1
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Chen S, Pei CX, Xu S, Li H, Liu YS, Wang Y, Jin C, Dean N, Gao XD. Rft1 catalyzes lipid-linked oligosaccharide translocation across the ER membrane. Nat Commun 2024; 15:5157. [PMID: 38886340 PMCID: PMC11182771 DOI: 10.1038/s41467-024-48999-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2023] [Accepted: 05/20/2024] [Indexed: 06/20/2024] Open
Abstract
The eukaryotic asparagine (N)-linked glycan is pre-assembled as a fourteen-sugar oligosaccharide on a lipid carrier in the endoplasmic reticulum (ER). Seven sugars are first added to dolichol pyrophosphate (PP-Dol) on the cytoplasmic face of the ER, generating Man5GlcNAc2-PP-Dol (M5GN2-PP-Dol). M5GN2-PP-Dol is then flipped across the bilayer into the lumen by an ER translocator. Genetic studies identified Rft1 as the M5GN2-PP-Dol flippase in vivo but are at odds with biochemical data suggesting Rft1 is dispensable for flipping in vitro. Thus, the question of whether Rft1 plays a direct or an indirect role during M5GN2-PP-Dol translocation has been controversial for over two decades. We describe a completely reconstituted in vitro assay for M5GN2-PP-Dol translocation and demonstrate that purified Rft1 catalyzes the translocation of M5GN2-PP-Dol across the lipid bilayer. These data, combined with in vitro results demonstrating substrate selectivity and rft1∆ phenotypes, confirm the molecular identity of Rft1 as the M5GN2-PP-Dol ER flippase.
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Affiliation(s)
- Shuai Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, China
| | - Cai-Xia Pei
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Si Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Hanjie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yi-Shi Liu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Yicheng Wang
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, China
| | - Cheng Jin
- State Key Laboratory of Mycology, Institute of Microbiology, Chinese Academy of Sciences, Beijing, China.
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, New York, USA.
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China.
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China.
- Key Laboratory of Biopharmaceutical Preparation and Delivery, Chinese Academy of Sciences, Beijing, China.
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2
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Ramírez AS, Locher KP. Structural and mechanistic studies of the N-glycosylation machinery: from lipid-linked oligosaccharide biosynthesis to glycan transfer. Glycobiology 2023; 33:861-872. [PMID: 37399117 PMCID: PMC10859629 DOI: 10.1093/glycob/cwad053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2023] [Revised: 06/26/2023] [Accepted: 06/27/2023] [Indexed: 07/05/2023] Open
Abstract
N-linked protein glycosylation is a post-translational modification that exists in all domains of life. It involves two consecutive steps: (i) biosynthesis of a lipid-linked oligosaccharide (LLO), and (ii) glycan transfer from the LLO to asparagine residues in secretory proteins, which is catalyzed by the integral membrane enzyme oligosaccharyltransferase (OST). In the last decade, structural and functional studies of the N-glycosylation machinery have increased our mechanistic understanding of the pathway. The structures of bacterial and eukaryotic glycosyltransferases involved in LLO elongation provided an insight into the mechanism of LLO biosynthesis, whereas structures of OST enzymes revealed the molecular basis of sequon recognition and catalysis. In this review, we will discuss approaches used and insight obtained from these studies with a special emphasis on the design and preparation of substrate analogs.
