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S M Haslam

Publications and source records attributed to S M Haslam.

26 records · Page 2Linked to original sources
PubMed1997

Characterisation of the phosphorylcholine-containing N-linked oligosaccharides in the excretory-secretory 62 kDa glycoprotein of Acanthocheilonema viteae.

The major excretory-secretory product of the rodent filarial nematode Acanthocheilonema viteae is a 62 kDa glycoprotein (ES-62), which has phosphorylcholine, attached to the N-linked carbohydrates. In this paper, we describe structural studies of N-glycans released from ES-62 by peptide N-glycosidase F. Three major classes of N-glycan structures were observed: high mannose type structures; those which had been fully trimmed to the trimannosyl core and were sub-stoichiometrically fucosylated; and those with a trimannosyl core, with and without core fucosylation, carrying between one and four additional N-acetylglucosamine resides. Of the three classes of glycans, only the last was found to be substituted with detectable levels of phosphorylcholine. The implications of these results with respect to the probable glycosylation pathways operating in A. viteae are discussed.

Animals↗
PubMed1996

Haemonchus contortus glycoproteins contain N-linked oligosaccharides with novel highly fucosylated core structures.

Structural studies on the N-linked oligosaccharides of Haemonchus contortus, an economically important nematode that parasitizes domestic ruminants, have revealed core fucosylation of a type not previously observed in any eukaryotic glycoprotein. Mass spectrometric analyses were performed on detergent extracts of homogenized adult H. contortus and on purified H11, a glycoprotein isolated from intestinal brush borders which has been previously shown to be an effective vaccine antigen. The major N-linked glycans identified in the present study have up to three fucose residues attached to their chitobiose cores. The fucoses are found at the 3- and/or 6-positions of the proximal GlcNAc and at the 3-position of the distal GlcNAc. The latter substitution is unique in N-glycans. Most anti-H11 monoclonal antibodies are known to recognize carbohydrate epitopes, and it is possible that the newly discovered multifucosylated core structures are highly immunogenic in this glycoprotein.

Acetylglucosamine↗
PubMed1996

Novel sulfated oligosaccharides containing 3-O-sulfated glucuronic acid from king crab cartilage chondroitin sulfate K. Unexpected degradation by chondroitinase ABC.

We prepared a series of oligosaccharides from king crab cartilage chondroitin sulfate K after exhaustive digestion with testicular hyaluronidase, and determined the structures of four tetrasaccharides and a pentasaccharide by fast atom bombardment mass spectrometry, high performance liquid chromatography analysis of chondroitinase AC-II digests, and 500-MHz 1H NMR spectroscopy. The tetrasaccharides shared the common core structure GlcAbeta1-3GalNAcbeta1-4GlcAbeta1-3GalNAc with various sulfation profiles. One structure was GlcAbeta1-3GalNAc(4S)beta1-4GlcAbeta1-3GalNAc(4S), whereas three of them have the following hitherto unreported structures including a novel glucuronate 3-O-sulfate: GlcA(3S)beta1-3GalNAc(4S)beta1-4GlcAbeta1-3GalNAc(4S), GlcAbeta1-3GalNAc(4S)beta1-4GlcA(3S)beta1-3GalNAc(4S), and GlcA(3S)beta1-3GalNAc(4S)beta1-4GlcA(3S)beta1-3GalNAc(4S), where 3S or 4S represents 3-O- or 4-O-sulfate, respectively. The structure of the pentasaccharide was determined as GlcA(3S)beta1-3GalNAc(4S)beta1-4GlcA(3S)beta1- 3GalNAc(4S)beta1-4GlcA. Chondroitinase ABC digestion of the tetrasaccharides with GlcA(3S) at the internal position destroyed the disaccharide unit containing GlcA(3S) derived from the reducing side and resulted in only the disaccharide unit from the non-reducing side. In contrast, these tetrasaccharides remained totally resistant to chondroitinase AC-II. The results indicated that it is necessary to reevaluate the disaccharide composition of chondroitin sulfate poly- or oligosaccharides purified from various biological sources, since they were usually determined after chondroitinase ABC digestion. It is probable that the structures containing GlcA(3S) would not have been detected.

Animals↗
PubMed1996

The occurrence of novel 9-O-sulfated N-glycolylneuraminic acid-capped alpha2-->5-Oglycolyl-linked oligo/polyNeu5Gc chains in sea urchin egg cell surface glycoprotein. Identification of a new chain termination signal for polysialyltransferase.

