A unique, terminally glucosylated oligosaccharide is a common feature on Leishmania cell surfaces

Funk, Valerie A.; Thomas‐Oates, Jane; Kielland, Sandra L.; Bates, Paul A.; Olafson, Robert W.

doi:10.1016/s0166-6851(96)02780-6

Cited by 29 publications

(17 citation statements)

References 36 publications

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“…Using gel filtration chromatography, some PAS-stained and Con A-reactive molecules were isolated from the sample in the void and some in the included volume. This result confirmed the findings of previous studies on the cell surface antigens of different Leishmania species suggesting that these cellsurface antigens were in glycoconjugate structure like gp63 [2,3,11,21,22,36]. In these studies gp63 was Table 1.…”

Section: Discussionsupporting

confidence: 91%

A preliminary approach to the separation of Leishmania cell‐surface antigens

Aksoy¹,

Özbilge²,

Keleş

et al. 2004

J of Separation Science

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The purpose of the current study was to characterize Leishmania cell-surface antigens by two different methods established for the purification of glycoproteins and proteins, and to point out a useful approach to define their size and mass heterogeneity. L. tropica parasites were initially isolated from patients with active cutaneous leishmaniasis and were then cultured in vitro. The parasite-cell layer was solubilised with 6 M guanidinium chloride (GuHCl) and subsequently prepared for the purification procedure. The methods used in this work were gel filtration chromatography and isopycnic density-gradient centrifugation. Because of the presence of a substantial amount of non-specific proteins in the culture medium, these methods were not effective alone in distinguishing these antigens. However, a good idea of their N-glycosylated structures could be obtained by using Periodic acid-Schiffs (PAS) and Con A lectin, and also size and mass heterogeneity. A combination of these methods effected a clear separation of the antigens. Amino acid analysis of the purified antigens was performed to positively identify them as well-known Leishmania cell-surface antigen gene products. The results confirmed the presence of more than one cell-surface antigen on the Leishmania parasite and the combination of gel chromatography and density-gradient centrifugation could be useful for their isolation.

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Section: Discussionsupporting

confidence: 91%

A preliminary approach to the separation of Leishmania cell‐surface antigens

Aksoy¹,

Özbilge²,

Keleş

et al. 2004

J of Separation Science

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“…Similarly, a large fraction of mature N-glycans of E. histolytica are composed of Glc 1 Man 5 GlcNAc 2 , as has been described in Leishmania (33). The presence of Glc 1 Man 5 GlcNAc 2 in mature glycoproteins suggests that it may have other functions in addition to serving as an intermediate in the N-glycan-dependent quality control of folding in the ER lumen (4 -6).…”

