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Ramírez AS, de Capitani M, Pesciullesi G, Kowal J, Bloch JS, Irobalieva RN, Reymond JL, Aebi M, Locher KP. Molecular basis for glycan recognition and reaction priming of eukaryotic oligosaccharyltransferase. Nat Commun 2022; 13:7296. [PMID: 36435935 PMCID: PMC9701220 DOI: 10.1038/s41467-022-35067-x] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Accepted: 11/17/2022] [Indexed: 11/28/2022] Open
Abstract
Oligosaccharyltransferase (OST) is the central enzyme of N-linked protein glycosylation. It catalyzes the transfer of a pre-assembled glycan, GlcNAc2Man9Glc3, from a dolichyl-pyrophosphate donor to acceptor sites in secretory proteins in the lumen of the endoplasmic reticulum. Precise recognition of the fully assembled glycan by OST is essential for the subsequent quality control steps of glycoprotein biosynthesis. However, the molecular basis of the OST-donor glycan interaction is unknown. Here we present cryo-EM structures of S. cerevisiae OST in distinct functional states. Our findings reveal that the terminal glucoses (Glc3) of a chemo-enzymatically generated donor glycan analog bind to a pocket formed by the non-catalytic subunits WBP1 and OST2. We further find that binding either donor or acceptor substrate leads to distinct primed states of OST, where subsequent binding of the other substrate triggers conformational changes required for catalysis. This alternate priming allows OST to efficiently process closely spaced N-glycosylation sites.
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Affiliation(s)
- Ana S. Ramírez
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Mario de Capitani
- grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Giorgio Pesciullesi
- grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Julia Kowal
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Joël S. Bloch
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Rossitza N. Irobalieva
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Jean-Louis Reymond
- grid.5734.50000 0001 0726 5157Department of Chemistry and Biochemistry, University of Bern, Bern, Switzerland
| | - Markus Aebi
- grid.5801.c0000 0001 2156 2780Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
| | - Kaspar P. Locher
- grid.5801.c0000 0001 2156 2780Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich, Switzerland
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Alg mannosyltransferases: From functional and structural analyses to the lipid-linked oligosaccharide pathway reconstitution. Biochim Biophys Acta Gen Subj 2022; 1866:130112. [PMID: 35217128 DOI: 10.1016/j.bbagen.2022.130112] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2021] [Revised: 02/06/2022] [Accepted: 02/12/2022] [Indexed: 11/21/2022]
Abstract
BACKGROUND N-glycosylation is initiated from the biosynthesis of lipid-linked oligosaccharide (LLO) on the endoplasmic reticulum (ER), which is catalyzed by a series of Alg (asparagine-linked glycosylation) proteins. SCOPE OF REVIEW This review summarizes our recent studies on the enzymology of Alg mannosyltransferases (MTases). We also discuss the membrane topology and physiological importance of several ER cytosolic Alg proteins. MAJOR CONCLUSIONS Utilizing an efficient prokaryotic protein expression system and a new LC-MS quantitative activity assay, we overexpressed all Alg MTases and performed enzymology studies. Moreover, by reconstituting the LLO pathway, the high-yield chemoenzymatic synthesis of high-mannose-type N-glycans was accomplished using recombinant Alg MTases. GENERAL SIGNIFICANCE The analysis of the enzymology and topology of Alg MTases has provided valuable biochemical information in the LLO biosynthesis pathway. In addition, an efficient chemoenzymatic strategy that could prepare various oligomannose-type N-glycans in sufficient amounts was established for further biological assays.
