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Yan S, Wang H, Schachter H, Jin C, Wilson IBH, Paschinger K. Ablation of N-acetylglucosaminyltransferases in Caenorhabditis induces expression of unusual intersected and bisected N-glycans. Biochim Biophys Acta Gen Subj 2018; 1862:2191-2203. [PMID: 29981898 PMCID: PMC6173287 DOI: 10.1016/j.bbagen.2018.07.002] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 06/30/2018] [Accepted: 07/04/2018] [Indexed: 12/17/2022]
Abstract
The modification in the Golgi of N-glycans by N-acetylglucosaminyltransferase I (GlcNAc-TI, MGAT1) can be considered to be a hallmark of multicellular eukaryotes as it is found in all metazoans and plants, but rarely in unicellular organisms. The enzyme is key for the normal processing of N-glycans to either complex or paucimannosidic forms, both of which are found in the model nematode Caenorhabditis elegans. Unusually, this organism has three different GlcNAc-TI genes (gly-12, gly-13 and gly-14); therefore, a complete abolition of GlcNAc-TI activity required the generation of a triple knock-out strain. Previously, the compositions of N-glycans from this mutant were described, but no detailed structures. Using an off-line HPLC-MALDI-TOF-MS approach combined with exoglycosidase digestions and MS/MS, we reveal that the multiple hexose residues of the N-glycans of the gly-12;gly-13;gly-14 triple mutant are not just mannose, but include galactoses in three different positions (β-intersecting, β-bisecting and α-terminal) on isomeric forms of Hex4-8HexNAc2 structures; some of these structures are fucosylated and/or methylated. Thus, the N-glycomic repertoire of Caenorhabditis is even wider than expected and exhibits a large degree of plasticity even in the absence of key glycan processing enzymes from the Golgi apparatus.
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Affiliation(s)
- Shi Yan
- Department für Chemie, Universität für Bodenkultur, 1190 Wien, Austria,Institut für Parasitologie, Veterinärmedizinische Universität Wien, 1210 Wien, Austria
| | - Huijie Wang
- Department für Chemie, Universität für Bodenkultur, 1190 Wien, Austria
| | - Harry Schachter
- Hospital for Sick Children and University of Toronto, Toronto, ON M5G 1X8, Canada
| | - Chunsheng Jin
- Institutionen för Biomedicin, Göteborgs universitet, 405 30 Göteborg, Sweden
| | - Iain B. H. Wilson
- Department für Chemie, Universität für Bodenkultur, 1190 Wien, Austria,To whom correspondence should be addressed:
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2
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Kytidou K, Beekwilder J, Artola M, van Meel E, Wilbers RHP, Moolenaar GF, Goosen N, Ferraz MJ, Katzy R, Voskamp P, Florea BI, Hokke CH, Overkleeft HS, Schots A, Bosch D, Pannu N, Aerts JMFG. Nicotiana benthamiana α-galactosidase A1.1 can functionally complement human α-galactosidase A deficiency associated with Fabry disease. J Biol Chem 2018; 293:10042-10058. [PMID: 29674318 PMCID: PMC6028973 DOI: 10.1074/jbc.ra118.001774] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Revised: 04/17/2018] [Indexed: 11/06/2022] Open
Abstract
α-Galactosidases (EC 3.2.1.22) are retaining glycosidases that cleave terminal α-linked galactose residues from glycoconjugate substrates. α-Galactosidases take part in the turnover of cell wall-associated galactomannans in plants and in the lysosomal degradation of glycosphingolipids in animals. Deficiency of human α-galactosidase A (α-Gal A) causes Fabry disease (FD), a heritable, X-linked lysosomal storage disorder, characterized by accumulation of globotriaosylceramide (Gb3) and globotriaosylsphingosine (lyso-Gb3). Current management of FD involves enzyme-replacement therapy (ERT). An activity-based probe (ABP) covalently labeling the catalytic nucleophile of α-Gal A has been previously designed to study α-galactosidases for use in FD therapy. Here, we report that this ABP labels proteins in Nicotiana benthamiana leaf extracts, enabling the identification and biochemical characterization of an N. benthamiana α-galactosidase we name here A1.1 (gene accession ID GJZM-1660). The transiently overexpressed and purified enzyme was a monomer lacking N-glycans and was active toward 4-methylumbelliferyl-α-d-galactopyranoside substrate (Km = 0.17 mm) over a broad pH range. A1.1 structural analysis by X-ray crystallography revealed marked similarities with human α-Gal A, even including A1.1's ability to hydrolyze Gb3 and lyso-Gb3, which are not endogenous in plants. Of note, A1.1 uptake into FD fibroblasts reduced the elevated lyso-Gb3 levels in these cells, consistent with A1.1 delivery to lysosomes as revealed by confocal microscopy. The ease of production and the features of A1.1, such as stability over a broad pH range, combined with its capacity to degrade glycosphingolipid substrates, warrant further examination of its value as a potential therapeutic agent for ERT-based FD management.
