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Affiliation(s)
- Ryan M Schmaltz
- The Department of Chemistry and Skaggs Institute for Chemical Biology, 10550 North Torrey Pines Road, La Jolla, California 92037, USA
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2
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Pak JE, Arnoux P, Zhou S, Sivarajah P, Satkunarajah M, Xing X, Rini JM. X-ray crystal structure of leukocyte type core 2 beta1,6-N-acetylglucosaminyltransferase. Evidence for a convergence of metal ion-independent glycosyltransferase mechanism. J Biol Chem 2006; 281:26693-701. [PMID: 16829524 DOI: 10.1074/jbc.m603534200] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Leukocyte type core 2 beta1,6-N-acetylglucosaminyltransferase (C2GnT-L) is a key enzyme in the biosynthesis of branched O-glycans. It is an inverting, metal ion-independent family 14 glycosyltransferase that catalyzes the formation of the core 2 O-glycan (Galbeta1-3[GlcNAcbeta1-6]GalNAc-O-Ser/Thr) from its donor and acceptor substrates, UDP-GlcNAc and the core 1 O-glycan (Galbeta1-3GalNAc-O-Ser/Thr), respectively. Reported here are the x-ray crystal structures of murine C2GnT-L in the absence and presence of the acceptor substrate Galbeta1-3GalNAc at 2.0 and 2.7A resolution, respectively. C2GnT-L was found to possess the GT-A fold; however, it lacks the characteristic metal ion binding DXD motif. The Galbeta1-3GalNAc complex defines the determinants of acceptor substrate binding and shows that Glu-320 corresponds to the structurally conserved catalytic base found in other inverting GT-A fold glycosyltransferases. Comparison of the C2GnT-L structure with that of other GT-A fold glycosyltransferases further suggests that Arg-378 and Lys-401 serve to electrostatically stabilize the nucleoside diphosphate leaving group, a role normally played by metal ion in GT-A structures. The use of basic amino acid side chains in this way is strikingly similar to that seen in a number of metal ion-independent GT-B fold glycosyltransferases and suggests a convergence of catalytic mechanism shared by both GT-A and GT-B fold glycosyltransferases.
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Affiliation(s)
- John E Pak
- Department of Molecular, University of Toronto, Toronto, Ontario M5S 1A8, Canada
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3
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Abstract
The vast majority of mammalian glycosyltransferases are endoplasmic reticulum (ER) and Golgi resident type II membrane proteins. As such, producing large quantities of properly folded and active enzymes for X-ray crystallographic analysis is a challenge. Described here are the methods that we have developed to facilitate the structural characterization of these enzymes. The approach involves the production of a soluble Protein A-tagged form of the catalytic domain in a mammalian cell expression system. Production is scaled up in a perfusion-fed bioreactor with media flow rates of 3-5 liters/day. Expression levels are typically in the 1- to 4-mg/liter range and a simple and efficient purification method based on immunoglobulin G (IgG)-Sepharose affinity chromatography has been developed. Our approach to delimiting the catalytic domain and deglycosylating it when necessary is also discussed. Finally, we describe the selenomethionine labeling protocol used in our X-ray crystal structure determination of leukocyte-type Core 2 beta1,6-N-acetylglucosaminyltransferase.
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Affiliation(s)
- John E Pak
- Department of Molecular and Medical Genetics, University of Toronto, Ontario, Canada
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4
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Hoh C, Dudziak G, Liese A. Optimization of the enzymatic synthesis of O-glycan core 2 structure by use of a genetic algorithm. Bioorg Med Chem Lett 2002; 12:1031-4. [PMID: 11909710 DOI: 10.1016/s0960-894x(02)00087-2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The enzymatic synthesis of Gal-beta 1,3[GlcNAc-beta 1,6]-GalNAc-alpha 1-OBn (core 2-Bn) using a multi-enzyme system consisting of a beta-galactosidase (EC 3.2.1.23) from bovine testes and a recombinant core 2 beta 1,6-GlcNAc transferase (C2GnT, EC 2.4.1.102) was empirically optimized by the use of a genetic algorithm. After variation of seven relevant parameters and performance of 56 experiments, two local maxima regarding the selection criteria could be found after four generations of optimization. The selectivity of core 2-Bn formation showed values up to 90%.
