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Controlled processivity in glycosyltransferases: A way to expand the enzymatic toolbox. Biotechnol Adv 2023; 63:108081. [PMID: 36529206 DOI: 10.1016/j.biotechadv.2022.108081] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 11/20/2022] [Accepted: 12/11/2022] [Indexed: 12/23/2022]
Abstract
Glycosyltransferases (GT) catalyse the biosynthesis of complex carbohydrates which are the most abundant group of molecules in nature. They are involved in several key mechanisms such as cell signalling, biofilm formation, host immune system invasion or cell structure and this in both prokaryotic and eukaryotic cells. As a result, research towards complete enzyme mechanisms is valuable to understand and elucidate specific structure-function relationships in this group of molecules. In a next step this knowledge could be used in GT protein engineering, not only for rational drug design but also for multiple biotechnological production processes, such as the biosynthesis of hyaluronan, cellooligosaccharides or chitooligosaccharides. Generation of these poly- and/or oligosaccharides is possible due to a common feature of several of these GTs: processivity. Enzymatic processivity has the ability to hold on to the growing polymer chain and some of these GTs can even control the number of glycosyl transfers. In a first part, recent advances in understanding the mechanism of various processive enzymes are discussed. To this end, an overview is given of possible engineering strategies for the purpose of new industrial and fundamental applications. In the second part of this review, we focused on specific chain length-controlling mechanisms, i.e., key residues or conserved regions, and this for both eukaryotic and prokaryotic enzymes.
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2
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Hao R, Zheng Z, Du X, Jiao Y, Deng Y. Cloning and characterization of O-xylosyltransferase gene fromPinctada fucata martensii. JOURNAL OF APPLIED ANIMAL RESEARCH 2019. [DOI: 10.1080/09712119.2019.1650051] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Affiliation(s)
- Ruijuan Hao
- Fisheries College, Guangdong Ocean University, Zhanjiang, People’s Republic of China
| | - Zhe Zheng
- Fisheries College, Guangdong Ocean University, Zhanjiang, People’s Republic of China
| | - Xiaodong Du
- Fisheries College, Guangdong Ocean University, Zhanjiang, People’s Republic of China
- Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang, People’s Republic of China
| | - Yu Jiao
- Fisheries College, Guangdong Ocean University, Zhanjiang, People’s Republic of China
| | - Yuewen Deng
- Fisheries College, Guangdong Ocean University, Zhanjiang, People’s Republic of China
- Pearl Breeding and Processing Engineering Technology Research Centre of Guangdong Province, Zhanjiang, People’s Republic of China
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3
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Jacob F, Alam S, Konantz M, Liang CY, Kohler RS, Everest-Dass AV, Huang YL, Rimmer N, Fedier A, Schötzau A, Lopez MN, Packer NH, Lengerke C, Heinzelmann-Schwarz V. Transition of Mesenchymal and Epithelial Cancer Cells Depends on α1-4 Galactosyltransferase-Mediated Glycosphingolipids. Cancer Res 2018; 78:2952-2965. [DOI: 10.1158/0008-5472.can-17-2223] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2017] [Revised: 11/13/2017] [Accepted: 03/20/2018] [Indexed: 11/16/2022]
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4
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Feng X, Ramamoorthy V, Pandit SS, Prieto A, Espeso EA, Calvo AM. cpsA regulates mycotoxin production, morphogenesis and cell wall biosynthesis in the fungus Aspergillus nidulans. Mol Microbiol 2017; 105:1-24. [PMID: 28370587 PMCID: PMC5506848 DOI: 10.1111/mmi.13682] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/21/2017] [Accepted: 03/26/2017] [Indexed: 01/07/2023]
Abstract
The model fungus Aspergillus nidulans synthesizes numerous secondary metabolites, including sterigmatocystin (ST). The production of this toxin is positively controlled by the global regulator veA. In the absence of veA (ΔveA), ST biosynthesis is blocked. Previously, we performed random mutagenesis in a ΔveA strain and identified revertant mutants able to synthesize ST, among them RM1. Complementation of RM1 with a genomic library revealed that the mutation occurred in a gene designated as cpsA. While in the ΔveA genetic background cpsA deletion restores ST production, in a veA wild-type background absence of cpsA reduces and delays ST biosynthesis decreasing the expression of ST genes. Furthermore, cpsA is also necessary for the production of other secondary metabolites, including penicillin, affecting the expression of PN genes. In addition, cpsA is necessary for normal asexual and sexual development. Chemical and microscopy analyses revealed that CpsA is found in cytoplasmic vesicles and it is required for normal cell wall composition and integrity, affecting adhesion capacity and oxidative stress sensitivity. The conservation of cpsA in Ascomycetes suggests that cpsA homologs might have similar roles in other fungal species.