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Affiliation(s)
- Ana S Ramírez
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
| | - Kaspar P Locher
- Institute of Molecular Biology and Biophysics, Eidgenössische Technische Hochschule (ETH), Zürich 8093, Switzerland
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3
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Ali MY, Liaqat F, Khazi MI, Sethupathy S, Zhu D. Utilization of glycosyltransferases as a seamless tool for synthesis and modification of the oligosaccharides-A review. Int J Biol Macromol 2023; 249:125916. [PMID: 37527764 DOI: 10.1016/j.ijbiomac.2023.125916] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2023] [Revised: 07/16/2023] [Accepted: 07/18/2023] [Indexed: 08/03/2023]
Abstract
Glycosyltransferases (GTs) catalyze the transfer of active monosaccharide donors to carbohydrates to create a wide range of oligosaccharide structures. GTs display strong regioselectivity and stereoselectivity in producing glycosidic bonds, making them extremely valuable in the in vitro synthesis of oligosaccharides. The synthesis of oligosaccharides by GTs often gives high yields; however, the enzyme activity may experience product inhibition. Additionally, the higher cost of nucleotide sugars limits the usage of GTs for oligosaccharide synthesis. In this review, we comprehensively discussed the structure and mechanism of GTs based on recent literature and the CAZY website data. To provide innovative ideas for the functional studies of GTs, we summarized several remarkable characteristics of GTs, including folding, substrate specificity, regioselectivity, donor sugar nucleotides, catalytic reversibility, and differences between GTs and GHs. In particular, we highlighted the recent advancements in multi-enzyme cascade reactions and co-immobilization of GTs, focusing on overcoming problems with product inhibition and cost issues. Finally, we presented various types of GT that have been successfully used for oligosaccharide synthesis. We concluded that there is still an opportunity for improvement in enzymatically produced oligosaccharide yield, and future research should focus on improving the yield and reducing the production cost.
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Affiliation(s)
- Mohamad Yassin Ali
- Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China; Department of Biochemistry, Faculty of Agriculture, Fayoum University, Fayoum 63514, Egypt
| | - Fakhra Liaqat
- Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Mahammed Ilyas Khazi
- Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Sivasamy Sethupathy
- Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China
| | - Daochen Zhu
- Biofuels Institute, School of Emergency Management, School of the Environment and Safety Engineering, Jiangsu University, Zhenjiang 212013, China.
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4
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Wenzel L, Hoffmann M, Rapp E, Rexer TFT, Reichl U. Cell-free N-glycosylation of peptides using synthetic lipid-linked hybrid and complex N-glycans. Front Mol Biosci 2023; 10:1266431. [PMID: 37767159 PMCID: PMC10520871 DOI: 10.3389/fmolb.2023.1266431] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Accepted: 08/14/2023] [Indexed: 09/29/2023] Open
Abstract
Cell-free, chemoenzymatic platforms are emerging technologies towards generating glycoconjugates with defined and homogeneous glycoforms. Recombinant oligosaccharyltransferases can be applied to glycosylate "empty," i.e., aglycosyalted, peptides and proteins. While bacterial oligosaccharlytransferases have been extensively investigated, only recently a recombinant eukaryotic single-subunit oligosaccharyltransferase has been successfully used to in vitro N-glycosylate peptides. However, its applicability towards synthesizing full-length glycoproteins and utilizing glycans beyond mannose-type glycans for the transfer have not be determined. Here, we show for the first time the synthesis of hybrid- and complex-type glycans using synthetic lipid carriers as substrates for in vitro N-glycosylation reactions. For this purpose, transmembrane-deleted human β-1,2 N-acetylglucosamintransferase I and II (MGAT1ΔTM and MGAT2ΔTM) and β-1,4-galactosyltransferase (GalTΔTM) have been expressed in Escherichia coli and used to extend an existing multi-enzyme cascade. Both hybrid and agalactosylated complex structures were transferred to the N-glycosylation consensus sequence of peptides (10 amino acids: G-S-D-A-N-Y-T-Y-T-Q) by the recombinant oligosaccharyltransferase STT3A from Trypanosoma brucei.
