scholarly journals O-glycan variability of egg-jelly mucins from Xenopus laevis: characterization of four phenotypes that differ by the terminal glycosylation of their mucins

2000 ◽  
Vol 352 (2) ◽  
pp. 449-463 ◽  
Author(s):  
Yann GUERARDEL ◽  
Ossarath KOL ◽  
Emmanuel MAES ◽  
Tony LEFEBVRE ◽  
Bénoni BOILLY ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Molecular Mass ◽  
Electrophoretic Analysis ◽  
High Molecular Mass ◽  
Methylation Analysis ◽  
Glycosylation Pattern ◽  
Jelly Coat ◽  
New Family ◽  
Egg Jelly

Eggs from Xenopus laevis are surrounded by several layers of jelly that are needed for proper fertilization. Jelly coat is composed of high-molecular-mass glycoconjugates to which are bound many globular proteins. O-glycans released from the jelly coat of X. laevis have been partially described in previous studies. In this study, we compared the glycosylation pattern of the egg jelly coat isolated from six specimens of X. laevis. The O-glycans were released from jelly coats by alkali/borohydride treatment. Structural characterization was performed through a combination of one- and two-dimensional 1H-NMR and methylation analysis. This allowed the description of a new family of sulphated O-glycans present in jelly coats of all X. laevis. However, the jelly O-glycans showed a low extent of polymorphism between specimens. This intra-specific variability was restricted to the terminal substitution of O-linked oligosaccharides. The differential expression of two glycosyltransferase [an α-(1 → 4) galactosyltransferase and an α-(1 → 3) fucosyltransferase] activities resulted in the characterization of four phenotypes of X. laevis. Furthermore, electrophoretic analysis suggested that the high-molecular-mass fraction of jelly coat was mostly composed of mucin-type glycoproteins. Blot analysis with lectins confirmed that the glycan variability was borne by these mucin-type components. However, fertilization assays suggested that the glycan polymorphism had no repercussion on egg fertilizability.

scholarly journals O-glycan variability of egg-jelly mucins from Xenopus laevis: characterization of four phenotypes that differ by the terminal glycosylation of their mucins

2000 ◽  
Vol 352 (2) ◽  
pp. 449 ◽  
Author(s):  
Yann GUERARDEL ◽  
Ossarath KOL ◽  
Emmanuel MAES ◽  
Tony LEFEBVRE ◽  
Bénoni BOILLY ◽  
...  
Keyword(s):  
Xenopus Laevis ◽  
Egg Jelly

scholarly journals Characterization of derivatives of the high-molecular-mass penicillin-binding protein (PBP) 1 of Mycobacterium leprae

2000 ◽  
Vol 350 (1) ◽  
pp. 75-80 ◽  
Author(s):  
Sebabrata MAHAPATRA ◽  
Sanjib BHAKTA ◽  
Jasimuddin AHAMED ◽  
Joyoti BASU
Keyword(s):  
Plasma Membrane ◽  
Molecular Mass ◽  
Mycobacterium Leprae ◽  
Binding Activity ◽  
High Molecular Mass ◽  
Class A ◽  
C Terminus ◽  
Fusion Junction ◽  
Derivatives Of

Mycobacterium leprae has two high-molecular-mass multimodular penicillin-binding proteins (PBPs) of class A, termed PBP1 and PBP1* [Lepage, Dubois, Ghosh, Joris, Mahapatra, Kundu, Basu, Chakrabarti, Cole, Nguyen-Disteche and Ghuysen (1997) J. Bacteriol. 179, 4627–4630]. PBP1-Xaa–β-lactamase fusions generated periplasmic β-lactamase activity when Xaa (the amino acid of PBP1 at the fusion junction) was residue 314, 363, 407, 450 or 480. Truncation of the N-terminal part of the protein up to residue Leu-147 generated a penicillin-binding polypeptide which could still associate with the plasma membrane, whereas [∆M1–R314]PBP1 (PBP1 lacking residues Met-1 to Arg-314) failed to associate with the membrane, suggesting that the region between residues Leu-147 and Arg-314 harbours an additional plasma membrane association site for PBP1. Truncation of the C-terminus up to 42 residues downstream of the KTG (Lys-Thr-Gly) motif also generated a polypeptide that retained penicillin-binding activity. [∆M1–R314]PBP1 could be extracted from inclusion bodies and refolded under appropriate conditions to give a form capable of binding penicillin with the same efficiency as full-length PBP1. This is, to the best of our knowledge, the first report of a soluble derivative of a penicillin-resistant high-molecular-mass PBP of class A that is capable of binding penicillin. A chimaeric PBP in which the penicillin-binding (PB) module of PBP1 was fused at its N-terminal end with the non-penicillin-binding (n-PB) module of PBP1* retained pencillin-binding activity similar to that of PBP1, corroborating the finding that the n-PB module of PBP1 is dispensable for its penicillin-binding activity.

scholarly journals Immunochemical characterization of mucins. Polypeptide (M1) and polysaccharide (A and Leb) antigens

1988 ◽  
Vol 254 (1) ◽  
pp. 185-193 ◽  
Author(s):  
J Bara ◽  
R Gautier ◽  
J Le Pendu ◽  
R Oriol
Keyword(s):  
Monoclonal Antibodies ◽  
Molecular Mass ◽  
High Molecular Mass ◽  
Density Gradient Ultracentrifugation ◽  
Blood Group Antigens ◽  
Lewis Blood Group ◽  
Progressive Loss ◽  
Cscl Density Gradient ◽  
Mucinous Cyst

Seven monoclonal antibodies (MAbs) reacting with high-molecular-mass components (greater than 20,000 kDa) isolated from an ovarian mucinous cyst of an A Le(a-b+) patient are described. By the use of immunoradiometric methods, these MAbs characterized seven different epitopes associated with components having a density of 1.45 g/ml by CsCl-density-gradient ultracentrifugation, like mucins. Two MAbs reacted with A and Lewis blood-group antigens respectively (polysaccharide epitopes). The five other MAbs characterized five M1 epitopes (called a, b, c, d and e), mainly associated with components of more than 20,000 kDa and 2000 kDa. They were completely destroyed by papain and 2-mercaptoethanol treatment (polypeptide epitopes). Moreover, timed trypsin digestion of native mucin resulted in a progressive loss of M1 activity and degraded these mucins into smaller M1-positive fragments. The a and c epitopes were partially degraded from relatively high-molecular-mass fragments (2000 kDa to 500 kDa) into a 100 kDa fragment. The b and d epitopes were completely degraded into smaller fragments ranging from 100 kDa to 40 kDa. The e epitope was completely destroyed by trypsin. These different pathways of M1 antigen degradation suggest the occurrence of different epitopes located in separate regions of the mucin molecules.

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