcpNAc group on the alpha-D-Manp-(1----6) arm is a characteristic feature of the sugar chains of this enzyme.
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Affiliation(s)
- H Katoh
- Department of Microbiology, Hoshi College of Pharmacy, Tokyo, Japan
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49
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50
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Lee KB, Loganathan D, Merchant ZM, Linhardt RJ. Carbohydrate analysis of glycoproteins. A review. Appl Biochem Biotechnol 1990; 23:53-80. [PMID: 2405775 DOI: 10.1007/bf02942052] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Many of the products prepared by biotechnological approaches, including recombinant genetic engineering, cell tissue culture, and monoclonal technologies, are glycoproteins. As little as five years ago, glycosylation was believed to play no significant role in the function of glycoproteins. Recent large scale testing of glycoprotein-based pharmaceuticals has indicated that both the extent and type of glycosylation can play a central role in glycoprotein activity. Although methods for compositional and sequence analysis of proteins and nucleic acids are generally available, similar methods have yet to be developed for carbohydrate oligomers and polymers. This review focuses on new, developing methods for the analysis and sequencing of the carbohydrate portion of glycoproteins. Included are: (1) the release of oligosaccharides and hydrolysis of carbohydrate chains using enzymatic and chemical methods; (2) fractionation by LPLC, electrophoresis, HPLC, and lectin affinity chromatography; (3) detection through the preparation of derivatives or by new electrochemical methods; (4) analysis by spectroscopic methods, including MS and high-field NMR; and (5) their sequencing through the use of multiple, well-integrated techniques. The ultimate goal of the analytical approaches discussed is to firmly establish structure and, thus, permit the study of structure-function relationships and eventually to allow the intelligent application of carbohydrate remodeling techniques in the preparation of new glycoproteins.
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Affiliation(s)
- K B Lee
- Division of Medicinal and Natural Products Chemistry, College of Pharmacy, University of Iowa, Iowa City 52242
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