| 1. |
- Prakobphol, A, et al.
(författare)
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Human low-molecular-weight salivary mucin expresses the sialyl lewisx determinant and has L-selectin ligand activity.
- 1998
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Ingår i: Biochemistry. - : American Chemical Society (ACS). - 0006-2960 .- 1520-4995. ; 37:14, s. 4916-27
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Tidskriftsartikel (refereegranskat)abstract
- Previously we showed that the low-molecular-weight mucin (MG2, encoded by MUC7), a major component of human submandibular/sublingual saliva, is a bacterial receptor that coats the tooth surface. Here we tested the hypothesis that the structure of its carbohydrate residues contains important information about its function. Purified MG2 (Mr 120 000) was digested with trypsin, and the resulting Mr 90 000 fragment, which carried primarily O-linked oligosaccharides, was subjected to reductive beta-elimination. The released oligosaccharides were characterized by using nuclear magnetic resonance spectroscopy and mass spectrometry. Of the 41 different structures we detected, the most prominent included NeuAcalpha2-->3Galbeta1-->3GalNAc-ol (sialyl-T antigen), Galbeta1-->4(Fucalpha1-->3)GlcNAcbeta1-->6(Galbeta1 -->3)GalNAc-ol [type 2 core with Lewisx (Lex) determinant], and NeuAcalpha2-->3Galbeta1-->4(Fucalpha1-->3)GlcNAcbet a1-->6(Galbeta1--> 3) GalNAc-ol [type 2 core with sialyl Lex (sLex) determinant]. We also detected di-, tri-, and pentasaccharides with one sulfate group. Lex, sLex, and related sulfated structures are ligands for selectins, adhesion molecules that mediate leukocyte trafficking. Therefore, we investigated whether MG2 was a selectin ligand. In an enzyme-linked immunosorbent assay, L-selectin chimeras interacted with immobilized MG2 in a Ca2+-dependent manner. L-Selectin chimeras also bound to MG2 immobilized on nitrocellulose. Together, these results suggest that the saccharides that MG2 carries could specify some of its important functions, which may include mediating leukocyte interactions in the oral cavity.
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| 2. |
- Prakobphol, A, et al.
(författare)
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Salivary agglutinin, which binds Streptococcus mutans and Helicobacter pylori, is the lung scavenger receptor cysteine-rich protein gp-340.
- 2000
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Ingår i: The Journal of biological chemistry. - 0021-9258 .- 1083-351X. ; 275:51, s. 39860-6
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Tidskriftsartikel (refereegranskat)abstract
- Salivary agglutinin is a high molecular mass component of human saliva that binds Streptococcus mutans, an oral bacterium implicated in dental caries. To study its protein sequence, we isolated the agglutinin from human parotid saliva. After trypsin digestion, a portion was analyzed by matrix-assisted laser/desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS), which gave the molecular mass of 14 unique peptides. The remainder of the digest was subjected to high performance liquid chromatography, and the separated peptides were analyzed by MALDI-TOF/post-source decay; the spectra gave the sequences of five peptides. The molecular mass and peptide sequence information showed that salivary agglutinin peptides were identical to sequences in lung (lavage) gp-340, a member of the scavenger receptor cysteine-rich protein family. Immunoblotting with antibodies that specifically recognized either lung gp-340 or the agglutinin confirmed that the salivary agglutinin was gp-340. Immunoblotting with an antibody specific to the sialyl Le(x) carbohydrate epitope detected expression on the salivary but not the lung glycoprotein, possible evidence of different glycoforms. The salivary agglutinin also interacted with Helicobacter pylori, implicated in gastritis and peptic ulcer disease, Streptococcus agalactiae, implicated in neonatal meningitis, and several oral commensal streptococci. These results identify the salivary agglutinin as gp-340 and suggest it binds bacteria that are important determinants of either the oral ecology or systemic diseases.
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| 3. |
- Thomsson, Kristina A, 1969, et al.
(författare)
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The salivary mucin MG1 (MUC5B) carries a repertoire of unique oligosaccharides that is large and diverse.
- 2002
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Ingår i: Glycobiology. - 0959-6658 .- 1460-2423. ; 12:1, s. 1-14
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Tidskriftsartikel (refereegranskat)abstract
- The high-molecular-mass salivary mucin MG1, one of two major mucins produced by human salivary glands, plays an important role in oral health by coating the tooth surface and by acting as a bacterial receptor. Here this mucin was purified from the submandibular/sublingual saliva of a blood group O individual. The presence of MUC5B as the major mucin in this preparation was confirmed by amino acid analysis and its reactivity with the monoclonal antibody PAN H2. To structurally characterize MG1 carbohydrates the O-glycans were released by reductive beta-elimination. Nuclear magnetic resonance spectroscopy of the nonfractionated mixture showed that (1) fucose was present in blood group H, Le(a), Le(x), Le(b), and Le(y) epitopes; (2) NeuAc was mainly linked alpha 2-3 to Gal or alpha 2-6 to GalNAcol; and (3) the major internal structures were core 1 and core 2 sequences. After this preliminary analysis the released oligosaccharides were separated into neutral (56%), sialylated (26%), and sulfated (19%) fractions, with an average length of 13, 17, and 41 sugar residues, respectively. Gas chromatography-mass spectrometry and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry of mixtures of neutral and sialylated oligosaccharides revealed at least 62 neutral and 25 sialylated oligosaccharides consisting of up to 20 monosaccharide residues. These results showed that the MG1-derived oligosaccharides were much longer than those of MG2, and only a few species were found on both molecules. Thus, these two mucins create an enormous repertoire of potential binding sites for microorganisms at one of the major portals where infectious organisms enter the body.
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