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Rexer TFT, Schildbach A, Klapproth J, Schierhorn A, Mahour R, Pietzsch M, Rapp E, Reichl U. One pot synthesis of GDP-mannose by a multi-enzyme cascade for enzymatic assembly of lipid-linked oligosaccharides. Biotechnol Bioeng 2017; 115:192-205. [PMID: 28922469 PMCID: PMC5765510 DOI: 10.1002/bit.26454] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2017] [Revised: 09/08/2017] [Accepted: 09/11/2017] [Indexed: 12/22/2022]
Abstract
Glycosylation of proteins is a key function of the biosynthetic‐secretory pathway in the endoplasmic reticulum (ER) and Golgi apparatus. Glycosylated proteins play a crucial role in cell trafficking and signaling, cell‐cell adhesion, blood‐group antigenicity, and immune response. In addition, the glycosylation of proteins is an important parameter in the optimization of many glycoprotein‐based drugs such as monoclonal antibodies. In vitro glycoengineering of proteins requires glycosyltransferases as well as expensive nucleotide sugars. Here, we present a designed pathway consisting of five enzymes, glucokinase (Glk), phosphomannomutase (ManB), mannose‐1‐phosphate‐guanyltransferase (ManC), inorganic pyrophosphatase (PmPpA), and 1‐domain polyphosphate kinase 2 (1D‐Ppk2) expressed in E. coli for the cell‐free production and regeneration of GDP‐mannose from mannose and polyphosphate with catalytic amounts of GDP and ADP. It was shown that GDP‐mannose is produced at various conditions, that is pH 7–8, temperature 25–35°C and co‐factor concentrations of 5–20 mM MgCl2. The maximum reaction rate of GDP‐mannose achieved was 2.7 μM/min at 30°C and 10 mM MgCl2 producing 566 nmol GDP‐mannose after a reaction time of 240 min. With respect to the initial GDP concentration (0.8 mM) this is equivalent to a yield of 71%. Additionally, the cascade was coupled to purified, transmembrane‐deleted Alg1 (ALG1ΔTM), the first mannosyltransferase in the ER‐associated lipid‐linked oligosaccharide (LLO) assembly. Thereby, in a one‐pot reaction, phytanyl‐PP‐(GlcNAc)2‐Man1 was produced with efficient nucleotide sugar regeneration for the first time. Phytanyl‐PP‐(GlcNAc)2‐Man1 can serve as a substrate for the synthesis of LLO for the cell‐free in vitro glycosylation of proteins. A high‐performance anion exchange chromatography method with UV and conductivity detection (HPAEC‐UV/CD) assay was optimized and validated to determine the enzyme kinetics. The established kinetic model enabled the optimization of the GDP‐mannose regenerating cascade and can further be used to study coupling of the GDP‐mannose cascade with glycosyltransferases. Overall, the study envisages a first step towards the development of a platform for the cell‐free production of LLOs as precursors for in vitro glycoengineering of proteins.
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Affiliation(s)
- Thomas F T Rexer
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Anna Schildbach
- Department of Downstream Processing, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Jan Klapproth
- Department of Downstream Processing, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Angelika Schierhorn
- Institute of Biochemistry and Biotechnology, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Reza Mahour
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Markus Pietzsch
- Department of Downstream Processing, Institute of Pharmacy, Martin Luther University Halle-Wittenberg, Halle (Saale), Germany
| | - Erdmann Rapp
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany
| | - Udo Reichl
- Max Planck Institute for Dynamics of Complex Technical Systems, Bioprocess Engineering, Magdeburg, Germany.,Otto-von-Guericke University Magdeburg, Chair of Bioprocess Engineering, Magdeburg, Germany
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Ramírez AS, Boilevin J, Lin CW, Ha Gan B, Janser D, Aebi M, Darbre T, Reymond JL, Locher KP. Chemo-enzymatic synthesis of lipid-linked GlcNAc2Man5 oligosaccharides using recombinant Alg1, Alg2 and Alg11 proteins. Glycobiology 2017; 27:726-733. [PMID: 28575298 PMCID: PMC5881667 DOI: 10.1093/glycob/cwx045] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Revised: 05/10/2017] [Accepted: 05/27/2017] [Indexed: 11/14/2022] Open
Abstract