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Affiliation(s)
- Xuehuan Feng
- Department of Biological Sciences, Northern Illinois University, Dekalb, IL 60115, USA
| | - Vellaisamy Ramamoorthy
- Department of Biological Sciences, Northern Illinois University, Dekalb, IL 60115, USA,Dept. of Plant Pathology Agricultural College and Research Institute Killikulam, Vallanadu - 628 252 Thoothukudi District Tamil Nadu, India
| | - Sandesh S. Pandit
- Department of Biological Sciences, Northern Illinois University, Dekalb, IL 60115, USA
| | - Alicia Prieto
- Centro de Investigaciones Biológicas, CSIC, Madrid, Spain
| | | | - Ana M. Calvo
- Department of Biological Sciences, Northern Illinois University, Dekalb, IL 60115, USA,Author to whom correspondence should be addressed [telephone: (815) 753-0451]; fax (815) 753-0461; ]
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5
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Culbertson AT, Tietze AA, Tietze D, Chou YH, Smith AL, Young ZT, Zabotina OA. A homology model of Xyloglucan Xylosyltransferase 2 reveals critical amino acids involved in substrate binding. Glycobiology 2016; 26:961-972. [DOI: 10.1093/glycob/cww050] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2015] [Accepted: 04/14/2016] [Indexed: 11/14/2022] Open
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6
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Kellokumpu S, Hassinen A, Glumoff T. Glycosyltransferase complexes in eukaryotes: long-known, prevalent but still unrecognized. Cell Mol Life Sci 2016; 73:305-25. [PMID: 26474840 PMCID: PMC7079781 DOI: 10.1007/s00018-015-2066-0] [Citation(s) in RCA: 56] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 09/28/2015] [Accepted: 10/08/2015] [Indexed: 01/08/2023]
Abstract
Glycosylation is the most common and complex cellular modification of proteins and lipids. It is critical for multicellular life and its abrogation often leads to a devastating disease. Yet, the underlying mechanistic details of glycosylation in both health and disease remain unclear. Partly, this is due to the complexity and dynamicity of glycan modifications, and the fact that not all the players are taken into account. Since late 1960s, a vast number of studies have demonstrated that glycosyltransferases typically form homomeric and heteromeric complexes with each other in yeast, plant and animal cells. To propagate their acceptance, we will summarize here accumulated data for their prevalence and potential functional importance for glycosylation focusing mainly on their mutual interactions, the protein domains mediating these interactions, and enzymatic activity changes that occur upon complex formation. Finally, we will highlight the few existing 3D structures of these enzyme complexes to pinpoint their individual nature and to emphasize that their lack is the main obstacle for more detailed understanding of how these enzyme complexes interact and function in a eukaryotic cell.
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Affiliation(s)
- Sakari Kellokumpu
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland.
| | - Antti Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
| | - Tuomo Glumoff
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Aapistie 7, 90220, Oulu, Finland
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7
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Kumar S, Sharma P, Arora K, Raje M, Guptasarma P. Calcium binding to beta-2-microglobulin at physiological pH drives the occurrence of conformational changes which cause the protein to precipitate into amorphous forms that subsequently transform into amyloid aggregates. PLoS One 2014; 9:e95725. [PMID: 24755626 PMCID: PMC3995793 DOI: 10.1371/journal.pone.0095725] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2013] [Accepted: 03/30/2014] [Indexed: 11/17/2022] Open
Abstract
Using spectroscopic, calorimetric and microscopic methods, we demonstrate that calcium binds to beta-2-microglobulin (β2m) under physiological conditions of pH and ionic strength, in biological buffers, causing a conformational change associated with the binding of up to four calcium atoms per β2m molecule, with a marked transformation of some random coil structure into beta sheet structure, and culminating in the aggregation of the protein at physiological (serum) concentrations of calcium and β2m. We draw attention to the fact that the sequence of β2m contains several potential calcium-binding motifs of the DXD and DXDXD (or DXEXD) varieties. We establish (a) that the microscopic aggregation seen at physiological concentrations of β2m and calcium turns into actual turbidity and visible precipitation at higher concentrations of protein and β2m, (b) that this initial aggregation/precipitation leads to the formation of amorphous aggregates, (c) that the formation of the amorphous aggregates can be partially reversed through the addition of the divalent ion chelating agent, EDTA, and (d) that upon incubation for a few weeks, the amorphous aggregates appear to support the formation of amyloid aggregates that bind to the dye, thioflavin T (ThT), resulting in increase in the dye's fluorescence. We speculate that β2m exists in the form of microscopic aggregates in vivo and that these don't progress to form larger amyloid aggregates because protein concentrations remain low under normal conditions of kidney function and β2m degradation. However, when kidney function is compromised and especially when dialysis is performed, β2m concentrations probably transiently rise to yield large aggregates that deposit in bone joints and transform into amyloids during dialysis related amyloidosis.
