1
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Durgin JS, Thokala R, Johnson L, Song E, Leferovich J, Bhoj V, Ghassemi S, Milone M, Binder Z, O'Rourke DM, O'Connor RS. Enhancing CAR T function with the engineered secretion of C. perfringens neuraminidase. Mol Ther 2022; 30:1201-1214. [PMID: 34813961 PMCID: PMC8899523 DOI: 10.1016/j.ymthe.2021.11.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 10/04/2021] [Accepted: 11/16/2021] [Indexed: 11/16/2022] Open
Abstract
Prior to adoptive transfer, CAR T cells are activated, lentivirally infected with CAR transgenes, and expanded over 9 to 11 days. An unintended consequence of this process is the progressive differentiation of CAR T cells over time in culture. Differentiated T cells engraft poorly, which limits their ability to persist and provide sustained tumor control in hematologic as well as solid tumors. Solid tumors include other barriers to CAR T cell therapies, including immune and metabolic checkpoints that suppress effector function and durability. Sialic acids are ubiquitous surface molecules with known immune checkpoint functions. The enzyme C. perfringens neuraminidase (CpNA) removes sialic acid residues from target cells, with good activity at physiologic conditions. In combination with galactose oxidase (GO), NA has been found to stimulate T cell mitogenesis and cytotoxicity in vitro. Here we determine whether CpNA alone and in combination with GO promotes CAR T cell antitumor efficacy. We show that CpNA restrains CAR T cell differentiation during ex vivo culture, giving rise to progeny with enhanced therapeutic potential. CAR T cells expressing CpNA have superior effector function and cytotoxicity in vitro. In a Nalm-6 xenograft model of leukemia, CAR T cells expressing CpNA show enhanced antitumor efficacy. Arming CAR T cells with CpNA also enhanced tumor control in xenograft models of glioblastoma as well as a syngeneic model of melanoma. Given our findings, we hypothesize that charge repulsion via surface glycans is a regulatory parameter influencing differentiation. As T cells engage target cells within tumors and undergo constitutive activation through their CARs, critical thresholds of negative charge may impede cell-cell interactions underlying synapse formation and cytolysis. Removing the dense pool of negative cell-surface charge with CpNA is an effective approach to limit CAR T cell differentiation and enhance overall persistence and efficacy.
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Affiliation(s)
- Joseph S Durgin
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Radhika Thokala
- Glioblastoma Translational Center of Excellence, The Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA
| | - Lexus Johnson
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Edward Song
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - John Leferovich
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Vijay Bhoj
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Saba Ghassemi
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Michael Milone
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Zev Binder
- Glioblastoma Translational Center of Excellence, The Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Donald M O'Rourke
- Glioblastoma Translational Center of Excellence, The Abramson Cancer Center, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA; Department of Neurosurgery, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA
| | - Roddy S O'Connor
- Center for Cellular Immunotherapies, Perelman School of Medicine at the University of Pennsylvania, 3400 Civic Center Boulevard, Building 421, SPE 8-105, Philadelphia, PA, USA; Department of Pathology & Laboratory Medicine, Perelman School of Medicine at the University of Pennsylvania, Philadelphia, PA, USA.
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2
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Low KE, Smith SP, Abbott DW, Boraston AB. The glycoconjugate-degrading enzymes of Clostridium perfringens: Tailored catalysts for breaching the intestinal mucus barrier. Glycobiology 2020; 31:681-690. [PMID: 32472136 DOI: 10.1093/glycob/cwaa050] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 05/21/2020] [Accepted: 06/01/2020] [Indexed: 01/07/2023] Open
Abstract
The gastrointestinal (GI) tract of humans and animals is lined with mucus that serves as a barrier between the gut microbiota and the epithelial layer of the intestine. As the proteins present in mucus are typically heavily glycosylated, such as the mucins, several enteric commensal and pathogenic bacterial species are well-adapted to this rich carbon source and their genomes are replete with carbohydrate-active enzymes targeted toward dismantling the glycans and proteins present in mucus. One such species is Clostridium perfringens, a Gram-positive opportunistic pathogen indigenous to the gut of humans and animals. The genome of C. perfringens encodes numerous carbohydrate-active enzymes that are predicted or known to target glycosidic linkages within or on the termini of mucus glycans. Through this enzymatic activity, the degradation of the mucosal layer by C. perfringens has been implicated in a number of GI diseases, the most severe of which is necrotic enteritis. In this review, we describe the wide array of extracellular glycoside hydrolases, and their accessory modules, that is possessed by C. perfringens, and examine the unique multimodularity of these proteins in the context of degrading the glycoconjugates in mucus as a potential component of disease.
