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Rosenau J, Grothaus IL, Yang Y, Kumar ND, Ciacchi LC, Kelm S, Waespy M. N-glycosylation modulates enzymatic activity of Trypanosoma congolense trans-sialidase. J Biol Chem 2022; 298:102403. [PMID: 35995210 PMCID: PMC9493392 DOI: 10.1016/j.jbc.2022.102403] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Revised: 08/15/2022] [Accepted: 08/16/2022] [Indexed: 11/24/2022] Open
Abstract
Trypanosomes cause the devastating disease trypanosomiasis, in which the action of trans-sialidase (TS) enzymes harbored on their surface is a key virulence factor. TS enzymes are N-glycosylated, but the biological functions of their glycans have remained elusive. In this study, we investigated the influence of N-glycans on the enzymatic activity and structural stability of TconTS1, a recombinant TS from the African parasite Trypanosoma congolense. We expressed the enzyme in Chinese hamster ovary Lec1 cells, which produce high-mannose type N-glycans similar to the TS N-glycosylation pattern in vivo. Our MALDI-TOF mass spectrometry data revealed that up to eight putative N-glycosylation sites were glycosylated. In addition, we determined that N-glycan removal via endoglycosidase Hf treatment of TconTS1 led to a decrease in substrate affinity relative to the untreated enzyme but had no impact on the conversion rate. Furthermore, we observed no changes in secondary structure elements of hypoglycosylated TconTS1 in CD experiments. Finally, our molecular dynamics simulations provided evidence for interactions between monosaccharide units of the highly flexible N-glycans and some conserved amino acids located at the catalytic site. These interactions led to conformational changes, possibly enhancing substrate accessibility and enzyme–substrate complex stability. The here-observed modulation of catalytic activity via N-glycans represents a so-far-unknown structure–function relationship potentially inherent in several members of the TS enzyme family.
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Affiliation(s)
- Jana Rosenau
- University of Bremen, Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, 28359 Bremen, Germany
| | - Isabell Louise Grothaus
- University of Bremen, Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, 28359 Bremen, Germany; University of Bremen, Hybrid Materials Interfaces Group, Faculty of Production Engineering, Bremen Center for Computational Materials Science, Center for Environmental Research and Sustainable Technology (UFT), and MAPEX Center for Materials and Processes, 28359 Bremen, Germany
| | - Yikun Yang
- University of Bremen, Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, 28359 Bremen, Germany
| | - Nilima Dinesh Kumar
- University of Bremen, Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, 28359 Bremen, Germany
| | - Lucio Colombi Ciacchi
- University of Bremen, Hybrid Materials Interfaces Group, Faculty of Production Engineering, Bremen Center for Computational Materials Science, Center for Environmental Research and Sustainable Technology (UFT), and MAPEX Center for Materials and Processes, 28359 Bremen, Germany
| | - Sørge Kelm
- University of Bremen, Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, 28359 Bremen, Germany
| | - Mario Waespy
- University of Bremen, Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, 28359 Bremen, Germany.
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de Lederkremer RM, Giorgi ME, Agusti R. trans-Sialylation: a strategy used to incorporate sialic acid into oligosaccharides. RSC Chem Biol 2022; 3:121-139. [PMID: 35360885 PMCID: PMC8827155 DOI: 10.1039/d1cb00176k] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 11/20/2021] [Indexed: 01/02/2023] Open
Abstract
Sialic acid, as a component of cell surface glycoconjugates, plays a crucial role in recognition events. Efficient synthetic methods are necessary for the supply of sialosides in enough quantities for biochemical and immunological studies. Enzymatic glycosylations obviate the steps of protection and deprotection of the constituent monosaccharides required in a chemical synthesis. Sialyl transferases with CMP-Neu5Ac as an activated donor were used for the construction of α2-3 or α2-6 linkages to terminal galactose or N-acetylgalactosamine units. trans-Sialidases may transfer sialic acid from a sialyl glycoside to a suitable acceptor and specifically construct a Siaα2-3Galp linkage. The trans-sialidase of Trypanosoma cruzi (TcTS), which fulfills an important role in the pathogenicity of the parasite, is the most studied one. The recombinant enzyme was used for the sialylation of β-galactosyl oligosaccharides. One of the main advantages of trans-sialylation is that it circumvents the use of the high energy nucleotide. Easily available glycoproteins with a high content of sialic acid such as fetuin and bovine κ-casein-derived glycomacropeptide (GMP) have been used as donor substrates. Here we review the trans-sialidase from various microorganisms and describe their application for the synthesis of sialooligosaccharides.