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Affiliation(s)
- Sukhdeep Kumar
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
| | - Prerna Sharma
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India; Council of Scientific and Industrial Research, Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
| | - Kanika Arora
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
| | - Manoj Raje
- Council of Scientific and Industrial Research, Institute of Microbial Technology (CSIR-IMTECH), Chandigarh, India
| | - Purnananda Guptasarma
- Department of Biological Sciences, Indian Institute of Science Education and Research (IISER) Mohali, SAS Nagar, Punjab, India
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8
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Duitch L, Toal S, Measey TJ, Schweitzer-Stenner R. Triaspartate: A Model System for Conformationally Flexible DDD Motifs in Proteins. J Phys Chem B 2012; 116:5160-71. [DOI: 10.1021/jp2121565] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Laura Duitch
- Department of Chemistry, Drexel University, 3141 Chestnut Street,
Philadelphia, Pennsylvania 19104, United States
| | - Siobhan Toal
- Department of Chemistry, Drexel University, 3141 Chestnut Street,
Philadelphia, Pennsylvania 19104, United States
| | - Thomas J. Measey
- Department of Chemistry, University of Pennsylvania, Philadelphia,
Pennsylvania 19104, United States
| | - Reinhard Schweitzer-Stenner
- Department of Chemistry, Drexel University, 3141 Chestnut Street,
Philadelphia, Pennsylvania 19104, United States
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9
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Takematsu H, Yamamoto H, Naito-Matsui Y, Fujinawa R, Tanaka K, Okuno Y, Tanaka Y, Kyogashima M, Kannagi R, Kozutsumi Y. Quantitative transcriptomic profiling of branching in a glycosphingolipid biosynthetic pathway. J Biol Chem 2011; 286:27214-24. [PMID: 21665948 DOI: 10.1074/jbc.m111.234526] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Cellular biosynthesis of macromolecules often involves highly branched enzyme pathways, thus cellular regulation of such pathways could be rather difficult. To understand the regulatory mechanism, a systematic approach could be useful. We genetically analyzed a branched biosynthetic pathway for glycosphingolipid (GSL) GM1 using correlation index-based responsible enzyme gene screening (CIRES), a novel quantitative phenotype-genotype correlation analysis. CIRES utilizes transcriptomic profiles obtained from multiple cells. Among a panel of B cell lines, expression of GM1 was negatively correlated with and suppressed by gene expression of CD77 synthase (CD77Syn), whereas no significant positive correlation was found for enzymes actually biosynthesizing GM1. Unexpectedly, a GM1-suppressive phenotype was also observed in the expression of catalytically inactive CD77Syn, ruling out catalytic consumption of lactosylceramide (LacCer) as the main cause for such negative regulation. Rather, CD77Syn seemed to limit other branching reaction(s) by targeting LacCer synthase (LacCerSyn), a proximal enzyme in the pathway, because they were closely localized in the Golgi apparatus and formed a complex. Moreover, turnover of LacCerSyn was accelerated upon CD77Syn expression to globally change the GSL species expressed. Collectively, these data suggest that transcriptomic assessment of macromolecule biosynthetic pathways can disclose a global regulatory mechanism(s) even when unexpected.
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Affiliation(s)
- Hiromu Takematsu
- Laboratory of Membrane Biochemistry and Biophysics, Graduate School of Biostudies, Kyoto University, Sakyo, Kyoto 606-8501, Japan.
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Alvarez-Manilla G, Troupe K, Fleming M, Martinez-Uribe E, Pierce M. Comparison of the substrate specificities and catalytic properties of the sister N-acetylglucosaminyltransferases, GnT-V and GnT-Vb (IX). Glycobiology 2009; 20:166-74. [PMID: 19846580 DOI: 10.1093/glycob/cwp158] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
N-Acetylglucosaminlyltransferase-V (GnT-V) synthesizes GlcNAcbeta1,6Man branched N-glycans both in vitro and in vivo. A paralog, GnT-Vb (or GnT-IX), has also been shown to synthesize both GlcNAcbeta1,6Man branched N- and O-glycans. GnT-V is expressed in most human and rodent tissues while GnT-Vb expression is limited mainly to neural tissue and testes. It is of interest, therefore, to compare the catalytic properties and reaction kinetics of these sister enzymes. The results demonstrate that while GnT-V was fully active without exogenous cation and in the presence of EDTA, the activity of GnT-Vb was stimulated over 4-fold in the presence of 10 mM Mn(++). The pH optimum for GnT-V was in the range of 6.5-7.0, while that of GnT-Vb was 8.0. common for glycosyltransferases active in brain. Both enzymes transferred GlcNAcbeta1,6 to the Man residue of the GlcNAcbeta1,2Man moiety of glycan substrates, and both enzymes acted effectively on a synthetic GlcNAcbeta1,2Manalpha1,2Glc-O-octyl trisaccharide acceptor. Moreover, although both enzymes utilized an N-linked asialo-agalacto-biantennary glycan as an acceptor, GnT-Vb displayed an almost 2.5-fold higher apparent K(m) value compared to GnT-V. Conversely, GnT-Vb very efficiently glycosylated a synthetic glycopeptide, Ac-H(2)N-Val-Glu-Pro-(GlcNAcbeta1,2-Man-O-)Thr-Ala-Val-CO-Ac, while GnT-V showed relatively poor activity toward this O-Man-linked glycopeptide acceptor, with a K(m) value of 20-fold higher than that of GnT-Vb. When the N-linked asialo-agalacto-biantennary glycan acceptor was utilized with GnT-Vb, the expected triantennary beta1,6-branched product was observed up to 8 h incubation. An additional product with two beta1,6-linked GlcNAc resides, however, was observed after prolonged (>8 h) incubation, consistent with an earlier report. This unusual tetraantennary product was observed with GnT-Vb only after substantial accumulation of the first triantennary product and not during the early stages of incubation.