The biosynthesis of eukaryotic lipid-linked oligosaccharides (LLOs) that act as donor substrates in eukaryotic protein N-glycosylation starts on the cytoplasmic side of the endoplasmic reticulum and includes the sequential addition of five mannose units to dolichol-pyrophosphate-GlcNAc2. These reactions are catalyzed by the Alg1, Alg2 and Alg11 gene products and yield Dol-PP-GlcNAc2Man5, an LLO intermediate that is subsequently flipped to the lumen of the endoplasmic reticulum. While the purification of active Alg1 has previously been described, Alg11 and Alg2 have been mostly studied in vivo. We here describe the expression and purification of functional, full length Alg2 protein. Along with the purified soluble domains Alg1 and Alg11, we used Alg2 to chemo-enzymatically generate Dol-PP-GlcNAc2Man5 analogs starting from synthetic LLOs containing a chitobiose moiety coupled to oligoprenyl carriers of distinct lengths (C10, C15, C20 and C25). We found that while the addition of the first mannose unit by Alg1 was successful with all of the LLO molecules, the Alg2-catalyzed reaction was only efficient if the acceptor LLOs contained a sufficiently long lipid tail of four or five isoprenyl units (C20 and C25). Following conversion with Alg11, the resulting C20 or C25 -containing GlcNAc2Man5 LLO analogs were successfully used as donor substrates of purified single-subunit oligosaccharyltransferase STT3A from Trypanosoma brucei. Our results provide a chemo-enzymatic method for the generation of eukaryotic LLO analogs and are the basis of subsequent mechanistic studies of the enigmatic Alg2 reaction mechanism.
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Affiliation(s)
- Ana S Ramírez
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Schafmattstrasse 20, CH-8093 Zürich, Switzerland
| | - Jérémy Boilevin
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Chia-Wei Lin
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Bee Ha Gan
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Daniel Janser
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Schafmattstrasse 20, CH-8093 Zürich, Switzerland
| | - Markus Aebi
- Institute of Microbiology, Eidgenössische Technische Hochschule (ETH), CH-8093 Zürich, Switzerland
| | - Tamis Darbre
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Jean-Louis Reymond
- Department of Chemistry and Biochemistry, University of Berne, CH-3012 Berne, Switzerland
| | - Kaspar P Locher
- Department of Biology, Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Schafmattstrasse 20, CH-8093 Zürich, Switzerland
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Li ST, Wang N, Xu S, Yin J, Nakanishi H, Dean N, Gao XD. Quantitative study of yeast Alg1 beta-1, 4 mannosyltransferase activity, a key enzyme involved in protein N-glycosylation. Biochim Biophys Acta Gen Subj 2016; 1861:2934-2941. [PMID: 27670784 DOI: 10.1016/j.bbagen.2016.09.023] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2016] [Revised: 09/20/2016] [Accepted: 09/21/2016] [Indexed: 12/24/2022]
Abstract
BACKGROUND Asparagine (N)-linked glycosylation begins with a stepwise synthesis of the dolichol-linked oligosaccharide (DLO) precursor, Glc3Man9GlcNAc2-PP-Dol, which is catalyzed by a series of endoplasmic reticulum membrane-associated glycosyltransferases. Yeast ALG1 (asparagine-linked glycosylation 1) encodes a β-1, 4 mannosyltransferase that adds the first mannose onto GlcNAc2-PP-Dol to produce a core trisaccharide Man1GlcNAc2-PP-Dol. ALG1 is essential for yeast viability, and in humans mutations in the ALG1 cause congenital disorders of glycosylation known as ALG1-CDG. Alg1 is difficult to purify because of its low expression level and as a consequence, has not been well studied biochemically. Here we report a new method to purify recombinant Alg1 in high yield, and a mass spectral approach for accurately measuring its β-1, 4 mannosyltransferase activity. METHODS N-terminally truncated yeast His-tagged Alg1 protein was expressed in Escherichia coli and purified by HisTrap HP affinity chromatography. In combination with LC-MS technology, we established a novel assay to accurately measure Alg1 enzyme activity. In this assay, a chemically synthesized dolichol-linked oligosaccharide analogue, phytanyl-pyrophosphoryl-α-N, N'-diacetylchitobioside (PPGn2), was used as the acceptor for the β-1, 4 mannosyl transfer reaction. RESULTS Using purified Alg1, its biochemical characteristics were investigated, including the apparent Km and Vmax values for acceptor, optimal conditions of activity, and the specificity of its nucleotide sugar donor. Furthermore, the effect of ALG1-CDG mutations on enzyme activity was also measured. GENERAL SIGNIFICANCE This work provides an efficient method for production of Alg1 and a new MS-based quantitative assay of its activity.