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Affiliation(s)
- Lisa Wenzel
- Department of Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Marcus Hoffmann
- Department of Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Erdmann Rapp
- Department of Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
- glyXera GmbH, Magdeburg, Germany
| | - Thomas F. T. Rexer
- Department of Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
| | - Udo Reichl
- Department of Bioprocess Engineering, Max Planck Institute for Dynamics of Complex Technical Systems, Magdeburg, Germany
- Chair of Bioprocess Engineering, Otto-Von-Guericke University Magdeburg, Magdeburg, Germany
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5
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Wang CD, Xu S, Chen S, Chen ZH, Dean N, Wang N, Gao XD. An in vitro assay for enzymatic studies on human ALG13/14 heterodimeric UDP-N-acetylglucosamine transferase. Front Cell Dev Biol 2022; 10:1008078. [PMID: 36200043 PMCID: PMC9527342 DOI: 10.3389/fcell.2022.1008078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 08/30/2022] [Indexed: 11/13/2022] Open
Abstract
The second step of eukaryotic lipid-linked oligosaccharide (LLO) biosynthesis is catalyzed by the conserved ALG13/ALG14 heterodimeric UDP-N-acetylglucosamine transferase (GnTase). In humans, mutations in ALG13 or ALG14 lead to severe neurological disorders with a multisystem phenotype, known as ALG13/14-CDG (congenital disorders of glycosylation). How these mutations relate to disease is unknown because to date, a reliable GnTase assay for studying the ALG13/14 complex is lacking. Here we describe the development of a liquid chromatography/mass spectrometry-based quantitative GnTase assay using chemically synthesized GlcNAc-pyrophosphate-dolichol as the acceptor and purified human ALG13/14 dimeric enzyme. This assay enabled us to demonstrate that in contrast to the literature, only the shorter human ALG13 isoform 2, but not the longer isoform 1 forms a functional complex with ALG14 that participates in LLO synthesis. The longer ALG13 isoform 1 does not form a complex with ALG14 and therefore lacks GnTase activity. Importantly, we further established a quantitative assay for GnTase activities of ALG13- and ALG14-CDG variant alleles, demonstrating that GnTase deficiency is the cause of ALG13/14-CDG phenotypes.
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Affiliation(s)
- Chun-Di Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Si Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Shuai Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zheng-Hui Chen
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, New York City, NY, United States
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- *Correspondence: Xiao-Dong Gao, ; Ning Wang,
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
- State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, Beijing, China
- *Correspondence: Xiao-Dong Gao, ; Ning Wang,
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6
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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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7
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Topological and enzymatic analysis of human Alg2 mannosyltransferase reveals its role in lipid-linked oligosaccharide biosynthetic pathway. Commun Biol 2022; 5:117. [PMID: 35136180 PMCID: PMC8827073 DOI: 10.1038/s42003-022-03066-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2021] [Accepted: 01/20/2022] [Indexed: 11/14/2022] Open
Abstract
N-glycosylation starts with the biosynthesis of lipid-linked oligosaccharide (LLO) on the endoplasmic reticulum (ER). Alg2 mannosyltransferase adds both the α1,3- and α1,6-mannose (Man) onto ManGlcNAc2-pyrophosphate-dolichol (M1Gn2-PDol) in either order to generate the branched M3Gn2-PDol product. The well-studied yeast Alg2 interacts with ER membrane through four hydrophobic domains. Unexpectedly, we show that Alg2 structure has diverged between yeast and humans. Human Alg2 (hAlg2) associates with the ER via a single membrane-binding domain and is markedly more stable in vitro. These properties were exploited to develop a liquid chromatography-mass spectrometry quantitative kinetics assay for studying purified hAlg2. Under physiological conditions, hAlg2 prefers to transfer α1,3-Man onto M1Gn2 before adding the α1,6-Man. However, this bias is altered by an excess of GDP-Man donor or an increased level of M1Gn2 substrate, both of which trigger production of the M2Gn2(α-1,6)-PDol. These results suggest that Alg2 may regulate the LLO biosynthetic pathway by controlling accumulation of M2Gn2 (α-1,6) intermediate. Despite the conservation of N-glycosylation, human and yeast Alg2 structures have diverged with distinct ER-binding topologies. The human enzyme is more stable than the yeast orthologue, and its activity is modulated by the concentration of donor or acceptor substrate.
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8
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Gücüm S, Sakson R, Hoffmann M, Grote V, Becker C, Pakari K, Beedgen L, Thiel C, Rapp E, Ruppert T, Thumberger T, Wittbrodt J. A patient-based medaka alg2 mutant as a model for hypo-N-glycosylation. Development 2021; 148:269015. [PMID: 34106226 PMCID: PMC8217707 DOI: 10.1242/dev.199385] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2020] [Accepted: 05/04/2021] [Indexed: 11/20/2022]
Abstract
Defects in the evolutionarily conserved protein-glycosylation machinery during embryonic development are often fatal. Consequently, congenital disorders of glycosylation (CDG) in human are rare. We modelled a putative hypomorphic mutation described in an alpha-1,3/1,6-mannosyltransferase (ALG2) index patient (ALG2-CDG) to address the developmental consequences in the teleost medaka (Oryzias latipes). We observed specific, multisystemic, late-onset phenotypes, closely resembling the patient's syndrome, prominently in the facial skeleton and in neuronal tissue. Molecularly, we detected reduced levels of N-glycans in medaka and in the patient's fibroblasts. This hypo-N-glycosylation prominently affected protein abundance. Proteins of the basic glycosylation and glycoprotein-processing machinery were over-represented in a compensatory response, highlighting the regulatory topology of the network. Proteins of the retinal phototransduction machinery, conversely, were massively under-represented in the alg2 model. These deficiencies relate to a specific failure to maintain rod photoreceptors, resulting in retinitis pigmentosa characterized by the progressive loss of these photoreceptors. Our work has explored only the tip of the iceberg of N-glycosylation-sensitive proteins, the function of which specifically impacts on cells, tissues and organs. Taking advantage of the well-described human mutation has allowed the complex interplay of N-glycosylated proteins and their contribution to development and disease to be addressed.