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Affiliation(s)
| | - Jules Beekwilder
- the Plant Sciences Group, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, and
| | | | | | - Ruud H P Wilbers
- the Plant Sciences Group, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, and
| | - Geri F Moolenaar
- Cloning and Protein Purification Facility, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden
| | - Nora Goosen
- Cloning and Protein Purification Facility, Leiden Institute of Chemistry, Einsteinweg 55, 2333 CC Leiden
| | | | | | | | | | - Cornelis H Hokke
- the Department of Parasitology, Centre of Infectious Diseases, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | | | - Arjen Schots
- the Plant Sciences Group, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, and
| | - Dirk Bosch
- the Plant Sciences Group, Wageningen University and Research, Droevendaalsesteeg 1, 6708 PB Wageningen, and
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3
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Kusumoto K, Shirahata S, Kamei Y. Purification and characterization of alpha-D-galactosidase produced by ADG cell line established from abalon digestive gland. Cytotechnology 2011; 33:47-52. [PMID: 19002810 DOI: 10.1023/a:1008175226819] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
ADG cell line was established from an abalonedigestive gland and previously characterized. ADGcells have the potential to grow in protein-freeculture and secrete l3 types of glycosidases. Inthis article, we determined the origin of ADG cell line,using electron microscopy, and purified a glycosidasesecreted by these cells. The electron microscopicanalysis showed that ADG cell line contains severalnuclei, which suggests that they may be derived fromprotist cells. Moreover, alpha-D-galactosidasethat hydrolyzes p-nitorophenyl galactopyranosidewas purified 130-fold from the spent culture medium ofADG cells. The molecular weight of the enzyme,determined by sodium dodecyl sulfate polyacrylamidegel electrophoresis and gel filtration analysis, wasshown to be 43 and 42 kDa, respectively, and itappeared to consist of a single polypeptide chain. The purified enzyme preparation was practically freefrom other glycosidases secreted from the cells. Catalytic activity was optimal at pH 5.5 and at atemperature of 37 degrees C. The enzyme was also the most stable at pH 5.5.
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Affiliation(s)
- K Kusumoto
- Cellular Regulation Technology Laboratory, Graduate School of Genetic Resources Technology, Kyushu University, 6-10-1 Hakozaki, Higashiku, Fukuoka, 812-8581, Japan
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Shen W, Li Y, Chen H, Jin Z, Xu X, Zhao J, Xie Z. Purification and application of α-galactosidase from germinating coffee beans (Coffea arabica). Eur Food Res Technol 2009; 228:969-74. [DOI: 10.1007/s00217-009-1013-4] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Abstract
In commercial coffee species (Coffea arabica and Coffea canephora), fruit development is a lengthy process, characterized by tissue changes and evolutions. For example, soon after fecundation and up to mid development, the fruit is mainly constituted of the pericarp and perisperm tissue. Thereafter, the perisperm gradually disappears and is progressively replaced by the endosperm (true seed). Initially present in a "liquid" state, the endosperm hardens as it ripens during the maturation phase, as a result of accumulation of storage proteins, sucrose and complex polysaccharides representing the main reserves of the seed. The last step of maturation is characterized by the dehydration of the endosperm and the color change of the pericarp. Important quantitative and qualitative changes accompany fruit growth, highlighting the importance of its study to better understand the final characteristics of coffee beans. Following a description of the coffee fruit tissues, this review presents some data concerning biochemical, enzymatic and gene expression variations observed during the coffee fruit development. The latter will also be analyzed in the light of recent data (electronic expression profiles) arising from the Brazilian Coffee Genome Project.