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Affiliation(s)
- Kristin E Low
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403 1 Ave S, Lethbridge T1J 4B1, Canada
| | - Steven P Smith
- Department of Biomedical and Molecular Sciences, Queen's University, 99 University Ave, Kingston K7L 3N6, Canada
| | - D Wade Abbott
- Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, 5403 1 Ave S, Lethbridge T1J 4B1, Canada
| | - Alisdair B Boraston
- Faculty of Biochemistry and Microbiology, University of Victoria, Victoria V8P 5C2, Canada
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3
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Miyazaki T, Park EY. Crystal structure of the Enterococcus faecalis α-N-acetylgalactosaminidase, a member of the glycoside hydrolase family 31. FEBS Lett 2020; 594:2282-2293. [PMID: 32367553 DOI: 10.1002/1873-3468.13804] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Revised: 04/26/2020] [Accepted: 04/28/2020] [Indexed: 12/15/2022]
Abstract
Glycoside hydrolases catalyze the hydrolysis of glycosidic linkages in carbohydrates. The glycoside hydrolase family 31 (GH31) contains α-glucosidase, α-xylosidase, α-galactosidase, and α-transglycosylase. Recent work has expanded the diversity of substrate specificity of GH31 enzymes, and α-N-acetylgalactosaminidases (αGalNAcases) belonging to GH31 have been identified in human gut bacteria. Here, we determined the first crystal structure of a truncated form of GH31 αGalNAcase from the human gut bacterium Enterococcus faecalis. The enzyme has a similar fold to other reported GH31 enzymes and an additional fibronectin type 3-like domain. Additionally, the structure in complex with N-acetylgalactosamine reveals that conformations of the active site residues, including its catalytic nucleophile, change to recognize the ligand. Our structural analysis provides insight into the substrate recognition and catalytic mechanism of GH31 αGalNAcases.
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Affiliation(s)
- Takatsugu Miyazaki
- Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, Japan
| | - Enoch Y Park
- Green Chemistry Research Division, Research Institute of Green Science and Technology, Shizuoka University, Japan
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4
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Rahfeld P, Withers SG. Toward universal donor blood: Enzymatic conversion of A and B to O type. J Biol Chem 2019; 295:325-334. [PMID: 31792054 DOI: 10.1074/jbc.rev119.008164] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Transfusion of blood, or more commonly red blood cells (RBCs), is integral to health care systems worldwide but requires careful matching of blood types to avoid serious adverse consequences. Of the four main blood types, A, B, AB, and O, only O can be given to any patient. This universal donor O-type blood is crucial for emergency situations where time or resources for typing are limited, so it is often in short supply. A and B blood differ from the O type in the presence of an additional sugar antigen (GalNAc and Gal, respectively) on the core H-antigen found on O-type RBCs. Thus, conversion of A, B, and AB RBCs to O-type RBCs should be achievable by removal of that sugar with an appropriate glycosidase. The first demonstration of a B-to-O conversion by Goldstein in 1982 required massive amounts of enzyme but enabled proof-of-principle transfusions without adverse effects in humans. New α-galactosidases and α-N-acetylgalactosaminidases were identified by screening bacterial libraries in 2007, allowing improved conversion of B and the first useful conversions of A-type RBCs, although under constrained conditions. In 2019, screening of a metagenomic library derived from the feces of an AB donor enabled discovery of a significantly more efficient two-enzyme system, involving a GalNAc deacetylase and a galactosaminidase, for A conversion. This promising system works well both in standard conditions and in whole blood. We discuss remaining challenges and opportunities for the use of such enzymes in blood conversion and organ transplantation.