We report the isolation and structural characterization of an oligo/polysialic acid-containing glycopeptide fraction (designated ESP-Sia) prepared from the egg cell surface complex of the sea urchin, Hemicentrotus pulcherrimus, by exhaustive pronase treatment. The carbohydrate chains isolated from ESP-Sia were shown to consist of O-linked oligo/polysialic acid-containing glycan units and N-linked carbohydrate chains. The present studies have revealed that the O-linked oligo/polysialic acid-containing glycan chains derived from the ESP-Sia were similar to those present in egg jelly coat polysialylated glycoprotein in being composed of tandem repeats of N-glycolylneuraminic acid (Neu5Gc) glycosidically linked in a novel fashion through the glycolyl group, (-->5-OglycolylNeu5Gcalpha2-->)n. However, they differ from the egg jelly coat in two key respects. First, the average degree of polymerization of the oligo/polysialic acid chains of ESP-Sia is only 3; a value far lower than that found in the jelly coat glycoprotein (average degree of polymerization was about 20). Second, ESP-Sia is uniquely characterized by the presence of 9-O-sulfated N-glycolylneuraminic acid (Neu5Gc9HSO3) residues at the nonreducing termini of the (-->5-OglycolylNeu5Gcalpha 2-->)n chains. The terminal sialyl residues in the Neu5Gc9HSO3 alpha2-->(-->5-OglycolylNeu5Gcalpha2-->)n chains were totally resistant to exosialidases. The discovery of Neu5Gc9HSO3 as the nonreducing terminal residue of oligo/poly(-->5-OglycolylNeu5Gcalpha 2-->) group is especially noteworthy in that Neu5Gc9HSO3 appears to be of limited distribution among glycoconjugates. Following the earlier discovery of oligo/polysialic acid chains capped with KDN, i.e. KDN alpha2-->(-->8Neu5Gcalpha2-->)n, found in rainbow trout egg polysialoglycoproteins, it now appears that the sulfated Neu5Gc can serve a similar capping function.

Acetylation↗
PubMed1996

Isolation and identification of novel sulfated and nonsulfated oligosialyl glycosphingolipids from sea urchin sperm.

Novel sulfated and nonsulfated oligosialylglycosphingolipids were isolated from sperm of the sea urchin, Hemicentrotus pulcherrimus, and their structures were established as follows: [formula: see text] This provides the first evidence for the natural occurrence of a tetrasialic acid structure in glycosphingolipids. The finding of sulfated oligosialyl chains is especially noteworthy in that the sulfate group exclusively resides on the C-8 of the nonreducing terminal residues of oligo/polysialyl chains and that sulfation appears to be a termination signal for elongation of oligosialyl chains. Sulfation at the nonreducing terminal Neu5Ac residues of oligosialyl chains was also found to facilitate the formation of an inter-residue lactone between the carboxyl group at the nonreducing terminal sulfated Neu5Ac and the hydroxyl group at C-9 of the penultimate Neu5Ac residue. The long chain base was 4-hydroxysphinganine (t18:0) and the major fatty acid species were identified as C20:1, C21:1, and C22:1.

Animals↗
PubMed1996

Characterization of carbohydrate structural features recognized by anti-arabinogalactan-protein monoclonal antibodies.

Arabinogalactan-proteins (AGPs) are a diverse class of plant cell surface proteoglycans implicated in a range of fundamental processes associated with plant cell development. Anti-AGP monoclonal antibodies have been used extensively for the investigation of the developmental regulation of AGPs although virtually nothing is known about the structure of the carbohydrate epitopes recognised by these antibodies. In this report, a series of methyl glycosides of monosaccharides and a range of oligosaccharides that are elements of the carbohydrate component of AGPs have been investigated for recognition by previously derived anti-AGP monoclonal antibodies. No clear evidence was obtained for the involvement of terminal arabinofuranosides, nor of the galactan backbone, in the recognition of the glycan structure of AGPs by any of the antibodies used in this study. Interestingly, the most effective inhibitor of the binding of the monoclonal antibodies MAC207, JIM4 and JIM13 to exudate gum antigens was an acidic trisaccharide, isolated from a partial acid hydrolysate of gum karaya which has the structure: GlcA beta(1-->3) GalA alpha(1-->2)Rha, determined by a combination of FAB-MS, GC-MS and NMR spectroscopy.

Antibodies, Monoclonal↗
PubMedDate not supplied

Hallmarks of Caenorhabditis elegans N-glycosylation: complexity and controversy.

Caenorhabditis elegans has become one of the most widely used model organisms for a range of molecular cell biological applications and is being increasingly used by glycobiologists. However, a major problem has been the lack of knowledge of the structure of the protein-linked glycans from this organism. In recent years several groups have published structural data, particularly N-glycan structural data. However, some of these data are contradictory. In this review we critically assess all the N-glycan structural data and consider how close we are in our goal of defining the glycome of C. elegans.

Animals↗