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Marraccini P, Rogers WJ, Caillet V, Deshayes A, Granato D, Lausanne F, Lechat S, Pridmore D, Pétiard V. Biochemical and molecular characterization of alpha-D-galactosidase from coffee beans. Plant Physiol Biochem 2005; 43:909-20. [PMID: 16310367 DOI: 10.1016/j.plaphy.2005.08.010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2005] [Revised: 06/20/2005] [Accepted: 08/18/2005] [Indexed: 05/05/2023]
Abstract
Alpha-D-Galactosidase (alpha-Gal; EC 3.2.1.22) is one of three principal enzymes involved in the modification or degradation of plant cell wall galactomannans. In the present paper it is shown that alpha-galactosidase activities in field-grown coffee beans are variable amongst cultivars of the two species investigated (Coffea arabica and C. canephora var. Robusta). Higher activities were found in Arabica cultivars. Using beans from greenhouse-cultivated C. arabica as a model, we showed that alpha-Gal activity was undetectable in the bean perispem tissue, but increased gradually during the endosperm development, to reach a peak at approximately 30 weeks after flowering (WAF) which coincided with the hardening of the endosperm. Alpha-Gal-specific transcripts detected at 22 and 27 WAF accompanied the peak of alpha-Gal activity, but were reduced to be undetectable in mature beans at 30 WAF, while alpha-Gal activity still persisted. Two isoforms were distinguished in 2-DE profiles of crude protein extracts by N-terminal sequencing analysis. Analysis of two-dimensional gel electrophoresis profiles demonstrated that both isoforms accumulated in a linear fashion throughout grain maturation. Alpha-Gal activity was also observed to increase to high levels during in vitro germination of coffee beans suggesting an important function of this enzyme in this process. Alpha-Gal cDNA sequences from Arabica and Robusta were sequenced and their deduced proteins appeared to be very similar, differing by only eight amino acids. Southern-blot analysis suggests that the enzyme was encoded by at least two genes in C. arabica that could explain the existence of the two isoforms identified in 2-DE profiles.
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Affiliation(s)
- Pierre Marraccini
- Nestlé Research Center, 101, avenue Gustave Eiffel, B.P. 9716, 37097 Tours cedex 2, France
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7
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Abstract
Ruminococcus gnavus is a Gram positive, nonspore-forming obligate anaerobe normally found in the human alimentary tract. In culture, this organism constitutively produces a 1-3 alpha-galactosidase. We fractionated and characterized this enzyme demonstrating hydrolysis of the B epitope on erythrocyte membranes and seroconversion to H epitope (blood type O). Since the enzyme yield was low, cell suspension studies could not be performed. Instead, hydrolysis of the B membrane epitope was studied with an ELISA. A highly purified enzyme product was analyzed for characteristics such as pH, ionic strength, and temperature optimum. Activity in red cell preservative solutions and in the presence of type B plasma was also demonstrated. Ruminococcus gnavus a 1-3 alpha-galactosidase has potential application in the enzymatic conversion of type B to O packed red blood cell units.
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Affiliation(s)
- D Jane Hata
- Division of Clinical Microbiology, Mayo Foundation, Rochester, Minnesota, USA
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Zhang Y, Yang J, Gao X, Jia Y, Ji S, Gong F, Liu Z, Ren H, Li S, Lan J, Cao Q. B→O blood conversion. Chin Sci Bull 2003; 48:269-73. [DOI: 10.1007/bf03183296] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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Onal S, Telefoncu A. Comparison of chitin and Amberlite IRA-938 for alpha-galactosidase immobilization. Artif Cells Blood Substit Immobil Biotechnol 2003; 31:19-33. [PMID: 12602814 DOI: 10.1081/bio-120018001] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Watermelon alpha-galactosidase (EC 3.2.1.22) was immobilized on a natural (chitin) and a synthetic anion-exchange (Amberlite IRA-938) support by covalent coupling methods. The procedure entails the activation of supports with 1,1'-carbonyldiimidazole (CDI), followed by immobilization of the enzyme on to these supports without and with a spacer arm; gamma-aminobutyric acid (GABA). Optimization of activation was performed by changing the CDI concentrations and coupling efficiencies. The comparison of two immobilization techniques for both chitin and Amberlite IRA-938 was made by comparing different enzyme concentrations against enzyme activity yield. Furthermore, the storage stability of the immobilized enzymes was also investigated and chitin immobilized alpha-galactosidase was found to be better. Although the activity yield of immobilized enzymes were the same for both supports, the short storage stability of immobilized enzyme on Amberlite IRA-938 is currently a drawback to its applications.