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Affiliation(s)
- Peter Rahfeld
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Stephen G Withers
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada; Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada; Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.
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5
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Rahfeld P, Wardman JF, Mehr K, Huff D, Morgan-Lang C, Chen HM, Hallam SJ, Withers SG. Prospecting for microbial α- N-acetylgalactosaminidases yields a new class of GH31 O-glycanase. J Biol Chem 2019; 294:16400-16415. [PMID: 31530641 DOI: 10.1074/jbc.ra119.010628] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2019] [Revised: 09/16/2019] [Indexed: 12/18/2022] Open
Abstract
α-Linked GalNAc (α-GalNAc) is most notably found at the nonreducing terminus of the blood type-determining A-antigen and as the initial point of attachment to the peptide backbone in mucin-type O-glycans. However, despite their ubiquity in saccharolytic microbe-rich environments such as the human gut, relatively few α-N-acetylgalactosaminidases are known. Here, to discover and characterize novel microbial enzymes that hydrolyze α-GalNAc, we screened small-insert libraries containing metagenomic DNA from the human gut microbiome. Using a simple fluorogenic glycoside substrate, we identified and characterized a glycoside hydrolase 109 (GH109) that is active on blood type A-antigen, along with a new subfamily of glycoside hydrolase 31 (GH31) that specifically cleaves the initial α-GalNAc from mucin-type O-glycans. This represents a new activity in this GH family and a potentially useful new enzyme class for analysis or modification of O-glycans on protein or cell surfaces.
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Affiliation(s)
- Peter Rahfeld
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada .,Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Jacob F Wardman
- Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Life Sciences Centre, Vancouver, British Columbia V6T 1Z3, Canada
| | - Kevin Mehr
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Drew Huff
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.,Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Connor Morgan-Lang
- Department of Microbiology and Immunology, University of British Columbia, Life Sciences Centre, Vancouver, British Columbia V6T 1Z3, Canada.,Graduate Program in Bioinformatics, University of British Columbia, Genome Sciences Centre, Vancouver, British Columbia V5Z 4S6, Canada
| | - Hong-Ming Chen
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada
| | - Steven J Hallam
- Department of Microbiology and Immunology, University of British Columbia, Life Sciences Centre, Vancouver, British Columbia V6T 1Z3, Canada.,Graduate Program in Bioinformatics, University of British Columbia, Genome Sciences Centre, Vancouver, British Columbia V5Z 4S6, Canada.,ECOSCOPE Training Program, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada.,Peter Wall Institute for Advanced Studies, University of British Columbia, Vancouver, British Columbia V6T 1Z1, Canada
| | - Stephen G Withers
- Department of Chemistry, University of British Columbia, Vancouver, British Columbia V6T 1Z3, Canada .,Michael Smith Laboratories, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada.,Department of Biochemistry and Molecular Biology, University of British Columbia, Life Sciences Centre, Vancouver, British Columbia V6T 1Z3, Canada
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6
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Enzymatic Conversion of RBCs by α-N-Acetylgalactosaminidase from Spirosoma linguale. Enzyme Res 2019; 2019:6972835. [PMID: 31186954 PMCID: PMC6521355 DOI: 10.1155/2019/6972835] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2019] [Accepted: 03/06/2019] [Indexed: 11/25/2022] Open
Abstract
Spirosoma linguale is a free-living nonpathogenic organism. Like many other bacteria, S. linguale produces a cell-associated α-N-acetylgalactosaminidase. This work was undertaken to elucidate the nature of this activity. The recombinant enzyme was produced, purified, and examined for biochemical attributes. The purified enzyme was ~50 kDa active as a homodimer in solution. It catalyzed hydrolysis of α-N-acetylgalactosamine at pH 7. Calculated KM was 1.1 mM with kcat of 173 s−1. The described enzyme belongs to the GH109 family.