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Affiliation(s)
- Rosa M de Lederkremer
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Universidad de Buenos Aires Buenos Aires Argentina
- CONICET - Universidad de Buenos Aires, Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR) Buenos Aires Argentina
| | - María Eugenia Giorgi
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Universidad de Buenos Aires Buenos Aires Argentina
- CONICET - Universidad de Buenos Aires, Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR) Buenos Aires Argentina
| | - Rosalía Agusti
- Facultad de Ciencias Exactas y Naturales, Departamento de Química Orgánica, Universidad de Buenos Aires Buenos Aires Argentina
- CONICET - Universidad de Buenos Aires, Centro de Investigaciones en Hidratos de Carbono (CIHIDECAR) Buenos Aires Argentina
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Waespy M, Gbem TT, Dinesh Kumar N, Solaiyappan Mani S, Rosenau J, Dietz F, Kelm S. Cooperativity of catalytic and lectin-like domain of Trypanosoma congolense trans-sialidase modulates its catalytic activity. PLoS Negl Trop Dis 2022; 16:e0009585. [PMID: 35130274 PMCID: PMC8865650 DOI: 10.1371/journal.pntd.0009585] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 02/23/2022] [Accepted: 01/23/2022] [Indexed: 12/15/2022] Open
Abstract
Trans-sialidases (TS) represent a multi-gene family of unusual enzymes, which catalyse the transfer of terminal sialic acids (Sia) from sialoglycoconjugates to terminal galactose or N-acetylgalactosamine residues of oligosaccharides without the requirement of CMP-Neu5Ac, the activated Sia used by typical sialyltransferases. Enzymes comprise a N-terminal catalytic domain (CD) followed by a lectin-like domain (LD). Most work on trypanosomal TS has been done on enzymatic activities focusing on the CD of TS from Trypanosoma cruzi (causing Chagas disease in Latin America), subspecies of Trypanosoma brucei, (causing human sleeping sickness in Africa) and Trypanosoma congolense (causing African Animal Trypanosomosis in livestock). Previously, we demonstrated that T. congolense TS (TconTS)-LD binds to several carbohydrates, such as 1,4-β-mannotriose. In this study we investigated the influence of TconTS3-LD on Sia transfer efficiency of TconTS1a-CD by swapping domains. in silico analysis on structure models of TconTS enzymes revealed the potential of domain swaps between TconTS1a and TconTS3 without structural disruptions of the enzymes overall topologies. Recombinant domain swapped TconTS1a/TS3 showed clear Sia transfer activity, when using fetuin and lactose as Sia donor and acceptor substrates, respectively. While Sia transfer activity remained unchanged from the level of TconTS1a, hydrolytic release of free Neu5Ac as a side product was suppressed resulting in increased transfer efficiency. Presence of 1,4-β-mannotriose during TS reactions modulates enzyme activities enhancing transfer efficiency possibly due to occupation of the binding site in TconTS1a-LD. Interestingly this effect was in the same range as that observed when swapping TconTS1a-CD and TconTS3-LD. In summary, this study demonstrate the proof-of-principle for swapping CDs and LDs of TconTS and that TconTS3-LD influences enzymatic activity of TconTS1a-CD providing evidence that LDs play pivotal roles in modulating activities and biological functions of TconTS and possibly other TS.
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Affiliation(s)
- Mario Waespy
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
| | - Thaddeus Termulun Gbem
- Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria, Africa
- Department of Biology, Ahmadu Bello University, Zaria, Nigeria, Africa
| | - Nilima Dinesh Kumar
- Department of Biomedical Sciences of Cells and Systems, University Medical Center Groningen, University of Groningen, Groningen, Netherlands
| | - Shanmugam Solaiyappan Mani
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
| | - Jana Rosenau
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
| | - Frank Dietz
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
| | - Sørge Kelm
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
- Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria, Africa
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da Fonseca LM, da Costa KM, Chaves VDS, Freire-de-Lima CG, Morrot A, Mendonça-Previato L, Previato JO, Freire-de-Lima L. Theft and Reception of Host Cell's Sialic Acid: Dynamics of Trypanosoma Cruzi Trans-sialidases and Mucin-Like Molecules on Chagas' Disease Immunomodulation. Front Immunol 2019; 10:164. [PMID: 30787935 PMCID: PMC6372544 DOI: 10.3389/fimmu.2019.00164] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2018] [Accepted: 01/18/2019] [Indexed: 12/27/2022] Open
Abstract
The last decades have produced a plethora of evidence on the role of glycans, from cell adhesion to signaling pathways. Much of that information pertains to their role on the immune system and their importance on the surface of many human pathogens. A clear example of this is the flagellated protozoan Trypanosoma cruzi, which displays on its surface a great variety of glycoconjugates, including O-glycosylated mucin-like glycoproteins, as well as multiple glycan-binding proteins belonging to the trans-sialidase (TS) family. Among the latter, different and concurrently expressed molecules may present or not TS activity, and are accordingly known as active (aTS) and inactive (iTS) members. Over the last thirty years, it has been well described that T. cruzi is unable to synthesize sialic acid (SIA) on its own, making use of aTS to steal the host's SIA. Although iTS did not show enzymatic activity, it retains a substrate specificity similar to aTS (α-2,3 SIA-containing glycotopes), displaying lectinic properties. It is accepted that aTS members act as virulence factors in mammals coursing the acute phase of the T. cruzi infection. However, recent findings have demonstrated that iTS may also play a pathogenic role during T. cruzi infection, since it modulates events related to adhesion and invasion of the parasite into the host cells. Since both aTS and iTS proteins share structural substrate specificity, it might be plausible to speculate that iTS proteins are able to assuage and/or attenuate biological phenomena depending on the catalytic activity displayed by aTS members. Since SIA-containing glycotopes modulate the host immune system, it should not come as any surprise that changes in the sialylation of parasite's mucin-like molecules, as well as host cell glycoconjugates might disrupt critical physiological events, such as the building of effective immune responses. This review aims to discuss the importance of mucin-like glycoproteins and both aTS and iTS for T. cruzi biology, as well as to present a snapshot of how disturbances in both parasite and host cell sialoglycophenotypes may facilitate the persistence of T. cruzi in the infected mammalian host.