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Affiliation(s)
- Christoph Hoh
- Forschungszentrum Jülich GmbH, Institut für Biotechnologie 2, D-52425 Jülich, Germany
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5
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Yoneda A, Asada M, Yamamoto S, Oki J, Oda Y, Ota K, Ogi Y, Fujishima S, Imamura T. Engineering neoglycoproteins with multiple O-glycans using repetitive pentapeptide glycosylation units. Glycoconj J 2001; 18:291-9. [PMID: 11788797 DOI: 10.1023/a:1013608930759] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Controlled protein remodeling with O-linked glycans has been limited by our incomplete understanding of the process of glycosylation. Here we describe a secretable fibroblast growth factor (FGF) with multiple mucin-type O-glycans produced by introducing a minimum pentapeptide glycosylation unit in a decarepeat format at its N- or C-terminus. Expressed in Chinese hamster ovary cells, chemical and biochemical analyses of the resultant proteins (Nm10-FGF and Cm10-FGF, respectively) demonstrated that all O-glycosylation units were glycosylated and the dominant structure was sialylated Gal[beta1-3]GalNAc. This indicates that minimum O-glycosylation unit in multirepeat format serves as a remarkably efficient acceptor in CHO cells. The Nm10-FGF and Cm10-FGF proteins maintained the mitogenic activity to vascular endothelial cells. In addition, intact Cm10-FGF and its desialylated form interacted with several lectins in the same way as mucin-type glycoproteins. The intact Cm10-FGF with multiple sialylated O-glycans exhibited a longer lifetime in circulating blood, whereas the Cm10-FGF with desialylated O-glycans exhibited a shorter lifetime than the deglycosylated form of Cm10-FGF. Our approach would thus appear to be highly effective for engineering neoglycoproteins, the characteristics of which are determined by their multiple mucin-type O-glycans.
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Affiliation(s)
- A Yoneda
- Gene Discovery Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 1-1-1 Higashi, Tsukuba, Ibaraki 305-8566, Japan
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6
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Fujiyama K, Ido Y, Misaki R, Moran DG, Yanagihara I, Honda T, Nishimura SI, Yoshida T, Seki T. Human N-acetylglucosaminyltransferase I. Expression in Escherichia coli as a soluble enzyme, and application as an immobilized enzyme for the chemoenzymatic synthesis of N-linked oligosaccharides. J Biosci Bioeng 2001. [DOI: 10.1016/s1389-1723(01)80318-2] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
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7
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Schwientek T, Yeh JC, Levery SB, Keck B, Merkx G, van Kessel AG, Fukuda M, Clausen H. Control of O-glycan branch formation. Molecular cloning and characterization of a novel thymus-associated core 2 beta1, 6-n-acetylglucosaminyltransferase. J Biol Chem 2000; 275:11106-13. [PMID: 10753916 DOI: 10.1074/jbc.275.15.11106] [Citation(s) in RCA: 79] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Core 2 O-glycan branching catalyzed by UDP-N-acetyl-alpha-D-glucosamine: acceptor beta1, 6-N-acetylglucosaminyltransferases (beta6GlcNAc-Ts) is an important step in mucin-type biosynthesis. Core 2 complex-type O-glycans are involved in selectin-mediated adhesion events, and O-glycan branching appears to be highly regulated. Two homologous beta6GlcNAc-Ts functioning in O-glycan branching have previously been characterized, and here we report a third homologous beta6GlcNAc-T designated C2GnT3. C2GnT3 was identified by BLAST analysis of human genome survey sequences. The catalytic activity of C2GnT3 was evaluated by in vitro analysis of a secreted form of the protein expressed in insect cells. The results revealed exclusive core 2 beta6GlcNAc-T activity. The product formed with core 1-para-nitrophenyl was confirmed by (1)H NMR to be core 2-para-nitrophenyl. In vivo analysis of the function of C2GnT3 by coexpression of leukosialin (CD43) and a full coding construct of C2GnT3 in Chinese hamster ovary cells confirmed the core 2 activity and failed to reveal I activity. The C2GnT3 gene was located to 5q12, and the coding region was contained in a single exon. Northern analysis revealed selectively high levels of a 5.5-kilobase C2GnT3 transcript in thymus with only low levels in other organs. The unique expression pattern of C2GnT3 suggests that this enzyme serves a specific function different from other members of the beta6GlcNAc-T gene family.
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Affiliation(s)
- T Schwientek
- School of Dentistry, University of Copenhagen, Norre Allé 20, 2200 Copenhagen N, Denmark.
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8
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Zhou D, Malissard M, Berger EG, Hennet T. Secretion and purification of recombinant beta1-4 galactosyltransferase from insect cells using pFmel-protA, a novel transposition-based baculovirus transfer vector. Arch Biochem Biophys 2000; 374:3-7. [PMID: 10640389 DOI: 10.1006/abbi.1999.1622] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The palette of transfer vectors available for generation of recombinant baculoviruses based on transposition-mediated recombination has been enlarged by constructing the pFmel-protA vector. The pFmel-protA plasmid includes the honeybee melittin secretion signal and a Staphylococcus aureus protein A fusion protein tag, which allows the secretion and purification of recombinant proteins. Using this system, the human beta1-4 galactosyltransferase-I protein was expressed in Sf9 insect cells at a level ranging from 22 to 28 U (4.8 to 6.0 mg)/L. The protein A tag enabled a simple monitoring of recombinant protein expression by enzyme-linked immunosorbent assay and Western blotting. Single step purification was achieved by immunoglobulin G affinity chromatography achieving a recovery yield of 28% and a specific activity of 1.9 U per mg of recombinant protein.