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Affiliation(s)
- Seçil Onal
- Department of Biochemistry, Faculty of Science, Ege University, Bornova-Izmir, Turkey.
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10
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Abstract
alpha-galactosidase activity in grape flesh (Vitis venifera L. Muscat of Alexandria) was characterized by a marked increase in its activity 4 weeks after fruit bearing. After 12 weeks the specific activity of the enzyme had increased 15-fold. Several other glycosidases were measured at different stages of fruit development but none showed the increased levels of activity displayed by this alpha-galactosidase. alpha-Galactosidase activity (unit/g.fresh wt) increased by 52% during postharvest storage, whereas the unripe grape showed a "stagnancy" for 10-15 days prior to the increase. An alpha-galactosidase was partially purified ca. 103-fold from grape flesh of Vitis labruscana Honey black, by a procedure involving ammonium sulfate fractionation, Biogel P-60, melibiose-agarose, and Sephacryl S-200 chromatographic separations. The enzyme was effectively separated by affinity chromatography on melibiose-agarose, and was a monomer of 40-45 kDa as determined by SDS-PAGE and Sephacryl S-200 chromatographic analysis. The hydrolysis rate of p-nitrophenyl-alpha-D-Gal (PNP-alpha-D-Gal) was 4.2 times higher than that of PNP-beta-D-Gal, implying an apparent alpha-anomer specificity, and natural oligosaccharides such as melibiose, stachyose, and raffinose were also considerably hydrolyzed. The enzyme was active over a narrow pH range with an optimal hydrolysis of stachyose and PNP-alpha-D-Gal at pH 6.0 and 7.0, respectively. EDTA or 1,10-phenanthroline did not substantially affect enzyme activity.
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Affiliation(s)
- H C Kang
- Department of Plant Nutrition, National Institute of Agricultural Science and Technology, Rural Development Administration, 441-707, Suwon, South Korea.
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11
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Defilippis VR, Villarreal LP. An Introduction to the Evolutionary Ecology of Viruses. Viral Ecology. Elsevier; 2000. pp. 125-208. [DOI: 10.1016/b978-012362675-2/50005-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
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12
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Savel'ev AN, Eneyskaya EV, Isaeva-Ivanova LS, Shabalin KA, Golubev AM, Neustroev KN. The carbohydrate moiety of alpha-galactosidase from Trichoderma reesei. Glycoconj J 1997; 14:897-905. [PMID: 9486422 DOI: 10.1023/a:1018510626305] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Alpha-galactosidase from Trichoderma reesei is a glycoprotein that contains O- and N-linked carbohydrate chains. There are 6 O-linked glycans per protein molecule that are linked to serine and threonine and can be released by beta-elimination. Among these are monomers: D-glucose, D-mannose, and D-galactose; dimers: alpha1-6 D-mannopyranosyl-alpha-D-glycopyranoside and alpha1-6 D-glucopyranosyl-alpha-D-galactopyranoside and one trimer: alpha-D-glucopyranosyl-alpha1-2 D-mannopyranosyl-alpha1-6 D-galactopyranoside. N-linked glycans are of the mannose-rich type and may be released by treating the protein with Endo-beta-N-acetyl glycosaminidase F or by hydrozinolysis. The enzyme was deglycosylated with Endo-beta-N-acetyl glycosaminidase F as well as with a number of exoglycosidases that partially remove the terminal residues of O-linked glycans. The effect of enzymatic deglycosylation on the properties of alpha-galactosidase has been considered. The effects of tunicamycin and 2-deoxyglucose on the secretion and glycosylation of the enzyme during culture growth have been analysed. The presence of two glycoforms of alpha-galactosidase differing in the number of N-linked carbohydrate chains and the microheterogeneity of the carbohydrate moiety of the enzyme are described.