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Affiliation(s)
- Sheng-Tao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
| | - Sha Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
| | - Jian Yin
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York 11794-5215, United States.
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, Jiangnan University, Wuxi 214122, China.
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Srichaisupakit A, Ohashi T, Misaki R, Fujiyama K. Production of initial-stage eukaryotic N-glycan and its protein glycosylation in Escherichia coli. J Biosci Bioeng 2014; 119:399-405. [PMID: 25449758 DOI: 10.1016/j.jbiosc.2014.09.016] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2014] [Revised: 09/13/2014] [Accepted: 09/17/2014] [Indexed: 11/20/2022]
Abstract
N-Glycosylation is a ubiquitous protein post-translational modification mechanism in eukaryotes. In this work, a synthetic pathway containing glycosyltransferases from Saccharomyces cerevisiae was introduced to Escherichia coli to synthesize lipid-linked mannosyl-chitobiose (Man-GlcNAc2) and trimannosyl-chitobiose (Man3-GlcNAc2). Transfer of Man3-GlcNAc2 onto a model periplasmic protein occurred in the engineered E. coli cell using oligosaccharyltransferase PglB from Campylobacter jejuni. Mass spectrometric analysis of the fluorescently labeled N-glycan indicated a glycan signal composed of 2 HexNAc and 3 Hex residues. The reversed-phase HPLC analysis suggested that the Hex residues were α1,3-, α1,6- and β1,4-linked mannoses. These results indicated that the constructed system synthesizes a Man3-GlcNAc2, identical to that observed in an early eukaryotic dolichol pathway. Finally, glycopeptide mass spectrometry confirmed the transfer of the assembled glycan moiety onto an engineered glycosylation motif of recombinant maltose binding protein. Surprisingly, the Man3-GlcNAc2 structure but not Man-GlcNAc2 was transferred onto maltose binding protein. This work showed that PglB protein might be able to accommodate the transfer of the further engineered glycan with greater complexity.
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Affiliation(s)
| | - Takao Ohashi
- International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Ryo Misaki
- International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan
| | - Kazuhito Fujiyama
- International Center for Biotechnology, Osaka University, Suita, Osaka 565-0871, Japan.
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7
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Revers L, Bill RM, Wilson IB, Watt GM, Flitsch SL. Development of recombinant, immobilised beta-1,4-mannosyltransferase for use as an efficient tool in the chemoenzymatic synthesis of N-linked oligosaccharides. BIOCHIMICA ET BIOPHYSICA ACTA 1999; 1428:88-98. [PMID: 10366763 DOI: 10.1016/s0304-4165(99)00048-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
The preparation of the conserved core structure of asparagine-linked oligosaccharides found in eukaryotic glycoproteins is an important step towards the synthesis of homogeneous neoglycoproteins. So far, however, the convenient generation of the Manbeta4GlcNAcbeta4GlcNAc (Gn2M) core trisaccharide has proved to be a major obstacle because of the inherent difficulties associated with the synthesis of beta-mannosides. Here we report the overproduction in Escherichia coli of full-length and transmembrane-deleted yeast beta-1, 4-mannosyltransferases as novel N-terminal fusions bearing a decahistidinyl sequence and the minimal human Myc epitope. The recombinant enzymes were highly active and were amenable to immobilisation by nickel(II) chelation and to immunodetection with an anti-Myc monoclonal antibody. The immobilised, transmembrane-deleted enzyme exhibited an apparent Km of 14 microM for the synthetic acceptor substrate analogue, phytanyl-pyrophosphoryl-alpha-N,N'-diacetylchitobioside (PPGn2), under saturating donor conditions. This figure is comparable to those previously reported for native and recombinant yeast beta-1, 4-mannosyltransferases with, respectively, the natural dolichyl-linked acceptor and PPGn2. The validity of the reaction product was confirmed by chromatographic and spectroscopic analysis.