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Affiliation(s)
- Gerardo Alvarez-Manilla
- Department of Biochemistry and Molecular Biology, Complex Carbohydrate Research Center, University of Georgia, Athens, GA 30602, USA
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11
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Shu HY, Fung CP, Liu YM, Wu KM, Chen YT, Li LH, Liu TT, Kirby R, Tsai SF. Genetic diversity of capsular polysaccharide biosynthesis in Klebsiella pneumoniae clinical isolates. MICROBIOLOGY-SGM 2009; 155:4170-4183. [PMID: 19744990 DOI: 10.1099/mic.0.029017-0] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
Klebsiella pneumoniae is an enteric pathogen causing community-acquired and hospital-acquired infections in humans. Epidemiological studies have revealed significant diversity in capsular polysaccharide (CPS) type and clinical manifestation of K. pneumoniae infection in different geographical areas of the world. We have sequenced the capsular polysaccharide synthesis (cps) region of seven clinical isolates and compared the sequences with the publicly available cps sequence data of five strains: NTUH-K2044 (K1 serotype), Chedid (K2 serotype), MGH78578 (K52 serotype), A1142 (K57 serotype) and A1517. Among all strains, six genes at the 5' end of the cps clusters that encode proteins for CPS transportation and processing at the bacterial surface are highly similar to each other. The central region of the cps gene clusters, which encodes proteins for polymerization and assembly of the CPS subunits, is highly divergent. Based on the collected sequence, we found that either the wbaP gene or the wcaJ gene exists in a given K. pneumoniae strain, suggesting that there is a major difference in the CPS biosynthesis pathway and that the K. pneumoniae strains can be classified into at least two distinct groups. All isolates contain gnd, encoding gluconate-6-phosphate dehydrogenase, at the 3' end of the cps gene clusters. The rmlBADC genes were found in CPS K9-positive, K14-positive and K52-positive strains, while manC and manB were found in K1, K2, K5, K14, K62 and two undefined strains. Our data indicate that, while overall genomic organization is similar between different pathogenic K. pneumoniae strains, the genetic variation of the sugar moiety and polysaccharide linkage generate the diversity in CPS molecules that could help evade host immune attack.
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Affiliation(s)
- Hung-Yu Shu
- Genome Research Center, National Yang-Ming University, Taipei, Taiwan, ROC.,Department of Bioscience Technology, Chang Jung Christian University, Tainan County, Taiwan, ROC
| | - Chang-Phone Fung
- Institute of Tropical Medicine, School of Medicine, National Yang-Ming University, Taipei, Taiwan, ROC.,Division of Infectious Diseases, Department of Medicine, Taipei Veterans General Hospital, Taipei, Taiwan, ROC
| | - Yen-Ming Liu
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Keh-Ming Wu
- Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan, ROC.,Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Ying-Tsong Chen
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Ling-Hui Li
- Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC
| | - Tze-Tze Liu
- Genome Research Center, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Ralph Kirby
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, ROC
| | - Shih-Feng Tsai
- Department of Life Sciences and Institute of Genome Sciences, National Yang-Ming University, Taipei, Taiwan, ROC.,Division of Molecular and Genomic Medicine, National Health Research Institutes, Zhunan, Miaoli County, Taiwan, ROC.,Genome Research Center, National Yang-Ming University, Taipei, Taiwan, ROC.,Institute of Biomedical Informatics, National Yang-Ming University, Taipei, Taiwan, ROC
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12
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Aguilan JT, Sundaram S, Nieves E, Stanley P. Mutational and functional analysis of Large in a novel CHO glycosylation mutant. Glycobiology 2009; 19:971-86. [PMID: 19470663 DOI: 10.1093/glycob/cwp074] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Inactivating mutations of Large reduce the functional glycosylation of alpha-dystroglycan (alpha-DG) and lead to muscular dystrophy in mouse and humans. The N-terminal domain of Large is most similar to UDP-glucose glucosyltransferases (UGGT), and the C-terminal domain is related to the human i blood group transferase beta1,3GlcNAcT-1. The amino acids at conserved motifs DQD+1 and DQD+3 in the UGGT domain are necessary for mammalian UGGT activity. When the corresponding residues were mutated to Ala in mouse Large, alpha-DG was not functionally glycosylated. A similar result was obtained when a DXD motif in the beta1,3GlcNAcT-1 domain was mutated to AIA. Therefore, the first putative glycosyltransferase domain of Large has properties of a UGGT and the second of a typical glycosyltransferase. Co-transfection of Large mutants affected in the different glycosyltransferase domains did not lead to complementation. While Large mutants were more localized to the endoplasmic reticulum than wild-type Large or revertants, all mutants were in the Golgi, and only very low levels of Golgi-localized Large were necessary to generate functional alpha-DG. When Large was overexpressed in ldlD.Lec1 mutant Chinese hamster ovary (CHO) cells which synthesize few, if any, mucin O-GalNAc glycans and no complex N-glycans, functional alpha-DG was produced, presumably by modifying O-mannose glycans. To investigate mucin O-GalNAc glycans as substrates of Large, a new CHO mutant Lec15.Lec1 that lacked O-mannose and complex N-glycans was isolated and characterized. Following transfection with Large, Lec15.Lec1 cells also generated functionally glycosylated alpha-DG. Thus, Large may act on the O-mannose, complex N-glycans and mucin O-GalNAc glycans of alpha-DG.