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Affiliation(s)
- A N Savel'ev
- St Petersburg Technical University, Biophysics Department, Russia
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13
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Phillips R, Smith D. Characterization of coffea canephora alpha-D-galactosidase blood group B activity. Artif Cells Blood Substit Immobil Biotechnol 1996; 24:489-502. [PMID: 8879423 DOI: 10.3109/10731199609117441] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Enzymatic conversion of type B to O erythrocytes with Coffea (coffee bean) alpha-D-galactosidase was first described by Harpaz and Flowers and subsequently adopted by others (1,2). An enzyme-linked immunosorbent assay (ELISA) and soluble oligosaccharide substrates were used to study deantigenation of B erythrocytes with the Coffea enzyme. For the ELISA, microtiter wells were coated with B membranes and treated with enzyme under a variety of conditions, probed with primary IgM monoclonal anti-B followed by secondary anti-murine mu-chain specific alkaline phosphatase conjugate, then developed with substrate. This technique has allowed the rapid determination of enzymatic activity over a broad range of conditions; the purpose being to determine parameters for efficiently enhancing enzyme activity. Solid phase activity was then compared to activity against soluble oligosaccharide substrates. We have determined that, under the conditions tested, only moderate increases in enzyme activity against the B epitope can be achieved by modifying reaction conditions with the native Coffea enzyme.
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Affiliation(s)
- R Phillips
- Department of Pathology, University of Missouri, Columbia 65212, USA
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14
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Caro HN, Sheikh NA, Taverne J, Playfair JH, Rademacher TW. Structural similarities among malaria toxins insulin second messengers, and bacterial endotoxin. Infect Immun 1996; 64:3438-41. [PMID: 8757890 PMCID: PMC174245 DOI: 10.1128/iai.64.8.3438-3441.1996] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Malaria toxin causes hypoglycemia and induction of tumor necrosis factor. Extracts of parasitized erythrocytes which were coeluted and copurified with one of the two subtypes of mammalian insulin-mimetic inositolphosphoglycans similarly induced fibroblast proliferation in the absence of serum. In addition, induction of tumor necrosis factor in macrophages by malaria toxin and by lipopolysaccharide from Escherichia coli was enhanced by pretreatment of these toxins with alpha-galactosidase. Thus, parasitized erythrocytes contain both soluble inositolphosphoglycan-like insulin second messengers and endotoxin-like lipidic molecules.
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Affiliation(s)
- H N Caro
- Molecular Medicine Unit, Department of Molecular Pathology, University College London Medical School, United Kingdom
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15
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Abstract
Soluble antigens, enzyme-linked immunosorbent assays (ELISA), and cell suspension assays were used to study the blood group B activity of Glycine max (soybean) alpha-D-galactosidase. The enzyme readily hydrolyzed the terminal alpha-D-galactosyl of the B antigen under a variety of conditions, converting it to H antigen. Conversion of the B antigen to H antigen produces blood type O which is universally transfusable. These preliminary studies are important in determining optimal conditions for enzymatic conversion of blood type B to O erythrocytes if efficient large-scale production of enzymatically converted, universally transfusable red blood cells is to be achieved.
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Affiliation(s)
- L Hobbs
- Department of Pathology, University of Missouri, Columbia 65212, USA
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16
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Abstract
A cDNA encoding coffee bean alpha-galactosidase was subcloned into baculovirus expression vectors, pVL-1393 and pAc-GP67B, for intracellular and extracellular expression in Spodoptera frugiperda (Sf9) insect cells, respectively. The expressed protein (recombinant alpha-galactosidase) was immunologically reactive with antisera raised against its native counterpart isolated from coffee beans and was biologically active towards the substrate p-nitrophenyl alpha-galactopyranoside. The subcellular distribution of recombinant alpha-galactosidase expressed from different vectors was analyzed by Western blotting, immunofluorescent labeling, and electron microscopy. In addition, recombinant alpha-galactosidase was compared to the native enzyme with respect to glycosylation, thermostability, and pH profile. Furthermore, a recombinant alpha-galactosidase molecule with a His6 tag at its C-terminus was constructed by an overlap PCR method so that the enzyme expressed in Sf9 cells can be purified by a simple affinity chromatography procedure.
