A detailed study of the periodate oxidation of sialic acids in glycoproteins.
TL;DR: Periodate oxidation of terminalN-acetyl- andN-glycoloylneuraminic acid residues in the mucins from edible bird nest substance and pig submandibular gland can be carried out under conditions which exclusively give rise to the formation of the C-7 analogues of these sialic acids.
Abstract: Periodate oxidation of terminalN-acetyl- andN-glycoloylneuraminic acid residues in the mucins from edible bird nest substance and pig submandibular gland, respectively, can be carried out under conditions which exclusively give rise to the formation of the C-7 analogues of these sialic acids. In contrast, the C-8 compounds can be obtained in a maximum yield of about 40%. Under identical conditions,N-glycoloylneuraminic acid is oxidized about 1.5 times faster than theN-acetylated derivative. After release of the sialic acids by acid hydrolysis, the characterization of the oxidation products was carried out by TLC, by GLC and GLC-MS of the corresponding pertrimethylsilyl derivatives, and by 500-MHz1H-NMR spectroscopy. In addition, molar response factors for GLC analysis and extinction coefficients in the orcinol/Fe3+/HCl assay were determined.
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TL;DR: Several new aspects of specificities of the first six reported siglecs are explored, using sialylated glycans presented in multivalent form, on synthetic polyacrylamide backbones, or on mucin polypeptides.
153 citations
TL;DR: The determination of sialic acids in serum, urine, or tissues or on cells is often used in clinical applications, because it seems to be a valuable marker for certain malignancies.
Abstract: Publisher Summary This chapter describes isolation, purification, and characterization of monomeric sialic acids. There are two basic procedures for liberating sialic acids from glycosidic linkages—enzymatic and acid hydrolysis. In the former case, a variety of sialidases may be used, which differ in specificity for sialic acid linkage or species. Quantitation of sialic acids usually requires purified samples because a number of substances are known to interfere with certain tests. Colorimetric sialic acid quantitation is still one of the most important methods to determine the amount of the sugars in a given sample accurately. Two basically different tests are used—the orcinol/Fe 3+ /HCl or resorcinol/Cu 2+ /HCl assay and the periodic acid/thiobarbituric acid test. The procedures for a microadaptation of the orcinol/Fe 3+ /HCl and the periodic acid/thiobarbituric acid assays are discussed. The determination of sialic acids in serum, urine, or tissues or on cells is often used in clinical applications, because it seems to be a valuable marker for certain malignancies.
150 citations
TL;DR: It is shown here that human plasma can indeed inhibit Sia-dependent binding of a recombinant soluble chimeric form of human CD22 (CD22Rg) to TNF-α activated HEC and that CD22 is capable of highly selective recognition of certain multimeric plasma sialoglycoproteins that carry α2-6-linked sialic acids.
148 citations
TL;DR: EBN extract could neutralize the infection of MDCK cells with influenza viruses and inhibit hemagglutination of influenza viruses to erythrocytes, but it could not inhibit the activity of influenza virus sialidase.
141 citations
Cites background from "A detailed study of the periodate o..."
...Analysis of sialic acid molecular species and linkages in the EBN extract Many studies have indicated that various bird nests have abundant sialic acid-containing sugar chains (Pozsgay et al., 1987; Reuter et al., 1989; Wieruszeski et al., 1987; Kakehi et al., 1994; Martin et al., 1977)....
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...Many studies have indicated that various bird nests have abundant sialic acid-containing sugar chains (Pozsgay et al., 1987; Reuter et al., 1989; Wieruszeski et al., 1987; Kakehi et al., 1994; Martin et al., 1977)....
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TL;DR: This study showed that sialic acids on the viral envelope facilitated HIV-1 infection of macrophages through interacting with Siglec receptors, and the expression of SigleC-1 correlated with viral sialIC acid-mediated host attachment, underscores the importance of viral sIALic acids in HIV infection and pathogenesis.
Abstract: Background
Human immunodeficiency virus type 1 (HIV-1) infects macrophages effectively, despite relatively low levels of cell surface-expressed CD4. Although HIV-1 infections are defined by viral tropisms according to chemokine receptor usage (R5 and X4), variations in infection are common within both R5- and X4-tropic viruses, indicating additional factors may contribute to viral tropism.