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Affiliation(s)
- Leonardo Marques da Fonseca
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Kelli Monteiro da Costa
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Victoria de Sousa Chaves
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Célio Geraldo Freire-de-Lima
- Laboratório de Imunomodulação, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Alexandre Morrot
- Laboratório de Pesquisa em Tuberculose, Faculdade de Medicina, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil.,Laboratório de Imunoparasitologia, Fundação Oswaldo Cruz, Rio de Janeiro, Brazil
| | - Lucia Mendonça-Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Jose Osvaldo Previato
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Leonardo Freire-de-Lima
- Laboratório de Glicobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil
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5
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Teixeira AF, Pereira JG, Pestana-Ascensão S, Silva MS. Trans-sialidase Protein as a Potential Serological Marker for African Trypanosomiasis. Protein J 2019; 38:50-57. [PMID: 30604107 DOI: 10.1007/s10930-018-09808-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Trypanosoma brucei is the etiological agent of African trypanosomiasis responsible for human and animal infections. T. brucei is transmitted by infected tsetse flies. There is no vaccine for the disease and drugs available for treatment are inefficient and high toxicity. In this context, it is a priority to find antigenic targets suitable for the development of new diagnostic tools, drugs and vaccines. In this work, we report that mice infected with T. b. brucei produce antibodies against trans-sialidase recombinant protein (TS). In addition, we also demonstrate that bloodstream T. b. brucei express messenger RNA related to the TS gene. Collectively, our data strongly suggest that bloodstream forms of T. b. brucei also express the TS gene, that to date was described only in the procyclic forms of the T. b. brucei. In conclusion, these results highlight the importance of TS protein as a possible antigen target during infection caused by T. b. brucei.
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Affiliation(s)
- Ana Filipa Teixeira
- Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Lisbon, Portugal
| | - João Gomes Pereira
- Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Sónia Pestana-Ascensão
- Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Lisbon, Portugal
| | - Marcelo Sousa Silva
- Global Health and Tropical Medicine, Institute of Hygiene and Tropical Medicine, Universidade Nova de Lisboa, Lisbon, Portugal. .,Immunoparasitology Laboratory, Department of Clinical and Toxicological Analysis, Federal University of Rio Grande do Norte, Natal, Brazil. .,Programa de Pós-graduação em Bioquímica, Centro de Biociências, Federal University of Rio Grande do Norte, Natal, Brazil. .,Programa de Pós-graduação em Ciências Farmacêuticas, Centro de Ciências da Saúde, Federal University of Rio Grande do Norte, Natal, Brazil.
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6
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Abstract
Sialic acids are cytoprotectors, mainly localized on the surface of cell membranes with multiple and outstanding cell biological functions. The history of their structural analysis, occurrence, and functions is fascinating and described in this review. Reports from different researchers on apparently similar substances from a variety of biological materials led to the identification of a 9-carbon monosaccharide, which in 1957 was designated "sialic acid." The most frequently occurring member of the sialic acid family is N-acetylneuraminic acid, followed by N-glycolylneuraminic acid and O-acetylated derivatives, and up to now over about 80 neuraminic acid derivatives have been described. They appeared first in the animal kingdom, ranging from echinoderms up to higher animals, in many microorganisms, and are also expressed in insects, but are absent in higher plants. Sialic acids are masks and ligands and play as such dual roles in biology. Their involvement in immunology and tumor biology, as well as in hereditary diseases, cannot be underestimated. N-Glycolylneuraminic acid is very special, as this sugar cannot be expressed by humans, but is a xenoantigen with pathogenetic potential. Sialidases (neuraminidases), which liberate sialic acids from cellular compounds, had been known from very early on from studies with influenza viruses. Sialyltransferases, which are responsible for the sialylation of glycans and elongation of polysialic acids, are studied because of their significance in development and, for instance, in cancer. As more information about the functions in health and disease is acquired, the use of sialic acids in the treatment of diseases is also envisaged.
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Affiliation(s)
- Roland Schauer
- Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, Kiel, Germany.
| | - Johannis P Kamerling
- Bijvoet Center for Biomolecular Research, Utrecht University, Utrecht, The Netherlands.
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Kashif M, Moreno-Herrera A, Lara-Ramirez EE, Ramírez-Moreno E, Bocanegra-García V, Ashfaq M, Rivera G. Recent developments in trans-sialidase inhibitors of Trypanosoma cruzi. J Drug Target 2017; 25:485-498. [DOI: 10.1080/1061186x.2017.1289539] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Muhammad Kashif
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa, Mexico
| | | | | | - Esther Ramírez-Moreno
- Escuela Nacional de Medicina y Homeopatía, Instituto Politécnico Nacional, Ciudad de Mexico, Mexico
| | | | - Muhammad Ashfaq
- Department of Chemistry, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Gildardo Rivera
- Centro de Biotecnología Genómica, Instituto Politécnico Nacional, Reynosa, Mexico
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Waespy M, Gbem TT, Elenschneider L, Jeck AP, Day CJ, Hartley-Tassell L, Bovin N, Tiralongo J, Haselhorst T, Kelm S. Carbohydrate Recognition Specificity of Trans-sialidase Lectin Domain from Trypanosoma congolense. PLoS Negl Trop Dis 2015; 9:e0004120. [PMID: 26474304 PMCID: PMC4608562 DOI: 10.1371/journal.pntd.0004120] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Accepted: 09/05/2015] [Indexed: 12/18/2022] Open
Abstract
Fourteen different active Trypanosoma congolense trans-sialidases (TconTS), 11 variants of TconTS1 besides TconTS2, TconTS3 and TconTS4, have been described. Notably, the specific transfer and sialidase activities of these TconTS differ by orders of magnitude. Surprisingly, phylogenetic analysis of the catalytic domains (CD) grouped each of the highly active TconTS together with the less active enzymes. In contrast, when aligning lectin-like domains (LD), the highly active TconTS grouped together, leading to the hypothesis that the LD of TconTS modulates its enzymatic activity. So far, little is known about the function and ligand specificity of these LDs. To explore their carbohydrate-binding potential, glycan array analysis was performed on the LD of TconTS1, TconTS2, TconTS3 and TconTS4. In addition, Saturation Transfer Difference (STD) NMR experiments were done on TconTS2-LD for a more detailed analysis of its lectin activity. Several mannose-containing oligosaccharides, such as mannobiose, mannotriose and higher mannosylated glycans, as well as Gal, GalNAc and LacNAc containing oligosaccharides were confirmed as binding partners of TconTS1-LD and TconTS2-LD. Interestingly, terminal mannose residues are not acceptor substrates for TconTS activity. This indicates a different, yet unknown biological function for TconTS-LD, including specific interactions with oligomannose-containing glycans on glycoproteins and GPI anchors found on the surface of the parasite, including the TconTS itself. Experimental evidence for such a scenario is presented.