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Affiliation(s)
- Sevinç Gücüm
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany.,HBIGS, Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany
| | - Roman Sakson
- HBIGS, Heidelberg Biosciences International Graduate School, Heidelberg University, 69120 Heidelberg, Germany.,Core facility for Mass Spectrometry and Proteomics, Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Marcus Hoffmann
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany
| | - Valerian Grote
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany
| | - Clara Becker
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Kaisa Pakari
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Lars Beedgen
- Center for Child and Adolescent Medicine, Department Pediatrics I, Heidelberg University, 69120 Heidelberg, Germany
| | - Christian Thiel
- Center for Child and Adolescent Medicine, Department Pediatrics I, Heidelberg University, 69120 Heidelberg, Germany
| | - Erdmann Rapp
- Max Planck Institute for Dynamics of Complex Technical Systems, 39106 Magdeburg, Germany.,glyXera GmbH, 39120 Magdeburg, Germany
| | - Thomas Ruppert
- Core facility for Mass Spectrometry and Proteomics, Zentrum für Molekulare Biologie der Universität Heidelberg (ZMBH), DKFZ-ZMBH Alliance, 69120 Heidelberg, Germany
| | - Thomas Thumberger
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
| | - Joachim Wittbrodt
- COS, Centre for Organismal Studies Heidelberg, Heidelberg University, 69120 Heidelberg, Germany
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Kocev A, Melamed J, Torgov V, Danilov L, Veselovsky V, Brockhausen I. The wclY gene of Escherichia coli serotype O117 encodes an α1,4-glucosyltransferase with strict acceptor specificity but broad donor specificity. Glycobiology 2020; 30:9003-9014. [PMID: 32421169 DOI: 10.1093/glycob/cwaa045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2020] [Revised: 05/11/2020] [Accepted: 05/12/2020] [Indexed: 11/14/2022] Open
Abstract
The O antigen of enterotoxigenic Escherichia coli serotype O117 consists of repeating units with the structure [-D-GalNAcβ1-3-L-Rhaα1-4-D-Glcα1-4-D-Galβ1-3-D-GalNAcα1-4]n. A related structure is found in E. coli O107 where Glc is replaced by a GlcNAc residue. The O117 and O107 antigen biosynthesis gene clusters are homologous and reveal the presence of four putative glycosyltransferase (GT) genes, wclW, wclX, wclY and wclZ, but the enzymes have not yet been biochemically characterized. We show here that the His6-tagged WclY protein expressed in E. coli Lemo21(DE3) cells is an α1,4-Glc-transferase that transfers Glc to the Gal moiety of Galβ1-3GalNAcα-OPO3-PO3-phenoxyundecyl as a specific acceptor and that the diphosphate moiety of this acceptor is required. WclY utilized UDP-Glc, TDP-Glc, ADP-Glc, as well as UDP-GlcNAc, UDP-Gal or UDP-GalNAc as donor substrates, suggesting an unusual broad donor specificity. Activity using GDP-Man suggested the presence of a novel Man-transferase in Lemo21(DE3) cells. Mutations of WclY revealed that both Glu residues of the Ex7E motif within the predicted GT domain are essential for activity. High GlcNAc-transferase (GlcNAc-T) activities of WclY were created by mutating Arg194 to Cys. A triple mutant identical to WclY in E. coli O107 was identified as an α1,4 GlcNAc-T. The characterization of WclY opens the door for the development of antibacterial approaches.