Methodology and Principal Findings
Using both solution and cell surface binding experiments, we showed that R5- and X4-tropic HIV-1 gp120 proteins recognized a family of I-type lectin receptors, the Sialic acid-binding immunoglobulin-like lectins (Siglec). The recognition was through envelope-associated sialic acids that promoted viral adhesion to macrophages. The sialic acid-mediated viral-host interaction facilitated both R5-tropic pseudovirus and HIV-1BaL infection of macrophages. The high affinity Siglec-1 contributed the most to HIV-1 infection and the variation in Siglec-1 expression on primary macrophages from different donors was associated statistically with sialic acid-facilitated viral infection. Furthermore, envelope-associated sialoglycan variations on various strains of R5-tropic viruses also affected infection.
Conclusions and Significance of the Findings
Our study showed that sialic acids on the viral envelope facilitated HIV-1 infection of macrophages through interacting with Siglec receptors, and the expression of Siglec-1 correlated with viral sialic acid-mediated host attachment. This glycan-mediated viral adhesion underscores the importance of viral sialic acids in HIV infection and pathogenesis, and suggests a novel class of antiviral compounds targeting Siglec receptors.
88 citations
Cites background or methods from "A detailed study of the periodate o..."
...The mild periodate oxidation was carried out with the addition of NaIO4 to the virus for 10 minutes and followed by neutralization of the periodate with glycerol [31]....
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...A similar reduction in binding was also observed when the soluble gp120 was treated by mild periodate oxidation, which truncates the glycerol side chain of sialic acids and leads to the loss of Siglec recognition [31,32] (Figure 3E)....
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References
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TL;DR: This chapter discusses the different aspects of thiobarbituric acid assay of sialic acid, which is suitable for measuring the release of bound sialoic acid by sialidase and hydrolysis of sIALic acid-containing material must be carried out for the measurement of total sialsic acids.
6,264 citations
TL;DR: This chapter presents literature data on the high-resolution, 1H-NMR spectroscopy of carbohydrates derived from glycoconjugates and discusses the results for carbohydrates related to the glycoproteins of N-glycosylic type.
Abstract: Publisher Summary This chapter discusses the application of high-resolution, 1H-nuclear magnetic resonance (NMR) spectroscopy to the structural analysis of carbohydrates related to glycoproteins. Glycoproteins are biopolymers consisting of a polypeptide backbone bearing one or more covalently linked carbohydrate chains. The carbohydrate chains of glycoproteins may be classified according to the type of linkage to the polypeptide backbone. N-Glycosylic chains are attached to the amide group of asparagine (Asn), whereas the O-glycosylic chains are linked to the hydroxyl group of amino acid residues such as serine (Ser), threonine (Thr), and hydroxylysine (Hyl). The high-resolution, 1H-NMR spectroscopy technique, in conjunction with methylation analysis, is extremely suitable for the structural studies of N-, as well as on O-, glycosylic glycans. For the interpretation of the 1H-NMR spectrum of a carbohydrate chain in terms of primary structural assignments, the concept of “structural reporter groups” was developed. This means that the chemical shifts of protons resonating at clearly distinguishable positions in the spectrum, together with their coupling constants and the line widths of their signals, bear the information essential to permit the assigning of the primary structure. This chapter presents literature data on the high-resolution, 1H-NMR spectroscopy of carbohydrates derived from glycoconjugates. It also discusses the results for carbohydrates related to the glycoproteins of N-glycosylic type.
797 citations
TL;DR: This simple method of specifically introducing a radioactive label into cell surface sialic acids is useful in the study of cell surfaceSialic acid-containing glycoproteins.
482 citations
230 citations
01 Jan 1982
TL;DR: The discovery and the widespread occurrence of the sialic acids in mammalian tissues has been correlated with a range of different biological functions (see chapter J), and the known spectrum of derivatives covered in this chapter continues to expand.
Abstract: The discovery and the widespread occurrence of the sialic acids in mammalian tissues (Blix 1936, Klenk 1941) has been correlated with a range of different biological functions (see chapter J) which continues to expand. Although the literature on sialic acid occurrence is large (Gottschalk 1960, Blix and Jeanloz 1969, Tuppy and Gottschalk 1972, Schauer 1973, Ng and Dain 1976), it has been essentially limited to the vertebrates and some examples from the Echinodermata and Bacteria. Only one survey of sialic acid distribution in different phyla has been published (Warren 1963). Current data on sialic acid structure is compiled in Table 1, introducing the known spectrum of derivatives covered in this chapter.
168 citations