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Affiliation(s)
- Mario Waespy
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
| | - Thaddeus T. Gbem
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
- Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria
| | - Leroy Elenschneider
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
| | - André-Philippe Jeck
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
| | - Christopher J. Day
- Institute for Glycomics, Griffith University Gold Coast Campus, Queensland, Australia
| | | | - Nicolai Bovin
- Shemyakin Institute of Bioorganic Chemistry, Russian Academy of Sciences, Moscow, Russia
| | - Joe Tiralongo
- Institute for Glycomics, Griffith University Gold Coast Campus, Queensland, Australia
| | - Thomas Haselhorst
- Institute for Glycomics, Griffith University Gold Coast Campus, Queensland, Australia
| | - Sørge Kelm
- Centre for Biomolecular Interactions Bremen, Faculty for Biology and Chemistry, University Bremen, Bremen, Germany
- Africa Centre of Excellence for Neglected Tropical Diseases and Forensic Biotechnology, Ahmadu Bello University, Zaria, Nigeria
- Institute for Glycomics, Griffith University Gold Coast Campus, Queensland, Australia
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Galactosyl-lactose sialylation using Trypanosoma cruzi trans-sialidase as the biocatalyst and bovine κ-casein-derived glycomacropeptide as the donor substrate. Appl Environ Microbiol 2014; 80:5984-91. [PMID: 25063655 DOI: 10.1128/aem.01465-14] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
trans-Sialidase (TS) enzymes catalyze the transfer of sialyl (Sia) residues from Sia(α2-3)Gal(β1-x)-glycans (sialo-glycans) to Gal(β1-x)-glycans (asialo-glycans). Aiming to apply this concept for the sialylation of linear and branched (Gal)nGlc oligosaccharide mixtures (GOS) using bovine κ-casein-derived glycomacropeptide (GMP) as the sialic acid donor, a kinetic study has been carried out with three components of GOS, i.e., 3'-galactosyl-lactose (β3'-GL), 4'-galactosyl-lactose (β4'-GL), and 6'-galactosyl-lactose (β6'-GL). This prebiotic GOS is prepared from lactose by incubation with suitable β-galactosidases, whereas GMP is a side-stream product of the dairy industry. The trans-sialidase from Trypanosoma cruzi (TcTS) was expressed in Escherichia coli and purified. Its temperature and pH optima were determined to be 25°C and pH 5.0, respectively. GMP [sialic acid content, 3.6% (wt/wt); N-acetylneuraminic acid (Neu5Ac), >99%; (α2-3)-linked Neu5Ac, 59%] was found to be an efficient sialyl donor, and up to 95% of the (α2-3)-linked Neu5Ac could be transferred to lactose when a 10-fold excess of this acceptor substrate was used. The products of the TcTS-catalyzed sialylation of β3'-GL, β4'-GL, and β6'-GL, using GMP as the sialic acid donor, were purified, and their structures were elucidated by nuclear magnetic resonance spectroscopy. Monosialylated β3'-GL and β4'-GL contained Neu5Ac connected to the terminal Gal residue; however, in the case of β6'-GL, TcTS was shown to sialylate the 3 position of both the internal and terminal Gal moieties, yielding two different monosialylated products and a disialylated structure. Kinetic analyses showed that TcTS had higher affinity for the GL substrates than lactose, while the Vmax and kcat values were higher in the case of lactose.
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Biochemical diversity in the Trypanosoma congolense trans-sialidase family. PLoS Negl Trop Dis 2013; 7:e2549. [PMID: 24340108 PMCID: PMC3855035 DOI: 10.1371/journal.pntd.0002549] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2013] [Accepted: 10/04/2013] [Indexed: 02/01/2023] Open
Abstract
Trans-sialidases are key enzymes in the life cycle of African trypanosomes in both, mammalian host and insect vector and have been associated with the disease trypanosomiasis, namely sleeping sickness and nagana. Besides the previously reported TconTS1, we have identified three additional active trans-sialidases, TconTS2, TconTS3 and TconTS4, and three trans-sialidase like genes in Trypanosoma congolense. At least TconTS1, TconTS2 and TconTS4 are found in the bloodstream of infected animals. We have characterised the enzymatic properties of recombinant proteins expressed in eukaryotic fibroblasts using fetuin as model blood glycoprotein donor substrate. One of the recombinant trans-sialidases, TconTS2, had the highest specific activity reported thus far with very low sialidase activity. The active trans-sialidases share all the amino acids critical for the catalytic reaction with few variations in the predicted binding site for the leaving or acceptor glycan. However, these differences cannot explain the orders of magnitudes between their transfer activities, which must be due to other unidentified structural features of the proteins or substrates selectivity. Interestingly, the phylogenetic relationships between the lectin domains correlate with their specific trans-sialylation activities. This raises the question whether and how the lectin domains regulate the trans-sialidase reaction. The identification and enzymatic characterisation of the trans-sialidase family in T. congolense will contribute significantly towards the understanding of the roles of these enzymes in the pathogenesis of Animal African Trypanosomiasis. Trypanosomiasis is a disease also known as sleeping sickness in humans (Human African Trypanosomiasis) and nagana in animals (Animal African Trypanosomiasis). This disease is caused by protozoan parasites of the genus Trypanosoma. Tsetse flies are responsible for the transmission of these parasites. Trypanosoma congolense is the main causative agent of nagana in cattle. The clinical signs of the disease have been linked to the presence of an enzyme called trans-sialidase. Interestingly, the enzyme alternates in different forms in the mammalian and the insect vector. Previous knowledge had shown that the parasite requires the enzyme for survival in the fly vector. Our current work has revealed other forms of the enzyme that could be essential for the persistence of the disease in mammalian and vector hosts. These enzymes, though similar in structural architecture, show differences in their activities that could be key in delineating their individual roles in the pathophysiology of the disease.