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Affiliation(s)
- A Zhu
- The Lindsley F. Kimball Research Institute of The New York Blood Center, New York, USA
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17
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Kachurin AM, Golubev AM, Geisow MM, Veselkina OS, Isaeva-Ivanova LS, Neustroev KN. Role of methionine in the active site of alpha-galactosidase from Trichoderma reesei. Biochem J 1995; 308 ( Pt 3):955-64. [PMID: 8948456 PMCID: PMC1136816 DOI: 10.1042/bj3080955] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
alpha-Galactosidase from Trichoderma reesei when treated with H2O2 shows a 12-fold increase in activity towards p-nitrophenyl alpha-D-galactopyranoside. A similar effect is produced by the treatment of alpha-galactosidase with other non-specific oxidants: NaIO4, KMnO4 and K4S4O8. In addition to the increase in activity, the Michaelis constant rises from 0.2 to 1.4 mM, the temperature coefficient decreases by a factor of 1.5 and the pH-activity curve falls off sharply with increasing pH. Galactose (a competitive inhibitor of alpha-galactosidase; Ki 0.09 mM for the native enzyme at pH 4.4) effectively inhibits oxidative activation of the enzyme, because the observed activity changes are related to oxidation of the catalytically important methionine in the active site. NMR measurements and amino acid analysis show that oxidation to methionine sulphoxide of one of five methionines is sufficient to activate alpha-galactosidase. Binding of galactose prevents this. Oxidative activation does not lead to conversion of other H2O2-sensitive amino acid residues, such as histidine, tyrosine, tryptophan and cysteine. The catalytically important cysteine thiol group is quantitatively titrated after protein oxidative activation. Further oxidation of methionines (up to four of five residues) can be achieved by increasing the oxidation time and/or by prior denaturation of the protein. Obviously, a methionine located in the active site of alpha-galactosidase is more accessible. The oxidative-activation phenomenon can be explained by a conformational change in the active site as a result of conversion of non-polar methionine into polar methionine sulphoxide.
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Affiliation(s)
- A M Kachurin
- Department of Molecular and Radiation Biophysics, St. Petersburg Nuclear Physics Institute, Gatchina, Russia
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Phillips R, Mawhinney T, Harmata M, Smith D. Characterization of Gallus domesticus alpha-N-acetyl-galactosaminidase blood group A2 activity. Artif Cells Blood Substit Immobil Biotechnol 1995; 23:63-79. [PMID: 7719446 DOI: 10.3109/10731199509117668] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
Soluble A antigens and an enzyme-linked immunosorbent assay (ELISA) using type A2 erythrocyte membranes were used to study the activity of an alpha-N-acetyl-galactosaminidase from Gallus domesticus (domestic chicken). The enzyme readily hydrolyzed the terminal N-acetyl-alpha-D-galactosamine of the A antigen under a variety of conditions, converting it to H antigen. Conversion of the A antigen to H antigen produces blood type O, which is universally transfusable. These preliminary studies are important in determining optimal conditions for enzymatic conversion of blood type A to O if efficient large scale production of enzymatically converted, universally transfusable red blood cells is to be achieved.
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Affiliation(s)
- R Phillips
- Department of Biochemistry, University of Missouri, Columbia 65212, USA
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19
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Abstract
Conversion of erythrocyte membrane B antigen to H antigen produces blood type O which is universally transfusable. If efficient large-scale production of enzymatically converted red blood cells is to be achieved, then optimal conditions for deantigenation must be determined. Cell suspension assays were used to study the blood group B activity of Glycine max (soybean) alpha-D-galactosidase on native human erythrocytes. The enzyme readily hydrolyzed the terminal alpha-D-galactosyl residue of the B antigen, converting it to H antigen. Optimal conditions for the enzymatic conversion of red cells with the Glycine enzyme are described. Normal cell morphology and function were maintained under optimal conditions.
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Affiliation(s)
- L Hobbs
- Department of Pathology, University of Missouri, Columbia 65212, USA
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20
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Abstract
An enzyme-linked immunosorbent assay (ELISA) for studying erythrocyte A, B and H epitope specific exoglycosidases is described. Human blood type B erythrocyte membranes and Coffea canephora alpha-D-galactosidase were used as a model. Membrane coated microtiter wells were incubated with exoglycosidase, probed with IgM monoclonal antibody, and then with anti-murine mu chain specific alkaline phosphatase conjugate. The assay is useful for studying exoglycosidase modification of the A, B and H epitopes on human erythrocyte membranes as well as in screening prokaryotic and eukaryotic extracts for blood group active enzymes. Furthermore, this technique has the advantage of simplicity, sensitivity, and objectivity of data interpretation.
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Affiliation(s)
- L Hobbs
- Department of Pathology, University of Missouri, Columbia
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