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7
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Reyes Martínez JE, Šardzík R, Voglmeir J, Flitsch SL. Enzymatic synthesis of colorimetric substrates to determine α-2,3- and α-2,6-specific neuraminidase activity. RSC Adv 2013. [DOI: 10.1039/c3ra44791j] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023] Open
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8
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Nakai H, Baumann MJ, Petersen BO, Westphal Y, Hachem MA, Dilokpimol A, Duus JØ, Schols HA, Svensson B. Aspergillus nidulans alpha-galactosidase of glycoside hydrolase family 36 catalyses the formation of alpha-galacto-oligosaccharides by transglycosylation. FEBS J 2010; 277:3538-51. [PMID: 20681989 DOI: 10.1111/j.1742-4658.2010.07763.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The alpha-galactosidase from Aspergillus nidulans (AglC) belongs to a phylogenetic cluster containing eukaryotic alpha-galactosidases and alpha-galacto-oligosaccharide synthases of glycoside hydrolase family 36 (GH36). The recombinant AglC, produced in high yield (0.65 g.L(-1) culture) as His-tag fusion in Escherichia coli, catalysed efficient transglycosylation with alpha-(1-->6) regioselectivity from 40 mm 4-nitrophenol alpha-d-galactopyranoside, melibiose or raffinose, resulting in a 37-74% yield of 4-nitrophenol alpha-D-Galp-(1-->6)-D-Galp, alpha-D-Galp-(1-->6)-alpha-D-Galp-(1-->6)-D-Glcp and alpha-D-Galp-(1-->6)-alpha-D-Galp-(1-->6)-D-Glcp-(alpha1-->beta2)-d-Fruf (stachyose), respectively. Furthermore, among 10 monosaccharide acceptor candidates (400 mm) and the donor 4-nitrophenol alpha-D-galactopyranoside (40 mm), alpha-(1-->6) linked galactodisaccharides were also obtained with galactose, glucose and mannose in high yields of 39-58%. AglC did not transglycosylate monosaccharides without the 6-hydroxymethyl group, i.e. xylose, L-arabinose, L-fucose and L-rhamnose, or with axial 3-OH, i.e. gulose, allose, altrose and L-rhamnose. Structural modelling using Thermotoga maritima GH36 alpha-galactosidase as the template and superimposition of melibiose from the complex with human GH27 alpha-galactosidase supported that recognition at subsite +1 in AglC presumably requires a hydrogen bond between 3-OH and Trp358 and a hydrophobic environment around the C-6 hydroxymethyl group. In addition, successful transglycosylation of eight of 10 disaccharides (400 mm), except xylobiose and arabinobiose, indicated broad specificity for interaction with the +2 subsite. AglC thus transferred alpha-galactosyl to 6-OH of the terminal residue in the alpha-linked melibiose, maltose, trehalose, sucrose and turanose in 6-46% yield and the beta-linked lactose, lactulose and cellobiose in 28-38% yield. The product structures were identified using NMR and ESI-MS and five of the 13 identified products were novel, i.e. alpha-D-Galp-(1-->6)-D-Manp; alpha-D-Galp-(1-->6)-beta-D-Glcp-(1-->4)-D-Glcp; alpha-D-Galp-(1-->6)-beta-D-Galp-(1-->4)-D-Fruf; alpha-D-Galp-(1-->6)-D-Glcp-(alpha1-->alpha1)-D-Glcp; and alpha-D-Galp-(1-->6)-alpha-D-Glcp-(1-->3)-D-Fruf.