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11
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Identification of trans-sialidases as a common mediator of endothelial cell activation by African trypanosomes. PLoS Pathog 2013; 9:e1003710. [PMID: 24130501 PMCID: PMC3795030 DOI: 10.1371/journal.ppat.1003710] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2013] [Accepted: 08/30/2013] [Indexed: 12/31/2022] Open
Abstract
Understanding African Trypanosomiasis (AT) host-pathogen interaction is the key to an "anti-disease vaccine", a novel strategy to control AT. Here we provide a better insight into this poorly described interaction by characterizing the activation of a panel of endothelial cells by bloodstream forms of four African trypanosome species, known to interact with host endothelium. T. congolense, T. vivax, and T. b. gambiense activated the endothelial NF-κB pathway, but interestingly, not T. b. brucei. The parasitic TS (trans-sialidases) mediated this NF-κB activation, remarkably via their lectin-like domain and induced production of pro-inflammatory molecules not only in vitro but also in vivo, suggesting a considerable impact on pathogenesis. For the first time, TS activity was identified in T. b. gambiense BSF which distinguishes it from the subspecies T. b. brucei. The corresponding TS were characterized and shown to activate endothelial cells, suggesting that TS represent a common mediator of endothelium activation among trypanosome species with divergent physiopathologies.
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Shkandina T, Herrmann M, Bilyy R. Sweet kiss of dying cell: sialidase activity on apoptotic cell is able to act toward its neighbors. Autoimmunity 2012; 45:574-8. [PMID: 22928616 DOI: 10.3109/08916934.2012.719951] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Apoptotic cells and subcellular microparticles expose increased sialidase activity on their surfaces, which results from caspase-3 dependent activation of plasma membrane associated Neuraminidase-1 (Neu1). Desialylation of dying cells is also known to promote efferocytosis. The intriguing question remained whether sialidase on the surface of dying cell merely acts on self targets (cis-action), or whether it can also cleave glycoepitopes of neighboring cells (trans-action). Here, we co-incubated human viable and apoptotic Jurkat lymphocytes or neutrophils with human erythrocytes and evaluated their glycoprofile for terminal sialic acids by agglutination assay, flow cytometry, ELISA and dot-blot analyses. Data suggest that erythrocytes were desialylated as soon as 3 hours after co-incubation with apoptotic cells, but not with viable ones. After co-incubation of L929 murine fibroblasts with viable or apoptotic murine L1210 cells the L929 cells gained a desialylated glycoprofile, only after co-incubation with apoptotic cells. Our data suggests that activated sialidase(s) on the surfaces of apoptotic cells are capable to desialylate neighboring cells in trans.
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Affiliation(s)
- Tanya Shkandina
- Institute of Cell Biology, National Academy of Sciences of Ukraine, Lviv, Ukraine
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13
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Sialic acid metabolism and sialyltransferases: natural functions and applications. Appl Microbiol Biotechnol 2012; 94:887-905. [PMID: 22526796 DOI: 10.1007/s00253-012-4040-1] [Citation(s) in RCA: 187] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2012] [Revised: 03/16/2012] [Accepted: 03/16/2012] [Indexed: 12/17/2022]
Abstract
Sialic acids are a family of negatively charged monosaccharides which are commonly presented as the terminal residues in glycans of the glycoconjugates on eukaryotic cell surface or as components of capsular polysaccharides or lipooligosaccharides of some pathogenic bacteria. Due to their important biological and pathological functions, the biosynthesis, activation, transfer, breaking down, and recycle of sialic acids are attracting increasing attention. The understanding of the sialic acid metabolism in eukaryotes and bacteria leads to the development of metabolic engineering approaches for elucidating the important functions of sialic acid in mammalian systems and for large-scale production of sialosides using engineered bacterial cells. As the key enzymes in biosynthesis of sialylated structures, sialyltransferases have been continuously identified from various sources and characterized. Protein crystal structures of seven sialyltransferases have been reported. Wild-type sialyltransferases and their mutants have been applied with or without other sialoside biosynthetic enzymes for producing complex sialic acid-containing oligosaccharides and glycoconjugates. This mini-review focuses on current understanding and applications of sialic acid metabolism and sialyltransferases.
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Coustou V, Plazolles N, Guegan F, Baltz T. Sialidases play a key role in infection and anaemia in Trypanosoma congolense animal trypanosomiasis. Cell Microbiol 2012; 14:431-45. [PMID: 22136727 DOI: 10.1111/j.1462-5822.2011.01730.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Animal African trypanosomiasis is a major constraint to livestock productivity and has an important impact on millions of people in developing African countries. This parasitic disease, caused mainly by Trypanosoma congolense, results in severe anaemia leading to animal death. In order to characterize potential targets for an anti-disease vaccine, we investigated a multigenic trans-sialidase family (TcoTS) in T. congolense. Sialidase and trans-sialidase activities were quantified for the first time, as well as the tightly regulated TcoTS expression pattern throughout the life cycle. Active enzymes were expressed in bloodstream form parasites and released into the blood during infection. Using genetic tools, we demonstrated a significant correlation between TcoTS silencing and impairment of virulence during experimental infection with T. congolense. Reduced TcoTS expression affected infectivity, parasitaemia and pathogenesis development. Immunization-challenge experiments using recombinant TcoTS highlighted their potential protective use in an anti-disease vaccine.