Section: Properties Of E Histolytica Nglycans That Distinguish Them mentioning

confidence: 86%

Unique Asn-linked Oligosaccharides of the Human Pathogen Entamoeba histolytica

Magnelli

Cipollo

Ratner

et al. 2008

Journal of Biological Chemistry

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N-Glycans of Entamoeba histolytica, the protist that causes amebic dysentery and liver abscess, are of great interest for multiple reasons. E. histolytica makes an unusual truncated N-glycan precursor (Man 5 GlcNAc 2 ), has few nucleotide sugar transporters, and has a surface that is capped by the lectin concanavalin A. Here, biochemical and mass spectrometric methods were used to examine N-glycan biosynthesis and the final N-glycans of E. histolytica with the following conclusions. Unprocessed Man 5 GlcNAc 2 , which is the most abundant E. histolytica N-glycan, is aggregated into caps on the surface of E. histolytica by the N-glycan-specific, anti-retroviral lectin cyanovirin-N. Glc 1 Man 5 GlcNAc 2 , which is made by a UDP-Glc: glycoprotein glucosyltransferase that is part of a conserved N-glycan-dependent endoplasmic reticulum quality control system for protein folding, is also present in mature N-glycans. A swainsonine-sensitive ␣-mannosidase trims some N-glycans to biantennary Man 3 GlcNAc 2 . Complex N-glycans of E. histolytica are made by the addition of ␣1,2-linked Gal to both arms of small oligomannose glycans, and Gal residues are capped by one or more Glc. In summary, E. histolytica N-glycans include unprocessed Man 5 GlcNAc 2 , which is a target for cyanovirin-N, as well as unique, complex N-glycans containing Gal and Glc.Entamoeba histolytica is the protist (single cell eukaryote) that causes millions of cases of amebic dysentery and liver abscess in regions where its fecal-oral spread cannot be prevented (1, 2). Asn-linked glycans (N-glycans) of E. histolytica are of great interest for seven reasons.First, E. histolytica is missing many of the glycosyltransferases that make lipid-linked precursors to N-glycans and so makes a Man 5 GlcNAc 2 -PP-dolichol rather than Glc 3 Man 9 GlcNAc 2 -PPdolichol, which is present in most animals, plants, and fungi (3, 4). Second, E. histolytica N-glycans contribute to the quality control of protein folding in the endoplasmic reticulum (ER) 2 (4 -6). In particular, E. histolytica has UDP-Glc:glycoprotein glucosyltransferase, calreticulin, glucosidase II, and ERGIC-53, which are the essential components of an N-glycan-dependent quality control system (4 -6).Third, the E. histolytica oligosaccharyltransferase (OST), which transfers N-glycans from the dolichol pyrophosphatelinked precursor to Asn on the nascent peptide in the lumen of the ER is composed of four subunits rather than seven or eight subunits found in metazoan, fungi, and plants (7). As a result, the E. histolytica OST has different kinetics than the OSTs of higher eukaryotes (8). As well, the E. histolytica OST prefers to transfer N-glycans, which resemble its own (Man 5 GlcNAc 2 ), rather than the longer N-glycans of metazoa and fungi (Glc 3 Man 9 GlcNAc 2 ) (8).Fourth, E. histolytica has a limited set of nucleotide sugar transporters (UDP-Gal and UDP-Glc), which transport activated sugars into the lumen of the ER and Golgi (9). UDP-Gal and UDP-Glc are used to make unique O-phosphodiesterlinked glycans ...

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“…In fact, there appear to be only two reports in the literature in which an unusual (GlcNAc) 2 (Man) 6 (Glc) 1 structure from a membrane-bound cell surface glycoprotein of the unicellu- lar parasite Leishmania mexicana amazonensis was described (Olafson et al, 1990;Funk et al, 1997). These authors explain the presence of the glucosylated structure by a lack of glucosidase II activity or a low level of activity of this enzyme.…”

Section: Discussionmentioning

confidence: 99%

Partially glucose-capped oligosaccharides are found on the hemoglobins of the deep-sea tube worm Riftia pachyptila

Zal

Küster

Brian³

et al. 1998

Glycobiology

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We report here the structural determination of N-linked oligosaccharides found on extracellular hemoglobins of the hydrothermal vent tube worm Riftia pachyptila. Structures were elucidated by a combination of electrospray ionization tandem mass spectrometry, matrix-assisted laser desorption/ionization mass spectrometry, normal-phase high performance liquid chromatography, and exoglycosidase digestion. The sugar chains were found to consist mainly of high-mannosetype glycans with some structures partially capped by one or two terminal glucose residues. The present study represents the first report of the occurrence of glucose capping of Nlinked carbohydrates in a secreted glycoprotein of a metazoan. Previously, glucose capping has only been described for a membrane-bound surface glycoprotein from the unicellular parasite Leishmania mexicana amazonensis.

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A unique, terminally glucosylated oligosaccharide is a common feature on Leishmania cell surfaces

Cited by 29 publications

References 36 publications

A preliminary approach to the separation of Leishmania cell‐surface antigens

A preliminary approach to the separation of Leishmania cell‐surface antigens

Unique Asn-linked Oligosaccharides of the Human Pathogen Entamoeba histolytica

Partially glucose-capped oligosaccharides are found on the hemoglobins of the deep-sea tube worm Riftia pachyptila

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