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Affiliation(s)
- Hiroyuki Nakai
- Enzyme and Protein Chemistry, Department of Systems Biology, Technical University of Denmark, Lyngby, Denmark
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9
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The -galactosidase type A gene aglA from Aspergillus niger encodes a fully functional -N-acetylgalactosaminidase. Glycobiology 2010; 20:1410-9. [DOI: 10.1093/glycob/cwq105] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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10
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Hsieh HY, Hsin-Yeh H, Chapman LF, Calcutt MJ, Mitra M, Smith DS. RecombinantClostridium perfringensalpha-N-Acetylgalactosaminidase Blood Group A2Degrading Activity. ACTA ACUST UNITED AC 2009; 33:187-99. [PMID: 15960079 DOI: 10.1081/bio-200055904] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Affiliation(s)
- Hsin-Yeh Hsieh
- Division of Biological Sciences, University of Missouri-Columbia, USA
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11
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Reilly TJ, Chance DL, Calcutt MJ, Tanner JJ, Felts RL, Waller SC, Henzl MT, Mawhinney TP, Ganjam IK, Fales WH. Characterization of a unique class C acid phosphatase from Clostridium perfringens. Appl Environ Microbiol 2009; 75:3745-54. [PMID: 19363079 PMCID: PMC2687270 DOI: 10.1128/aem.01599-08] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2008] [Accepted: 03/29/2009] [Indexed: 11/20/2022] Open
Abstract
Clostridium perfringens is a gram-positive anaerobe and a pathogen of medical importance. The detection of acid phosphatase activity is a powerful diagnostic indicator of the presence of C. perfringens among anaerobic isolates; however, characterization of the enzyme has not previously been reported. Provided here are details of the characterization of a soluble recombinant form of this cell-associated enzyme. The denatured enzyme was approximately 31 kDa and a homodimer in solution. It catalyzed the hydrolysis of several substrates, including para-nitrophenyl phosphate, 4-methylumbelliferyl phosphate, and 3' and 5' nucleoside monophosphates at pH 6. Calculated K(m)s ranged from 0.2 to 0.6 mM with maximum velocity ranging from 0.8 to 1.6 micromol of P(i)/s/mg. Activity was enhanced in the presence of some divalent cations but diminished in the presence of others. Wild-type enzyme was detected in all clinical C. perfringens isolates tested and found to be cell associated. The described enzyme belongs to nonspecific acid phosphatase class C but is devoid of lipid modification commonly attributed to this class.
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Affiliation(s)
- Thomas J Reilly
- Department of Veterinary Pathobiology, University of Missouri, Columbia, 65211, USA.
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13
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Weignerová L, Filipi T, Manglová D, Křen V. Induction, purification and characterization of α-N-acetylgalactosaminidase from Aspergillus Niger. Appl Microbiol Biotechnol 2008; 79:769-74. [DOI: 10.1007/s00253-008-1485-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2008] [Revised: 03/31/2008] [Accepted: 03/31/2008] [Indexed: 11/24/2022]
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14
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Tang JB, Yang HM, Song SL, Zhu P, Ji AG. Effect of Glycine and Triton X-100 on secretion and expression of ZZ–EGFP fusion protein. Food Chem 2008; 108:657-62. [DOI: 10.1016/j.foodchem.2007.11.034] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2007] [Revised: 11/01/2007] [Accepted: 11/15/2007] [Indexed: 10/22/2022]
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15
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Garratty G. Modulating the red cell membrane to produce universal/stealth donor red cells suitable for transfusion. Vox Sang 2007; 94:87-95. [PMID: 18034787 DOI: 10.1111/j.1423-0410.2007.01003.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Two approaches have been used to produce universal group O donor red blood cells (RBCs) from groups A, B, and AB RBCs. The first involves cleavage of the terminal immunodominant sugars from carbohydrate chains on the RBC membrane, using specific enzymes, to produce so-called enzyme-converted group O (ECO) RBCs. ECO RBCs have been produced from whole units of B RBCs and transfused successfully to humans. Group A RBCs (especially A(1) RBCs) have been more difficult. New sources of enzymes have produced ECO RBCs from A(1) and A(2) RBCs that do not react with powerful monoclonal anti-A. Unfortunately, there are still problems encountered with polyclonal human antibodies (i.e. cross-matching). The second approach interferes with an antibody reaching its specific antigen on the RBC membrane by bonding polyethylene glycol (PEG) to the RBC. PEG will attract water molecules, yielding a combination that may block most RBC antigens, including A and B antigens. Initial excitement generated by preliminary reports of the possibility of producing 'stealth' PEG-RBCs were tempered by the findings of in vitro serological problems and possible reduced in vivo RBC survival. Many of these problems were solved, but recent findings that PEG is immunogenic in animals and humans, and that PEG antibodies can shorten the survival of PEG-RBCs (in rabbits) and pegylated proteins (e.g. PEG-asparaginase) in humans, are disturbing, suggesting that 'stealth' RBCs may never become a reality.
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Affiliation(s)
- G Garratty
- American Red Cross Blood Services, Southern California Region, Pomona, CA 91768, USA.
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