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Affiliation(s)
- Virginie Coustou
- Univ. de Bordeaux, Microbiologie fondamentale et Pathogénicité, Bordeaux, France.
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15
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Schauer R, Kamerling JP. The Chemistry and Biology of Trypanosomal trans-Sialidases: Virulence Factors in Chagas Disease and Sleeping Sickness. Chembiochem 2011; 12:2246-64. [DOI: 10.1002/cbic.201100421] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2011] [Indexed: 11/10/2022]
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16
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Koliwer-Brandl H, Gbem TT, Waespy M, Reichert O, Mandel P, Drebitz E, Dietz F, Kelm S. Biochemical characterization of trans-sialidase TS1 variants from Trypanosoma congolense. BMC BIOCHEMISTRY 2011; 12:39. [PMID: 21801439 PMCID: PMC3173295 DOI: 10.1186/1471-2091-12-39] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/22/2011] [Accepted: 07/30/2011] [Indexed: 02/01/2023]
Abstract
Background Animal African trypanosomiasis, sleeping sickness in humans and Nagana in cattle, is a resurgent disease in Africa caused by Trypanosoma parasites. Trans-sialidases expressed by trypanosomes play an important role in the infection cycle of insects and mammals. Whereas trans-sialidases of other trypanosomes like the American T. cruzi are well investigated, relatively little research has been done on these enzymes of T. congolense. Results Based on a partial sequence and an open reading frame in the WTSI database, DNA sequences encoding for eleven T. congolense trans-sialidase 1 variants with 96.3% overall amino acid identity were amplified. Trans-sialidase 1 variants were expressed as recombinant proteins, isolated and assayed for trans-sialylation activity. The purified proteins produced α2,3-sialyllactose from lactose by desialylating fetuin, clearly demonstrating their trans-sialidase activity. Using an HPLC-based assay, substrate specificities and kinetic parameters of two variants were characterized in detail indicating differences in substrate specificities for lactose, fetuin and synthetic substrates. Both enzymes were able to sialylate asialofetuin to an extent, which was sufficient to reconstitute binding sites for Siglec-4. A mass spectrometric analysis of the sialylation pattern of glycopeptides from fetuin revealed clear but generally similar changes in the sialylation pattern of the N-glycans on fetuin catalyzed by the trans-sialidases investigated. Conclusions The identification and characterization of a trans-sialidase gene family of the African parasite T. congolense has opened new perspectives for investigating the biological role of these enzymes in Nagana and sleeping sickness. Based on this study it will be interesting to address the expression pattern of these genes and their activities in the different stages of the parasite in its infection cycle. Furthermore, these trans-sialidases have the biotechnological potential to be used for enzymatic modification of sialylated glycoconjugates.
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Affiliation(s)
- Hendrik Koliwer-Brandl
- Centre for Biomolecular Interactions Bremen, Department of Biology and Chemistry, University of Bremen, Germany
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17
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Kim S, Oh DB, Kang HA, Kwon O. Features and applications of bacterial sialidases. Appl Microbiol Biotechnol 2011; 91:1-15. [PMID: 21544654 DOI: 10.1007/s00253-011-3307-2] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2011] [Revised: 04/02/2011] [Accepted: 04/05/2011] [Indexed: 11/28/2022]
Abstract
Sialidases, or neuraminidases (EC 3.2.1.18), belong to a class of glycosyl hydrolases that release terminal N-acylneuraminate residues from the glycans of glycoproteins, glycolipids, and polysaccharides. In bacteria, sialidases can be used to scavenge sialic acids as a nutrient from various sialylated substrates or to recognize sialic acids exposed on the surface of the host cell. Despite the fact that bacterial sialidases share many structural features, their biochemical properties, especially their linkage and substrate specificities, vary widely. Bacterial sialidases can catalyze the hydrolysis of terminal sialic acids linked by the α(2,3)-, α(2,6)-, or α(2,8)-linkage to a diverse range of substrates. In addition, some of these enzymes can catalyze the transfer of sialic acids from sialoglycans to asialoglycoconjugates via a transglycosylation reaction mechanism. Thus, some bacterial sialidases have been applied to synthesize complex sialyloligosaccharides through chemoenzymatic approaches and to analyze the glycan structure. In this review article, the biochemical features of bacterial sialidases and their potential applications in regioselective hydrolysis reactions as well as sialylation by transglycosylation for the synthesis of sialylated complex glycans are discussed.