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Affiliation(s)
- L Revers
- The Edinburgh Centre for Protein Technology, Department of Chemistry, University of Edinburgh, King's Buildings, West Mains Road, Edinburgh EH9 3JJ, UK
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8
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Abstract
The oligosaccharide substrate for the N-linked protein glycosylation is assembled at the membrane of the endoplasmic reticulum. Dolichyl pyrophosphate serves as a carrier in this biosynthetic pathway. In this review, we discuss the function of the lipid carrier dolichol in oligosaccharide assembly and give an overview of the biosynthesis of the different sugar donors required for the building of the oligosaccharide. Yeast genetic techniques have made it possible to identify many different loci encoding specific glycosyltransferases required for the precise and ordered assembly of the dolichyl pyrophosphate-linked oligosaccharide. Based on the knowledge obtained from studying this pathway in yeast, we compare it to the process of N-linked protein glycosylation in archaea. We suggest that N-linked glycosylation in eukaryotes and in archaea share a common evolutionary origin.
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Affiliation(s)
- P Burda
- Mikrobiologisches Institut, ETH Zürich, Schmelzbergstr. 7, CH-092 Zürich, Switzerland
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9
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Lee SK, Li G, Yu SL, Alexander H, Alexander S. The Dictyostelium discoideum beta-1,4-mannosyltransferase gene, mntA, has two periods of developmental expression. Gene 1997; 204:251-8. [PMID: 9434191 DOI: 10.1016/s0378-1119(97)00553-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The precise roles of protein glycosylation in multicellular development are poorly understood. We have characterized the mntA gene from Dictyostelium discoideum which encodes the beta-1,4-mannosyltransferase enzyme that catalyzes the reaction: GDP-Man + dolichol-PP-GlcNAc2 --> dolichol-PP-GlcNAc2-Man + GDP. This gene has a central role in the synthesis of the lipid-linked oligosaccharide precursor which becomes the core of all asparagine-linked (N-linked) glycans. The mntA gene contains a single small intron and encodes a 493 aa protein with a predicted molecular size of 56 kDa. It is located 5' to the repE gene on chromosome IV and is transcribed in the opposite orientation to repE with which it shares a 585 bp of upstream intergenic region. The predicted mntA gene product shares 38% homology with the S. cerevisiae ALG1 gene product. The MntA protein has a region homologous to the putative dolichol-binding region in the yeast ALG1 protein, but it is located in a different part of the molecule. Northern analysis revealed that the expression of the mntA gene is regulated during multicellular development with two periods of mRNA accumulation. The mntA gene product has a classical endoplasmic reticulum retention motif, and is the first Dictyostelium gene encoding a protein that is active in this organelle. The identification of this gene will allow expanded studies of the role of N-linked glycans in multicellular development.
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Affiliation(s)
- S K Lee
- Division of Biological Sciences, University of Missouri, Columbia 65211, USA
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10
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Watt GM, Revers L, Webberley MC, Wilson IB, Flitsch SL. The chemoenzymatic synthesis of the core trisaccharide of N-linked oligosaccharides using a recombinant beta-mannosyltransferase. Carbohydr Res 1997; 305:533-41. [PMID: 9648271 DOI: 10.1016/s0008-6215(97)00261-9] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The chemical synthesis of the beta-mannosyl linkage of N-glycans has presented a great challenge to synthetic carbohydrate chemists. We have therefore investigated the application of beta-mannosyltransferases to the preparative synthesis N-linked core oligosaccharides. In this paper we report the chemoenzymatic synthesis of beta-D-mannopyranosyl-(1-->4)-2-acetamido-2-deoxy-beta-D-glucopyranosyl- (1-->4)-2-acetamido-2-deoxy-alpha-D-glucopyranose on a preparative scale using a phytanyl-linked acceptor in the presence of a recombinant beta-(1-->4)-mannosyltransferase.