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Affiliation(s)
- Jennifer T Aguilan
- Department of Cell Biology, Albert Einstein College Medicine, New York, NY 10461, USA
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13
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Ku SY, Yip P, Cornell KA, Riscoe MK, Behr JB, Guillerm G, Howell PL. Structures of 5-methylthioribose kinase reveal substrate specificity and unusual mode of nucleotide binding. J Biol Chem 2007; 282:22195-206. [PMID: 17522047 DOI: 10.1074/jbc.m611045200] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The methionine salvage pathway is ubiquitous in all organisms, but metabolic variations exist between bacteria and mammals. 5-Methylthioribose (MTR) kinase is a key enzyme in methionine salvage in bacteria and the absence of a mammalian homolog suggests that it is a good target for the design of novel antibiotics. The structures of the apo-form of Bacillus subtilis MTR kinase, as well as its ADP, ADP-PO(4), AMPPCP, and AMPPCP-MTR complexes have been determined. MTR kinase has a bilobal eukaryotic protein kinase fold but exhibits a number of unique features. The protein lacks the DFG motif typically found at the beginning of the activation loop and instead coordinates magnesium via a DXE motif (Asp(250)-Glu(252)). In addition, the glycine-rich loop of the protein, analogous to the "Gly triad" in protein kinases, does not interact extensively with the nucleotide. The MTR substrate-binding site consists of Asp(233) of the catalytic HGD motif, a novel twin arginine motif (Arg(340)/Arg(341)), and a semi-conserved W-loop, which appears to regulate MTR binding specificity. No lobe closure is observed for MTR kinase upon substrate binding. This is probably because the enzyme lacks the lobe closure/inducing interactions between the C-lobe of the protein and the ribosyl moiety of the nucleotide that are typically responsible for lobe closure in protein kinases. The current structures suggest that MTR kinase has a dissociative mechanism.
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Affiliation(s)
- Shao-Yang Ku
- Program in Molecular Structure and Function, Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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14
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Persson M, Letts JA, Hosseini-Maaf B, Borisova SN, Palcic MM, Evans SV, Olsson ML. Structural Effects of Naturally Occurring Human Blood Group B Galactosyltransferase Mutations Adjacent to the DXD Motif. J Biol Chem 2007; 282:9564-9570. [PMID: 17259183 DOI: 10.1074/jbc.m610998200] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human blood group A and B antigens are produced by two closely related glycosyltransferase enzymes. An N-acetylgalactosaminyltransferase (GTA) utilizes UDP-GalNAc to extend H antigen acceptors (Fuc alpha(1-2)Gal beta-OR) producing A antigens, whereas a galactosyltransferase (GTB) utilizes UDP-Gal as a donor to extend H structures producing B antigens. GTA and GTB have a characteristic (211)DVD(213) motif that coordinates to a Mn(2+) ion shown to be critical in donor binding and catalysis. Three GTB mutants, M214V, M214T, and M214R, with alterations adjacent to the (211)DVD(213) motif have been identified in blood banking laboratories. From serological phenotyping, individuals with the M214R mutation show the B(el) variant expressing very low levels of B antigens, whereas those with M214T and M214V mutations give rise to A(weak)B phenotypes. Kinetic analysis of recombinant mutant GTB enzymes revealed that M214R has a 1200-fold decrease in k(cat) compared with wild type GTB. The crystal structure of M214R showed that DVD motif coordination to Mn(2+) was disrupted by Arg-214 causing displacement of the metal by a water molecule. Kinetic characterizations of the M214T and M214V mutants revealed they both had GTA and GTB activity consistent with the serology. The crystal structure of the M214T mutant showed no change in DVD coordination to Mn(2+). Instead a critical residue, Met-266, which is responsible for determining donor specificity, had adopted alternate conformations. The conformation with the highest occupancy opens up the active site to accommodate the larger A-specific donor, UDP-GalNAc, accounting for the dual specificity.
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Affiliation(s)
- Mattias Persson
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, 2500 Valby, Copenhagen, Denmark
| | - James A Letts
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
| | - Bahram Hosseini-Maaf
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University and The Blood Centre, Lund University Hospital, SE-22185 Lund, Sweden
| | - Svetlana N Borisova
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
| | - Monica M Palcic
- Carlsberg Laboratory, Gamle Carlsberg Vej 10, 2500 Valby, Copenhagen, Denmark.
| | - Stephen V Evans
- Department of Biochemistry and Microbiology, University of Victoria, Victoria, British Columbia V8W 3P6, Canada
| | - Martin L Olsson
- Division of Hematology and Transfusion Medicine, Department of Laboratory Medicine, Lund University and The Blood Centre, Lund University Hospital, SE-22185 Lund, Sweden.