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Affiliation(s)
- Seonghun Kim
- Microbe-based Fusion Technology Research Center, Jeonbuk Branch Institute, Korea Research Institute of Bioscience and Biotechnology, 181 Ipsin-gil, Jeongeup, South Korea
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Greganova E, Bütikofer P, Acosta-Serrano A. The protease resistant surface (PRS) glycoconjugate from Trypanosoma congolense has an inositol-acylated glycosylphosphatidylinositol anchor, containing a significant proportion of myristate at the sn-2 position. Mol Biochem Parasitol 2010; 171:50-4. [DOI: 10.1016/j.molbiopara.2010.02.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2009] [Revised: 01/28/2010] [Accepted: 02/01/2010] [Indexed: 11/28/2022]
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Sartor PA, Agusti R, Leguizamón MS, Campetella O, de Lederkremer RM. Continuous nonradioactive method for screening trypanosomal trans-sialidase activity and its inhibitors. Glycobiology 2010; 20:982-90. [PMID: 20375068 DOI: 10.1093/glycob/cwq056] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Trypanosoma cruzi, the agent of American trypanosomiasis is unable to synthesize sialic acid (SA). Instead of using the corresponding nucleotide sugar as donor of the monosaccharide, the transfer occurs from alpha-2,3-linked SA in the host sialoglycoconjugates to terminal beta-galactopyranosyl units of the parasite mucins. For that purpose, T. cruzi expresses a glycosylphosphatidylinositol-anchored trans-sialidase (TcTS) that is shed into the milieu, being detected in the blood during the acute phase of the infection. The essential role of TcTS in infection and the absence of a similar activity in mammals make this enzyme an attractive target for the development of alternative chemotherapies. However, there is no effective inhibitor toward this enzyme. In vitro, 3'-sialyllactose (SL) as donor and radioactive lactose as acceptor substrate are widely used to measure TcTS activity. The radioactive sialylated product is then isolated by anion exchange chromatography and measured. Here we describe a new nonradioactive assay using SL or fetuin as donor and benzyl beta-d-Fuc-(1-->6)-alpha-d-GlcNAc (1) as acceptor. Disaccharide 1 was easily synthesized by regioselective glycosylation of benzyl alpha-d-GlcNAc with tetra-O-benzoyl-d-fucose followed by debenzoylation. Compound 1 lacks the hydroxyl group at C-6 of the acceptor galactose and therefore is not a substrate for galactose oxidase. Our method relies on the specific quantification of terminal galactose produced by trans-sialylation from the donor to the 6-deoxy-galactose (D-Fuc) unit of 1 by a spectrophotometric galactose oxidase assay. This method may also discriminate sialidase and trans-sialylation activities by running the assay in the absence of acceptor 1.
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Affiliation(s)
- Paula A Sartor
- Departamento de Microbiología, Facultad de Medicina, Universidad de Buenos Aires, 1121 Buenos Aires, Argentina
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20
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Kim S, Oh DB, Kwon O, Kang HA. Identification and functional characterization of the NanH extracellular sialidase from Corynebacterium diphtheriae. ACTA ACUST UNITED AC 2010; 147:523-33. [DOI: 10.1093/jb/mvp198] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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21
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Monti E, Bonten; E, D'Azzo A, Bresciani R, Venerando B, Borsani G, Schauer R, Tettamanti G. Sialidases in Vertebrates. Adv Carbohydr Chem Biochem 2010; 64:403-79. [DOI: 10.1016/s0065-2318(10)64007-3] [Citation(s) in RCA: 135] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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22
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Montagna GN, Donelson JE, Frasch ACC. Procyclic Trypanosoma brucei expresses separate sialidase and trans-sialidase enzymes on its surface membrane. J Biol Chem 2006; 281:33949-58. [PMID: 16956887 DOI: 10.1074/jbc.m604951200] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The procyclic stage of Trypanosoma brucei in the insect vector expresses a surface-bound trans-sialidase (TbTS) that transfers sialic acid from glycoconjugates in the environment to glycosylphosphatidylinositol-anchored proteins on its surface membrane. RNA interference against TbTS abolished trans-sialidase activity in procyclic cells but did not diminish sialidase activity, suggesting the presence of a separate sialidase enzyme for hydrolyzing sialic acid. A search of the T. brucei genome sequence revealed seven other putative genes encoding proteins with varying similarity to TbTS. RNA interference directed against one of these proteins, TbSA C, greatly decreased the sialidase activity but had no effect on trans-sialidase activity. The deduced amino acid sequence of TbSA C shares only 40% identity with TbTS but conserves most of the relevant residues required for catalysis. However, the sialidase has a tryptophan substitution for a tyrosine at position 170 that is crucial in binding the terminal galactose that accepts the transferred sialic acid. When this same tryptophan substitution in the sialidase was placed into the recombinant trans-sialidase, the mutant enzyme lost almost all of its trans-sialidase activity and increased its sialidase activity, further confirming that the gene and protein identified correspond to the parasite sialidase. Thus, in contrast to all other trypanosomes analyzed to date that express either a trans-sialidase or a sialidase but not both, T. brucei expresses these two enzymatic activities in two separate proteins. These results suggest that African trypanosomes could regulate the amount of critical sialic acid residues on their surface by modulating differential expression of each of these enzymes.
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Affiliation(s)
- Georgina N Montagna
- Instituto de Investigaciones Biotecnológicas, Universidad de General San Martín, 1650 San Martín, Pcia de Buenos Aires, Argentina
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23
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Schauer R. Sialic acids: fascinating sugars in higher animals and man. ZOOLOGY 2006; 107:49-64. [PMID: 16351927 DOI: 10.1016/j.zool.2003.10.002] [Citation(s) in RCA: 306] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2003] [Accepted: 10/13/2003] [Indexed: 01/29/2023]
Abstract
Sialic acids are acidic monosaccharides, which are among the most important molecules of higher animals, and occur in some microorganisms. They are bound to complex carbohydrates and occupy prominent positions, especially in cell membranes. Their structural diversity is high and, correspondingly, the mechanisms for their biosynthesis are complex. Sialic acid substituents strongly influence the activity of catabolic enzymes, in particular the sialidases, and thus the turnover rate of glycoconjugates. These sugars are involved in manifold cell functions. Due to the surface location of the acidic molecules they shield macromolecules and cells from enzymatic and immunological attacks. But they also represent recognition sites for various physiological receptors as well as for toxins and microorganisms, and thus allow their colonization. Many viruses use sialic acids for the infection of cells. As sialic acids also play a decisive role in tumor biology they prove to be rather versatile molecules that modulate cell biological events in a sensitive way. It is discussed that their evolvement may have stimulated evolution and rendered organisms less vulnerable to environmental attacks. However, disturbance of their metabolism may cause diseases.