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Affiliation(s)
- Alexander Kocev
- Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, ON K7L3N6, Canada
| | - Jacob Melamed
- Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, ON K7L3N6, Canada
| | - Vladimir Torgov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, Russia
| | - Leonid Danilov
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, Russia
| | - Vladimir Veselovsky
- N.D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Leninsky Prospekt 47, Moscow, Russia
| | - Inka Brockhausen
- Department of Biomedical and Molecular Sciences, Queen's University, 18 Stuart St., Kingston, ON K7L3N6, Canada
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10
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Synthesis of lipid-linked oligosaccharides by a compartmentalized multi-enzyme cascade for the in vitro N-glycosylation of peptides. J Biotechnol 2020; 322:54-65. [PMID: 32653637 DOI: 10.1016/j.jbiotec.2020.07.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Revised: 06/18/2020] [Accepted: 07/08/2020] [Indexed: 01/21/2023]
Abstract
A wide range of glycoproteins can be recombinantly expressed in aglycosylated forms in bacterial and cell-free production systems. To investigate the effect of glycosylation of these proteins on receptor binding, stability, efficacy as drugs, pharmacodynamics and pharmacokinetics, an efficient glycosylation platform is required. Here, we present a cell-free synthetic platform for the in vitro N-glycosylation of peptides mimicking the endoplasmic reticulum (ER) glycosylation machinery of eukaryotes. The one-pot, two compartment multi-enzyme cascade consisting of eight recombinant enzymes including the three Leloir glycosyltransferases, Alg1, Alg2 and Alg11, expressed in E. coli and S. cerevisiae, respectively, has been engineered to produce the core lipid-linked (LL) oligosaccharide mannopentaose-di-(N-acetylglucosamine) (LL-Man5). Pythanol (C20H42O), a readily available alcohol consisting of regular isoprenoid units, was utilized as the lipid anchor. As part of the cascade, GDP-mannose was de novo produced from the inexpensive substrates ADP, polyphosphate and mannose. To prevent enzyme inhibition, the nucleotide sugar cascade and the glycosyltransferase were segregated into two compartments by a cellulose ester membrane with 3.5 kDa cut-off allowing for the effective diffusion of GDP-mannose across compartments. Finally, as a proof-of-principle, pythanyl-linked Man5 and the single-subunit oligosaccharyltransferase Trypanosoma brucei STT3A expressed in Sf9 insect cells were used to in vitro N-glycosylate a synthetic peptide of ten amino acids bearing the eukaryotic consensus motif N-X-S/T.
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11
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Chao Q, Ding Y, Chen ZH, Xiang MH, Wang N, Gao XD. Recent Progress in Chemo-Enzymatic Methods for the Synthesis of N-Glycans. Front Chem 2020; 8:513. [PMID: 32612979 PMCID: PMC7309569 DOI: 10.3389/fchem.2020.00513] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2020] [Accepted: 05/18/2020] [Indexed: 01/06/2023] Open
Abstract
Asparagine (N)-linked glycosylation is one of the most common co- and post-translational modifications of both intra- and extracellularly distributing proteins, which directly affects their biological functions, such as protein folding, stability and intercellular traffic. Production of the structural well-defined homogeneous N-glycans contributes to comprehensive investigation of their biological roles and molecular basis. Among the various methods, chemo-enzymatic approach serves as an alternative to chemical synthesis, providing high stereoselectivity and economic efficiency. This review summarizes some recent advances in the chemo-enzymatic methods for the production of N-glycans, including the preparation of substrates and sugar donors, and the progress in the glycosyltransferases characterization which leads to the diversity of N-glycan synthesis. We discuss the bottle-neck and new opportunities in exploiting the chemo-enzymatic synthesis of N-glycans based on our research experiences. In addition, downstream applications of the constructed N-glycans, such as automation devices and homogeneous glycoproteins synthesis are also described.