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Affiliation(s)
- D Zhou
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, Zürich, CH-8057, Switzerland
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9
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Malissard M, Zeng S, Berger EG. Expression of functional soluble forms of human beta-1, 4-galactosyltransferase I, alpha-2,6-sialyltransferase, and alpha-1, 3-fucosyltransferase VI in the methylotrophic yeast Pichia pastoris. Biochem Biophys Res Commun 2000; 267:169-73. [PMID: 10623593 DOI: 10.1006/bbrc.1999.1946] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The cDNAs encoding soluble forms of human beta-1, 4-galactosyltransferase I (EC 2.4.1.22), alpha-2,6-sialyltransferase (EC 2.4.99.1), and alpha-1,3-fucosyltransferase VI (EC 2.4.1.65), respectively, have been expressed in the methylotrophic yeast Pichia pastoris. The vector pPIC9 was used, which contains the N-terminal signal sequence of Saccharomyces cerevisiae alpha-factor to allow entry into the secretory pathway. The recombinant enzymes had similar kinetic properties as their native counterparts. Their identity was confirmed by Western blotting. Recombinant enzymes may be used for in vitro synthesis of oligosaccharides.
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Affiliation(s)
- M Malissard
- Institute of Physiology, University of Zürich, Winterthurerstrasse 190, Zürich, CH-8057, Switzerland.
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10
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Zeng S, Gallego RG, Dinter A, Malissard M, Kamerling JP, Vliegenthart JF, Berger EG. Complete enzymic synthesis of the mucin-type sialyl Lewis x epitope, involved in the interaction between PSGL-1 and P-selectin. Glycoconj J 1999; 16:487-97. [PMID: 10815985 DOI: 10.1023/a:1007065803554] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Sialyl Lewis x (sLe(x)) is an established selectin ligand occurring on N- and O-linked glycans. Using a completely enzymic approach starting from p-nitrophenyl N-acetyl-alpha-D-galactosaminide (GalNAc(alpha1-pNp as core substrate, the sLe(x)-oligosaccharide Neu5Ac(alpha2-3)Gal(beta1-4)[Fuc(alpha1-3)]GlcNAc(beta1-6)[Gal(bet a1-3)]GalNAc(alpha1-pNp, representing the O-linked form, was synthesized in an overall yield of 32%. In a first step, Gal(beta1-3)GalNAc(alpha1-pNp was prepared in a yield of 52% using UDP-Gal and an enriched preparation of beta3-galactosyltransferase (EC 2.4.1.122) from rat liver. UDP-GlcNAc and a recombinant affinity-purified preparation of core 2 beta6-N-acetylglucosaminyltransferase (EC 2.4.1.102) fused to Protein A were used to branch the core 1 structure, affording GlcNAc(beta1-6)[Gal(beta1-3)]GalNAc(alpha1-pNp in a yield of >85%. The core 2 structure was galactosylated using UDP-Gal and purified human milk beta4-galactosyltransferase 1 (EC 2.4.1.38) (yield of >85%), then sialylated using CMP-Neu5Ac and purified recombinant alpha3-sialyltransferase 3 (EC 2.4.99.X) (yield of 87%), and finally fucosylated using GDP-Fuc and recombinant human alpha3-fucosyltransferase 6 (EC 2.4.1.152) produced in Pichia pastoris (yield of 100%). Overall 1.5 micromol of product was prepared. MALDI TOF mass spectra, and 1D and 2D TOCSY and ROESY 1H NMR analysis confirmed the obtained structure.
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Affiliation(s)
- S Zeng
- Physiologisches Institut, Universität Zürich, Switzerland
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11
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Dudziak G, Zeng S, Berger EG, Gallego RG, Kamerling JP, Kragl U, Wandrey C. In situ generated O-glycan core 1 structure as substrate for Gal(beta 1-3)GalNAc beta-1,6-GlcNAc transferase. Bioorg Med Chem Lett 1998; 8:2595-8. [PMID: 9873587 DOI: 10.1016/s0960-894x(98)00464-8] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
beta-Galactosidase from bovine testes was used in a one pot reaction together with a recombinant beta-1,6-GlcNAc transferase for the synthesis of GlcNAc(beta 1-6)GalNAc(alpha 1-OBn) (core 6-Bn). The galactosidase, which reversibly links galactose via a (beta 1-3) linkage to N-acetylgalactosamine, provides the substrate for the GlcNAc transferase in situ. The synthesis was carried out with a yield > 90%.
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Affiliation(s)
- G Dudziak
- Forschungszentrum Jülich GmbH, Institut für Biotechnologie, Jülich, Germany
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