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Affiliation(s)
- Roland Schauer
- Biochemical Institute, University of Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany.
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Ab initio calculations on various sialic acids provide valuable information about sialic acid-specific enzymes. ACTA ACUST UNITED AC 2004. [DOI: 10.1016/j.theochem.2004.01.013] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Vimr ER, Kalivoda KA, Deszo EL, Steenbergen SM. Diversity of microbial sialic acid metabolism. Microbiol Mol Biol Rev 2004; 68:132-53. [PMID: 15007099 PMCID: PMC362108 DOI: 10.1128/mmbr.68.1.132-153.2004] [Citation(s) in RCA: 445] [Impact Index Per Article: 22.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Sialic acids are structurally unique nine-carbon keto sugars occupying the interface between the host and commensal or pathogenic microorganisms. An important function of host sialic acid is to regulate innate immunity, and microbes have evolved various strategies for subverting this process by decorating their surfaces with sialylated oligosaccharides that mimic those of the host. These subversive strategies include a de novo synthetic pathway and at least two truncated pathways that depend on scavenging host-derived intermediates. A fourth strategy involves modification of sialidases so that instead of transferring sialic acid to water (hydrolysis), a second active site is created for binding alternative acceptors. Sialic acids also are excellent sources of carbon, nitrogen, energy, and precursors of cell wall biosynthesis. The catabolic strategies for exploiting host sialic acids as nutritional sources are as diverse as the biosynthetic mechanisms, including examples of horizontal gene transfer and multiple transport systems. Finally, as compounds coating the surfaces of virtually every vertebrate cell, sialic acids provide information about the host environment that, at least in Escherichia coli, is interpreted by the global regulator encoded by nanR. In addition to regulating the catabolism of sialic acids through the nan operon, NanR controls at least two other operons of unknown function and appears to participate in the regulation of type 1 fimbrial phase variation. Sialic acid is, therefore, a host molecule to be copied (molecular mimicry), eaten (nutrition), and interpreted (cell signaling) by diverse metabolic machinery in all major groups of mammalian pathogens and commensals.
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Affiliation(s)
- Eric R Vimr
- Laboratory of Sialobiology and Microbial Metabolomics, Department of Pathobiology, University of Illinois at Urbana-Champaign, Urbana, Illinois 61802, USA.
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Schrader S, Tiralongo E, Paris G, Yoshino T, Schauer R. A nonradioactive 96-well plate assay for screening of trans-sialidase activity. Anal Biochem 2003; 322:139-47. [PMID: 14596820 DOI: 10.1016/j.ab.2003.07.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Trans-sialidase (E.C. 3.2.1.18) catalyzes the transfer of preferably alpha2,3-linked sialic acid to another glycan or glycoconjugate, forming a new alpha2,3 linkage to galactose or N-acetylgalactosamine. Here, we describe a nonradioactive 96-well plate fluorescence test for monitoring trans-sialidase activity with high sensitivity, specificity, and reproducibility using sialyllactose and 4-methylumbelliferyl-beta-D-galactoside as donor and acceptor substrates, respectively. The assay conditions were optimized using the trans-sialidase from Trypanosoma congolense and its general applicability was confirmed with recombinant trans-sialidase from Trypanosoma cruzi. Using this procedure, a large number of samples can be tested quickly and reliably, for instance in monitoring trans-sialidase during enzyme purification and the production of monoclonal antibodies, for enzyme characterization, and for identifying potential substrates and inhibitors. The trans-sialidase assay reported here was capable of detecting trans-sialidase activity in the low-mU range and may be a valuable tool in the search for further trans-sialidases in various biological systems.
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Affiliation(s)
- Silke Schrader
- Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, 24098, Kiel, Germany.
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27
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Tiralongo E, Martensen I, Grötzinger J, Tiralongo J, Schauer R. Trans-sialidase-like sequences from Trypanosoma congolense conserve most of the critical active site residues found in other trans-sialidases. Biol Chem 2003; 384:1203-13. [PMID: 12974389 DOI: 10.1515/bc.2003.133] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Trypanosoma congolense is the agent of Nagana, the trypanosomiasis in African ruminants. Trypanosomes express an enzyme called trans-sialidase, which is believed to play an important role in maintaining pathogenicity of the parasites. Thus far, only two complete trans-sialidase sequences have been characterised, one from the American trypanosome T. cruzi and one from the African trypanosome T. brucei brucei. Although the crystal structure of T. cruzi trans-sialidase has recently been published [Buschiazzo et al., Mol. Cell 10 (2002), pp. 757-768], a number of questions concerning the exact transfer mechanism remain unanswered. The availability of further trans-sialidase sequences will ensure a better understanding of how transfer activity can be achieved and will provide the opportunity to develop highly specific, structure-based trans-sialidase inhibitors. Utilising a PCR-based approach two different trans-sialidase gene copies from T. congolense were identified, which share only 50% identity with each other, but show significant similarity with known viral, bacterial and trypanosomal sialidases and trans-sialidases. In both partial sequences most of the critical active site residues common to other trypanosomal sialidases and trans-sialidases are conserved. This is further illustrated by modelling the active site of the longer of the two partial gene sequences.
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Affiliation(s)
- Evelin Tiralongo
- Biochemisches Institut, Christian-Albrechts-Universität zu Kiel, Olshausenstrasse 40, D-24098 Kiel, Germany
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