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15
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Patel RY, Balaji PV. Fold-recognition and comparative modeling of human beta3GalT I, II, IV, V and VI and beta3GalNAcT I: prediction of residues conferring acceptor substrate specificity. J Mol Graph Model 2006; 26:255-68. [PMID: 17212986 DOI: 10.1016/j.jmgm.2006.12.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2006] [Revised: 11/19/2006] [Accepted: 12/10/2006] [Indexed: 11/19/2022]
Abstract
beta3GalTs are type II transmembrane proteins that transfer galactose from UDP-Gal donor substrate to acceptor GlcNAc, GalNAc or Gal in beta1-->3-linkage. beta1-->3-linked galactose have been found to be a part of many glycans like glycosphingolipids, core tetrasaccharide of proteoglycans, type 1 chains. The 3-D structure of none of the beta3GalTs is known to date. In this study, the 3-D structures of human beta3GalT I, II, IV, V, VI and beta3GalNAcT I have been modeled using fold-recognition and comparative modeling methods. Residues that constitute the UDP-Gal binding site have been predicted. The models are able to qualitatively rationalize data from the site-directed mutagenesis experiments reported in the literature. Residues likely to be involved in conferring differential acceptor substrate specificity have been predicted by a combination of specificity determining positions prediction (SDPs) and subsequent mapping on the generated 3-D models.
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Affiliation(s)
- Ronak Y Patel
- School of Biosciences and Bioengineering, Indian Institute of Technology Bombay, Powai, Mumbai 400076, India
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16
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Götting C, Müller S, Schöttler M, Schön S, Prante C, Brinkmann T, Kuhn J, Kleesiek K. Analysis of the DXD motifs in human xylosyltransferase I required for enzyme activity. J Biol Chem 2004; 279:42566-73. [PMID: 15294915 DOI: 10.1074/jbc.m401340200] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Human xylosyltransferase I (XT-I) is the initial enzyme involved in the biosynthesis of the glycosaminoglycan linker region in proteoglycans. Here, we tested the importance of the DXD motifs at positions 314-316 and 745-747 for enzyme activity and the nucleotide binding capacity of human XT-I. Mutations of the 314DED316 motif did not have any effect on enzyme activity, whereas alterations of the 745DWD747 motif resulted in reduced XT-I activity. Loss of function was observed after exchange of the highly conserved aspartic acid at position 745 with glycine. However, mutation of Asp745 to glutamic acid retained full enzyme activity, indicating the importance of an acidic amino acid at this position. Reduced substrate affinity was observed for mutants D747G (Km=6.9 microm) and D747E (Km=4.4 microm) in comparison with the wild-type enzyme (Km=0.9 microm). Changing the central tryptophan to a neutral, basic, or acidic amino acid resulted in a 6-fold lower Vmax, with Km values comparable with those of the wild-type enzyme. Despite the major effect of the DWD motif on XT-I activity, nucleotide binding was not abolished in the D745G and D747G mutants, as revealed by UDP-bead binding assays. Ki values for inhibition by UDP were determined to be 1.9-24.6 microm for the XT-I mutants. The properties of binding of XT-I to heparin-beads, the Ki constants for noncompetitive inhibition by heparin, and the activation by protamine were not altered by the generated mutations.
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Affiliation(s)
- Christian Götting
- Institut für Laboratoriums- und Transfusionsmedizin, Herz- und Diabeteszentrum Nordrhein-Westfalen, Universitätsklinik der Ruhr-Universität Bochum, Georgstrasse 11, 32545 Bad Oeynhausen, Germany.
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17
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Gulberti S, Fournel-Gigleux S, Mulliert G, Aubry A, Netter P, Magdalou J, Ouzzine M. The functional glycosyltransferase signature sequence of the human beta 1,3-glucuronosyltransferase is a XDD motif. J Biol Chem 2003; 278:32219-26. [PMID: 12794088 DOI: 10.1074/jbc.m207899200] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human beta 1,3-glucuronosyltransferase I (GlcAT-I) is the key enzyme responsible for the completion of glycosaminoglycan-protein linkage tetrasaccharide of proteoglycans (GlcA beta 1,3Gal beta 1,3Gal beta 1,4Xyl beta 1-O-serine). We have investigated the role of aspartate residues Asp194-Asp195-Asp196 corresponding to the glycosyltransferase DXD signature motif, in GlcAT-I function by UDP binding experiments, kinetic analyses, and site-directed mutagenesis. We presented the first evidence that Mn2+ is not only essential for GlcAT-I activity but is also required for cosubstrate binding. In agreement, kinetic studies were consistent with a metal-activated enzyme model whereby activation probably occurs via binding of a Mn2+.UDP-GlcA complex to the enzyme. Mutational analysis showed that the Asp194-Asp195-Asp196 motif is a major element of the UDP/Mn2+ binding site. Furthermore, determination of the individual role of each aspartate showed that substitution of Asp195 as well as Asp196 to alanine strongly impaired GlcAT-I activity, whereas Asp194 replacement produced only a moderate alteration of the enzyme activity. These findings along with molecular modeling and three-dimensional structure comparison of the GlcAT-I catalytic center with that of the Bacillus subtilis glycosyltransferase SpsA provided evidence that the interactions of Asp195 with the ribose moiety of UDP and of Asp196 with the metal cation Mn2+ were crucial for GlcAT-I function. Altogether, these results indicated that, similarly to the SpsA enzyme, the nucleotide binding site of GlcAT-I contains a XDD motif rather than a DXD motif.