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Affiliation(s)
| | | | | | | | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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12
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Li ST, Lu TT, Xu XX, Ding Y, Li Z, Kitajima T, Dean N, Wang N, Gao XD. Reconstitution of the lipid-linked oligosaccharide pathway for assembly of high-mannose N-glycans. Nat Commun 2019; 10:1813. [PMID: 31000718 PMCID: PMC6472349 DOI: 10.1038/s41467-019-09752-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2018] [Accepted: 03/29/2019] [Indexed: 11/11/2022] Open
Abstract
The asparagine (N)-linked Man9GlcNAc2 is required for glycoprotein folding and secretion. Understanding how its structure contributes to these functions has been stymied by our inability to produce this glycan as a homogenous structure of sufficient quantities for study. Here, we report the high yield chemoenzymatic synthesis of Man9GlcNAc2 and its biosynthetic intermediates by reconstituting the eukaryotic lipid-linked oligosaccharide (LLO) pathway. Endoplasmic reticulum mannosyltransferases (MTases) are expressed in E. coli and used for mannosylation of the dolichol mimic, phytanyl pyrophosphate GlcNAc2. These recombinant MTases recognize unique substrates and when combined, synthesize end products that precisely mimic those in vivo, demonstrating that ordered assembly of LLO is due to the strict enzyme substrate specificity. Indeed, non-physiological glycans are produced only when the luminal MTases are challenged with cytosolic substrates. Reconstitution of the LLO pathway to synthesize Man9GlcNAc2 in vitro provides an important tool for functional studies of the N-linked glycoprotein biosynthesis pathway. Attachment of the oligosaccharide Man9GlcNAc2 is required for glycoprotein folding and secretion but synthesizing this compound for structural and functional studies has remained challenging. Here, the authors achieve efficient Man9GlcNAc2 synthesis by reconstituting its biosynthetic pathway in vitro.
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Affiliation(s)
- Sheng-Tao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Tian-Tian Lu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Yi Ding
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Zijie Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Toshihiko Kitajima
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China
| | - Neta Dean
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY, 11794-5215, USA
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China.
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 214122, Wuxi, China.
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Xu XX, Li ST, Wang N, Kitajima T, Yoko-O T, Fujita M, Nakanishi H, Gao XD. Structural and functional analysis of Alg1 beta-1,4 mannosyltransferase reveals the physiological importance of its membrane topology. Glycobiology 2019; 28:741-753. [PMID: 29939232 DOI: 10.1093/glycob/cwy060] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 06/24/2018] [Indexed: 12/20/2022] Open
Abstract
In eukaryotes, the biosynthesis of a highly conserved dolichol-linked oligosaccharide (DLO) precursor Glc3Man9GlcNAc2-pyrophosphate-dolichol (PP-Dol) begins on the cytoplasmic face of the endoplasmic reticulum (ER) and ends within the lumen. Two functionally distinguished heteromeric glycosyltransferase (GTase) complexes are responsible for the cytosolic DLO assembly. Alg1, a β-1, 4 mannosyltransferase (MTase) physically interacts with Alg2 and Alg11 proteins to form the multienzyme complex which catalyzes the addition of all five mannose to generate the Man5GlcNAc2-PP-Dol intermediate. Despite the fact that Alg1 plays a central role in the formation of the multi-MTase has been confirmed, the topological information of Alg1 including the molecular mechanism of membrane association are still poorly understood. Using a combination of bioinformatics and biological approaches, we have undertaken a structural and functional study on Alg1 protein, in which the enzymatic activities of Alg1 and its variants were monitored by a complementation assay using the GALpr-ALG1 yeast strain, and further confirmed by a liquid chromatography-mass spectrometry-based in vitro quantitative assay. Computational and experimental evidence confirmed Alg1 shares structure similarity with Alg13/14 complex, which has been defined as a membrane-associated GT-B GTase. Particularly, we provide clear evidence that the N-terminal transmembrane domain including the following positively charged amino acids and an N-terminal amphiphilic-like α helix domain exposed on the protein surface strictly coordinate the Alg1 orientation on the ER membrane. This work provides detailed membrane topology of Alg1 and further reveals its biological importance at the spatial aspect in coordination of cytosolic DLO biosynthesis.
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Affiliation(s)
- Xin-Xin Xu
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Sheng-Tao Li
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Ning Wang
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Toshihiko Kitajima
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Takehiko Yoko-O
- Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology (AIST), AIST Tsukuba Central 6, Higashi, Tsukuba, Japan
| | - Morihisa Fujita
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Hideki Nakanishi
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
| | - Xiao-Dong Gao
- Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, 1800 Lihu Avenue, Wuxi, China
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