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Affiliation(s)
- G M Watt
- Edinburgh Centre for Protein Technology, Department of Chemistry, University of Edinburgh, UK
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11
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Watt GM, Revers L, Webberley MC, Wilson IBH, Flitsch SL. Eine effiziente enzymatische Synthese des Core-Trisaccharids von N-Glycanen mit einer rekombinanten β-Mannosyltransferase. Angew Chem Int Ed Engl 1997. [DOI: 10.1002/ange.19971092120] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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12
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Schutzbach JS. The role of the lipid matrix in the biosynthesis of dolichyl-linked oligosaccharides. Glycoconj J 1997; 14:175-82. [PMID: 9111134 DOI: 10.1023/a:1018533620002] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The enzymes in the dolichol pathway are membrane-proteins that utilize a combination of hydrophilic and extremely hydrophobic substrates. The enzymes in this pathway that have been purified and characterized to any extent have either been shown to be stabilized by mixed phospholipid/detergent micelles, or else require a lipid matrix for catalytic activity. Further understanding of the mechanisms of these essential enzymes may require developing methods for the reconstitution of the glycosyltransferases and their hydrophobic substrates in appropriate lipid matrices.
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Affiliation(s)
- J S Schutzbach
- The University of Alabama at Birmingham, Department of Microbiology, 35294-0019, USA
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13
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Fang X, Gibbs BS, Coward JK. Synthesis and evaluation of synthetic analogues of dolichyl-P-P-chitobiose as oligosaccharyltransferase substrates. Bioorg Med Chem Lett 1995. [DOI: 10.1016/0960-894x(95)00460-b] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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14
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Wilson IB, Webberley MC, Revers L, Flitsch SL. Dolichol is not a necessary moiety for lipid-linked oligosaccharide substrates of the mannosyltransferases involved in in vitro N-linked-oligosaccharide assembly. Biochem J 1995; 310 ( Pt 3):909-16. [PMID: 7575426 PMCID: PMC1135982 DOI: 10.1042/bj3100909] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Dolichol is utilized in vivo as an unusually large anchor on which the precursor for N-linked oligosaccharides is assembled by a series of glycosyltransferases. The role of dolichol in enzyme substrate recognition is investigated. Thus the biosynthetic intermediate NN'-diacetylchitobiose was chemically linked to either dolichol or the much shorter fully saturated tetraisoprenoid phytanol. Both lipids were used as substrates by a recombinant, soluble beta-1,4-mannosyltransferase. beta-[3H]Mannosylated lipids from this reaction were then used as substrates for the subsequent mannosyltransferases from yeast or rat liver microsomes. It was found that both the dolichyl- and phytanyl-linked substrates were easily mannosylated to form Man5GlcNAc2, with some further mannosylation to Man7GlcNAc2 and Man9GlcNAc2 at low concentrations of lipid-linked substrate. It is concluded that dolichol is not necessary in vitro as part of the substrate for the mannosyltransferases in the biosynthetic pathway for N-glycosylation.
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Affiliation(s)
- I B Wilson
- Dyson Perrins Laboratory, University of Oxford, U.K
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15
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Flitsch SL, Goodridge DM, Guilbert B, Revers L, Webberley MC, Wilson IB. The chemoenzymatic synthesis of neoglycolipids and lipid-linked oligosaccharides using glycosyltransferases. Bioorg Med Chem 1994; 2:1243-50. [PMID: 7757420 DOI: 10.1016/s0968-0896(00)82075-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
The application of glycosyltransferases to the chemoenzymatic synthesis of neoglycosphingolipids and lipid-linked oligosaccharides allows the regio- and stereoselective formation of glycosidic bonds. In our laboratory galactosyl-, sialyl-, and fucosyltransferases have been used to assemble oligosaccharide headgroups directly on a sphingosine derivative without the need for any protection group strategies, including the Lewisx antigen. In complementary studies on N-linked oligosaccharide biosynthesis, chemically phosphorylated dolichol analogues have been tested as substrates for Dol-P-Man synthetase. Also, the substrate recognition of the core beta-1,4-mannosyltransferase from yeast has been investigated using a range of chitobiose derivatives as potential substrates.
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