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Affiliation(s)
- Sandrine Gulberti
- UMR 7561 CNRS-Université Henri Poincaré Nancy 1, Faculté de Médecine, 54505 Vandoeuvre-lès-Nancy, France
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18
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Montiel MD, Krzewinski-Recchi MA, Delannoy P, Harduin-Lepers A. Molecular cloning, gene organization and expression of the human UDP-GalNAc:Neu5Acalpha2-3Galbeta-R beta1,4-N-acetylgalactosaminyltransferase responsible for the biosynthesis of the blood group Sda/Cad antigen: evidence for an unusual extended cytoplasmic domain. Biochem J 2003; 373:369-79. [PMID: 12678917 PMCID: PMC1223490 DOI: 10.1042/bj20021892] [Citation(s) in RCA: 62] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2002] [Revised: 03/31/2003] [Accepted: 04/04/2003] [Indexed: 11/17/2022]
Abstract
The nucleotide sequence of the short and long transcripts of beta1,4- N -acetylgalactosaminyltransferase have been submitted to the DDBJ, EMBL, GenBank(R) and GSDB Nucleotide Sequence Databases under accession nos AJ517770 and AJ517771 respectively. The human Sd(a) antigen is formed through the addition of an N -acetylgalactosamine residue via a beta1,4-linkage to a sub-terminal galactose residue substituted with an alpha2,3-linked sialic acid residue. We have taken advantage of the previously cloned mouse cDNA sequence of the UDP-GalNAc:Neu5Acalpha2-3Galbeta-R beta1,4- N -acetylgalactosaminyltransferase (Sd(a) beta1,4GalNAc transferase) to screen the human EST and genomic databases and to identify the corresponding human gene. The sequence spans over 35 kb of genomic DNA on chromosome 17 and comprises at least 12 exons. As judged by reverse transcription PCR, the human gene is expressed widely since it is detected in various amounts in almost all cell types studied. Northern blot analysis indicated that five Sd(a) beta1,4GalNAc transferase transcripts of 8.8, 6.1, 4.7, 3.8 and 1.65 kb were highly expressed in colon and to a lesser extent in kidney, stomach, ileum and rectum. The complete coding nucleotide sequence was amplified from Caco-2 cells. Interestingly, the alternative use of two first exons, named E1(S) and E1(L), leads to the production of two transcripts. These nucleotide sequences give rise potentially to two proteins of 506 and 566 amino acid residues, identical in their sequence with the exception of their cytoplasmic tail. The short form is highly similar (74% identity) to the mouse enzyme whereas the long form shows an unusual long cytoplasmic tail of 66 amino acid residues that is as yet not described for any other mammalian glycosyltransferase. Upon transient transfection in Cos-7 cells of the common catalytic domain, a soluble form of the protein was obtained, which catalysed the transfer of GalNAc residues to alpha2,3-sialylated acceptor substrates, to form the GalNAcbeta1-4[Neu5Acalpha2-3]Galbeta1-R trisaccharide common to both Sd(a) and Cad antigens.
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Affiliation(s)
- Maria-Dolores Montiel
- Unité de Glycobiologie Structurale et Fonctionnelle, UMR CNRS no 8576, Laboratoire de Chimie Biologique, Université des Sciences et Technologies de Lille, F-59655 Villeneuve d'Ascq, France
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19
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Zhang D, Li N, Swaminathan K, Zhang LH. A motif rich in charged residues determines product specificity in isomaltulose synthase. FEBS Lett 2003; 534:151-5. [PMID: 12527377 DOI: 10.1016/s0014-5793(02)03835-8] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Isomaltulose synthase (PalI) catalyzes hydrolysis of sucrose and formation of alpha-1,6 and alpha-1,1 bonds to produce isomaltulose (alpha-D-glucosylpyranosyl-1,6-D-fructofranose) and small amount of trehalulose (alpha-D-glucosylpyranosyl-1,1-D-fructofranose). A potential isomaltulose synthase-specific motif ((325)RLDRD(329)), that contains a 'DxD' motif conserved in many glycosyltransferases, was identified based on sequence comparison with reference to the secondary structural features of PalI and homologs. Site-directed mutagenesis analysis of the motif showed that the four charged amino acid residues (Arg(325), Arg(328), Asp(327) and Asp(329)) influence the enzyme kinetics and determine the product specificity. Mutation of these four residues increased trehalulose formation by 17-61% and decreased isomaltulose by 26-67%. We conclude that the 'RLDRD' motif controls the product specificity of PalI.
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Affiliation(s)
- Daohai Zhang
- Laboratory of Biosignals and Bioengineering, Institute of Molecular and Cell Biology, The National University of Singapore, Singapore 117609, Singapore
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20
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Zak BM, Crawford BE, Esko JD. Hereditary multiple exostoses and heparan sulfate polymerization. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1573:346-55. [PMID: 12417417 DOI: 10.1016/s0304-4165(02)00402-6] [Citation(s) in RCA: 147] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Hereditary multiple exostoses (HME, OMIM 133700, 133701) results from mutations in EXT1 and EXT2, genes encoding the copolymerase responsible for heparan sulfate (HS) biosynthesis. Members of this multigene family share the ability to transfer N-acetylglucosamine to a variety of oligosaccharide acceptors. EXT1 and EXT2 encode the copolymerase, whereas the roles of the other EXT family members (EXTL1, L2, and L3) are less clearly defined. Here, we provide an overview of HME, the EXT family of proteins, and possible models for the relationship of altered HS biosynthesis to the ectopic bone growth characteristic of the disease.
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Affiliation(s)
- Beverly M Zak
- Glycobiology Research and Training Center, Department of Cellular and Molecular Medicine, University of California, San Diego, La Jolla 92093-0687, USA
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21
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Lazarus BD, Milland J, Ramsland PA, Mouhtouris E, Sandrin MS. Histidine 271 has a functional role in pig alpha-1,3galactosyltransferase enzyme activity. Glycobiology 2002; 12:793-802. [PMID: 12499401 DOI: 10.1093/glycob/cwf092] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Alpha(1,3)Galactosyltransferase (GT) is a Golgi-localized enzyme that catalyzes the transfer of a terminal galactose to N-acetyllactosamine to create Galalpha(1,3)Gal. This glycosyltransferase has been studied extensively because the Galalpha(1,3)Gal epitope is involved in hyperacute rejection of pig-to-human xenotransplants. The original crystal structure of bovine GT defines the amino acids forming the catalytic pocket; however, those directly involved in the interaction with the donor nucleotide sugars were not characterized. Comparison of amino acid sequences of GT from several species with the human A and B transferases suggest that His271 of pig GT may be critical for recognition of the donor substrate, UDP-Gal. Using pig GT as the representative member of the GT family, we show that replacement of His271 with Ala, Leu, or Gly caused complete loss of function, in contrast to replacement with Arg, another basic charged residue, which did not alter the ability of GT to produce Galalpha(1,3)Gal. Molecular modeling showed that His271 may interact directly with the Gal moiety of UDP-Gal, an interaction possibly retained by replacing His with Arg. However, replacing His271 with amino acids found in alpha(1,3)GalNAc transferases did not change the donor nucleotide specificity. Thus His271 is critical for enzymatic function of pig GT.
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Affiliation(s)
- Brooke D Lazarus
- John Connell Laboratory for Glycobiology, The Austin Research Institute, Austin and Repatriation Medical Centre, Studley Road, Heidelberg 3084, Australia
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22
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Stolz J, Munro S. The components of the Saccharomyces cerevisiae mannosyltransferase complex M-Pol I have distinct functions in mannan synthesis. J Biol Chem 2002; 277:44801-8. [PMID: 12235155 DOI: 10.1074/jbc.m208023200] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The yeast Saccharomyces cerevisiae processes N-linked glycans in the Golgi apparatus in two different ways. Whereas most of the proteins of internal membranes receive a simple core-type structure, a long branched polymer termed mannan is attached to the glycans of many of the proteins destined for the cell wall. The first step in mannan synthesis is the initiation and extension of an alpha-1,6-linked polymannose backbone. This requires the sequential action of two enzyme complexes, mannan polymerases (M-Pol) I and II. M-Pol I contains the proteins Mnn9p and Van1p, although the stoichiometry and individual contributions to enzyme action are unclear. We report here that the two proteins are each present as a single copy in the complex. Both proteins contain a DXD motif found in the active site of many glycosyltransferases, and mutations in this motif in Mnn9p or Van1p reveal that both proteins contribute to mannose polymerization. However, the effects of these mutations on both the in vivo and in vitro activity are distinct, suggesting that the two proteins may have different roles in the complex. Finally, we show that a simple glycoprotein based on hen egg lysozyme can be used as a substrate for modification by purified M-Pol I in vitro.
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Affiliation(s)
- Jurgen Stolz
- MRC Laboratory of Molecular Biology, Hills Road, Cambridge CB2 2QH, United Kingdom
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23
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Ihara H, Ikeda Y, Koyota S, Endo T, Honke K, Taniguchi N. A catalytically inactive beta 1,4-N-acetylglucosaminyltransferase III (GnT-III) behaves as a dominant negative GnT-III inhibitor. EUROPEAN JOURNAL OF BIOCHEMISTRY 2002; 269:193-201. [PMID: 11784313 DOI: 10.1046/j.0014-2956.2001.02640.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
beta 1,4-N-Acetylglucosaminyltransferase III (GnT-III) plays a regulatory role in the biosynthesis of N-glycans, and it has been suggested that its product, a bisecting GlcNAc, is involved in a variety of biological events as well as in regulating the biosynthesis of the oligosaccharides. In this study, it was found, on the basis of sequence homology, that GnT-III contains a small region that is significantly homologous to both snail beta 1,4GlcNAc transferase and beta1,4Gal transferase-1. Subsequent mutational analysis demonstrated an absolute requirement for two conserved Asp residues (Asp321 and Asp323), which are located in the most homologous region of rat GnT-III, for enzymatic activity. The overexpression of Asp323-substituted, catalytically inactive GnT-III in Huh6 cells led to the suppression of the activity of endogenous GnT-III, but no significant decrease in its expression, and led to a specific inhibition of the formation of bisected sugar chains, as shown by structural analysis of the total N-glycans from the cells. These findings indicate that the mutant serves a dominant negative effect on a specific step in N-glycan biosynthesis. This type of 'dominant negative glycosyltransferase', identified has potential value as a powerful tool for defining the precise biological roles of the bisecting GlcNAc structure.
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Affiliation(s)
- Hideyuki Ihara
- Department of Biochemistry, Osaka University Medical School, Suita, Osaka, Japan
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